• Title/Summary/Keyword: bias effect

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Anti-Diabetic Medications Do Not Influence Risk of Lung Cancer in Patients with Diabetes Mellitus: a Systematic Review and Meta-analysis

  • Nie, Shu-Ping;Chen, Hui;Zhuang, Mao-Qiang;Lu, Ming
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6863-6869
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    • 2014
  • Objectives: Several preclinical and observational studies have shown that anti-diabetic medications (ADMs) may modify the risk of lung cancer. We performed a systematic review and meta-analysis evaluating the effect of metformin, sulfonylureas (SUs), thiazolidinediones (TZDs), and insulin on the risk of lung cancer in patients with diabetes mellitus (DM). Materials and Methods: We conducted a systematic search of Pubmed and Web of Science, up to August 20, 2013. We also searched the Conference Proceedings Citation Index (CPCI) and China National Knowledge Infrastructure (CNKI) for abstracts from major meetings. Fixed or random effect pooled measures were selected based on heterogeneity among studies, which was evaluated using Q test and the I2 of Higgins and Thompson. Meta-regression was used to explore the sources of between-study heterogeneity. Publication bias was analyzed by Begg's funnel plot and Egger's regression test. Associations were assessed by odds ratios (ORs) with 95% confidence intervals (CIs). Results: A total of 15 studies (11 cohort, 4 case-control) were included in this meta-analysis. In observational studies no significant association between metformin (n=11 studies; adjusted OR=0.99, 95%CI: 0.87-1.12), SUs (n=5 studies; adjusted OR=0.98, 95%CI: 0.79-1.22), or TZDs (n=7 studies; adjusted OR=0.92, 95%CI: 0.75-1.13), insulin (n=6 studies; adjusted OR=1.13, 95%CI: 0.79-1.62) use and risk of developing lung cancer was noted. There was considerable inherent heterogeneity between studies not explained by study design, setting, or location. Conclusions: Meta-analysis of existing studies does not support a protective or harmful association between ADMs use and risk of lung cancer in patients with DM. There was considerable heterogeneity across studies, and future, well-designed, prospective studies would be required for better understanding of any association.

News Impacts and the Asymmetry of Oil Price Volatility (뉴스충격과 유가변동성의 비대칭성)

  • Mo, SooWon
    • Environmental and Resource Economics Review
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    • v.13 no.2
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    • pp.175-194
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    • 2004
  • Volumes of research have been implemented to estimate and predict the oil price. These models, however, fail in accurately predicting oil price as a model composed of only a few observable variables is limiting. Unobservable variables and news that have been overlooked in past research, yet have a high likelihood of affecting the oil price. Hence, this paper analyses the news impact on the price. The standard GARCH model fails in capturing some important features of the data. The estimated news impact curve for the GARCH model, which imposes symmetry on the conditional variances, suggests that the conditional variance is underestimated for negative shocks and overestimated for positive shocks. Hence, this paper introduces the asymmetric or leverage volatility models, in which good news and bad news have different impact on volatility. They include the EGARCH, AGARCH, and GJR models. The empirical results showed that negative shocks introduced more volatility than positive shocks. Overall, the AGARCH and GJR were the best at capturing this asymmetric effect. Furthermore, the GJR model successfully revealed the shape of the news impact curve and was a useful approach to modeling conditional heteroscedasticity.

