• Title/Summary/Keyword: Bias Tests

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Helicobacter pylori and Pancreatic Cancer Risk: a Meta-analysis Based on 2,049 Cases and 2,861 Controls

  • Wang, Yin;Zhang, Fu-Cheng;Wang, Yao-Jun
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.11
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    • pp.4449-4454
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    • 2014
  • Aim: Helicobacter pylori (H. pylori) have been considered as a risk factor for many cancers. We conducted this meta-analysis to clarify the association between H. pylori infection and the risk of pancreatic cancer. Methods: We searched the Medicine/Pubmed and Embase databases, studies about the association between H. pylori infection and pancreatic cancer published up to Jan.2014 were included. Finally, a total of 9 studies were used for this a meta-analysis. The odds ratios (ORs) and 95% confidence interval (95%CI) of H. pylori infection on pancreatic cancer with respect to control groups were evaluated. Two authors independently assessed the methodological quality and extracted data. This meta-analysis was conducted using software, state (version 12.0) to investigate heterogeneity among individual studies and to summarize the studies. Using the fixed-effects or random-effects model, depending on the absence or presence of significant heterogeneity. Sensitivity analysis was performed to assess the influence of each individual study on the pooled ORs by omitting a single study each time. Publication bias was evaluated by funnel plot, using Egger's and Begg's tests. Results: There was no significant association between H. pylori infection and pancreatic cancer risk in the summary ORs,(OR=1.06, 95%CI: 0.74-1.37) through the random-effect method, but heterogeneity among studies was significant ($I^2$=58.9%), so we put the studies into two subgraphs (eastern and western). The results about western (OR=1.14 95%CI:0.89, 1.40) showed heterogeneity among the western countries of $I^2$=6.6%, with no significant association between Hp+ and pancreatic cancer, but the eastern countries (OR=0.62, 95%CI:0.49, 0.76), $I^2$=0, suggested that decreasing pancreas-cancer risk in subjects with Hp+ infection. Simultaneously, 7 studies examined CagA+ strains was (OR=0.84 95%CI:0.63, 1.04), $I^2$=36% with the random-effect method, subgraphs indicated that CagA+ could decrease the risk of pancreatic cancer in the eastern subjects (OR=0.66, 95%CI:0.52-0.80), but the association was not statistically significant in the western subjects (OR=0.95, 95%CI:0.73, 1.16). Conclusion: Hp+ and CagA+ infection are associated with a decreased risk of pancreatic cancer in eastern populations but have no significant associations in western countries.

Prognostic Significance of Beclin-1 Expression in Colorectal Cancer: a Meta-analysis

  • Han, Ye;Xue, Xiao-Feng;Shen, Hu-Gang;Guo, Xiao-Bo;Wang, Xu;Yuan, Bin;Guo, Xing-Po;Kuang, Yu-Ting;Zhi, Qiao-Ming;Zhao, Hong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.11
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    • pp.4583-4587
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    • 2014
  • Objective: Beclin-1 has recently been observed as an essential marker of autophagy in several cancers. However, the prognostic role of Beclin-1 in colorectal neoplasia remains controversial. Our study aimed to evaluate the potential association between Beclin-1 expression and the outcome of colorectal cancer patients. Materials and Methods: All related studies were systematically searched in Pubmed, Embase, Springer and Chinese National Knowledge Infrastructure databases (CNKI), and then a meta-analysis was performed to determine the association of Beclin-1 expression with clinical outcomes. Finally, a total of 6 articles were included in our analysis. Results: Our data showed that high Beclin-1 expression in patients with CRC was associated with poor prognosis in terms of tumor distant metastasis (OR=2.090, 95%CI=1.061-4.119, p=0.033) and overall survival (RR=1.422, 95%CI=1.032-1.959, p=0.031). However, we did not found any correlation between Beclin-1 over-expression and tumor differentiation (OR=1.711, 95%CI=0.920-3.183, p=0.090). In addition, there was no evidence of publication bias as suggested by Egger's tests for tumor distant metastasis (p=1.000), differentiation (p=1.000) and OS (p=0.308). Conclusions: Our present meta-analysis indicated that elevated Beclin-1 expression iss associated with tumor metastasis and a poor prognosis in patients with CRC. Beclin-1 might serve as an efficient prognostic indicator in CRC, and could be a new molecular target in CRC therapy.

