• Title/Summary/Keyword: Relation coefficient

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The Effects of Job Stress of Nurses Working in the General Hospitals on Their Turnover Intention -Mediating Effects Organizational Commitment- (종합병원 간호사의 직무스트레스가 이직의도에 미치는 영향 -조직몰입의 매개효과-)

  • Kim, Gyeong-Suk;Cho, In-Sook
    • Journal of the Korean Applied Science and Technology
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    • v.36 no.2
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    • pp.656-667
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    • 2019
  • This study is a descriptive research to grasp the effects of job stress on turnover intention and to confirm the mediating effect of organizational commitment according to the extent of job stress, organizational commitment and turnover intention in the relations between job stress and Turnover Intention of nurses working in general hospitals. Method: The subjects of this study were 199 nurses are working in general hospitals, that have more than 200 beds and less than 400 beds, located in Gwangju. I surveyed them using a structured questionnaire for collecting data from Sep. 01, 2017 to Sep. 20, 2017. The collected data were analyzed by the frequency, the percentage, t-test, ANOVA, Scheffe's Test, Pearson's Correlation Coefficient, Multiple Regression Analysis and Sobel Results: In the first step, job stress as an independent variable had a statistically significant effect on organizational commitment(${\beta}=-.321$, p<.001). In the second step, job stress, an independent variable, also had an important effect on turnover intention as a dependent variable(${\beta}=.389$, p<.001). Job stress and organizational commitment were meaningful predictor variables of turnover intention in the third step. The explanatory power of two variables was 45.5%. The value ${\beta}$ of job stress in the third step was .203(p<.001) which was smaller than its value ${\beta}$,.389(p<.001), in the second step. That meant organizational commitment had the mediating effect on turnover intention. The Sobel Test was conducted to verify the significance of the extent of the mediating effects of organizational commitment. The test result was that the value Z was -3.694 and the mediating effect of organizational commitment was significant on the relation between job stress and turnover intention(p<.002). Conclusion: this study is expected be useful to find ways to reduce subjects' turnover intention by decreasing their job stress, increasing their organizational commitment and developing intervention programs as basic data.

Performance evaluation of hyperspectral bathymetry method for morphological mapping in a large river confluence (초분광수심법 기반 대하천 합류부 하상측정 성능 평가)

  • Kim, Dongsu;Seo, Youngcheol;You, Hojun;Gwon, Yeonghwa
    • Journal of Korea Water Resources Association
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    • v.56 no.3
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    • pp.195-210
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    • 2023
  • Additional deposition and erosion in large rivers in South Korea have continued to occur toward morphological stabilization after massive dredging through the four major river restoration project, subsequently requiring precise bathymetry monitoring. Hyperspectral bathymetry method has increasingly been highlighted as an alternative way to estimate bathymetry with high spatial resolution in shallow depth for replacing classical intrusive direct measurement techniques. This study introduced the conventional Optimal Band Ratio Analysis (OBRA) of hyperspectral bathymetry method, and evaluated the performance in a domestic large river in normal turbid and flow condition. Maximum measurable depth was estimated by applying correlation coefficient and root mean square error (RMSE) produced during OBRA with cascadedly applying cut-off depth, where the consequent hyperspectral bathymetry map excluded the region over the derived maximum measurable depth. Also non-linearity was considered in building relation between optimal band and depth. We applied the method to the Nakdong and Hwang River confluence as a large river case and obtained the following features. First, the hyperspectal method showed acceptable performance in morphological mapping for shallow regions, where the maximum measurable depth was 2.5 m and 1.25 m in the Nakdong and Hwang river, respectively. Second, RMSE was more feasible to derive the maximum measurable depth rather than the conventional correlation coefficient whereby considering various scenario of excluding range of in situ depths for OBRA. Third, highly turbid region in Hwang River did not allow hyperspectral bathymetry mapping compared with the case of adjacent Nakdong River, where maximum measurable depth was down to half in Hwang River.

