• Title/Summary/Keyword: stepwise multiple linear regression analysis

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Analysis of Within-Field Spatial Variation of Rice Growth and Yield in Relation to Soil Properties

  • Ahn Nguyen Tuan;Shin Jin Chul;Lee Byun-Woo
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.50 no.4
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    • pp.221-237
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    • 2005
  • For developing the site-specific fertilizer management strategies of crop, it is essential to know the spatial variability of soil factors and to assess their influence on the variability of crop growth and yield. In 2002 and 2003 cropping seasons within-field spatial variability of rice growth and yield was examined in relation to spatial variation of soil properties in the· two paddy fields having each area of ca. $6,600m^2$ in Suwon, Korea. The fields were managed without fertilizer or with uniform application of N, P, and K fertilizer under direct-seeded and transplanted rice. Stable soil properties such as content of clay (Clay), total nitrogen (TN), organic mater (OM), silica (Si), cation exchange capacity (CEC), and rice growth and yield were measured in each grid of $10\times10m$. The two fields showed quite similar spatial variation in soil properties, showing the smallest coefficient of variation (CV) in Clay $(7.6\%)$ and the largest in Si $(21.4\%)$. The CV of plant growth parameters measured at panicle initiation (PIS) and heading stage (HD) ranged from 6 to $38\%$, and that of rice yield ranged from 11 to $21\%$. CEC, OM, TN, and available Si showed significant correlations with rice growth and yield. Multiple linear regression model with stepwise procedure selected independent variables of N fertilizer level, climate condition and soil properties, explaining as much as $76\%$ of yield variability, of which $21.6\%$ is ascribed to soil properties. Among the soil properties, the most important soil factors causing yield spatial variability was OM, followed by Si, TN, and CEC. Boundary line response of rice yield to soil properties was represented well by Mitcherich equation (negative exponential equation) that was used to quantify the influence of soil properties on rice yield, and then the Law of the Minimum was used to identify the soil limiting factor for each grid. This boundary line approach using five stable soil properties as limiting factor explained an average of about $50\%$ of the spatial yield variability. Although the determination coefficient was not very high, an advantage of the method was that it identified clearly which soil parameter was yield limiting factor and where it was distributed in the field.

Relationship between Eating Attitude in Female Adolescent and Psychological, Biological Factors ; Depression, Aggression, Impulsiveness and Blood Cholesterol Level (여고생 식이태도와 심리적 및 생리적 요인과의 상관관계 ; 우울감, 공격성, 충동성 및 혈중 콜레스테롤에 대하여)

  • Park, June-Sung;Lee, Joon-Seok;Lee, Jang-Han;Yang, Byung-Hwan;Cho, Yun-Gyoo
    • Korean Journal of Psychosomatic Medicine
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    • v.9 no.2
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    • pp.182-193
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    • 2001
  • The purpose of this study is to evaluate correlation of adolescent eating attitude and psychological factors which might influence the eating attitude such as depression, aggression and impulsiveness. The author also tried to identify relationship between adolescent eating attitude and biological factors such as serum cholesterol level and triglyceride level. Two hundred and forty one female high school students without physical disorder were selected as study subjects. For the study, Eating Attitude Test-26KA (EAT -26KA), Beck Depression Inventory (BDI) -Korean version, Barrat Impulsiveness scale (BIS) -Korean version, and Buss-DurKee Hostility Inventory (BDHI) -Korean version were used. Serum cholesterol level and triglyceride level were also investigated. For the purpose of identifying factors which could influence eating attitude of adolescence, stepwise multiple linear regression analysis was done. Total score of BDHI could be most significant factor to explain eating attitude, and BDI, serum cholesterol/triglyceride level be second, third position respectively. But, BIS was not significant predicting parameter. The contributing portion of these factors to explain eating behavior was 25.9%.

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Effects of Low Glycemic Index Nutrition Education on the Blood Glucose Control in Patients with Type 2 Diabetes Mellitus (제 2형 당뇨 환자의 저혈당지수 영양교육이 혈당관리에 미치는 영향)