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Genetic Variant in CLPTM1L Confers Reduced Risk of Lung Cancer: a Replication Study in Chinese and a Meta-analysis

  • Luo, Xia;Lamsal, Laxmi Pangeni;Xu, Wen-Juan;Lu, Jie;Lu, Yan-Jun;Shen, Ying;Guan, Qing
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.21
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    • pp.9241-9247
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    • 2014
  • Background: Rs31489 in the cleft lip and palate transmembrane1-like gene (CLPTM1L) has been identified to be associated with lung cancer through genome-wide association studies (GWAS). However, some recent replication studies yielded inconclusive results. Thus, we undertook this study to investigate the precise effect of rs31489 on lung cancer susceptibility. Materials and Methods: A hospital-based case-control study in 1,673 Chinese subjects (611 individuals with lung cancer and 1,062 controls) and a meta-analysis among 32,199 subjects (16,364 cases and 15,835 controls) were performed in this study. Results: In our case-control study, rs31489 was inversely associated with lung cancer (AC versus CC: OR=0.68, 95%CI=0.52-0.88; additive model: OR=0.68, 95%CI=0.54-0.85; dominant model: OR=0.65, 95%CI =0.51-0.84). Stratification analysis by smoking status showed a significant association and strong genetic effect in non-smokers but not in smokers. Our meta-analysis further confirmed the association, although with significant heterogeneity contributed by study design and source of controls, as shown by stratified analysis. Sensitive and cumulative analyses both indicated robust stability of our results. In addition, there was no observable publication bias in our meta-analysis. Conclusions: Overall, the findings from our replication study and meta-analysis demonstrated that CLPTM1L gene rs31489 is significantly associated with lung cancer.

Bit-Rate Analysis of Various Symmetric ESQWs SEED under Optimized Input Power (최적 입사 광 전력 하에서의 대칭 ESQWs SEED의 비트 전송률 특성 분석)

  • Lim, Youn-Sup;Choi, Young-Wan
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.7
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    • pp.66-79
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    • 1999
  • We investigate the effects of high input power on the performance of optical bistable symmetric self-electooptic effect devices (S-SEEDs) using extremely shallow quantum wells (ESQWs). In this study, we consider the four ESQWs SEEDs; anti-reflection (AR)-coated ESQWs S-SEED, back-to-back AR coated ESQWs S-SEED, asymmetric F뮤교-Perot (AFP) ESQWs S-SEED, and back-to-back AFP-ESQWs S-SEED. As the input power increases, device performances such as on/off contrast ratio, on/off reflectivity difference are seriously degraded because of ohmic heating and exciton saturation. On the other hand, switching speed of the device increases up to certain value and then begins to decrease. With reasonable optimization of the input power for the best switching speed operation of the devices in a cascading optical interconnection system, we simulate and analyze the system bit-rate of the various ESQWs S-SEEDs, for a mesa of $5{\times}5{\mu}m^2$ size, changing the namber of quantum wells for the external bias of 0 V and -5V.

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A Study on the Effect of Customer Orientation in the Hospital Coordinator's role ambiguity and support situations (병원코디네이터의 역할모호성 및 지원상황이 고객지향성에 미치는 영향에 관한 연구)

  • Kim, Young-Hyuk
    • Korea Journal of Hospital Management
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    • v.18 no.3
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    • pp.1-26
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    • 2013
  • To improve the competitiveness of the hospital provides high quality medical services in a hospital coordinator role is emphasized. This study on customer orientation of the role ambiguity in order to identify the impact of degree of customer orientation were analyzed for demographic differences. Dependent variable, customer orientation affects role ambiguity as independent variables, and regression analysis were set. And the control variables are set to support situational factors, customer orientation on the role ambiguity and hierarchical regression analysis was performed. Obtained through empirical results are as follows: First, according to the demographic characteristics of the hospital coordinator customer orientation, the difference between gender and medical subjects are not shown. Age, education, work experience, job title, and the hospital on the pattern of customer orientation has shown a difference. Second, according to the hospital coordinator role ambiguity about its impact on customer orientation analysis can be a role implementation, job implementation, opinion communication in achieving customer orientation was negatively affected. Third, role ambiguity, and customer orientation factors for the moderating effects of organizational support for the role of customer orientation can role implementation, job implementation, opinion communication was a statistically significant. Fourth, the role ambiguity factors and customer orientation for the administrative support for the moderating effect of customer orientation and role implementation is significant, but job implementation, opinion communication were statistically significant. Fifth, the role ambiguity factors and customer support for customer orientation and customer orientation for the moderating effects of role performance and the opinion communication was not statistically significant. However, job implementation was statistically significant. The limitations of this study are as follows: First, role ambiguity, situational factors and support due to limitations of the variable factors that may affect the customer orientation of a number of factors were excluded. So many exogenous variables in the measurement process can affect. Second, the variables measured as problems of self-assessment by the variable measuring the respondent's bias may occur. Third, This study is difficult to generalize. In other words, several areas of the province conducted by the empirical results of the survey as a limit on the overall generalization can follow.