Studies on the chemical composition of citrus fruits in Korea(II) -Changes of acid and sugar components with growth- (한국산(韓國産) 감귤류(柑橘類)의 화학성분(化學成分)에 관(關)한 연구(硏究) (II) -주요품종별(主要品種別) 당(糖) 및 산조성(酸組成)의 시기별(時期別) 변화(變化)에 관(關)하여-)

  • Park, H.;Kim, Y.S.;Kim, Z.U.
    • Applied Biological Chemistry
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    • v.9
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    • pp.41-57
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    • 1968
  • Changes of acids (total, titratable and combined form) and sugars (total, reducing and non-reducing) in the edible part and the rind of 17 varieties the in growing and ripening period were investigated. The results were summarized as follows. 1) The percentage of rind was notably decreased in growing period and slightly in the ripening period- It may suggest that the rates of translocation of metabolite from leaves to each part of fruit are different with growth phase. 2) The heavier the weight of fruit, the higher the percentage of rind was and the varieties having over 200 g per fruit showed the value over 30 in the rind percentage and over 15 in the number seeds per fruit. 3) Total acid contents in the rind were highest at the maximum grow th of fruit except in Citrus grandis having tie lowest value (below 20 me/100 g F.W). of total acid at maximum point in which total acid content is steadily increase. 4) Total acid and titratable acid in the edible part and total acid and combined acid in whole fruit life showed 0.933 and 0.970 of correlation coefficient significant at 1% level respectively, and most acid in the edible part was titratable acid(73%) whereas acid in the rind consists mostly of combined acid. 5) The content of combined acid in the ripening period increased in the edible part and decreased in the rind. It may be contributed to translocation of some cations from the rind to the edible part. 6) The grouping criteria on citrus fruit were applicable on melon, watermelon and tomatoes. 7) The contents of total sugar and non-reducing sugar in the edible part were continuously increased whereas the content of reducing sugar were decreased in certain varieties, notablly in citrus natsudaidai. The correlation coefficient between total sugar and reducing sugar in the edible part with ripening decreased as $0.849^{**},\;0.732^{**}.\;0.583^*$. ( $^{**}$: significant at 1% level and $^{*}:$: at 5%) 8) 61% of total sugar in the edible part was non-reducing sugar whereas 88% of total sugar in the rind was reducing form at the end of ripening and the correlation coefficient between total and non-reducing sugar in the edible part was 0.861 end total and reducing sugar in the rind was 0.972, both significant at 1% level. 9) Varieties having the percentage of the rind below 36 showed higher value than I in the ratio of total sugar in the edible part to one in the rind. It may suggest that there exists any intimate relation between relative sugar content and growth rate of fruit parts. 10) Citrus unshiu in Guje island showed lower values in the content of acid and sugar, and the rind percentage but higher sweetness index (the ratio of total sugar to titratable acid) comparing with the same variety in Jeiu.

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Mineral Nutrition of Field-Grown Rice Plant -II Recovery of fertilizer nitrogen, phosphorus, and potassium in relation to climatic zone and physical or chemical characteristics of soil profile (포장재배(圃場栽培) 수도(水稻)의 무기영양(無機營養) -II 삼요소(三要素) 이용율(利用率)과 기상권(氣象圈) 및 토양단면(土壤斷面)의 물리(物理)·화학적(化學的) 성질(性質)과의 관계(關係))

