• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.209-218
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• 2012

Repeatability and reproducibility in solid weight and effective porosity measurements have been discussed using 8 core samples with different diameters, lengths, rock types, and effective porosities. Further, the effect of temperature on the effective porosity measurement has been discussed as well. Effective porosity of each sample has been measured 7 times with vacuum saturation method with vacuum pressure of 1 torr and vacuum time of 80 minutes. Firstly, effective porosity of each sample is measured one by one, so that it can provide a reference value. Then for reproducibility check, effective porosity measurements with vacuum saturation of 2, 4, and 8 samples simultaneously have been performed. And finally, repeated measurements for 3 times for each sample are made for repeatability check. Average deviation from the reference set in solid weight showed 0.00 $g/cm^3$, which means perfect repeatability and reproducibility. For effective porosity, average deviations are less than 0.07% and 0.05% in repeatability and reproducibility test sets, respectively, which are in good agreement too. Most of porosities measured in reproducibility test lies within the deviation range in repeatability test sets. Thus, simultaneous vacuum saturation of several samples has little impact on the effective porosity measurement when high vacuum pressure of 1 torr is used. Air temperature can cause errors on submerged weight read and even effective porosity, because it is closely related to the temperature, density, and buoyancy of water. Consequently, for accurate measurement of effective porosity in a laboratory, efforts for maintaining air or water temperature constant during the experiment, or a temperature correction from other information are needed.

• Journal of Plant Biology
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• v.37 no.3
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• pp.387-394
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• 1994

Effects of environmental factors of light, temperature, nitrogen sources and water stress were analyzed quantitatively on the nodule formation and nitrogen fixation activity of autumn olive plant (Elaeagnu$ umbellala Thunb.) during the seedling growth. Seedlings showed the maximum nitrogenase activity of $72.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ in the early nodulation stage. The relative growth rate and T/R ratio changed from $1.60%{\cdot}d^{-1}$ and 1.12 in the earlier stage to $3.75%{\cdot}d^{-1}$ and 2.31 in the later stage, respectively. light conditions of 20-25, 1015 and 4-6% resulted in decreases of 41, 54 and 71% of the nitrogenase activity, respectively. Nodules incubated in 15, 20, 25 and $30^{\circ}C$ showed the activities of 5.4, 24.7, 51.6 and $58.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ respectively. Pretreatment with low temperature ($15^{\circ}C$) followed incubation at $30^{\circ}C$ attained higher nitrogenase activity ($66.5\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$) than that with higher temperature ($35^{\circ}C$). The oxygen pressure above 16 kPa is necessary for saturation of the nodule activity, but the activity was inhibited severely by physical impact such as the exision or isolation of nodules from the root. The relative activities of early nodules grown in pH 5.5, 6.5 and 8.0 were 89, 100 and 40% and those grown in 1 and 3 mM of $NO_3\;and\;NH_4$ were 6, 1 and 68, 50%, respectively. Watering levels of 20, 50 and 100 mL during the seedling growth resulted in 35, 120 and 8 mg of nodule formation and 33.6, 58.4 and $8.4\;\mu\textrm{M}\;C_2H_4{\cdot}g\;fr\;wt\;nodule^{-1}{\cdot}h^{-1}$ of the nitrogenase activity, respectively. Water stress with 86% decrease of soil water content caused temporary wilting point of leaf and a complete disappearance of nitrogenase activity of nodules, though the water content and transpiration rate in plant were reduced to 90 and 53%, respectively.tively.

• Journal of dental hygiene science
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• v.8 no.4
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• pp.267-274
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• 2008

