• Journal of Environmental Science International
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• v.9 no.1
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• pp.13-18
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• 2000

The purpose of this study is to estimate the low-flow statistics at the mountainous watershed. The formulation for the estimation of the design low-flow statistics was obtained by means of a hydraulic approach applied to a simple conceptual model for a mountainous watershed. Three of the independent variables associated with the low-flow statistics is watershed area(A), average basin slope(S) and the base flow recession constant(K); Watershed area was measured from topographic maps and average basin slope is approximated in this study using Strahler's slope determining method. And base flow recession constant computed using Vogel and Kroll's method. Unfortunately, this method is usually unavailable at ungaged sites. In this study, recession constant at ungaged sites is estimated using graphical regression method used by Giese and Mason. The model for estimating low-flow statistics were applied to all 61 catchments in the Sumjin, Mankyung basin.

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.366-374
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• 2018

In this paper the relationship between the business performance and the importance perception of management activities is analyzed. The analysis is conducted by dividing the analysis time-frame into before and after the economic recession. In addition, we consider the type of industry and the type of government support policy that the companies participate in. According to the results, the management activities, such as the introduction of domestic external technologies and the release of new products, are to have a significant impact on business performance for both before and after the economic recession. The introduction of foreign external technologies is significant before the economic recession, but after the economic recession the fund raising activity is shown to be significant. Management activities that affect business performance of large/small businesses, IT/non-IT companies, high/low R&D firms and the companies participated in various government support policies are different. In other words, it can be found that the support of management activities that can enhance performance should be done in an appropriate way considering the characteristics of the company rather than being provided to all companies in common.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1857-1862
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• 2012

To assess the impact of household income and economic recession on participation in CRC screening, we estimated annual participating proportions from 2007 to 2009 for different CRC screening modalities according to household income levels. A total of 8,042 subjects were derived from the fourth Korean National Health and Nutrition Examination Survey (KNHANES IV). Multivariate logistic regression analysis was used to estimate odds ratios and 95% confidence intervals for CRC screening with household income quartiles by gender in each year. People were less likely to attend a high-cost CRC screening such as a sigmoidoscopy or colonoscopy independent of the income quartile during the economic recession. Income disparities for participating in opportunistic cancer screening appear to have existed among both males and females during the three years (2007-2009), but were most distinctive in 2009. An increase in mortality of CRC can therefore be expected due to late detection in periods of economic crisis. Accordingly, the government should expand the coverage of CRC screening to prevent excess deaths by reducing related direct and indirect costs during the economic recession.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.785-797
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• 1998

This study has been done to prove that keratinized gingiva is required for the periodontal health and to analyse the adequate width that is necessary. Until now, the study on frenum has been documented on changing its location. But the location or the formation of the frenum has not been reported. This experiment has used 173 patients from the department of periodontology of Dankook University to investigate the width of keratinized gingiva, the formation of the frenum and its location for the frequency. This study also looks into the relationship between the gingival recession and the structure of the frenum, and affects they have on periodontal health. The width of the keratinized gingiva in the mandible has been found to be highest in the lateral incisor than in the central incisor. The width decreased from the canine to the first premolar until it reached the molar. The interproximal area of the mandibular frenum was 77.9%, which was greater than the frequency (22.1%) from the midline of the teeth. The highest frequency of frenum was at 30.6% in between the both central incisor then second greatest at 20.6% in between the right canine and the right first premolar. Frenum was not found in between the second premolar and the distal area. In the morphology of the frenum, it was found that 43.4% out of 551 parts were found to be a single narrow frenum, and the double or triple ligamented form of the complex frenum were found in similar frequency of 237 parts, but the broad frenum was rarely frequent. The incisal area was popular mostly with the single narrow frenum, the left premolar area frequented 57.4%, and the right premolar frequented 64.7%. Because the distance between the frenum apex and the gingival margin measured to be about 5mm or greater, the frenum apex started in the mucogingival junction and not just below the keratinized gingiva. In the 551 area investigated, 48.3% of gingiva showed recession, incisal area had recession the least at 44.9%, right buccal side at 47.4%, and right buccal side frequented the highest at 52.1%. The teeth that showed recession recessed at the average of 2.151.0.mm and the left canine showed the greatest amount of gingival recession. In the investigation to find out if the keratinized gingiva and the gingiva recession had mutually related somehow, the width of keratinized gingiva showed no affect on the probing depth, but had affected in the gingiva recession. This investigation showed that the gingival recession and the morphology of the frenum related in that, the single narrow frenum had recessed the least and the broad frenum recessed the most. With this analysis, a conclusion was drawn that the morphology of the frenum had affected in the gingical recession.