  • Kim, Mi-Ja;Kwon, Sun-Ja;Ly, Sun-Yung
    • Journal of Nutrition and Health
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    • v.43 no.1
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    • pp.46-56
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    • 2010
  • This study was intended to assess the effects of low glycemic index (LGI) nutrition education on dietary management and glycemic control of patients with type 2 diabetes mellitus. The subjects were 48 sex-matched patients with type 2 diabetes mellitus, aged $66.5\;{\pm}\;6.2$ years, visiting a public health center. They were divided into two groups: the control group (males 10, females 14) and the educated group (males 10, females 14). The educated group was provided with a LGI nutrition education program for 7 weeks. The control group was educated only one time for general diabetic education. Anthropometric indices, knowledge and perception of efficacy of low glycemic index carbohydrates, dietary glycemic index (DGI) and glycemic load (DGL), fasting blood glucose, and HbA1c were assessed. In the educated group body weight, body mass index and systolic blood pressure (from $138.0\;{\pm}\;18.9\;mmHg$ to $130.6\;{\pm}\;15.0\;mmHg$) were significantly reduced after the nutrition education (p < 0.05). The scores of knowledge and perception of efficacy of low glycemic index carbohydrates increased significantly in the educated group. Dietary glycemic index and glycemic load of the educated group decreased significantly from $103.4\;{\pm}\;67.6$ to $45.4\;{\pm}\;27.1$ (p < 0.001), and from $173.3\;{\pm}\;135.9$ to $66.8\;{\pm}\;50.4$ (p < 0.001), respectively. Also fasting blood glucose and HbA1c levels of the educated group significantly decreased from $124.5\;{\pm}\;28.8\;mg/dL$ to $96.7\;{\pm}\;21.6\;mg/dL$ (p < 0.001) and from $7.1\;{\pm}\;1.3%$ to $6.4\;{\pm}\;1.2%$ (p < 0.05), respectively. The score of knowledge and perception of efficacy of low glycemic index significantly correlated with fasting blood glucose and HbA1c levels negatively. DGI, DGL and duration of diabetes significantly correlated with HbA1c level positively. From stepwise multiple linear regression analysis, DGI, DGL and the duration of diabetes were extracted as factors influencing HbA1c level of the subjects. The results of this study suggest that low glycemic index nutrition education programs is an effective intervention measure for the glycemic control in type 2 diabetic patients.

The Relationship between Posttraumatic Stress Disorder and the Quality of Life among the Vietnam War Veterans (베트남전 참전 퇴역 군인에서 외상후스트레스장애와 삶의 질과의 관계)

  • Oum, Se-Joon;Choi, Jin-Hee;Kim, Tae-Yong;Chung, Hae-Gyung;Chung, Moon-Yong;So, Hyung-Seok
    • Korean Journal of Psychosomatic Medicine
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    • v.19 no.2
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    • pp.83-91
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    • 2011
  • Objectives: Posttraumatic stress disorder(PTSD) has devastating effects on multiple aspects of the quality of life(QoL). Therefore, the purpose of this study is to compare the QoL between PTSD group and non-PTSD group, and identify the variables affecting the QoL of the Vietnam War veterans. Methods: We recruited 39 veterans with PTSD and 43 veterans without PTSD, all of whom had deployed to the Vietnam War. We used the Korean version of Mini International Neuropsychiatric Interview-Plus, the Korean version of Clinician-Administered PTSD Scale, Combat Exposure Scale and the Korean version of World Health Organization Quality of Life Assessment Instrument abbreviated version. We used independent samples t-test to identify the differences between PTSD and non-PTSD group in each domains of the quality of life. We also used stepwise multiple linear regression analysis to figure out the variables affecting the QoL of the Vietnam War veterans. Results: In the PTSD group, all domains of the QoL and the QoL total score(p<0.01) were significantly lower than those in the non-PTSD group. In the Vietnam War veterans, PTSD, major depressive disorder and education levels were the variables affecting the QoL. Among these, PTSD uniquely explained the QoL of the overall and general health(${\beta}$=-1.411, $R^2$=0.180), the physical health domain(${\beta}$=-2.806, $R^2$=0.089) and the total score (${\beta}$=-11.479, $R^2$=0.104). Conclusions: These results suggest that among the Vietnam War veterans, the QoL of the PTSD group is significantly lower than that of the non-PTSD group. Among the combat exposed veterans, PTSD may be one of the main reasons that affect the multiple domains of the QoL.

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Correlation between menton deviation and dental compensation in facial asymmetry using cone-beam CT (Cone-beam CT를 이용한 안면비대칭자에서 이부편위에 따른 치성보상의 양상분석)

  • Park, Soo-Byung;Park, Jeong-Heuy;Jung, Yun-Hoa;Jo, Bong-Hye;Kim, Yong-Il
    • The korean journal of orthodontics
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    • v.39 no.5
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    • pp.300-309
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    • 2009
  • Objective: The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry. Methods: Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis. Results: From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (${\Delta\angle}LM6$-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (${\Delta\angle}UM6$-FH plane (dev.-ndev.)) (p < 0.01). Two angular measurements (${\Delta\angle}LM6$-Mn plane (dev.-ndev.), ${\Delta\angle}UM6$-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant $r^2$ value of 0.589. Conclusions: This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.

