• Title/Summary/Keyword: Relative bias

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Growth Modelling of Listeria monocytogenes in Korean Pork Bulgogi Stored at Isothermal Conditions

  • Lee, Na-Kyoung;Ahn, Sin Hye;Lee, Joo-Yeon;Paik, Hyun-Dong
    • Food Science of Animal Resources
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    • v.35 no.1
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    • pp.108-113
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    • 2015
  • The purpose of this study was to develop predictive models for the growth of Listeria monocytogenes in pork Bulgogi at various storage temperatures. A two-strain mixture of L. monocytogenes (ATCC 15313 and isolated from pork Bulgogi) was inoculated on pork Bulgogi at 3 Log CFU/g. L. monocytogenes strains were enumerated using general plating method on Listeria selective medium. The inoculated samples were stored at 5, 15, and $25^{\circ}C$ for primary models. Primary models were developed using the Baranyi model equations, and the maximum specific growth rate was shown to be dependent on storage temperature. A secondary model of growth rate as a function of storage temperature was also developed. As the storage temperature increased, the lag time (LT) values decreased dramatically and the specific growth rate of L. monocytogenes increased. The mathematically predicted growth parameters were evaluated based on the modified bias factor ($B_f$), accuracy factor ($A_f$), root mean square error (RMSE), coefficient of determination ($R^2$), and relative errors (RE). These values indicated that the developed models were reliably able to predict the growth of L. monocytogenes in pork Bulgogi. Hence, the predictive models may be used to assess microbiological hygiene in the meat supply chain as a function of storage temperature.

Development and Application of Criteria for Evaluating Educational Web Sites (교육용 웹 사이트 평가를 위한 준거의 개발 및 적용)

  • Kim, Mi-Ryang
    • The Journal of Korean Association of Computer Education
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    • v.6 no.1
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    • pp.41-54
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    • 2003
  • Educational web sites are proliferating at an astonishing rate, however many of those web sites are of poor or unknown quality. Educators are in need of instruments to assist in evaluating educational web sites for authenticity, applicability, authorship, bias, and usability, etc. The ability to critically evaluate educational content form numerous web sites is an important skill in this information age. In this paper, indicators of educational web site quality have been identified from literature review and our own research, and classified within 8 categories. To test the relative contribution of each indicator to the satisfaction level from using educational web sites, a questionnaire survey was administered. Subjects were asked to visit the educational web site of his or her choice and rate the quality level of each indicator. 255 completed questionnaires were turned in for analysis. Cronbach's Alpha test and factor analysis were applied to test the reliability and validity of the data. Stepwise regression analysis was applied to test the relationship between the satisfaction level and 14 independent factors. Implications from the statistical analysis as well as the guidelines for evaluating educational web sites were provided.

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Effect of anti-rheumatic agents on periodontal parameters and biomarkers of inflammation: a systematic review and meta-analysis

  • Han, Ji-Young;Reynolds, Mark A.
    • Journal of Periodontal and Implant Science
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    • v.42 no.1
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    • pp.3-12
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    • 2012
  • Purpose: Anti-rheumatic agents target common molecular pathways of inflammation in rheumatoid arthritis (RA) and periodontitis. The purpose of this study was to determine the relative effect of anti-rheumatic agents on the levels of inflammatory biomarkers and periodontal inflammation in RA patients with periodontitis. Methods: A systematic review and meta-analysis were conducted of studies comparing periodontal parameters of inflammation, such as bleeding on probing, and biomarkers of inflammation in RA patients with periodontitis and healthy adults with and without periodontitis. The search included the electronic databases MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar, inclusive through October 2011, with no language restrictions. Hand searches were conducted of the bibliographies of related journals and systematic reviews. Observational and interventional studies assessing the effects of antirheumatic therapy qualified for inclusion. Two reviewers performed independent data extraction and risk-of-bias assessment. Of the 187 identified publications, 13 studies fulfilled the inclusion criteria. Results: When compared to healthy adults without periodontitis, RA subjects were found to have significantly higher levels of bleeding on probing and limited evidence of higher levels of interleukin-$1{\beta}$ and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in gingival crevicular fluid and saliva. No consistent differences were found in periodontal parameters and inflammatory biomarkers between RA subjects and adults with periodontitis. Studies evaluating the effect of anti-TNF-${\alpha}$ therapy in RA subjects with periodontitis have yielded inconsistent results. Conclusions: There are limited data, however, to suggest that anti-TNF-${\alpha}$ agents can reduce local production of inflammatory cytokines and periodontal inflammation in RA patients with periodontitis.