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The Effect of Management Earnings Forecasts on Future Earnings Quality (경영자의 이익예측정보공시가 미래 이익의 질에 미치는 영향)

  • Kim, Seon-Gu
    • Journal of the Korea Convergence Society
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    • v.8 no.11
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    • pp.363-372
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    • 2017
  • This study analyzed how management earnings forecasts would have an effect on future earnings quality. The analysis period of study was from 2003 till 2009 (ofrom 2004 till 2011) based on variables of interest (dependent variables) and the annual data from a total of 475 companies that publicly announced manager's operating earnings forecasts among securities listing companies were used for analysis. As a result, first, it appeared that the more optimistic the manager's earnings forecasts were for the current term, the lower the future earnings quality was. Second, it was found that the lower the accuracy of the manager's earnings forecasts was for the current term, the lower the future earnings quality was. Such findings suggest that management earnings forecasts will be used for determining future earnings quality.

Review of Moxibustion Treatment for Hypertension in Clinical Trials (임상연구에서 나타난 고혈압 뜸치료법에 대한 고찰)

  • Liu, Yan;Park, Ji-Eun;Kim, Ae-Ran;Jung, Hee-Jung;Choi, Sun-Mi
    • Journal of Acupuncture Research
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    • v.28 no.5
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    • pp.87-96
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    • 2011
  • Objectives : The aim of this study is to review clinical trials using moxibustion on hypertension and to assess their methodology and results. Methods : Electronic literature searches for clinical trials (randomized trial, non-randomized trial, before-after study) of moxibustion were performed in nine electronic databases (four international databases and five Korean databases) and handsearch. English, Korean or Chinese articles were included. Laboratory or animal studies were excluded. Results : A total of twelve studies met the inclusion criteria. Seven randomized controlled trial, three non-randomized trials and two before-after studies were included. Seven studies used direct moxibustion(two are scarring one) and five used indirect one. Five of twelve studies used moxibustion treatment just one time, except for that most frequency was once daily or 2-3 times per week for 1-2 months. Of ten randomized or non-randomized studies, three used antihypertension drug control and another three used waiting list control. Compare to baseline, change of blood pressure after moxibustion treatment was significant in all studies. However, the results of effect in blood pressure between moxibustion and controlled were not consistent. Methodological quality of clinical trials included in this review was low and has risk of bias, especially in blinding of parcitipant. Conclusions : There are little high-quality clinical trials of moxibustion for hypertension. To evaluate the effect of moxibustion, more rigorous trials are warranted. Also, methodology of clinical trials have to be descripted in detail.

Frequency-dependent C-V Characteristic-based Extraction of Interface Trap Density in Normally-off Gate-recessed AlGaN/GaN Heterojunction Field-effect Transistors

  • Choi, Sungju;Kang, Youngjin;Kim, Jonghwa;Kim, Jungmok;Choi, Sung-Jin;Kim, Dong Myong;Cha, Ho-Young;Kim, Hyungtak;Kim, Dae Hwan
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.5
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    • pp.497-503
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    • 2015
  • It is essential to acquire an accurate and simple technique for extracting the interface trap density ($D_{it}$) in order to characterize the normally-off gate-recessed AlGaN/GaN hetero field-effect transistors (HFETs) because they can undergo interface trap generation induced by the etch damage in each interfacial layer provoking the degradation of device performance as well as serious instability. Here, the frequency-dependent capacitance-voltage (C-V) method (FDCM) is proposed as a simple and fast technique for extracting $D_{it}$ and demonstrated in normally-off gate-recessed AlGaN/GaN HFETs. The FDCM is found to be not only simpler than the conductance method along with the same precision, but also much useful for a simple C-V model for AlGaN/GaN HFETs because it identifies frequency-independent and bias-dependent capacitance components.