• Journal of Periodontal and Implant Science
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• v.43 no.4
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• pp.160-167
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• 2013

Purpose: This study examined the factors that can be associated with the appearance of the interproximal papilla. Methods: One hundred and forty-seven healthy interproximal papillae between the maxillary central incisors were examined. For each subject, a digital photograph and periapical radiograph of the interdental embrasure were taken using a 1-mm grid metal piece. The following parameters were recorded: the amount of recession of the interproximal papilla, contact point-bone crest distance, contact point-cemento-enamel junction (CEJ) distance, CEJ-bone crest distance, inter-radicular distance, tooth shape, embrasure space size, interproximal contact area, gingival biotype, papilla height, and papilla tip form. Results: The amount of recession of the interproximal papilla was associated with the following: 1) increase in contact point-bone crest, contact point-CEJ, and CEJ-bone crest distance; 2) increase in the inter-radicular distance; 3) triangular tooth shape; 4) decrease in the interproximal contact area length; 5) increase in the embrasure space size; and 6) flat papilla tip form. On the other hand, the amount of gingival recession was not associated with the gingival biotype or papilla height. In the triangular tooth shape, the contact point-bone crest distance and inter-radicular distance were longer, the interproximal contact area length was shorter, and the embrasure space size was larger. The papilla tip form became flatter with increasing inter-radicular distance and CEJ-bone crest distance. Conclusions: The relative position of the interproximal papilla in healthy subjects was associated with the multiple factors and each factor was related to the others. A triangular tooth shape carries a higher risk of recession of the interproximal papilla because the proximal contact point is positioned more incisally and the bone crest is positioned more apically. This results in an increase in recession of the interproximal papilla and flat papilla tip form.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.6
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• pp.438-444
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• 2021

Objectives: Loss of the interdental papilla is multi-factorial and creates a multitude of problems. Autogenous connective tissue/biomaterial-based regeneration has been attempted for decades to reconstitute the black space created due to the loss of papilla. The aim of this present study was to regenerate papillary recession defects using an amnion-chorion membrane (ACM) allograft and to evaluate the clinical outcome up to six months postoperatively. Materials and Methods: Twenty patients with 25 Nordland and Tarnow's Class I/II interdental papillary recession defects were treated with ACM and coronal advancement of the gingivo-papillary unit via a semilunar incision on the labial aspect followed by a sulcular incision in the area of interest. A photographic image analysis was carried out using the GNU Image Manipulation software program from the baseline to three and six months postoperatively. The black triangle height (BTH) and the black triangle width (BTW) were calculated using the pixel size and were then converted into millimeters. The mean and standard deviation values were determined at baseline and then again at three and six months postoperatively. The probability values (P<0.05 and P≤0.01) were considered statistically significant and highly significant, respectively. An analysis of variance and post hoc Bonferroni test were carried out to compare the mean values. Results: Our evaluation of the BTH and BTW showed a statistically and highly significant difference from the baseline until both three and six months postoperatively (P=0.01). A post hoc Bonferroni test disclosed a statistically significant variance from the baseline until three and six months postoperatively (P<0.05) and a non-significant difference from three to six months after the procedure (P≥0.05). Conclusion: An ACM allograft in conjunction with a coronally advanced flap could be a suitable minimally invasive alternative for papillary regeneration.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.1
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• pp.21-26
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• 1996

The amount of the annual groundwater recharge for the five major river basins in South Korea is estimated to be 9,000 million cubic meters for one groundwater hydrologic year, of which amount corresponds to the available amount of groundwater. It is proposed from the analysis of hydrographs that the groundwater hydrologic year stare at the end of February. The basin which affects the groundwater outflow behaves as being homogeneous in the macroscopic sense, because recession coefficients(k) are independent of the basin area and nearly constant. Also, the curve of April goundwater recession decreases more steeply than that of September groundwater recession, because of the larger amount of evapotranspiration during the period of April groundwater recession.

