• Title/Summary/Keyword: cluster sampling

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Prevalence and associates of obesity and overweight among school-age children in a rural community of Thailand

  • Nonboonyawat, Teechaya;Pusanasuwannasri, Wuttipat;Chanrat, Nattanon;Wongthanavimok, Natta;Tubngern, Danutanut;Panutrakul, Piengkwan;Mungthin, Mathirut;Nivesvivat, Thirapa;Hatthachote, Panadda;Rangsin, Ram;Piyaraj, Phunlerd
    • Clinical and Experimental Pediatrics
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    • v.62 no.5
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    • pp.179-186
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    • 2019
  • Purpose: Information about overweight and obesity among students in rural areas of Thailand is limited. Therefore, we aimed to determine overweight and obesity prevalences and associated factors among school-aged children in a rural community of Thailand. Methods: We selected 9 public schools through cluster sampling in 2 provinces located in central Thailand in 2016. Anthropometric measurements were measured using standard techniques, classified as overweight (>1 standard deviation [SD]) and obese (>2 SD) with respect to their age and sex using 2007 World Health Organization reference charts. Standardized questionnaires on risk factors were sent to parents to be completed together with their child. Results: Among 1,749 students, 8.98% had overweight and 7.26% had obesity. Mean age (range) was 11.5 years (5-18 years). Independent factors associated with overweight and obesity included primary school student (reference as secondary school) (adjusted odds ratio [aOR], 2.25; 95% confidence interval [CI], 1.24-4.08; P=0.07), mother's body mass index (aOR, 1.07; 95% CI, 1.02-1.12; P=0.001), self-employed father (aOR, 1.99; 95% CI, 1.12-3.55; P=0.018), number of siblings (aOR, 0.61; 95% CI, 0.47-0.81; P=0.001), having sibling(s) with obesity (aOR, 1.82; 95% CI, 1.20-2.77; P=0.005), more than one (aOR, 7.16; 95% CI, 2.40-21.32; P<0.001), consuming 2-3 ladles of rice/meal (aOR, 2.14; 95% CI, 1.38-3.32; P=0.001), consuming >3 ladles of rice/meal (aOR, 2.69; 95% CI, 1.11-6.46; P=0.27), watching <2 hours of television/day (aOR, 2.18; 95% CI, 1.19-4.01; P=0.012), and watching >2 hours of television/day (aOR, 2.60; 95% CI, 1.36-4.96; P=0.004). Conclusion: Many sociodemographic, dietary, and behavioral factors were related to overweight and obesity among school-aged children not only in urban but also rural communities of Thailand.

Comparison of Benthic Macroinvertebrate Communities at Two Headwater Streams Located with Different Temperature Regions in South Korea (온도 분포가 다른 두 산림 하천의 저서성대형무척추동물 군집 특성 비교)

  • Lee, Da-Yeong;Lee, Dae-Seong;Park, Chanwoo;Yun, Soon Jin;Lim, Jong-Hwan;Park, Young-Seuk
    • Korean Journal of Ecology and Environment
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    • v.54 no.2
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    • pp.87-95
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    • 2021
  • Macroinvertebrates in forest streams affect the overall health of other streams in the same water system. In this study, we compared differences in the benthic macroinvertebrate community at two headwater streams located at different latitudes in the southern and northern parts of South Korea. We calculated the community temperature index (CTI), which represents the thermal preferences of the benthic communities. Hierarchical cluster analyses (HCA) were conducted to compare the similarities among sampling sites. In addition, we analyzed the relationship between community composition and environmental and community characteristics using non-metric multidimensional scaling (NMDS). Our results showed that CTI was significantly different between the two regions, indicating that these benthic macroinvertebrate communities have different thermal preferences. These two regions were clearly distinguished from each other in the HCA; furthermore, seasonal differences in benthic community composition were observed within each region. The functional feeding groups present in the benthic macroinvertebrate communities were different even though their habitat was similar.