Personnel Dosimetry Performance Test (개인방사선 피폭선량판독 성능시험)

  • Na, Seong-Ho;Han, Seung-Jae;Lee, Dew-Hey;Cho, Dae-Hyung
    • Journal of Radiation Protection and Research
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    • v.21 no.2
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    • pp.131-138
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    • 1996
  • This paper describes the methods and results of the personnel dosimetry performance tests which were been implemented for the first time in Korea in 1995. Seven categories, except the neutron category prescribed in the ANSI N13.11-1993, were adopted in the test. Fifteen types of dosimeters were participated by fourteen dosimeter processing institutes. A total of 129 dosimeters were selected to test-each type - 15 dosimeters for each of the seven categories and 24 for the controls. A total of 144 radiation categories were employed in the test and a total of 2560 (including 400 controls)dosimeters were submitted-7 categories for each type of the fifteen types dosimeters and 39 categories for the retest. The performance index in each category. sum of the absolute value of the bias and the standard deviation value of the performance quotient. was estimated by the use of delivered and processed dose equivalents according to the standard procedure. The performance in a given category was assessed as acceptable, for the deep and shallow dose equivalents (or the absorbed dose), if the performance index was less than 0.5. The test results showed 54% of the processors passed in the first test, 33% in the retest and 13% in the second retest.

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Determination of Mean Shear Wave Velocity to the Depth of 30m Based on Shallow Shear Wave Velocity Profile (얕은 심도 전단파속도 분포를 이용한 30m 심도 평균 전단파속도의 결정)

  • Sun, Chang-Guk;Chung, Choong-Ki;Kim, Dong-Soo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.1 s.53
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    • pp.45-57
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    • 2007
  • The mean shear wave velocity to the depth of 30 m (Vs30) derived from the western Vs is the current site classification criterion for determining the design seismic ground motion taking into account the site amplification potential. In order to evaluate the Vs30 at a site, a shear wave velocity (Vs) Profile extending to at least 30 m in depth must be acquired from in-situ seismic test. In many cases, however, the resultant depth of the Vs profile may not extend to 30 m, owing to the unfavorable field condition and the limitation of adopted testing techniques. In this study, the Vs30 and the mean shear wave velocity to a depth shallower, than 30 m (VsDs) were computed from the Vs profiles more than 30 m in depth obtained by performing various seismic tests at total 72 sites in Korea, and a correlation between Vs30 and VsDs was drawn based on the computed mean Vs data. In addition, a method for extrapolating the Vs profile from shallow depth to 30 m was developed by building a shape curve based on the average data of all Vs profiles. For evaluating the Vs30 from the shallow Vs profiles, both the methods using VsDs and shape curve result in less bias than the simplest method of extending the lowermost Vs equally to 30 m in depth, and are usefully applicable particularly in the cases of the Vs profiles extending to at least 10 m in depth.

A Simple Test for Optimal Fiscal and Monetary Policy Regimes: The Case of Korea (재정(財政)·통화정책(通貨政策)의 적정관계(適正關係)에 대한 고찰(考察) : 재정우위(財政優位)모델에 의한 실증적(實證的) 분석(分析))

  • Whang, Seong-hyeon
    • KDI Journal of Economic Policy
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    • v.13 no.4
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    • pp.141-153
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    • 1991
  • The optimal choice of the tax rate and the inflation rate framework is extended to yield relevant interpretations for the optimal fiscal and monetary policy regime in Korea. To study the relationship between the government budget and monetary growth in different environments of policy coordination, two models assuming different degrees of fiscal dominance are developed. By modelling differing institutional arrangements of the fiscal and the monetary authority from an optimal government finance viewpoint, we find the optimal relationship among some important fiscal and monetary variables. By testing the existence of the relationship empirically, we find the characteristics of the optimal policy-mix regime in Korea. The first model-the strong from of fiscal dominance-studies the optimal collection of seigniorage in a period-by-period optimization with standard assumptions on the income velocity of money, deriving a general testable result: the optimal inflation/tax rate ratio co-vary with the marginal revenue ratio. The second model-the weak form of fiscal dominance-studies an implication of the inflationary bias of discretionary monetary policy in the presence of fiscal side distortions. This model shows that the tax rate and the inflation rate can have a positive correlation. Empirical tests of the theoretical results are done for the Korean economy for 1972-1989 period. The test results show that the macroeconomic policy regime in Korea can be characterized by the strong form of fiscal dominance, implying the importance of the government budget in explaining money growth and inflation.

