• Title/Summary/Keyword: Random Effects Model

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Meta-analysis of Change in Weight and Heart Rate for Phentermine in Obesity (비만환자의 펜터민 복용에 따른 체중과 심박수 변화에 대한 메타분석)

  • Woo, Yeonju;Jeong, Hyomi
    • Journal of health informatics and statistics
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    • v.43 no.4
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    • pp.290-299
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    • 2018
  • Objectives: This study aimed to evaluate the change in weight and heart rate associated with the use of phentermine through meta-analysis based on the published literatures. Methods: Eight electronic databases, PubMed, EMBASE, Cochrane library, and five domestic databases were used to search the literature. Randomized controlled trials that evaluated the change in weight and heart rate with the use of phentermine compared with placebo were included in this study. The fixed-effect model weighted by the Mantel-Haenszel method was used in the meta-analysis, and the random-effects model was used when heterogeneity was present. Results: We included 12 studies comprising 677 patients. The change in weight observed with the use of phentermine (SMD = -1.37, 95% CI: -1.55, -1.19) was statistically significant compared with that observed with placebo. As per the subgroup analysis results, the change in weight by publication year, country, phentermine dosage, follow-up check was not heterogeneous. The change in heart rate observed with the use of phentermine (SMD = 0.64, 95% CI: 0.35, 0.92) was significant compared with that observed with placebo. Conclusions: Weight loss and increased heart rate were confirmed in phentermine compared with placebo.

An Artificial Intelligence Approach to Waterbody Detection of the Agricultural Reservoirs in South Korea Using Sentinel-1 SAR Images (Sentinel-1 SAR 영상과 AI 기법을 이용한 국내 중소규모 농업저수지의 수표면적 산출)

  • Choi, Soyeon;Youn, Youjeong;Kang, Jonggu;Park, Ganghyun;Kim, Geunah;Lee, Seulchan;Choi, Minha;Jeong, Hagyu;Lee, Yangwon
    • Korean Journal of Remote Sensing
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    • v.38 no.5_3
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    • pp.925-938
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    • 2022
  • Agricultural reservoirs are an important water resource nationwide and vulnerable to abnormal climate effects such as drought caused by climate change. Therefore, it is required enhanced management for appropriate operation. Although water-level tracking is necessary through continuous monitoring, it is challenging to measure and observe on-site due to practical problems. This study presents an objective comparison between multiple AI models for water-body extraction using radar images that have the advantages of wide coverage, and frequent revisit time. The proposed methods in this study used Sentinel-1 Synthetic Aperture Radar (SAR) images, and unlike common methods of water extraction based on optical images, they are suitable for long-term monitoring because they are less affected by the weather conditions. We built four AI models such as Support Vector Machine (SVM), Random Forest (RF), Artificial Neural Network (ANN), and Automated Machine Learning (AutoML) using drone images, sentinel-1 SAR and DSM data. There are total of 22 reservoirs of less than 1 million tons for the study, including small and medium-sized reservoirs with an effective storage capacity of less than 300,000 tons. 45 images from 22 reservoirs were used for model training and verification, and the results show that the AutoML model was 0.01 to 0.03 better in the water Intersection over Union (IoU) than the other three models, with Accuracy=0.92 and mIoU=0.81 in a test. As the result, AutoML performed as well as the classical machine learning methods and it is expected that the applicability of the water-body extraction technique by AutoML to monitor reservoirs automatically.

Estimation of Annual Trends and Environmental Effects on the Racing Records of Jeju Horses (제주마 주파기록에 대한 연도별 추세 및 환경효과 분석)

  • Lee, Jongan;Lee, Soo Hyun;Lee, Jae-Gu;Kim, Nam-Young;Choi, Jae-Young;Shin, Sang-Min;Choi, Jung-Woo;Cho, In-Cheol;Yang, Byoung-Chul
    • Journal of Life Science
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    • v.31 no.9
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    • pp.840-848
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    • 2021
  • This study was conducted to estimate annual trends and the environmental effects in the racing records of Jeju horses. The Korean Racing Authority (KRA) collected 48,645 observations for 2,167 Jeju horses from 2002 to 2019. Racing records were preprocessed to eliminate errors that occur during the data collection. Racing times were adjusted for comparison between race distances. A stepwise Akaike information criterion (AIC) variable selection method was applied to select appropriate environment variables affecting racing records. The annual improvement of the race time was -0.242 seconds. The model with the lowest AIC value was established when variables were selected in the following order: year, budam classification, jockey ranking, trainer ranking, track condition, weather, age, and gender. The most suitable model was constructed when the jockey ranking and age variables were considered as random effects. Our findings have potential for application as basic data when building models for evaluating genetic abilities of Jeju horses.