The purpose of this study was to examine the use of dentifrice among children in a bid to provide information on dentifrice including its function to children's parents, the major consumers of dentifrice for child. And it's additionally meant to offer useful information on the production of toothpaste for kid. The subjects in this study were parents with children, who dwelled in Seoul and Gyeonggi province. After a self-administered survey was conducted for about three months from May to July 2007 to gather data on their use of dentifrice for child, a comparative analysis was implemented. The findings of the study were as follows: 1. Concerning the state of the use of their children's dentifrice, the largest number of the children(58.1%) started to use toothpaste at the age of one or down, and the most common first toothpaste they used was dentifrice for preschooler(86.8%). As for whether to use fluoride-containing toothpaste, the largest group of the parents(58.1%) gave an affirmative answer. Regarding the form of the toothpaste in use, the majority of their children used toothpaste of cream type(86.2%). The greatest group of the children used the amount of toothpaste that was as large as the three-tenths or four-tenths of the bristles(35.9%). 2. As for the state of the use of dentifrice for kid, the greatest group used that kind of toothpaste(81.4%). In the event of those who didn't use it, the last time when their children used toothpaste for kid was when they were at the western age of 3(33.9%) and 4(33.9%). Concerning the reason why they replaced toothpaste for kid with one for adult, the largest group of the parents did that on their own judgment(58.1%). As to the right time for replacing toothpaste for kid by one for adult, the greatest group considered it advisable for children to start using toothpaste for adult at the western age of 4 or 5(43.2%). 3. In relation to the state of the purchase of toothpaste for their children, the largest group was under the moderate influence of the children when they bought it(45.2%). The greatest group attached importance to the ingredients of toothpaste(41.6%), and the most preferred ingredient was fluoride(56.3%). 53.0 percent took consideration on the content of ingredients or the instructions. 4. In regard to priorities for the choice of toothpaste for their children, they gave top priority to brand(16.7%), followed by quality(14.6%) and ingredients(13.5%). The age of the parents made a statistically significant difference to the children's age when they started using toothpaste, and how they started to do that and whether they used fluoride-containing toothpaste were statistically significantly different according to that as well(p < 0.01). In regard to the impact of the occupation of the parents, the use of fluoride-containing toothpaste was more common among the stay-at-home mothers(p < 0.01).

• Journal of dental hygiene science
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• v.13 no.3
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• pp.304-313
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• 2013

The purpose of this study was to examine the influence of the communication competence and empathy abilities of dental hygiene students on their interpersonal relationship abilities. The subjects in this study were 578 students who majored in dental hygiene at five randomly selected colleges. Out of the colleges, three were located in North Chungcheong province, and one was located in the city of Daejeon. The other one was located in South Gyeongsang province. Data were gathered using structured questionnaires from April 1 to May 7, 2013. The major findings of the study were as follows: 1. The respondents got a mean of $3.23{\pm}0.49$, $85.80{\pm}10.12$ and $83.27{\pm}8.37$ in interpersonal relationship abilities, communication competence and empathy abilities respectively. 2. As for communication competence, empathy abilities and interpersonal relationship abilities by general characteristics, there were statistically significant differences according to age, academic year, clinical practice experience and satisfaction with major. 3. The relationship of communication competence and empathy abilities to interpersonal relationship abilities was analyzed, and interpersonal relationship abilities were found to have a strong significant positive correlation to communication competence, empathy abilities and the subfactors of the two. 4. As a result of analyzing which variables affected interpersonal relationship abilities, it's found that interpersonal relationship abilities were under the influence of age, clinical practice experience, communication competence, empathy abilities. These variables made a 57.2% prediction of interpersonal relationship abilities. The above-mentioned findings suggest that communication competence and empathy abilities exerted an influence on interpersonal relationship abilities. Therefore curriculums and educational programs should be developed in consideration of these variables to ensure the stable college lives and successful relationship building of dental hygiene students who are on the way to adulthood and will serve as health care personnels in the future.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.223-229
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• 2013

The aim of this study was to examine the effectiveness of oral health promotion program in a group of 9~18-year-old children and adolescents living in four orphanages in Dong-gu, Daejeon. The program was based on oral disease prevention program including oral health education, fluoride application and scaling every six months. Oral health status of total 109 orphans was examined by one dentists who were trained in 2010 Korean National Oral Health Survey. Dental caries index, community periodontal index and modified patient hygiene performance index (M-PHP) were checked using dental unit chair. Child oral health impact profile (COHIP) and subjective oral health recognition survey were carried out. Compared with data of 2010 national sample, the mean of decayed, missing and filled teeth showed no difference between the subjects and test values, but the means of decayed teeth, decayed surface, toothbrushing frequency of the subjects showed to become worse with advancing years in spite of oral health promotion program. COHIP, subjective oral health status showed lower than test values, too. In M-PHP and Calculus index, the subjects showed better by periodic oral health education and scaling. We suggest that oral health promotion program for orphans include oral disease treatment program as well as preventive program to improve oral health of orphans efficiently. And, oral health promotion program has to be connected with psychological support for improving quality of life of orphans.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.487-494
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• 2017

