• Title, Summary, Keyword: Test of heterogeneity

Search Result 155, Processing Time 0.033 seconds

A Meta-analysis of the Timed Up and Go test for Predicting Falls (낙상 위험 선별검사 Timed Up and Go test의 예측 타당도 메타분석)

  • Park, Seong-Hi;Lee, On-Seok
    • Quality Improvement in Health Care
    • /
    • v.22 no.2
    • /
    • pp.27-40
    • /
    • 2016
  • Purpose: Globally, falls are a major public health problem. The study aimed to evaluate the predictive validity of the Timed Up and Go test (TUGT) as a screening tool for fall risk. Methods: An electronic search was performed Medline, EMBASE, CINAHL, Cochran Library, KoreaMed and the National Digital Science Library and other databases, using the following keywords: 'fall', 'fall risk assessment', 'fall screening', 'mobility scale', and 'risk assessment tool'. The QUADAS-II was applied to assess the internal validity of the diagnostic studies. Thirteen studies were analyzed using meta-analysis with MetaDisc 1.4. Results: The selected 13 studies reporting predictive validity of TUGT of fall risks were meta-analyzed with a sample size of 1004 with high methodological quality. Overall predictive validity of TGUT was as follows. The pooled sensitivity 0.72 (95% confidence interval [CI]: 0.67-0.77), pooled specificity 0.58 (95% CI: 0.54-0.63) and sROC AUC was 0.75 respectively. Heterogeneity among studies was a moderate level in sensitivity. Conclusion: The TGUT's predictive validity for fall risk is at a moderate level. Although there is a limit to interpret the results for heterogeneity between the literature, TGUT is an appropriate tool to apply to all patients at a potential risk of accidental fall in a hospital or long-term care facility.

Experimental observation and realistic modeling of initiation and propagation of the rock fracture by acoustic emission

  • Wang, Shu-Hong;Lee, Chung-In;Jeon, Seok-Won;Lee, Hee-Kwang;Tang, Chun-An
    • Proceedings of the Korean Society for Rock Mechanics Conference
    • /
    • /
    • pp.79-93
    • /
    • 2006
  • It is well known that acoustic emission (AE) is indicator of rock fracturing or damage as rock is brought to failure under the uniaxial compressive loads. In this paper, an experimental study on the source location of acoustic emission on the cylindrical specimens of granite under uniaxial compression test was made. The AE source location was made by measuring the six channel AE data. Comparing to this experiment, the numerical method is applied to model the initiation and propagation of fracture by AE using a numerical code, RFPA (Realistic Failure Process Analysis). This code incorporates the mesoscopic heterogeneity in Young's modulus and rock strength characteristic of rock masses. In the numerical models, values of Young's modulus and rock strength are realized according to a Weibull distribution in which the distribution parameters represent the level of heterogeneity of the medium. The results of the simulations show that RFPA can be used not only to produce acoustic emission similar to those measurements in our experiments, but also to predict fracturing patterns under uniaxial loading condition.

  • PDF

The Determinants of Blockholder Presence: Evidence from Korea

  • KIM, Hung Sik;CHO, Kyung-Shick
    • The Journal of Asian Finance, Economics, and Business
    • /
    • v.7 no.4
    • /
    • pp.29-39
    • /
    • 2020
  • The purpose of this study is to investigate the determinants of blockholder presence in the Korean stock market. This study examines previous theories and studies, points that previous studies did not examine, and proposes two hypotheses. To verify two hypotheses, fundamental data were collected from firms listed on Korea Exchange from 2005 to 2017. As explanatory variables, we use the factors and characteristics of the firms used in the previous studies. Logistic regression analysis was conducted to test the determinants of blockholder presence. We find that firm size is the most distinctive factor determining the presence of blockholder, and firm idiosyncratic risk is the most similar factor determining the existence of each blockholder. Tobin Q shows significant value in family and government, and R&D intensity appears to be a negative related to the presence of blockholder in financial institutions. We also find that the determinant of blockholder presence differs from the mechanisms that govern each individual blockholder type when all blockholders grouped together. This suggests that there is blockholder heterogeneity within Korea listing firms. Our findings contribute to investors and policy makers who interested in the determinants of the presence of blockholder and blockhoder heterogeneity in Korea stock market.