• Safety and Health at Work
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• v.3 no.4
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• pp.294-297
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• 2012

Previous studies on the vast increase in suicide mortality in Southeast Asia have indicated that suicide rates increase in parallel with a rise in unemployment or during periods of economic recession. This paper examines the effects of economic recession on suicidal rates amongst agriculture, fisheries, and forestry workers in Korea. Monthly time-series gross domestic product (GDP) data were linked with suicidal rates gathered from the cause of death records between1993-2008. Data were analyzed using generalized additive models to analyze trends, while a polynomial lag model was used to assess the unconstrained time lag effects of changes in GDP on suicidal rate. We found that there were significant inverse correlations between changes in GDP and suicide for a time lag of one to four months after the occurrence of economic event. Furthermore, it was evident that the overall relative risks of suicide were high enough to bring about social concern.

• Journal of Construction Engineering and Project Management
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• v.1 no.3
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• pp.1-8
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• 2011

Available data on the recent global financial crisis (GFC) show that it lasted between the second quarter (Q2) of 2007 and the fourth quarter (Q4) of 2009. Australia is one of the first economies to fully recover from this crisis. This study explorles the role played by the Australian construction industry in stimulating economic growth during the recession. In order to investigate the macro-variability trend during the financial crisis, data were collected and analysed relating to the quarterly GDP of Australia and selected countries between Q1 2000 and Q4 2009. Specifically, changes in the construction industry's GDP were compared with aggregate GDP changes in Australian economy and similar indices in the 'Group of 7' (G7) countries and Organisation for Economic Co-operation and Development (OECD) countries. Moreover, specific attention was focused on Germany, France, Japan, United States of America (USA) and United Kingdom (UK). Graphical and Pearson's correlation methods were used to analyse the relationships between changes in construction GDP and Australia's overall economic growth during the recession. In addition, an attempt was made to develop a regression model for predicting economic growth during the recent recession using changes in gross fixed capital formation (GFCF), changes in construction GDP and the impact of these changes on national economy. Analysis shows a slight contraction in construction activities during the crisis; however construction triggered significant growth in the economy during the crisis period and afterwards. This appears to be the major difference between Australia and other major economies that have experienced a longer recession.

• Journal of Periodontal and Implant Science
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• v.46 no.1
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• pp.22-34
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• 2016

Purpose: Gingival recession is a major esthetic concern and may lead to root sensitivity during periodontal treatment. Coronally advanced flaps (CAFs) with and without acellular dermal matrix (ADM) are widely used in root coverage procedures. The aim of this study was to analyze the efficacy of CAF in combination with ADM in the treatment of gingival recession. Methods: PubMed, The Cochrane Library, and Embase were used to identify relevant articles. The articles were screened, data were extracted, and the quality of the studies was assessed by three reviewers with expertise in clinical practice, trials, statistics, and biomedical editing. The clinical endpoints of interest included changes in recession, probing depth (PD), clinical attachment level (CAL), and keratinized tissue (KT). Results: Ten randomized controlled trials were identified, including six studies that compared CAFs with ADM and CAFs using connective tissue grafting (CTG) and four studies that compared CAFs with or without ADM. No statistically significant differences were found between the use of ADM and CTG, whereas statistically significant differences were found between groups in which ADM and CAF were combined and groups that underwent CAF alone with regard to recession coverage, CAL, and KT. The combination of CAF with an ADM allograft achieved more favorable recession coverage and recovery of CAL and KT than CAF alone. Conclusions: The results from the ADM and CTG groups suggest that both procedures may be equally effective in clinical practice. Given the limitations of this study, further investigation is needed to clarify the effectiveness of ADM and CAF in clinical practice.