Correlation of Arsenic and Heavy Metals in Paddy Soils and Rice Crops around the Munmyung Au-Ag Mines (문명 금은광산 주변 논토양에서 As 및 중금속의 토양과 벼작물의 상관성 평가)

  • Kwon, Ji Cheol;Park, Hyun-Jung;Jung, Myung Chae
    • Economic and Environmental Geology
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    • v.48 no.4
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    • pp.337-349
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    • 2015
  • This study has focused on investigation of correlation for As and heavy metals in paddy soil and rice crops sampled in the vicinity of the abandoned Munmyung Au-Ag mine. Soil samples extracted by various methods including aqua regia, 1 M $MgCl_2$, 0.01 M $CaCl_2$ and 0.05 M EDTA were analyzed for As and heavy metals (Cd, Cu, Pb and Zn). Rice grain samples grown on the soils were also analyzed for the same elements to evaluate the relationships between soils and rice crops. According to soil extraction methods, As and heavy metal contents in the soils were decreased in the order of aqua regia > 0.01 M $CaCl_2$ > 1 M $MgCl_2$ > 0.05 M EDTA. In addition to correlation analysis, statistically significant correlation with the four extraction methods (p<0.01) were found in the soil and rice samples. As calculation of biological accumulation coefficients (BACs) of the rice crops for As and heavy metals, the BACs for Cd, Zn and Cu were relatively higher than those for As and Pb. This study also carried out a stepwise multiple linear regression analysis to identify the dominant factors influencing metal extraction rates of the paddy soils. Furthermore, daily intakes of As and heavy metals from regularly consumed the rice grain (287 g/day) grown on the contaminated soils by the mining activities were estimated, and found that Cd and As intakes from the rice reached up to 73.7% and 51.8% for maximum allowance levels of trace elements suggested by WHO, respectively. Therefore, long-term consumption of the rice poses potential health problems to residents around the mine, although no adverse health effects have yet been observed.

Personality Characteristics of Patients with Obstructive Sleep Apnea and Simple Snoring : A Preliminary Study (2014.21.1.21폐쇄성수면무호흡증과 단순코골이 환자의 성격 특성 : 예비연구)

  • Kang, Jae Myeong;Kang, Seung-Gul;Lee, Yu Jin;Jeong, Joo Hyun;Kang, Il Gyu;Hwang, Hee Young;Kim, Ji-Eun;Lee, Heon-Jeong;Shin, Seung-Heon;Park, Kee Hyung;Kim, Seon Tae
    • Sleep Medicine and Psychophysiology
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    • v.21 no.1
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    • pp.21-28
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    • 2014
  • Objective: Few studies have evaluated the personality characteristics of patients with obstructive sleep apnea (OSA) and simple snoring. We investigated the personality characteristics of OSA and simple snoring patients and compared differences in personality between the two groups using the Eysenck Personality Questionnaire (EPQ). Materials and Methods: Two hundred and thirty-seven patients who were suspected to have OSA or simple snoring participated in this study. A self-questionnaire which included the EPQ was administered to all participants. All subjects underwent polysomnography in a sleep laboratory and those with an apnea-hypopnea index (AHI) ${\geq}5$ were included in the OSA group, while those with an AHI <5 were included in the simple snoring group. Results: OSA patients had significantly lower scores for Psychoticism (F=4.563, p=0.034) than simple snorers. There were no significant differences in Extraversion (F=3.029, p=0.083), Lie (F=0.398, p=0.529), or Neuroticism (F=3.367, p=0.068) scores between the two groups. In the correlation analysis of the OSA group, AHI was positively correlated with Extraversion score (r= 0.16, p=0.029) and negatively correlated with Lie score (B=-0.31, p<0.001). Using multiple stepwise linear regression analysis with the four EPQ parameter scores as dependent variables, Lie score was associated with older age (B=0.14, p<0.001) and lower AHI (B=-0.05, p<0.001), Psychoticism score was associated with higher Pittsburgh Sleep Quality Index (PSQI ; B=0.14, p<0.001), Neuroticism score was associated with higher PSQI (B=0.34, p=0.001) and female sex (B=3.15, p=0.003), and Extraversion score was associated with younger age (B=-0.08, p=0.020) and higher body mass index (B=0.26, p=0.023). Conclusion: This study suggests that patients with OSA are significantly less prone to psychotic personality characteristics than those with simple snoring. Among OSA patients, higher AHI was correlated with low falsehood and high extraversion tendencies.