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Lack of Effects of HER-2/neu on Prognosis in Colorectal Cancer: a Meta-analysis

  • Han, Jun;Meng, Qing-Yang;Liu, Xiao;Xi, Qiu-Lei;Zhuang, Qiu-Lin;Wu, Guo-Hao
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.14
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    • pp.5551-5556
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    • 2014
  • Background: The prognostic value of human epidermal growth factor receptor-2 (HER-2/neu) for survival of patients with colorectal cancer (CRC) is still ambiguous. We therefore performed a meta-analysis to evaluate its prognostic significance. Materials and Methods: We searched the MEDLINE and EMBASE databases for published literature investigating associations between HER-2/neu status and overall survival of patients with CRC. A meta-analysis was performed using a DerSimonian-Laird model and publication bias was investigated by Begg's and Egger's tests. Subgroup analysis was also conducted according to the study design type, study quality score, cut-off value for HER-2/neu overexpression, publication region, patient number and publication year. Results: A total of 17 eligible studies involving 2,347 patients were identified for this meta-analysis. The combined hazard ratio (HR) was 1.31 (95% confidence interval (CI): 0.96-1.79), suggesting that HER-2/neu overexpression was not significantly associated with overall survival of patients with CRC. However, subgroup analysis revealed that HER-2/neu overexpression had an unfavorable impact on survival when the analysis was restricted to subgroups of study quality score ${\leq}5 $(HR=1.56, 95%CI: 1.17-2.10), Asian patients (HR=1.74, 95%CI: 1.22-2.49), patient number ${\leq}106$ (HR=1.57, 95%CI: 1.01-2.44), publication year before 2003 (HR=1.59, 95%CI: 1.02-2.49), and prospectively designed study (HR=3.62, 95%CI: 1.42-9.24). The effect disappeared in subgroups of study quality scores > 5 (HR=0.69, 95%CI: 0.33-1.44), non Asian patients (HR=1.14, 95%CI: 0.77-1.70), patients' number > 106 (HR=1.07, 95%CI: 0.67-1.72), publication year after 2003 (HR=1.13, 95%CI: 0.76-1.69), and retrospectively designed study (HR=1.22, 95%CI: 0.89-1.67). Conclusions: Our meta-analysis suggests that HER-2/neu overexpression might not be a significantly prognostic indicator for patients with CRC. Further studies are required to confirm these results.

Study on the way how to make the recruiting Examination of 'Machinery·Metal' Subject in Technical High School. (중등임용시험 '기계·금속' 과목의 출제방안 연구)

  • Choi, Jun-Seop;Lee, Seoung-Won;Kim, Jong-Chan;Jung, Bong-Kyoon;Park, Sang-Jin;Kwon, Cha-Mi
    • 대한공업교육학회지
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    • v.31 no.2
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    • pp.111-127
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    • 2006
  • The purpose of this study is to analyze current recruiting examination and to categorize and construct test item that assess a variety of Mechanic Metal teachers in technical high school for appointing new Mechanic Metal teacher. The future developmental directions in this study are as follows: First, the examination for appointing secondary school new Mechanic Metal Teacher reflects the curriculum of the teacher education and technical high school, must be nomalize. Second, the rational readjustment of the basic necessary subjects for Machinery Metal recruiting examination is required. Third, the Mechanic Metal recruiting examination must prepare the criteria for the domain ratio of presenting problems and improve with level of presenting the question items which demands a knowledge, application and critical thinking. Fourth, in order to avoid the bias of the some subject tendency with committee making questions of different domain, more participation of a committee making questions is required. Fifth, the practical evaluation must be executed by the effective method to be able to make up for the limit of paper and pencil tests Sixth, as the long-term prospect to secure the professionalism of teacher, the recruiting examination of teachers must be carried out with the Machinery and Metal subject, respectively.

Simultaneous analysis method of 89Sr and 90Sr in liquid sample using automated separation system (자동핵종분리장치를 이용한 액체시료 중 89Sr, 90Sr 동시분석법 연구)

  • Kim, Heewon;Lee, Yong-Jin;Kim, Sun-Ha;Lee, Jin-Hong;Lim, Jong-Myoung;Kim, Hyuncheol
    • Analytical Science and Technology
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    • v.33 no.6
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    • pp.274-284
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    • 2020
  • This study described the analytical method for simultaneous determination of 89Sr and 90Sr in liquid sample using automated separation system. Radiostrontium in 0.5 kg of liquid sample was concentrated as SrCO3 to reduce the volume of sample, and purified from the sample using Sr-resin 2 mL (BV, Bed volume). The behavior of Sr and interferences such as Ba, Ca and Y were estimated with various flow rate ranging from 1 to 4 mL min-1. The detailed procedure for the purification of Sr on Sr-resin was presented. The purified radiostronitum was measured in Cerenkov mode and then measured in Scintillation mode by mixing scintillation cocktail. The measured value in both modes were used to calculate the activity of 89Sr and 90Sr. The performance tests were carried out the lab-control-sample having various activity ratio of between 89Sr and 90Sr. The recovery of Sr was ranged from 68 to 94 %. The relative bias of 89Sr activity was ranged from -5 to 20 %, and it was ranged from -10 to 10 % for 90Sr.