There is little evidence on the effects of environmental tobacco smoke (ETS) on prevalence of periodontal disease. The aims of this study were to explore the trends of prevalence of periodontal disease and types of exposure to smoke, including ETS according to the survey year, identify factors affecting periodontal disease, and compare the effect size of periodontal disease between active smokers and secondhand smokers. Data on 11,643 individuals were obtained from the fourth and fifth Korean National Health and Nutritional Examination Surveys. Information on exposure to ETS at home and work was self-reported. Severity of periodontal disease was evaluated using the community periodontal index. A multivariate logistic regression analysis was performed to model periodontal disease using types of smoking and the survey year. Overall, the prevalence of periodontal disease was 26.0% (n=3,029) and about 9% of the study population were secondhand smokers. The prevalence of periodontal disease among smokers was significantly increased according to smoking types by year. Active smokers showed a statistically significant adjusted odds ratio (aOR) for having periodontal disease except in the year 2007, whereas secondhand smokers had significant associations only in 2010 (aOR, 1.68; 95% confidence interval, 1.05 to 2.70) compared to non-smokers. For secondhand smokers, the statistical relationship of predicting periodontal disease was weaker than that of active smokers. However, ETS should separately be considered as an important risk factor for periodontal disease. This study suggested the need for further investigation of the impact of ETS on prevalence of periodontal disease using in-depth research designs and objective measurements for assessing periodontal disease and ETS.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.6
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• pp.1022-1031
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• 2008

Pound cakes were prepared with Citrus mandarin powder(CMP) cultivated in JeJu Island, Korea. The impact of CMP amount level, which was incorporated into wheat flour by the ration of 0, 5, 10, 15, and 20% based on a flour weight, on the rheology and sensory profile of the pound cakes was measured. Moisture content of 13.70%, crude protein 5.12%, crude lipid 1.30%, crud ash 1.92%, respectively. Also evaluation was performed on the changes in physicochemical properties of the pound cakes during storage at 4 and $30^{\circ}C$. According to the amylogram, gelatinization temperature of the control dough was $63.35^{\circ}C$ and those of the dough with CMP were $63.85{\sim}66.55^{\circ}C$. Maximum viscosity of the dough was 686 B.U in the control, those were 575 B.U, 553 B.U, 504 B.U and 401 B.U in the dough with 5, 10, 15, and 20% CMP, respectively. The retrogradation degree(setback value) of CMP dough was $31{\sim}57%$ lower than that of the control dough under the same conditions. Water holding capacity of pound cake was increased gradually in proportion to the amount of CMP. The CMP addition decreased the brightuess(L) of pound cakes but increased redness(a) and yellowness(b). Hardness of pound cakes was significantly increased by CMP addition, while springiness, adhesiveness and cohesiveness were decreased. Based on sensory evaluation, pound cakes added with CMP were not significantly different in color and texture, while that of 10% CMP was significantly high in taste, flavor, and overall preferences, compared to the control. pH of pound cake with CMP was decreased during storage, showing that pH of CMP samples was lower than the control. Titrated acidity of pound cake with CMP was increased rapidly from storage for 10 days, which the changes in degree was fast in accordance with CMP amount. The Hunter's color value of pound cake with CMP was decreased, as the storage time proceeded. In the samples prepared with CMP, the firmness, adhesiveness, gumminess and chewiness was increased as the storage time proceeded, while springiness and cohesiveness was decreased.

• Korean Journal of Environment and Ecology
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• v.34 no.2
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• pp.170-178
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• 2020

There are few landscape ecological analyses of Khingan fir (Abies nephrolepis) and other habitats of the sub-alpine zone in South Korea. In this study, we tried to quantitatively interpret and assess the habitat characteristics by analyzing 15 landscape indices according to the differences in tree layer coverage, in the Khingan fir habitat growing naturally in the sub-alpine zone of Seoraksan National Park. It was difficult to identify the tendency of landscape ecology to increase and decrease the tree layer coverage in the study site, which was the entire Khingan fir habitat in Seoraksan National Park. However, the Khingan fir habitat was found to be generally low in coverage, and population density as the tree layer coverage of less than 50 percent accounts for 85 percent of the total habitat. Moreover, the Khingan fir habitat in the 10 to 50 percent range was fragmented into a total of 286 patches, making it relatively less connected to the habitat. The total edge length and edge density, which could determine the edge effect of the main part according to the physical form, were the highest in the habitat of 26 to 50 percent coverage, indicating a relatively high impact from outside than habitats of other coverages. The shape with the tree layer coverage of between 10 and 50 percent was more complex even with patches of the same size, and it is believed that these characteristics make it more susceptible to habitat fragmentation and external confounding. We expect that the results of this study can be useful for time series analysis of spatial expansion or reduction of the Khingan fir habitat in Seoraksan National Park and provide the reference data for the morphological change and movement of patches and the connectivity and break-off between forests.