An Empirical Study of Students' Start-Up Activities: Integrated Approach of Student-Focused Cognitive Model and Supportive Activities of University (대학생 창업활동에 대한 실증적 연구 : 대학생 중심의 인지적 모델과 대학지원의 통합적 접근)

  • Chang, Sooduck;Lee, Jaehoon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.9 no.4
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    • pp.65-76
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    • 2014
  • The basic purpose of this study is to examine the relationship among entrepreneurial intention, university supports for startup, and startup activities of university students. For the study, we identified the influence factors of students' startup intention based on reviewing preceding studies and examined how these factors affect their intention of new venture startup. In addition, this study attempted to examine how these factors that can have a significant impact on entrepreneurial intention affect startup activities and analyzed how entrepreneurial intention would mediate the relationship between these influence factors and startup activities. A total of 769 students who chosen by random were surveyed and all questionnaires were sent by mail to the universities that entrepreneurship education and entrepreneurial programs were selected as the forerunners from the government. As a result, this study revealed that student's psychological traits such as entrepreneurial self-efficacy and risk-taking have significant effect on the intention of startup. And student's exposure to the role models and various entrepreneurial experiences such as entrepreneurship education and entrepreneurial student's club in the university has significantly positive influence on the intention of startup. This study also found that the effects of these explanatory variables of this research on startup activities have been partially mediated by entrepreneurial intention. The entrepreneurial intention was also proven to have a significant effect on startup activities. Finally, the extent to which university supports activities for students' startup moderated the relationship between entrepreneurial intention and university students' startup activities. We believe that these results of this study contribute to the understanding of the entrepreneurship process both theoretical and practical perspectives.

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Multiscale Analysis on Expectation of Mechanical Behavior of Polymer Nanocomposites using Nanoparticulate Agglomeration Density Index (나노 입자의 군집밀도를 이용한 고분자 나노복합재의 기계적 거동 예측에 대한 멀티스케일 연구)

  • Baek, Kyungmin;Shin, Hyunseong;Han, Jin-Gyu;Cho, Maenghyo
    • Composites Research
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    • v.30 no.5
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    • pp.323-330
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    • 2017
  • In this study, multiscale analysis in which the information obtained from molecular dynamics simulation is applied to the continuum mechanics level is conducted to investigate the effects of clustering of silicon carbide nanoparticles reinforced into polypropylene matrix on mechanical behavior of nanocomposites. The elastic behavior of polymer nanocomposites is observed for various states of nanoparticulate agglomeration according to the model reflecting the degradation of interphase properties. In addition, factors which mainly affect the mechanical behavior of the nanocomposites are identified, and new index 'clustering density' is defined. The correlation between the clustering density and the elastic modulus of nanocomposites is understood. As the clustering density increases, the interfacial effect decreased and finally the improvement of mechanical properties is suppressed. By considering the random distribution of the nanoparticles, the range of elastic modulus of nanocomposites for same value of clustering density can be investigated. The correlation can be expressed in the form of exponential function, and the mechanical behavior of the polymer nanocomposites can be effectively predicted by using the nanoparticulate clustering density.

Prevalence of Human Papillomavirus 16 in Esophageal Cancer Among the Chinese Population: a Systematic Review and Meta-analysis

  • Zhang, Shao-Kai;Guo, Lan-Wei;Chen, Qiong;Zhang, Meng;Liu, Shu-Zheng;Quan, Pei-Liang;Lu, Jian-Bang;Sun, Xi-Bin
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.23
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    • pp.10143-10149
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    • 2015
  • Background and Aim: No firm evidence of HPV infection in esophageal cancer has been established to date. The aim of this meta-analysis was to investigate the prevalence of HPV 16 in esophageal cancer in China, which had a high burden of the disease. Materials and Methods: Studies on HPV infection and esophageal cancer were identified and a random-effects model was used to pool the summary prevalence and corresponding 95% confidence intervals (CIs). Results: A total of 3,429 esophageal cancer cases were evaluated from 26 eligible studies in this meta-analysis. The summary estimate for HPV16 prevalence was 0.381 (95% CI: 0.283, 0.479). The prevalence varied by geographical areas of the study, publication year, HPV detection method and types of specimen. In sensitivity analysis, HPV 16 prevalence ranged from 0.368 (95% CI: 0.276, 0.460) to 0.397 (95% CI: 0.286, 0.508). Conclusions: The results indicate a relatively high level of HPV 16 prevalence in esophageal cancer among Chinese population, although there was variation between different variables. Further studies are needed to elucidate the role of HPV in esophageal carcinogenesis with careful consideration of study design and laboratory detection method, providing more accurate assessment of the HPV status in esophageal cancer.