A Research on Housing, Economic Conditions and Housing Satisfaction of Working College Students in Seoul - Focus on comparison according to the financial stress level and types of housing - (서울지역 자력형 대학생의 주거·경제생활 실태 및 주거환경 만족도 - 임대료 마련 스트레스 수준과 주택유형별 비교를 중심으로 -)

  • Lee, Yeun sook;Ko, Ji yeong;Oh, Chan ohk;Lee, Eu ddeum
    • Design Convergence Study
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    • v.14 no.6
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    • pp.29-55
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    • 2015
  • This study aimed to examine and compare housing conditions and satisfaction degree of working college students in Seoul metropolitan area, depending on their stress level from economic burden and living housing type. The interview using the questionnaire was conducted. The subjects were 199 working college students aged between 19 and 35. The two-tier cluster sampling method were used, the region and representative university within the region. The comparison of satisfaction degree per type of housing of working college students has been conducted to find 3 characteristic patterns of satisfaction degree per housing condition from the stress of preparing the fund for rent, and students with high degree of stress from arranging rent showed relatively low degree of satisfaction in most items. 6 patterns have been identified in terms of housing types, and most of the students living in the Gosiwon, the poorest condition and housing type, showed the lowest degree of satisfaction, while those residing in the officetel turned out to the most satisfied. This study gives implications of housing welfare for working college students.

The Spatial Patterns of Organic Matter Content and Macrobenthos during Summer in the Muan Bay Intertidal Zone, Korea (하계 무안만 조간대에서의 유기물 함량 및 대형저서동물의 공간 분포특성)

  • Eun Young Ko;Kyoung Seon Lee
    • Journal of Marine Life Science
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    • v.8 no.2
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    • pp.121-127
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    • 2023
  • The study was performed in order to understand the association between organic matter content in the sediments and the distribution of macrobenthos in the intertidal zone of the Muan bay. The sediment samples obtained from 21 sampling sites in August 2019 were analyzed for sediment composition and organic matter content (Ignition loss; IL and Total organic carbon; TOC). Further the macro benthos was sorted and enumerated. The sediments of inner area of bay has coarser composition where mouth part of bay, the sediments were predominantly silty. The highest organic matter content (both of IL and TOC) was measured at station 10 located near the Mokpo area while the lowest values was measured at station 20 adjacent to the north side of the bay. The 4 most abundant species accounted for more than 10% of all specimens were Assiminea sp., Musculista senhousia, Cerithideopsilla cingulate and Heteromastus filiformis. The maximum number of species and density were observed at station 10. Cluster analysis and non-metric multidimensional scaling (MDS) allow identification of four benthic assemblages based on species abundance. The correlation analysis revealed that there was a significant difference (p<0.05) in the density with TOC. Based on the analysis; it was found that the distribution of macrobenthos varied with the differences in sediment composition and organic matter content.

A Survey of Primary and Secondary School Students' Views in Relation to a Career in Science (과학 진로와 관련된 초중등 학생들의 인식 조사)

  • Yoon, Jin;Pak, Sung-Jae;Myeong, Jeon-Ok
    • Journal of The Korean Association For Science Education
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    • v.26 no.6
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    • pp.675-690
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    • 2006
  • This study investigated students' views in relation to a career in science as a first step towards developing science career education programs and materials. The instrument was developed through preliminary surveys. The questionnaire was sent to, administered and returned by 3608 students including 1036 primary, 1137 middle, and 1435 high school students, who were selected through stratified cluster sampling from all over the country. The results were analyzed using statistical package program. The students' image view of science, preference for science and science learning, perception of science achievement, career hope for oneself, degree of hope in getting science-related job, perception about science-related career, important factors of science career choice, and their hope for science/non-science career and the reason for their choice in the past and present were investigated. The results show that "science as an experimentation activity" was the most frequent image view of science. The preference for science and science learning was more positive than the perception of science achievement. The percentage of total students who want to have science career was 21%, and this percentage of middle school students was especially low. The most frequent answers for advantages of science career were 'useful for national development', 'possible to get new knowledge', and those for disadvantages were 'dangerous', and 'too much to study'. The most frequent reason for students' choice of a science career was 'interest in science and science learning'. Judging from these results, the basic direction for science career education should be in raising the students' preference for and interest in science learning. The positive awareness for a career in science and vision for a science job in the future should be given through a science career education and science career education proper to the students' developmental stage and characteristics is more important.