• Journal of dental hygiene science
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• v.15 no.6
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• pp.703-711
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• 2015

The high dental treatment cost has been considered as one of the major reasons for inappropriate dental treatment in Korea. The aim of this study was to investigate the opinions of expansion of National Health Insurance (NHI) in dental treatment fields not covered with NHI and buying private dental insurance. This survey was carried out targeting 266 adults from their 30s to 50s with convenience sampling. The higher orders in stress of dental treatment cost were orthodontic treatment, dental implant, prosthodontic treatment, and caries treatment not covered with NHI. The higher orders in needs of expansion of NHI were caries treatment not covered with NHI, prosthodontic treatment, and orthodontic treatment. The agreement percentages with age restriction in NHI were scaling 57.1%, denture 23.3%, implant 14.3%, respectively. The subjective oral health had impact on the stress of dental treamtent cost and expansion on NHI. Although only 8.3% subjects had private dental insurance, 68.4% of the subjects had positive opinions buying private dental insurance. The correlation coefficients between stress of dental treatment cost and buying private dental insurance were implant 0.408, caries treatment not covered with NHI 0.404, denture 0.394, crown and bridge 0.375, and orthodontic treatment 0.313. Expansion of NHI in dental treatment and development of private dental insurance was suggested to treat dental disease in appropriate time.

• Management & Information Systems Review
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• v.3
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• pp.287-316
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• 1999

Cyberspace permits us to more beyond traditional face-to-face, mail and telephone surveys, yet still to examine basic issues regarding the quality of data collection: sampling, questionnaire design, survey distribution, means of response, and database creation. This article address each of these issues by contrasting and comparing traditional survey methods(Paper-and-Pencil) with Internet or Personal Computer networks-mediated (Screen-and-Keyboard) survey methods also introduces researchers to this revolutionary and innovative tool and outlines a variety of practical methods for using the Internet or Personal Computer Networks. The revolution in telecommunications technology has fostered the rapid growth of the Internet all over the world. The Internet is a massive global network and comprising many national and international networks of interconnected computers. The Internet or Personal Computer Networks could be the comprehensive interactive tool that will facilitate the development of the skills. The Internet or Personal Computer Networks provides a virtual frontier to expand our access to information and to increase our knowledge and understanding of public opinion, political behavior, social trends and lifestyles through survey research. Comparable to other technological advancements, the Internet or Personal Computer Networks presents opportunities that will impact significantly on the process and quality of survey research now and in the twenty-first century. There are trade-offs between traditional and the Internet or Personal Computer Networks survey. The Internet or Personal Computer Networks is an important channel for obtaining information for target participants. The cost savings in time, efforts, and material were substantial. The use of the Internet or Personal Computer Networks survey tool will increase the quality of research environment. There are several limitations to the Internet or Personal Computer Network survey approach. It requires the researcher to be familiar with Internet navigation and E-mail, it is essential for this process. The use of Listserv and Newsgroup result in a biased sample of the population of corporate trainers. However, it is this group that participates in technology and is in the fore front of shaping the new organizations of interest, and therefore it consists of appropriate participants. If this survey method becomes popular and is too frequently used, potential respondents may become as annoyed with E-mail as the sometimes are with mail survey and junk mail. Being a member of the Listserv of Newsgroup may moderate that reaction. There is a need to determine efficient, effective ways for the researcher to strip identifiers from E-mail, so that respondents remain anonymous, while simultaneously blocking a respondent from responding to a particular survey instrument more than once. The optimum process would be on that is initiated by the researcher : simple, fast and inexpensive to administer and has credibility with respondents. This would protect the legitimacy of the sample and anonymity. Creating attractive Internet or Personal Computer Networks survey formats that build on the strengths of standardized structures but also capitalize on the dynamic and interactive capability of the medium. Without such innovations in survey design, it is difficult to imagine why potential survey respondents would use their time to answer questions. More must be done to create diverse and exciting ways of building an credibility between respondents and researchers on the Internet or Personal Computer Networks. We believe that the future of much exciting research is based in the Electronic survey research. The ability to communicate across distance, time, and national boundaries offers great possibilities for studying the ways in which technology and technological discourse are shaped. used, and disseminated ; the many recent doctoral dissertations that treat some aspect of electronic survey research testify to the increase focus on the Internet or Personal Computer Networks. Thus, scholars should begin a serious conversation about the methodological issues of conducting research In cyberspace. Of all the disciplines, Internet or Personal Computer Networks, emphasis on the relationship between technology and human communication, should take the lead in considering research in the cyberspace.