  • Park, Hoon;Shin, Chun Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.6 no.1
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    • pp.17-26
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    • 1973
  • A survey on nutrient recovery by rice plant was carried out countrywide in 1967 and 1968. The relationships between percent recovery of fertilizer nutrient and climatic zone or deposition mode, drainage grade, and texture of paddy soil profile, or chemical characteristics of surface soil were as follows. 1. The percent recovery of fertilizer nitrogen was highest in south and least in north, and that of potassium was highest in south and least in middle climatic zone. 2. Since the percent recovery of Phosphorus variates yearly with climatic zone, mode of deposition drainage grade or soil texture, it seemed to depend greatly on soil-weather interaction. 3. Nitrogen recovery was highest in alluvial colluvial (AC) and it was followed by alluvial (A), fluvomarine (FM) and old alluvial in decreasing order while potassium recovery was OA>AC>A>FM. 4. The greater the drainage was, the higher the nitrogen recovery. The recovery of potassium and phosphorus tended to show high in moderately well drain, and low in poorly and well drain. 5. Nitrogen recovery was highest in fine silty and gradually decreased with coarseness. That of potassium or phosphorus was greater in those below fine loamy than in those above coarse silty. 6. Nitrogen recovery was high in Jisan, Geugrag, and Sindab series, and low in Hwadong, Gyuam, Yongji and Hwabong series. 7. Nitrogen recovery showed significant positive correlation with the content of organic matter (OM), Ca, CEC of surface soil and only in the year of high phosphorus recovery it had significant negative correlation with soil phosphorus. Phosphorus recovery had significant posititive correlation with CEC, Mg or Ca. 8. Potassium recovery showed negative correlation with K/(Ca+Mg), P, OM or K while positive correlation with Ca, Mg, CEC but significant only with K/(Ca+Mg) in the year of low potassium recovery. In the year of high K recovery it showed positive correlation with P, OM, K/(Ca+Mg) or K while negative with CEC, Mg or Ca but significant only with P, OM or CEC. Soil potassium has significant positive correlation with soil OM and P only in the year of low potassium recovery. 9. The percent recovery of N, P or K showed negative correlation coefficient with pH without significant. 10. There was significant positive correlation between OM and P, K or K/(Ca+Mg), P and K or K/(Ca+Mg), K and K/(Ca+Mg), Mg or CEC, Ca and K/(Ca+Mg), Mg, CEC or pH, Mg and CEC while significant negative correlation between Mg and OM, P or K/(Ca+Mg), P and CEC, Ca and K/(Ca+Mg). 11. From the percent rcovery of fertilizer and soil chemical characteristics it was known that soil organic matter increase nitrogen uptake, that K uptake has closer relation to K/(Ca+Mg) than K, that Mg affects P ugtake, and that the annual difference of P and K recovery was partly explainable.

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Semiweekly variation of Spring Phytoplankton Community in Relation to the Freshwater Discharges from Keum River Estuarine Weir, Korea (금강하구언 담수방류와 춘계 식물플랑크톤 군집의 단주기 변동)