Association Between Pancreatitis and Subsequent Risk of Pancreatic Cancer: a Systematic Review of Epidemiological Studies

  • Tong, Gui-Xian;Geng, Qing-Qing;Chai, Jing;Cheng, Jing;Chen, Peng-Lai;Liang, Han;Shen, Xing-Rong;Wang, De-Bin
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.12
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    • pp.5029-5034
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    • 2014
  • This study aimed to summarize published epidemiological evidence for the relationship between pancreatitis and subsequent risk of pancreatic cancer (PC). We searched Medline and Embase for epidemiological studies published by February $5^{th}$, 2014 examining the risk of PC in pancreatitis patients using highly inclusive algorithms. Information about first author, year of publication, country of study, recruitment period, type of pancreatitis, study design, sample size, source of controls and attained age of subjects were extracted by two researchers and Stata 11.0 was used to perform the statistical analyses and examine publication bias. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with the random effects model. A total of 17 articles documenting 3 cohort and 14 case-control studies containing 14,667 PC cases and 17,587 pancreatitis cases were included in this study. The pooled OR between pancreatitis and PC risk was 7.05 (95%CI: 6.42-7.75). Howeever, the pooled ORs of case-control and cohort studies were 4.62 (95%CI: 4.08-5.22) and 16.3 (95%CI: 14.3-18.6) respectively. The risk of PC was the highest in patients with chronic pancreatitis (pooled OR=10.35; 95%CI: 9.13-11.75), followed by unspecified type of pancreatitis (pooled OR=6.41; 95%CI: 4.93-8.34), both acute and chronic pancreatitis (pooled OR=6.13; 95%CI: 5.00-7.52), and acute pancreatitis (pooled OR=2.12; 95%CI: 1.59-2.83). The pooled OR of PC in pancreatitis cases diagnosed within 1 year was the highest (pooled OR=23.3; 95%CI: 14.0-38.9); and the risk in subjects diagnosed with pancreatitis for no less than 2, 5 and 10 years were 3.03 (95%CI: 2.41-3.81), 2.82 (95%CI: 2.12-3.76) and 2.25 (95%CI: 1.59-3.19) respectively. Pancreatitis, especially chronic pancreatitis, was associated with a significantly increased risk of PC; and the risk decreased with increasing duration since diagnosis of pancreatitis.

Effect of Cognitive Behavioral Therapy (CBT) for Perinatal Depression: A Systematic Review and Meta-Analysis (산전우울 임부를 위한 인지행동치료 프로그램의 효과: 체계적 문헌고찰 및 메타분석)

  • Shin, Hyeon-Hee;Shin, Yeong-Hee;Kim, Ga-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.271-284
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    • 2016
  • This study was carried out to evaluate the efficacy of CBT for perinatal depression through systematic literature review and meta-analysis. The following databases were used to search the literature: CINAHL, PubMed, EMBASE, Koreamed, Library of Korean Congress, KISS, and Korean Academic Publication Database. Keywords included 'perinatal depression,' 'pregnant women,' and 'cognitive behavioral therapy,' and the evaluated articles were published up to May 2016. Using the R program, the effect size of perinatal depression and anxiety were calculated by random-effects model. The heterogeneity of the effect size was analyzed by data moderator analysis using the meta-ANOVA. Furthermore, the funnel plot, Egger's regression test, fail-safe N, trim-and-fill test, and publication bias analysis were conducted and used to verify the results. Out of the 180 selected articles, 16 clinical trial studies were meta-analyzed. Each articles were evaluated for the risk of bias by the checklist of SIGN; the overall risk of bias was low. The effect size of CBT for perinatal depression was Hedges' g=-0.55 (95% CI: -0.76~-0.33), which was a moderate level, while for anxiety reduction, Hedges' g=-0.20 (95% CI: -0.48~-0.08) and it was not statistically significant. Heterogeneity or risk of publication bias were low. This meta-analytic study found that CBT is moderately effective in reducing perinatal depression in pregnant women.