Prediction of Heterogeneous Hydraulic Conductivity and Contaminant Transport for the Landfill on Marine Clay (비균질성을 고려한 해성점토매립장의 수리전도도 추정과 오염이동특성)

  • 장연수;정상용
    • Geotechnical Engineering
    • /
    • v.13 no.1
    • /
    • pp.85-100
    • /
    • 1997
  • The heterogeneity of hydraulic conductivity of Metropolitan Waste Landfill is analized by using geostatistical methods and the contaminant transport analysis is performed by using heterogeneous hydraulic conductivity. The hydraulic conductivity data are obtained from laboratory pressurized permeability tests and the insitu, Slug test. Geostatistical methods used in this analysis are Ordinary Kriging and conditional simulation. It is concluded that the heterogeneities of hydraulic conductivity obtained from conditional simulation are greater than those from Ordinary Kriging analysis. The movement of the contaminant on the hydraulic conductivity with greater heterogeneity obtained from conditional simulation is faster than that observed in Ordinary Kriging analysis.

  • PDF

Daily Mean Temperature and Urolithiasis Presentation in Six Cities in Korea: Time-Series Analysis

  • Chi, Byung Hoon;Chang, In Ho;Choi, Se Young;Suh, Dong Churl;Chang, Chong won;Choi, Yun Jung;Lee, Seo Yeon
    • Journal of Korean Medical Science
    • /
    • v.32 no.6
    • /
    • pp.999-1008
    • /
    • 2017
  • Seasonal variation in urinary stone presentation is well described in the literature. However, previous studies have some limitations. To explore overall cumulative exposure-response and the heterogeneity in the relationships between daily meteorological factors and urolithiasis incidence in 6 major Korean cities, we analyzed data on 687,833 urolithiasis patients from 2009 to 2013 for 6 large cities in Korea: Seoul, Incheon, Daejeon, Gwangju, Daegu, and Busan. Using a time-series design and distributing lag nonlinear methods, we estimated the relative risk (RR) of mean daily urolithiasis incidence (MDUI) associated with mean daily meteorological factors, including the cumulative RR for a 20-day period. The estimated location-specific associations were then pooled using multivariate metaregression models. A positive association was confirmed between MDUI and mean daily temperature (MDT), and a negative association was shown between MDUI and mean daily relative humidity (MDRH) in all cities. The lag effect was within 5 days. The multivariate Cochran Q test for heterogeneity at MDT was 12.35 (P = 0.136), and the related $I^2$ statistic accounted for 35.2% of the variability. Additionally, the Cochran Q test for heterogeneity and $I^2$ statistic at MDHR were 26.73 (P value = 0.148) and 24.7% of variability in the total group. Association was confirmed between daily temperature, relative humidity and urolithiasis incidence, and the differences in urolithiasis incidence might have been partially attributable to the different frequencies and the ranges in temperature and humidity between cities in Korea.

TRANSMISSION OF PREVOTELLA INTERMEDIA BY GENOMIC DAN FINGERPRINTING (P.intermedia의 유전자 이종성과 가족내 전이에 관한 연구)

  • Lee, Seoung-Min;Kim, Kack-Kyun;Chung, Chong-Pyoung
    • Journal of Periodontal and Implant Science
    • /
    • v.25 no.1
    • /
    • pp.89-98
    • /
    • 1995
  • P. intermedia are considered an important pathogen in adult periodontitis, rapidly progressing periodontitis, refractory periodontitis, pregnancy gingivitis, acute necrotizing ulcerative gingivitis, pubertal gingivitis. So far 2 DNA homology groups and 3 serotypes of P. intermedia have been reported but there is no data available as yet regarding genetic diversity for the species P. intermedia. The purpose of this study is to investigate, using bacterial DNA restriction endonuclease analysis, genetic diversity between individual strains of P. intermedia which are indistinguishable by serotyping and biotyping, occurrence of an intrafamilial transmission and genetic heterogeneity between P. intermedia strains isolated within a patient and within the same serotypes. The families who have had no systemic disease, no experience of periodontal treatment for the previous 1 year and no experience of antibiotics for the previous 6 months were selected and subgingival plaque was collected at 4 sites in each person and incubated in the anaerobic chamber. P. intermedia were identified by colony shape, gram stain, biochemical test, SK-I03(Sunstar Inc.) test and IIF using monoclonal antibody was perfomed for the determination of serotypes. P. intermedia strains were grown in BHI broth and whole genomic DNA was extracted and digested by restriction endonuclease. The resulting DNA fragments were separated by agarose gel electrophoresis, stained and photographed under UV. As the results of this study, intrafamilial vertial transmissions could be assessed in 2 families and horizintal transmissions in another 2 families. There were different DNA digest patterns within a patient, so P. intermedia showed that individuals could be colonized by multiple clonal types at anyone time. And different serotypes could be found within a patient and in the same serotype within a patient, obvius genetic heterogeneity could not be assessed. But in the same serotype in different famies, there were differences in the DNA digest patterns.