  • Yih, Won-Ho;Myung, Geum-Og;Yoo, Yeong-Du;Kim, Young-Geel;Jeong, Hae-Jm
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.10 no.3
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    • pp.154-163
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    • 2005
  • Irregular discharges of freshwater through the water gates of the Keum River Estuarine Weir, Korea, whose construction had been completed in 1998 with its water gates being operated as late as August 1994, drastically modified the estuarine environment. Sharp decrease of salinity along with the altered concentrations of inorganic nutrients are accompanied with the irregular discharges of freshwater into the estuary under the influence of regular semi-diurnal tidal effect. Field sampling was carried out on the time of high tide at 2 fixed stations(St.1 near the Estuarine Weir and St.2 off Kunsan Ferry Station) every other day for 4 months from mid-February 2004 to investigate into the semi-weekly variation of spring phytoplankton community in relation to the freshwater discharges from Keum River Estuarine Weir. CV(coefficient of variation) of salinity measurements was roughly 2 times greater in St.1 than that in St.2, reflecting extreme salinity variation in St.1 Among inorganic nutrients, concentrations of N-nutrients($NO_3^-,\;NO_2^-$ and $NH_4^+$) were clearly higher in St.1, to imply the more drastic changes of the nutrient concentrations in St.1. than St.2 following the freshwater discharges. As a component of phytoplankton community, diatoms were among the top dominants in terms of species richness as well as biomass. Solitary centric diatom, Cyclotella meneghiniana, and chain-forming centric diatom, Skeletonema costatum, dominated over the phytoplankton community in order for S-6 weeks each (Succession Interval I and II), and the latter succeeded to the former from the time of <$10^{\circ}C$ of water temperature. Cyanobacterial species, Aphanizomenon Posaquae and Phormidium sp., which might be transported into the estuary along with the discharged freshwater, occupied high portion of total biomass during Succession Interval III(mid-April to late-May). During this period, freshwater species exclusively dominated over the phytoplankton community except the low concentrations of the co-occurring 2 estuarine diatoms, Cyclotella meneghiniana and Skeletonema costatum. During the 4th Succession Interval when the water temperature was over $18^{\circ}C$, the diatom, Guinardia delicatula, was predominant for a week with the highest dominance of $75\%$ in discrete samples. To summarize, during all the Succession Intervals other than Succession Interval III characterized by the extreme variation of salinity under cooler water temperature than $18^{\circ}C$, the diatoms were the most important dominants for species succession in spring. If the scale and frequency of the freshwater discharge could have been adjusted properly even during the Succession Interval III, the dominant species would quite possibly be replaced by other estuarine diatom species rather than the two freshwater cyanobacteria, Aphanizomenon flosaquae and Phormidium sp.. The scheme of field sampling every other day for the present study was concluded to be the minimal requirement in order to adequately explore the phytoplankton succession in such estuarine environment as in Keum River Estuary: which is stressed by the unpredictable and unavoidable discharges of freshwater under the regular semi-diurnal tide.

Development of a Traffic Accident Prediction Model and Determination of the Risk Level at Signalized Intersection (신호교차로에서의 사고예측모형개발 및 위험수준결정 연구)

  • 홍정열;도철웅
    • Journal of Korean Society of Transportation
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    • v.20 no.7
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    • pp.155-166
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    • 2002
  • Since 1990s. there has been an increasing number of traffic accidents at intersection. which requires more urgent measures to insure safety on intersection. This study set out to analyze the road conditions, traffic conditions and traffic operation conditions on signalized intersection. to identify the elements that would impose obstructions in safety, and to develop a traffic accident prediction model to evaluate the safety of an intersection using the cop relation between the elements and an accident. In addition, the focus was made on suggesting appropriate traffic safety policies by dealing with the danger elements in advance and on enhancing the safety on the intersection in developing a traffic accident prediction model fir a signalized intersection. The data for the study was collected at an intersection located in Wonju city from January to December 2001. It consisted of the number of accidents, the road conditions, the traffic conditions, and the traffic operation conditions at the intersection. The collected data was first statistically analyzed and then the results identified the elements that had close correlations with accidents. They included the area pattern, the use of land, the bus stopping activities, the parking and stopping activities on the road, the total volume, the turning volume, the number of lanes, the width of the road, the intersection area, the cycle, the sight distance, and the turning radius. These elements were used in the second correlation analysis. The significant level was 95% or higher in all of them. There were few correlations between independent variables. The variables that affected the accident rate were the number of lanes, the turning radius, the sight distance and the cycle, which were used to develop a traffic accident prediction model formula considering their distribution. The model formula was compared with a general linear regression model in accuracy. In addition, the statistics of domestic accidents were investigated to analyze the distribution of the accidents and to classify intersections according to the risk level. Finally, the results were applied to the Spearman-rank correlation coefficient to see if the model was appropriate. As a result, the coefficient of determination was highly significant with the value of 0.985 and the ranks among the intersections according to the risk level were appropriate too. The actual number of accidents and the predicted ones were compared in terms of the risk level and they were about the same in the risk level for 80% of the intersections.