The Effect of Breastfeeding Duration and Parity on the Risk of Epithelial Ovarian Cancer: A Systematic Review and Meta-analysis

  • Sung, Ho Kyung;Ma, Seung Hyun;Choi, Ji-Yeob;Hwang, Yunji;Ahn, Choonghyun;Kim, Byoung-Gie;Kim, Yong-Man;Kim, Jae Weon;Kang, Sokbom;Kim, Jaehoon;Kim, Tae Jin;Yoo, Keun-Young;Kang, Daehee;Park, Suekyung
    • Journal of Preventive Medicine and Public Health
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    • v.49 no.6
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    • pp.349-366
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    • 2016
  • Objectives: We conducted a systematic review and meta-analysis to summarize current evidence regarding the association of parity and duration of breastfeeding with the risk of epithelial ovarian cancer (EOC). Methods: A systematic search of relevant studies published by December 31, 2015 was performed in PubMed and EMBASE. A random-effect model was used to obtain the summary relative risks (RRs) and 95% confidence intervals (CIs). Results: Thirty-two studies had parity categories of 1, 2, and ${\geq}3$. The summary RRs for EOC were 0.72 (95% CI, 0.65 to 0.79), 0.57 (95% CI, 0.49 to 0.65), and 0.46 (95% CI, 0.41 to 0.52), respectively. Small to moderate heterogeneity was observed for one birth (p<0.01; Q = 59.46; $I^2=47.9%$). Fifteen studies had breastfeeding categories of <6 months, 6-12 months, and >13 months. The summary RRs were 0.79 (95% CI, 0.72 to 0.87), 0.72 (95% CI, 0.64 to 0.81), and 0.67 (95% CI, 0.56 to 0.79), respectively. Only small heterogeneity was observed for <6 months of breastfeeding (p = 0.17; Q = 18.79, $I^2=25.5%$). Compared to nulliparous women with no history of breastfeeding, the joint effects of two births and <6 months of breastfeeding resulted in a 0.5-fold reduced risk for EOC. Conclusions: The first birth and breastfeeding for <6 months were associated with significant reductions in EOC risk.

Association Between the GSTP1 Codon 105 Polymorphism and Gastric Cancer Risk: an Updated Meta-analysis

  • Bao, Li-Dao;Niu, Jian-Xiang;Song, Hui;Wang, Yi;Ma, Rui-Lian;Ren, Xian-Hua;Wu, Xin-Lin
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.8
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    • pp.3687-3693
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    • 2012
  • Objective: The current meta-analysis was performed to address a more accurate estimation of the association between glutathione S-transferase P1 (GSTP1) codon 105 polymorphism and risk of gastric cancer (GC), which has been widely reported with conflicting results. Methods: A comprehensive literature search was conducted to identify all the relevant studies. Fixed or random effect models were selected based on the heterogeneity test. Publication bias was estimated using Begg's funnel plots and Egger's regression test. Results: A total of 20 studies containing 2,821 GC cases and 6,240 controls were finally included in the analyses. Overall, no significant association between GSTP1 polymorphism and GC risk was observed in worldwide populations. However, subgroup analysis stratified by ethnicity showed that GSTP1 polymorphism was significantly associated with increased risk of GC in Asians (G vs. A, OR = 1.273, 95%CI=1.011-1.605; GG vs. AA, OR=2.103, 95%CI=1.197-3.387; GG vs. AA+AG, OR =2.103, 95%CI=1.186-3.414). In contrast, no significant association was found in Caucasians in any genetic models, except for with AG vs. AA (OR=0.791, 95%CI=0.669-0.936). Furthermore, the GSTP1 polymorphism was found to be significantly associated with GC in patients with H. pylori infection and in those with a cardiac GC. Subgroup analysis stratified by Lauren's classification and smoking status showed no significant association with any genetic model. No studies were found to significantly influence the pooled effects in each genetic mode, and no potential publication bias was detected. Conclusion: This meta-analysis suggested that the GSTP1 polymorphism might be associated with increased risk of GC in Asians, while GSTP1 heterozygote genotype seemed to be associated with reduced risk of GC. Since potential confounders could not be ruled out completely, further studies are needed to confirm these results.