Characteristics of temporal-spatial variations of zooplankton community in Gomso Bay in the Yellow Sea, South Korea (서해 곰소만에 출현하는 동물플랑크톤 군집의 시·공간적 변동 특성)

  • Young Seok Jeong;Min Ho Seo;Seo Yeol Choi;Seohwi Choo;Dong Young Kim;Sung-Hun Lee;Kyeong-Ho Han;Ho Young Soh
    • Korean Journal of Environmental Biology
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    • v.41 no.4
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    • pp.720-734
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    • 2023
  • To understand the spatiotemporal distribution pattern of zooplankton and the environmental factors influencing zooplankton abundance in Gomso Bay, major harvesting area of Manila clam (Venerupis philippinarum) in South Korea, zooplankton sampling was conducted four times in autumn (October 2022), winter (January 2023), early spring (March 2023), and spring (May 2023). Among the environmental factors of Gomso Bay, water temperature, chlorophyll a concentration (Chl-a), dissolved oxygen (DO), and pH observed different patterns, while salinity and suspended particulate matter(SPM) showed no significant statistical differences between the survey periods. The zooplankton in Gomso Bay occurred 33, 29, 27, and 29 taxonomic groups during each respective survey period. In October 2022 and May 2023, arthropod plankton were dominated, while in January and March 2023, protozoa were primarily dominant. Among the Arthropods, copepods including Acartia hongi, Paracalanus parvus s. l., Corycaeus spp., and Oithona spp. commonly found along Korean coastal areas of the Yellow Sea, were dominated. Cluster analysis based on zooplankton abundance indicated a single community (stable condition) in each season, attributed to low dissimilarity distances, while three distinct clusters (autumn, winter-early spring, spring) between seasons indicated a highly seasonal environment in Gomso Bay.

Community Structure of Macrobenthic Assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea (월성 원자력발전소 주변해역에 서식하는 대형저서동물의 군집구조)

  • Seo, In-Soo;Moon, Hyung-Tae;Choi, Byoung-Mi;Kim, Mi-Hyang;Kim, Dae-Ik;Yun, Jae-Seong;Byun, Ju-Young;Choi, Hue-Chang;Son, Min-Ho
    • Korean Journal of Environmental Biology
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    • v.27 no.4
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    • pp.341-352
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    • 2009
  • This study was carried out to investigated community structure of macrobenthic assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea and seasonal sampling was performed from October 2007 to July 2008. A total of 163 macrobenthic fauna were collected. The overall average macrobenthos density and biomass were 1,005 individuals $m^{-2}$ and $21.81\;gWWt\;m^{-2}$, respectively. Based on the LeBris (1988) index, there were 10 dominant species accounting for approximately 69.00% of total individuals. The major dominant species were the polychaetes Spiophanes bombyx (349 inds. $m^{-2}$), Mediomastus californiensis (82 inds. $m^{-2}$), Sigambra tentaculata (55 inds. $m^{-2}$), Magelona japonica (50 inds. $m^{-2}$), Scoletoma longifolia (33 inds. $m^{-2}$) and the Unidentified amphipod (Amphipoda spp., 72 inds. $m^{-2}$). The conventional multi-variate statistics (cluster analysis and non-metric multi-dimensional scaling) applied to assess spatial variation in macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 major station groups. The major group 1 was associated with sand dominated stations and was characterized by high abundance of the bivalves Mactra chinensis, Siliqua pulchella and the polychaete Protodorvillea egena. On the other hand, major group 2 was connected with mud dominated stations and was numerically dominated by the polychaetes M. californiensis, M. japonica, Sternaspis scutata, S. longifolia and the bivalves Thyasira tokunagai and Theora fragilis. However, macrobenthic community structure were no significant differences between the environmental variables (sediment type and depth) and heated discharge.