Physical Activity and Risk of Lung Cancer: A Meta-Analysis of Prospective Cohort Studies

  • Sun, Jia-Yang;Shi, Lei;Gao, Xu-Dong;Xu, Shao-Fa
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.7
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    • pp.3143-3147
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    • 2012
  • Background: Previous studies investigating the association of physical activity with risk of lung cancer reported conflicting results. In order to update and improve available evidence on any link, a meta-analysis was performed. Method: We searched the PubMed database for prospective cohort studies investigating the relation of physical activity with risk of lung cancer. The pooled relative risk (RR) with its 95% confidence intervals (95%CI) was used to assess the association. Results: We included 14 prospective studies with a total of 1,644,305 participants, with 14,074 incident lung cancer cases documented during follow-up. Meta-analysis of all 14 studies suggested both high and medium levels of physical activity to be associated with decreased risk of lung cancer compared to the reference group with low level of physical activity (for high level, RR = 0.77, 95%CI 0.73-0.81, P < 0.001; for medium level, RR = 0.87, 95%CI 0.83-0.90, P < 0.001). Subgroup analyses by gender found obvious associations in both men and women. No publication bias was observed. Conclusion: Our findings suggest that high and medium levels of physical activity have a beneficial effect on lung cancer by reducing the overall risk of tumour development among both men and women.

Meta-analysis of Six Randomized Control Trials of Chemotherapy Plus Anti-HER Monoclonal Antibody for Advanced Gastric and Gastroesophageal Cancer

  • Luo, Huai-Qing;Han, Li;Jiang, Yan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.13
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    • pp.5343-5348
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    • 2014
  • Background: A meta-analysis was performed to examine the benefit/risk ratio for the addition of anti- HER MoAbs to chemotherapy in patients with advanced gastric and gastroesophageal cancer from six randomized phase II/III trials. Materials and Methods: We searched relative trials from Pubmed, EMBASE, Cochrane library databases, China National Knowledge Infrastructure databases, Google Scholar and the NIH ClinicalTrials. Primary outcomes were overall response rate (ORR), progression-free survival (PFS), overall survival (OS). Secondary outcomes were toxicities. All analyses were performed using STATA 12.0. Results: This meta-analysis included six randomized controlled trials (RCTs) with 2, 297 patients and we demonstrated that the anti-HER MoAbs arm did have a positive effect on ORR in the anti-HER MoAbs arm (OR 1.28, 95% CI 1.00-1.64, p=0.01). There was an increasing benefit regarding OS (HR 0.74, 95% CI 0.60-0.88, p<0.05) and PFS (HR 0.72, 95% CI 0.60-0.84, p<0.05) in the anti-HER2 subgroup, but a reduction of OS (HR 1.11, 95% CI 0.87-1.36, p<0.05) and PFS (HR 1.13, 95% CI 0.98 -1.28, P<0.05) in anti-EGFR subgroup. Some grade 3-4 toxicity had a significantly higher incidence in the anti-HER MoAbs arm. There was no significant publication bias for all endpoints. Conclusions: The addition of trstuzumab MoAb to chemotherapy for gastric and gastroesophageal cancer significantly improved outcome of OS and PFS endpoints, while other MoAbs led to no improvement in results. Some adverse events were increased in anti-HER MoAbs arm compared with the control.