  • PDF

창원지역 화강암의 수리분산 특성

  • 김무진;함세영;황한석;김문수
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
    • /
    • /
    • pp.187-190
    • /
    • 2001
  • This study is concerned with the hydrodispersive characteristics of granite in Changwon area. A single-well injection/recovery tracer test was conducted to determine longitudinal dispersivity of the granite, using sodium chloride tracer The dispersivity values obtained from the injection phase are 0.48 m (for between PW-1 and OW-3) and 0.72 m (for between PW-1 and OW-4). That obtained from the recovery phase is 0.68 m. The result of the tracer test indicates that the anisotropy and heterogeneity of the granite and the direction of flow.

  • PDF

The Mediating Effects of the Manufacturing Capability and the Testing and Inspection Capability on the Relation between Small and Medium Venture Firms' External Information Network Heterogeneity and Technology Commercialization Capability (제조 역량과 시험 및 검사 역량이 중소벤처기업의 외부 정보 네트워크의 다양성과 기술 사업화 역량 사이의 관계에 미치는 매개 효과)

  • Hau, Yong Sauk
    • Journal of Digital Convergence
    • /
    • v.15 no.10
    • /
    • pp.233-241
    • /
    • 2017
  • This study has attempted to empirically analyze the mediating effects of small and medium venture firms' manufacturing capability and testing and inspection capability on the relation between their external information network heterogeneity and technology commercialization capability with a view to diversifying the research stream on the influential factors to small and medium firms' technology commercialization capability. By performing the ordinary least squares regression analysis, the Sobel test, and the Baron and Kenny test based on the 683 data of South Korean small and medium venture firms with the IBM SPSS version 23, this study provides the three empirical findings to be useful for future studies on the roles of small and medium venture firms' the manufacturing capability and testing and inspection capability. First, small and medium venture firms' manufacturing capability partially mediates the positive effect of their external information network heterogeneity on their technology commercialization capability. Second, their testing and inspection capability partially mediates this positive effect. Third, their manufacturing capability and testing and inspection capability jointly and partially mediates this positive effect.

Motor imagery on upper extremity function for persons with stroke: a systematic review and meta-analysis

  • Lee, Dongsu;Hwang, Sujin
    • Physical Therapy Rehabilitation Science
    • /
    • v.8 no.1
    • /
    • pp.52-59
    • /
    • 2019
  • Objective: The purpose of this review was to investigate whether motor imagery training has an effect on the recovery of upper extremity function in individuals with hemiparetic stroke or not. Design: A systematic review and meta-analysis. Methods: PubMed and three other databases were searched up to December 18th, 2018 and randomized controlled trials (RCTs) evaluating motor imagery training on upper extremity function in persons with a diagnosis of hemiparetic stroke were included. This review selected the following information from each study: surname of the first author, published year, nation, population, intervention, therapeutic intensity of intervention, therapeutic comparison, outcome measures, additional therapy, summary of results, and descriptive statistics of outcome measures. Results: This review selected seventeen RCTs with 487 stroke survivors and the following intervention methods: six motor imagery training with additional therapeutic technology, two motor imagery training with additional modified constraint-induced therapy, four mirror therapy, and five motor imagery training. Ten RCTs were eligible for meta-analysis after systematic review. The motor imagery group were more effective than the control group based on the Fugl-Meyer assessment (3.43; 95% confidence interval [CI], 1.65 to 5.22; heterogeneity [$chi^2=8.03$, df=8, $I^2=0%$], test of overall effect Z=3.76; test for subgroup differences [$chi^2=2.56$, df=2, $I^2=21.8%$]) and the Action Research Arm Test (1.32; 95% CI, -8.12 to 10.76; heterogeneity [$Tau^2=70.74$, $chi^2=15.22$, df=3, $I^2=80%$], test of overall effect Z=3.76). Conclusions: The results of this review suggests that motor imagery shows positive effectiveness on improving upper extremity function in persons with hemiparetic stroke.

$PM_{10}$ Exposure and Non-accidental Mortality in Asian Populations: A Meta-analysis of Time-series and Case-crossover Studies

  • Park, Hye Yin;Bae, Sanghyuk;Hong, Yun-Chul
    • Journal of Preventive Medicine and Public Health
    • /
    • v.46 no.1
    • /
    • pp.10-18
    • /
    • 2013
  • Objectives: We investigated the association between particulate matter less than $10{\mu}m$ in aerodynamic diameter ($PM_{10}$) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. Methods: Among the 819 published studies searched from PubMed and EMBASE using key words related to $PM_{10}$ exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per $10{\mu}g/m^3$ increase of daily $PM_{10}$ from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. Results: Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per $10{\mu}g/m^3$ increase of daily $PM_{10}$ for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. Conclusions: We found a significant positive association between $PM_{10}$ exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.