A Review of Multivariate Analysis Studies Applied for Plant Morphology in Korea (국내 식물 형태 연구에 사용된 다변량분석 논문에 대한 재고)

  • Chang, Kae Sun;Oh, Hana;Kim, Hui;Lee, Heung Soo;Chang, Chin-Sung
    • Journal of Korean Society of Forest Science
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    • v.98 no.3
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    • pp.215-224
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    • 2009
  • A review was given of the role of traditional morphometrics in plant morphological studies using 54 published studies in three major journals and others in Korea, such as Journal of Korean Forestry Society, Korean Journal of Plant Taxonomy, Korean Journal of Breeding, Korean Journal of Apiculture, Journal of Life Science, and Korean Journal of Plant Resources from 1997 to 2008. The two most commonly used techniques of data analysis, cluster analysis (CA) and principal components analysis (PCA) with other statistical tests were discussed. The common problem of PCA is the underlying assumptions of methods, like random sampling and multivariate normal distribution of data. The procedure was intended mainly for continuous data and was not efficient for data which were not well summarized by variances or covariances. Likewise CA was most appropriate for categorical rather than continuous data. Also, the CA produced clusters whether or not natural groupings existed, and the results depended on both the similarity measure chosen and the algorithm used for clustering. An additional problems of the PCA and the CA arised with both qualitative and quantitative data with a limited number of variables and/or too few numbers of samples. Some of these problems may be avoided if a certain number of variables (more than 20 at least) and sufficient samples (40-50 at least) are considered for morphometric analyses, but we do not think that the methods are all mighty tools for data analysts. Instead, we do believe that reasonable applications combined with focus on objectives and limitations of each procedure would be a step forward.

A study on the adjustment problems of the aged (노후적응에 관한 연구 - 생활만족도 및 가족의 교류도를 중심으로-)