MTHFR Polymorphisms and Pancreatic Cancer Risk:Lack of Evidence from a Meta-analysis

  • Li, Lei;Wu, Sheng-Di;Wang, Ji-Yao;Shen, Xi-Zhong;Jiang, Wei
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.5
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    • pp.2249-2252
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    • 2012
  • Objective: Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been reported to be associated with pancreatic cancer, but the published studies had yielded inconsistent results.We therefore performed the present meta-analysis. Methods: A search of Google scholar, PubMed, Cochrane Library and CNKI databases before April 2012 was conducted to summarize associations of MTHFR polymorphisms with pancreatic cancer risk. Assessment was with odds ratios (ORs) and 95% confidence intervals (CIs). Publication bias were also calculated. Results: Four relative studies on MTHFR gene polymorphisms (C667T and A1298C) were involved in this meta-analysis. Overall, C667T(TT vs. CC : OR = 1.61, 95%CI = 0.78 - 3.34; TT vs. CT : OR = 1.41, 95%CI = 0.88-2.25; dominant model: OR = 0.68, 95%CI = 0.40-1.17; recessive model: OR = 0.82, 95%CI = 0.52-1.30) and A1298C(CC vs. AA:OR=1.01, 95%CI=0.47-2.17; CC vs. AC: OR=0.99,95%CI=0.46-2.14; dominant model: OR=1.01, 95%CI = 0.47-2.20; recessive model: OR = 1.01, 95%CI = 0.80-1.26) did not increase pancreatic cancer risk. Conclusion: This meta-analysis indicated that MTHFR polymorphisms (C667T and A1298C) were not associated with pancreatic cancer risk.

Obesity and Risk of Bladder Cancer: A Meta-analysis of Cohort Studies

  • Qin, Qi;Xu, Xin;Wang, Xiao;Zheng, Xiang-Yi
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.5
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    • pp.3117-3121
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    • 2013
  • Objective: Previous epidemiologic studies demonstrated that obesity might associated with the risk of bladder cancer. However, many of the actual association findings remained conflicting. To better clarify and provide a comprehensive summary of the correlation between obesity and bladder cancer risk, we conducted a meta-analysis to summarize results of studies on the issue. Stratified analyses were also performed on potential variables and characteristics. Methods: Studies were identified by searching in PubMed and Wanfang databases, covering all the papers published from their inception to March 10, 2013. Summary relative risks (SRRs) with their corresponding 95% confidence intervals (CIs) were calculated by either random-effect or fixed-effect models. Results: A total of 11 cohort studies were included in our meta-analysis, which showed that obesity was associated with an increased risk for bladder cancer in all subjects (RR=1.10, 95% CI=1.06-1.16; p=0.215 for heterogeneity; $I^2$=24.0%). Among the 9 studies that controlled for cigarette smoking, the pooled RR was 1.09 (95% CI 1.01-1.17; p=0.131 for heterogeneity; $I^2$=35.9%). No significant publication bias was detected (p = 0.244 for Egger's regression asymmetry test). Conclusions: Our results support the conclusion that obesity is associated with the increased risk of bladder cancer. Further research is needed to generate a better understanding of the correlation and to provide more convincing evidence for clinical intervention in the prevention of bladder cancer.

The quantitative study on the Renying·Qi mouth comparison pulse diagnosis (인영(人迎)·기구비교맥법(氣口比較脈法)의 정량화(定量化)에 관(關)한 연구(硏究))

  • Cho, Myung-Rae;Kim, Moo-Shin;Ryu, Choong-Ryul;Choi, Chan-Hun;Jang, Kyeong-Seon;So, Cheol-Ho;Park, Young-Dae
    • Journal of Acupuncture Research
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    • v.19 no.2
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    • pp.149-163
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    • 2002
  • Objective : We have studied literatures of Renying Qi mouth comparison pulse diagnosis theory and distinguished the excess, deficiency and quick-temper of pulse as the measurement parameter of Renying Qi mouth pulse diagnosis. Methods : We have acquired pulse signals of Renying Qi mouth by using diagnostic equipment of Renying Qi mouth pulsation and estimated reappearance of pulse signals. Results : 1. The measurement parameter of Renying Qi mouth pulse diagnosis distinguishes the excess, deficiency and quick-temper of pulse through relative comparison of Renying Qi mouth. 2. When we acquired the pulse singals of Renying Qi mouth by using diagnostic equipment, the property, measuring area, bias pressure, contact or adhesion state of the sensor are considered. 3. As getting the pulse signal of Renying Qi mouth, the sensor of a sound detective mode is effective. 4. The diagnostic equipment of Renying Qi mouth pulse is assessed as being significant reappearance.