Yield Response to Nitrogen Topdress Rate at Panicle Initiation Stage under Different Growth and Nitrogen Nutrition Status of Rice Plant (벼 유수분화기 생장 및 질소영양상태에 따른 수량의 수비질소 반응)

  • Kim, Min-Ho;Fu, Jin-Dong;Lee, Byun-Woo
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.51 no.7
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    • pp.571-583
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    • 2006
  • To secure high yield and good quality of rice, plant growth and nitrogen (N) nutrition status should be taken into account for managing panicle N topdressing (PN). This research aimed at investigating the rice yield response to PN under different plant growth and N nutrition status that was conditioned by different rates of basal and tillering N fertilizer (BTN). Stepwise multiple regression (SMR) was used for the analysis of yield response to (i) BTN and PN, and (ii) shoot N content at PIS (BTNup) and shoot N uptake from PIS to harvest (PNup). Rice yield increased significantly as BTN and PN Increased, but there was no significant interaction between BTN and PN. Yield increased almost linearly with the increasing BTN and PN up to $10{\sim}12$ and $6{\sim}7\;kgN/10a$, and with the increasing BTNup and PNup up to $6{\sim}7$ and $5{\sim}6\;kgN/10a$, respectively. But yield increment tended to decrease above those levels. These declines resulted from the decreased ripened grain ratio and 1000 grain weight even though spikelet number per unit area increased more at above those N levels. Spikelet number per unit area had the linear relationships with the shoot N uptake until heading, and with yield. Like most yield response curves, yield response in this experiment followed the diminishing return function with BTNup, PNup, and plant N uptake from seeding to harvest. Regardless of the degree of BTNup and PNup, yield had a quadratic relationship ($R^{2}$>0.88) with whole shoot N accumulation until harvest, suggesting that the yield determination was closely related with the whole shoot N uptake until harvest regardless of the differences in seasonal shoot N uptake.

Plasma Levels of High Molecular Weight Adiponectin are Associated with Cardiometabolic Risks in Patients with Hypertension (고혈압 환자에서 혈장 고분자량 아디포넥틴 농도와 심장-대사위험인자와의 관련성 연구)

  • Chung, Hye-Kyung;Shin, Min-Jeong
    • Journal of Nutrition and Health
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    • v.41 no.8
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    • pp.733-741
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    • 2008
  • In the present study, we comprehensively examined the associations of plasma levels of total adiponectin and high molecular weight (HMW) adiponectin with the features of cardiometabolic risks including body fat distribution, dyslipidemia, insulin resistance and inflammatory markers in a cross-sectional study of 110 treated hypertensive patients. Blood lipid profiles, high sensitivity C-reactive protein (hsCRP) and homeostasis model assessment of insulin resistance (HOMA- IR) derived from fasting glucose and insulin concentrations were determined. Plasma levels of tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) were analyzed using ELISA. The results showed that plasma levels of HMW-adiponectin were negatively associated with body mass index (BMI, r = - 0.203, p < 0.05) and waist circumference (r = -0.307, p < 0.01), which was not shown in total adiponectin. Plasma levels of HMW-adiponectin were negatively associated with triglyceride (r = -0.223, p < 0.05) and positively associated with HDL-cholesterol (r = 0.228, p < 0.05). Plasma levels of adiponectin were positively associated with HDL-cholesterol (r = 0.224, p < 0.05). Plasma levels of HMW-adiponectin were negatively associated with hsCRP (r = -0.276, p < 0.01) and IL-6 (r = -0.272, p < 0.01). In addition, there were weak associations between plasma levels of HMWadiponectin and TNF-${\alpha}$ (r = -0.163, p = 0.07) and ICAM-1 (r = -0.158, p = 0.09). However, there were no significant associations of total adiponectin with inflammatory markers except hsCRP (r = -0.203, p < 0.05). Stepwise multiple linear regression analysis showed that only plasma levels of HMW-adiponectin was an independent factor influencing serum levels of hsCRP, a marker of systemic low grade inflammation, after adjusting for age, gender, BMI, waist circumference, alcohol intake, smoking status, blood lipids, total adiponectin and drug use (p < 0.01). These results suggest that HMW-adiponectin, rather than total adiponectin, is likely to be closely associated with the features of cardiometabolic risks in treated hypertensive patients and might be effective biomarker for the prediction of cardiovascular disease.