A Study on Qulity Perceptions and Satisfaction for Medical Service Marketing (의료서비스 마케팅을 위한 품질지각과 만족에 관한 연구)

  • Yoo, Dong-Keun
    • Journal of Korean Academy of Nursing Administration
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    • v.2 no.1
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    • pp.97-114
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    • 1996
  • INSTRODUCTION Service quality is, unlike goods quality, an abstract and elusive constuct. Service quality and its requirements are not easily understood by consumers, and also present some critical research problems. However, quality is very important to marketers and consumers in that it has many strategic benefits in contributing to profitability of marketing activities and consumers' problem-solving activities. Moreover, despite the phenomenal growth of medical service sector, few researchers have attempted to define and model medical service quality. Especially, little research has focused on the evaluation of medical service quality and patient satisfaction from the perspectives of both the provider and the patient. As competition intensifies and patients are demanding higher quality of medical service, medical service quality and patient satisfaction has emerged as a critical research topic. The major purpose of this article is to explore the concept of medical service quality and its evaluation from both nurse and patient perspectives. This article attempts to achieve its purpose by (1)classfying critical service attibutes into threecategories(satisfiers, hygiene factors, and performance factors). (2)measuring the relative importance of need criteria, (3)evaluating SERVPERF model and SERVQUAL model in medical service sector, and (4)identifying the relationship between perceived quality and overall patient satisfaction. METHOD Data were gathered from a sample of 217 patients and 179 nurses in Seoul-area general hospitals. From the review of previous literature, 50 survey items representing various facets of the medical service quality were developed to form a questionnaire. A five-point scale ranging from "Strongly Agree"(5) to "Strongly Disagree"(1) accompanied each statement(expectation statements, perception statements, and importance statements). To measure overall satisfaction, a seven-point scale was used, ranging from "Very Satisfied"(7) to "Very Dissatisfied"(1) with no verbal labels for scale points 2 through 6 RESULTS In explaining the relationship between perceived performance and overall satisfaction, only 31 variables out of original 50 survey items were proven to be statistically significant. Hence, a penalty-reward analysis was performed on theses 31 critical attributes to find out 17 satisfiers, 8 hygiene factors, and 4 performance factors in patient perspective. The role(category) of each service quality attribute in relation to patient satisfaction was com pared across two groups, that is, patients and nurses. They were little overlapped, suggesting that two groups had different sets of 'perceived quality' attributes. Principal components factor analyses of the patients' and nurses' responses were performed to identify the underlying dimensions for the set of performance(experience) statements. 28 variables were analyzed by using a varimax rotation after deleting three obscure variables. The number of factors to be extracted was determined by evaluating the eigenvalue scores. Six factors wereextracted, accounting for 57.1% of the total variance. Reliability analysis was performed to refine the factors further. Using coefficient alpha, scores of .84 to .65 were obtained. Individual-item analysis indicated that all statements in each of the factors should remain. On 26 attributes of 31 critical service quality attributes, there were gaps between actual patient's importance of need criteria and nurse perceptions of them. Those critical attributes could be classified into four categories based on the relative importance of need criteria and perceived performance from the perspective of patient. This analysis is useful in developing strategic plans for performance improvement. (1) top priorities(high importance and low performance) (in this study)- more health-related information -accuracy in billing - quality of food - appointments at my convenience - information about tests and treatments - prompt service of business office -adequacy of accommodations(elevators, etc) (2) current strengths(high importance and high performance) (3)unnecessary strengths(low importance and high performance) (4) low priorities(low importance and low performance) While 26 service quality attributes of SERPERF model were significantly related to patient satisfation, only 13 attributes of SERVQUAL model were significantly related. This result suggested that only experience-based norms(SERVPERF model) were more appropriate than expectations to serve as a benchmark against which service experiences were compared(SERVQUAL model). However, it must be noted that the degree of association to overall satisfaction was not consistent. There were some gaps between nurse percetions and patient perception of medical service performance. From the patient's viewpoint, "personal likability", "technical skill/trust", and "cares about me" were most significant positioning factors that contributed patient satisfaction. DISCUSSION This study shows that there are inconsistencies between nurse perceptions and patient perceptions of medical service attributes. Also, for service quality improvement, it is most important for nurses to understand what satisfiers, hygiene factors, and performance factors are through two-way communications. Patient satisfaction should be measured, and problems identified should be resolved for survival in intense competitive market conditions. Hence, patient satisfaction monitoring is now becoming a standard marketing tool for healthcare providers and its role is expected to increase.