  • 서병숙
    • Journal of the Korean Home Economics Association
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    • v.27 no.2
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    • pp.133-148
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    • 1989
  • This study attempts of analyze empirically the living status of the elderly in Korea by finding out the problems of it in the family and by clarifying the influences of the family environmental variables and the values on the adjustment of the aged. To carryout the aim of this study, the causes and the patterns of the problems for the aged had been found out through the review of literature. Based on them the questionnaire was prepared including the questions of the values, family environmental vriables as well as the degree of satisfaction of thier liver and the extent of life interchange. The former variables were taken as independent and the latter were taken as dependent variables, so that the relationship between the two variables could be exemplified. The 400 aged over 60 living in Seoul and the other cities were selected through the purposive sampling and interviewed. The answers of the 376 respondents, 94% of the sample, were analyzed for this study. The following results have been found out through the various statistical analysis such as frequency distribution, chi-square test, pearson's correlation, analysis of variance and cluster analysis. At first, the results from the examination of the frequency distribution regarding the living status of the aged are; I) sixteen percent of the respondents living with their married offspring were receiving economical support, though they pointed out the problems of the extended family are the inconveniences with their children (60%) and simpleness (20%) of their livers. It seems that the aged in Korea are poor and have negative opinion on the relationship with their offspring even if they live in the same house. Secondly, it has been found out that the family environmental variables, especially such as sex, occupation, residence, education, level, living ability and the family type, play and important role not only on the degree of satisfaction of their liver but also on the extent of interchange of their lives. However, the variables such as religion and whether the spouse is alive or not do not play and important role. Thirdly, the reported main reasons of their delightness were healthy life (1.87%), the well-being of their offspring (2.08%), the spouse's long life (3.38%), religious activity (5.05%), the hobby activity (4.31%) and the participation in the social activity (5.05%). While, they mainly concern about the illness (1.98%), offspring (2.00%), econmic difficulties (3.39%), inharmonious home (3.81%) and the despicable treatment (3.81%). The respondents wer classified into two groups, they are dependent and independent, using cluster analysis. Health, social activity, offspiring, religion, couple's long life among the factors which lead them to be delighted were turned out to be statistically signhificant at 0.01 significance level between the two groups. As far as their worrisome matters are concerned, health and economic difficulties were significantly different between the two groups. Fourthly, regarding the life interchange, it has been proved that there is a statistically significant differences betwwen the two groups in the economic and the emotional satisfaction, help for ordinary life, status in the family, subjective and objective relationship with offspring, but not in economic dependency and the activity status. Fifthly, it has been noted that there is a high correlation between the degree of life's satisfaction and the extent of life interchange. On the basis of the results mentioned above, it could be concluded taht; i) The majority of the aged in Korea are not economically active, and thus they live with their married offspring even of they have a negative opinion on the subjective relationship with them. This can be pointed out as the main problem of the aged and thus it needs to be studied further. ii) the environmental variables such as age, sex education level, family type and occuption (which can not be changed by their effrot) turned out to give an important effect on the extent of the life interchange among the aged. iii) The respondents who are identified as independent group have a higher degree of life satisfaction and family status than the group identified as defendent. Thus, it can be inferred that it is possible for them to adjust their life by making an effort to modify themselves. iv) The high correlation between the extent of life interchange and the degree of life satisfaction indicates that the elderly themselves can adjust in order to obtain the higher degree of life satisfaction. Therefore, the following suggestions are derived from this study. First of all, the aged should try to be psychologically independent. Second, they need to control themselves in order to achieve self-assurance. Third, the community have to prepare a program of self-development for the aged. Fourth, the social welfare policy that can solve the problem of illness and poverty of the elderly should be introduced, so that their minimum requirements can be satisfied.

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Evaluation of Ecological Niche for Major Tree Species in the Natural Deciduous Forest of Mt. Chumbong (점봉산(點鳳山) 일대(一帶) 천연활엽수림(天然闊葉樹林)의 주요(主要) 구성(構成) 수종(樹種)에 대한 생태지위(生態地位) 평가(評價))

  • Kim, Guang Ze;Kim, Ji Hong
    • Journal of Korean Society of Forest Science
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    • v.90 no.3
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    • pp.380-387
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    • 2001
  • The characteristics of ecological niche, breadth and overlap, for seventeen major tree species were evaluated in the natural deciduous forest in Mt. Chumbong area. Employed by the plot sampling method, the environmental gradient for vertical niche was based on the intensity of light within the forest, and that for horizontal niche was based on multi-dimensional resources in distribution pattern. The result showed that Fraxinus rhynchophylla had the highest value of vertical niche breadth and Maackia amurensis had the lowest, and Acer pseudo-sieboldianum had the highest value of horizontal niche breadth and Betula costata had the lowest. There was no significant correlation between both measures of niche breadth. However, the tolerance index for each species was positively correlated to the values of niche breadth. Spearman's rank correlation coefficients were applied to test the correlationship between the species ranks of tolerance index and those of two ecological niche breadths. The coefficient of $r_s=0.432$ ($P{\leq}0.1$) was not enough to support significant correlationship between the tolerance index and vertical niche breadth at the 95% probability. If Carpinus cordata, rarely reach canopy of the forest due to its own growth form, are excluded from the analysis, coefficient was calculated as $r_s=0.650$ ($P{\leq}0.01$), resulting in highly significant correlationship. The Spearman's rank correlation coefficient was $r_s=0.797$ ($P{\leq}0.01$) for tolerance indices and the values of horizontal niche breadth, indicating highly significant. Four distinctive species groups, produced by cluster analysis on the basis of ecological niche overlap for each pair of species, were in considerable accord with the positively associated species constellation pattern created by the inter-species association analysis.

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