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Ginseng consumption and risk of cancer: A meta-analysis

  • Jin, Xin;Che, Dao-biao;Zhang, Zhen-hai;Yan, Hong-mei;Jia, Zeng-yong;Jia, Xiao-bin
    • Journal of Ginseng Research
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    • v.40 no.3
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    • pp.269-277
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    • 2016
  • Background: The findings of currently available studies are not consistent with regard to the association between the risk of cancer and ginseng consumption. Therefore, we aimed to evaluate this association by conducting a meta-analysis of different studies. Methods: To systematically evaluate the effect of ginseng consumption on cancer incidence, six databases were searched, including PubMed, Ovid Technologies, Embase, The Cochrane Library, China National Knowledge Infrastructure, and Chinese VIP Information, from 1990 to 2014. Statistical analyses based on the protocol employed for a systematic review were conducted to calculate the summary relative risks (RRs) and 95% confidence intervals (CIs). Results: We identified nine studies, including five cohort studies, three case-control studies, and one randomized controlled trial, evaluating the association between ginseng consumption and cancer risk; these studies involved 7,436 cases and 334,544 participants. The data from the meta-analysis indicated a significant 16% lower risk of developing cancer in patients who consumed ginseng (RR = 0.84, 95% CI = 0.76-0.92), with evidence of heterogeneity (p = 0.0007, $I^2$ = 70%). Stratified analyses suggested that the significant heterogeneity may result from the incidence data for gastric cancer that were included in this study. Publication bias also showed the same result as the stratified analyses. In addition, subgroup analyses for four specific types of cancer (colorectal cancer, lung cancer, gastric cancer, and liver cancer) were also performed. The summary RRs for ginseng intake versus no ginseng consumption were 0.77 for lung cancer, 0.83 for gastric cancer, 0.81 for liver cancer, and 0.77 for colorectal cancer. Conclusion: The findings of this meta-analysis indicated that ginseng consumption is associated with a significantly decreased risk of cancer and that the effect is not organ specific.

Impact of Outliers on the Statistical Measures of the Environmental Monitoring Data in Busan Coastal Sea (이상자료가 연안 환경자료의 통계 척도에 미치는 영향)

  • Cho, Hong-Yeon;Lee, Ki-Seop;Ahn, Soon-Mo
    • Ocean and Polar Research
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    • v.38 no.2
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    • pp.149-159
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    • 2016
  • The statistical measures of the coastal environmental data are used in a variety of statistical inferences, hypothesis tests, and data-driven modeling. If the measures are biased, then the statistical estimations and models may also be biased and this potential for bias is great when data contain some outliers defined as extraordinary large or small data values. This study aims to suggest more robust statistical measures as alternatives to more commonly used measures and to assess the performance these robust measures through a quantitative evaluation of more typical measures, such as in terms of locations, spreads, and shapes, with regard to environmental monitoring data in the Busan coastal sea. The detection of outliers within the data was carried out on the basis of Rosner's test. About 5-10% of the nutrient data were found to contain outliers based on Rosner's test. After removal (zero-weighting) of the outliers in the data sets, the relative change ratios of the mean and standard deviation between before and after outlier-removal conditions revealed the figures 13 and 33%, respectively. The variation magnitudes of skewness and kurtosis are 1.36 and 8.11 in a decreasing trend, respectively. On the other hand, the change ratios for more robust measures regarding the mean and standard deviation are 3.7-10.5%, and the variation magnitudes of robust skewness and kurtosis are about only 2-4% of the magnitude of the non-robust measures. The robust measures can be regarded as outlier-resistant statistical measures based on the relatively small changes in the scenarios before and after outlier removal conditions.