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Distributions of 137Cs and 90Sr in the Soil of Uljin, South Korea (울진토양에서의 137Cs 및 90Sr 분포)

  • Song, JiYeon;Kim, Wan;Maeng, Seongjin;Lee, Sang Hoon
    • Journal of Radiation Protection and Research
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    • v.41 no.1
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    • pp.49-55
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    • 2016
  • Background: For the purpose of baseline data collection and enhancement of environmental monitoring the distribution studies of $^{137}Cs$ and $^{90}Sr$ in the soil of Uljin province was performed and the relation between surface soil activities and soil properties (pH, TOC and median of the surface soil) was analyzed. Materials and Methods: For 14 spots within 10 km from the NPP surface soil samples were collected and soils for depth profile were sampled for 3 spots in April 2011. Using ${\gamma}$-ray spectrometry with HPGe detector, the concentrations of $^{137}Cs$ were determined and the concentrations of $^{90}Sr$ were measured by counting ${\beta}$-activity of $^{90}Y$ (in equilibrium with $^{90}Sr$) in a gas flow proportional counter. Results and Discussion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ were $<0.479-39.6Bq{\cdot}(kg-dry)^{-1}$ (avg. $7.51Bq{\cdot}(kg-dry)^{-1}$) and $0.209-1.85Bq{\cdot}(kg-dry)^{-1}$ (avg. $0.74Bq{\cdot}(kg-dry)^{-1}$) which were similar to the reported values from other regions in Korea. The activity ratio of $^{137}Cs$ to $^{90}Sr$ in surface soils was around 9.67, which is much bigger than the initial value of 1.75 for worldwide fallouts because of faster downward movement of $^{90}Sr$ after fallout than that of $^{137}Cs$. For depth profile studies soils were collected down to 40 cm depth for the locations of Deokgu, Hujeong and Maehwa. The $^{137}Cs$ concentration distribution of the first two showed maximum values at top soils and decreased rapidly in exponential manner, while $^{90}Sr$ showed two local maximum values for soils near top and about 30 cm depth. Through linear fittings between the $^{137}Cs$ and $^{90}Sr$ concentrations of surface soil and pH, TOC and median of the surface soil, the only probable relationship obtained was between $^{137}Cs$ and TOC (determination coefficient $R^2=0.6$). Conclusion: The concentration ranges of $^{137}Cs$ and $^{90}Sr$ in Uljin were similar to the reported values from other regions in Korea. The only probable relationship obtained between activities and soil properties was between $^{137}Cs$ and TOC.

A Study on the Knowledge, Attitude and Practice of Handwashing of Middle School Students (일부 중학생의 손씻기 지식, 태도 및 실천에 관한 연구)