A Study on the Wear comfort and the Wearing Effects of Maternity Girdles (시판 임산부용 거들의 착용감 및 착용효과에 관한 연구)

  • 최혜선
    • Journal of the Korean Home Economics Association
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    • v.29 no.3
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    • pp.11-21
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    • 1991
  • The study has been intended to find out meaningful information about the development of a prototype of enhanced maternity girdle. The girdles of three different models which were available in the market have been carried out by three six-month pregnant women and three nine-month pregnant women. The results of the study are as follows. 1. All three girdles showed improved wear effects in order of model A, model B, model C. Body surface area measurement and two body surface angles of abdomen are significantly dicreased by wearing and type of girdles. It is presumed that the reasons of good wear effect of model A is low expansion rate of the material and tight fitness of the model. Model B is made of material whose expansion rate is higher than model A. Also abdominal part of the model B is bias cut which is considered to result better stretch and consequently lower wear effect. 2. For wear comfort, subjects preferred in order of model B, model C, and model A. All subjects feel more comfortable after wearing girdles 30 minutes than after wearing girdles 1 day. Comparing 2 subject groups, 6-month pregnant group feel more comfortable about wearing girdles than 9-month pregnant group. 3. The girdles are expanded as a whole in order of model B, model C and model A. Considering the expansion rate of some specific area of the girdles, abdominal area expands more than hip area which expands more than thigh area. The expansion rates of girdles worn to 6-month pregnant group are very low at all area, while the expansion rates of girdles worn to 9-month pregnant group are very high.

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Association between Praziquantel and Cholangiocarcinoma in Patients Infected with Opisthorchis viverrini: A Systematic Review and Meta-Analysis

  • Kamsa-Ard, Supot;Laopaiboon, Malinee;Luvira, Vor;Bhudhisawasdi, Vajarabhongsa
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.11
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    • pp.7011-7016
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    • 2013
  • Background: The liver fluke, Opisthorchis viverrini, and the associated incidence of subsequent cholangiocarcinoma (CCA) are still a public health problem in Thailand, and praziquantel (PZQ) remains the antihelminthic drug of choice for treatment. Evidence in hamsters shows that repeated infection and PZQ treatments could increase the risk of CCA. However, the existing evidence in humans is inconclusive regarding increased risk of CCA with frequency of PZQ intake. Objectives: To investigate the relationship between number of repeated PZQ treatments and CCA in patients with O viverrini infection. Materials and Methods: The reviewed studies were searched in EMBASE, MEDLINE, ProQuest, PubMed and SCOPUS from inception to October, 2012 using prespecified keywords. The risk of bias (ROB) of included studies was independently assessed by two reviewers using a quality scale from the Newcastle-Ottawa Scale (NOS). Risk effect of PZQ was estimated as a pooled odds ratio (OR) with its 95% confidence interval (95%CI) in the random-effects model using DerSimonian and Laird's estimator. Results: Three studies involving 637 patients were included. Based on the random effects model performed in two included studies of 237 patients, the association between PZQ treatments and CCA was not statistical significant with a pooled OR of 1.8 (95%CI; 0.81 to 4.16). Conclusions: The present systematic review and meta-analysis provides inconclusive evidence of risk effect of PZQ on increasing the risk of CCA and significant methodological limitations. Further research is urgently needed to address the shortcomings found in this review, especially the requirement for histological confirmation.