Systematic Review on the Effect of Forest Healing Activities on the Elderly (산림치유 활동이 노인에게 미치는 효과에 대한 체계적 문헌고찰)

  • Mijin Lee;Jungkee Choi;Soyeon Kim
    • Journal of Korean Society of Forest Science
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    • v.112 no.1
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    • pp.93-104
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    • 2023
  • Life expectancy is increasing due to the aging of the population, which is in turn exacerbating problems such as the prevalence of various geriatric diseases. This study was established to provide basic data for the expansion of forest healing activities for the elderly by systematically analyzing the literature on how such activities affect this age group. For the collection of studies, the Korean databases RISS, KISS, Korea Med, and Science On were used, while PubMed, Cochrane Central, MDPI, and Google Scholar were used to identify reports published elsewhere. To assess the quality of the methodology used in the collected studies, the risk of bias was analyzed using Cochrane's RoB2 and RoBANS. Among 1,856 reports initially identified, 21 were finally selected for analysis in this study, which were limited to research papers on forest healing activities for the elderly published between 2000 and January 2022. In this review, the subjects were those aged 60 or older, with a total of 750 participants, ranging from at least 7 to a maximum of 88 per study. The analysis showed that the most frequently performed tests in each category were on depression as a psychological indicator in 7 studies, MMSE(Mini Mental State Examination) as a cognitive indicator in 2 studies, on blood pressure as a physiological indicator in 4 studies, on melatonin as a biochemical indicator in 2 studies, and on body fat and muscle strength as physical indicators in 3 studies. Of the 21 studies, 19 used two or more test items, with psychological indicators being most commonly measured. For the future application of forest healing activities for the elderly, various forest healing programs to prevent cognitive function decline should be developed and distributed, and follow-up studies should be continuously presented to provide the basis for forest healing activities.

Allometric equation for estimating aboveground biomass of Acacia-Commiphora forest, southern Ethiopia

  • Wondimagegn Amanuel;Chala Tadesse;Moges Molla;Desalegn Getinet;Zenebe Mekonnen
    • Journal of Ecology and Environment
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    • v.48 no.2
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    • pp.196-206
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    • 2024
  • Background: Most of the biomass equations were developed using sample trees collected mainly from pan-tropical and tropical regions that may over- or underestimate biomass. Site-specific models would improve the accuracy of the biomass estimates and enhance the country's measurement, reporting, and verification activities. The aim of the study is to develop site-specific biomass estimation models and validate and evaluate the existing generic models developed for pan-tropical forest and newly developed allometric models. Total of 140 trees was harvested from each diameter class biomass model development. Data was analyzed using SAS procedures. All relevant statistical tests (normality, multicollinearity, and heteroscedasticity) were performed. Data was transformed to logarithmic functions and multiple linear regression techniques were used to develop model to estimate aboveground biomass (AGB). The root mean square error (RMSE) was used for measuring model bias, precision, and accuracy. The coefficient of determination (R2 and adjusted [adj]-R2), the Akaike Information Criterion (AIC) and the Schwarz Bayesian information Criterion was employed to select most appropriate models. Results: For the general total AGB models, adj-R2 ranged from 0.71 to 0.85, and model 9 with diameter at stump height at 10 cm (DSH10), ρ and crown width (CW) as predictor variables, performed best according to RMSE and AIC. For the merchantable stem models, adj-R2 varied from 0.73 to 0.82, and model 8) with combination of ρ, diameter at breast height and height (H), CW and DSH10 as predictor variables, was best in terms of RMSE and AIC. The results showed that a best-fit model for above-ground biomass of tree components was developed. AGBStem = exp {-1.8296 + 0.4814 natural logarithm (Ln) (ρD2H) + 0.1751 Ln (CW) + 0.4059 Ln (DSH30)} AGBBranch = exp {-131.6 + 15.0013 Ln (ρD2H) + 13.176 Ln (CW) + 21.8506 Ln (DSH30)} AGBFoliage = exp {-0.9496 + 0.5282 Ln (DSH30) + 2.3492 Ln (ρ) + 0.4286 Ln (CW)} AGBTotal = exp {-1.8245 + 1.4358 Ln (DSH30) + 1.9921 Ln (ρ) + 0.6154 Ln (CW)} Conclusions: The results demonstrated that the development of local models derived from an appropriate sample of representative species can greatly improve the estimation of total AGB.