  • Jang, Yun-Jeong;Na, Bak-Ju;Kim, Keon-Yeop;Bae, Seok-Hwan;Kim, Chul-Woung;Kim, Eun-Young;Lee, Moo-Sik
    • Korean Journal of Health Education and Promotion
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    • v.24 no.4
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    • pp.1-22
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    • 2007
  • Objectives: This study attempted to understand the relationship between handwashing knowledge, attitude and practice of middle school students and to provide the basic information for handwashing training of the students and help them to form a healthy habit. Methods: Data was collected by a standardized self-administered questionnaire between Sep. 20 to Oct. 6 2006 with a total of 710 students in 1, 2, 3 grades at 6 middle schools in metropolitan cities(490 students from four schools situated in an urban center, 220 from 2 in a suburban district). The data was then analyzed using the SPSS WIN 12.0 program, employing many statistical techniques such as chi-square($x^2$) test, t-test, ANOVA analysis with post hoc test, correlations analysis, and regression analysis. Results: The results of the study were as follows. First, total number of handwashing times of middle school students is 6.69 per day. 66.1% of the students used soap and most of the students washed hands for $6{\sim}10$ seconds(44.7%). Second, in the knowledge of handwashing, "both of the parents"(p<0.01), "catholic", "city"(p<0.05) were the highest and the practice of handwashing was active with "city", "high economic level"(p<0.05) and "both of the parents"(p<0.01). In the experience of teaching handwashing, "Yes" was 24.3% which was statistically significant with handwashing knowledge(p<0.05), attitude and practice(p<0.01). Third, in the correlation of handwashing knowledge, attitude and practice, there was statistical significancy between handwashing attitude and knowledge(p<0.01) and showed positive correlation with the knowledge(.534). The practice of handwashing has meaningful difference from the knowledge and the attitude and the coefficient of correlation shows positive co-relation in knowledge(.335) and attitude(0525). Fourth, based on the result for regression analysis with handwashing knowledge, attitude and practice as dependent variables, handwashing knowledge showed statistical significancy with sex, type of school(p<0.05) and residential area(p<0.01). There were also statistical significancy between handwashing attitude and knowledge(p<0.01) and between handwashing practice and religion, knowledge(p<0.05) and economic level, attitude(p<0.01). Conclusion: There were consistent results with handwashing knowledge, attitude and practice. If they had better knowledge, their attitude was more positive and if they had better knowledge and more positive attitude, their practice was active. The knowledge, attitude and practice of the students who learned about handwashing were higher than those of the students who had no experience of learning handwashing. To enhance handwashing habit of middle school students, the handwashing environment should be maintained. The training plans should also be made according to sex, type of school, economic level, residential area, and the consistent study on handwashing training is required.

Variation of Stomatal Traits of Natural Population of Quercus spp. (참나무 천연집단(天然集團)의 기공형질변이(氣孔形質變異))

  • Kim, Chi Moon;Kwon, Ki Won;Moon, Heung Kyu
    • Journal of Korean Society of Forest Science
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    • v.66 no.1
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    • pp.82-94
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    • 1984
  • The variation of stomatal density and stomatal length of four species of oaks was studied for the purpose of examining the differences among populations and among individual trees within population. Nine populations of Quercus mongolica, four populations of Q. serrata and Q. variabilis respectively, and three populations of Q. acutissima were selected in the natural stands of oaks distributed through the whole country. Twelve leaves were sampled from each of 20 trees from each population. The length of 20 stomata and ten replications of stomatal density were measured from collodion replicas of each leaf under a microscope. Average stomatal densities and lengths ranged through $600-1000/mm^2$ and $19-26{\mu}m$ respectively in all of the species studied. The stomatal densities and lengths presented significant differences statistically at the level of 1 or 5% among populations and among individual trees within population in all the species. Quercus mongolica, especially, showed large variation among populations, while Q. variabilis did very narrow variation compared to the other species. The coefficients of variation of stomatal densities and lengths among individual trees within population exhibited small values of 3.7-12.0% and 1.4-5.3% respectively in all the populations of the species. The average stomatal densities of Q. mongolica showed statistically significant correlation of multiple correlation coefficient of $R_{df{\cdot}2.6}=0.868^*$ and multiple regression equation of $Y=0.041X_1(G.M.T.S.)+0.489X_2(G.M.H.S.)+22.37$ with the sum of growing season mean daily temperature and the sum of growing season mean daily humidity of the stand studied. However the average stomatal lengths showed no relation with the same meteological variables. The figures of frequency distribution of the measurements of leaves or the mean values of individual trees did not show normal distribution curves in some populations. The curves, as well as the results of ANOVA, exhibited the differences among populations.

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