Search

Resampling methods offers effective estimates of parameters and its asymptotic distribution. In this study, it is recommended to use the bootstrap method as an alternative to the classical and knife (one exclusion procedure) test statistics in evaluating the significance of the Pearson correlation coefficient by applying the bootstrap method to the simple linear regression model. This procedure provides an effective alternative to test the significance of the Pearson correlation coefficient. In the application, the model parameters, standard errors, Pearson coefficients of correlation, bias and % 95 confidence intervals belonging to bootstrap and jackknife methods in estimated with the help of a real data and the obtained results are interpreted. As a result, the test statistic obtained by the bootstrap method is proposed as an alternative to the classical and jackknife test statistics. [ABSTRACT FROM AUTHOR]

Objective: The anatomic changes of the patent ductus arteriosus (PDA) in adult patients can complicate its transcatheter occlusion. The aim of the study was to determine procedural approaches to facilitate transcatheter closure of PDA in adult patients using the Amplatzer duct occluder (ADO). Methods: In this prospective study, 33 consecutive adult patients with a moderate to large-sized PDA underwent transcatheter closure. Conventional antegrade approach was used in 14 patients, while retrograde wire-guided assisted approach in remaining 18 patients to access the PDA antegrade. If the initial procedure failed, snare-assisted technique was used to pass through the ductus antegradely. For comparative statistics, the Student's t-test, Mann-Whitney U test and Chi-square test were used as appropriate. Results: Thirty-two patients had successful PDA occlusion. PDA ostium could be engaged in 10 of 14 patients by conventional approach, while 17 of remaining 18 patients by retrograde wire-guided assisted approach (p=0.07). PDAs could be passed antegradely using the snare-assisted technique in those five patients in whom the initial procedure failed. The mean size of implanted devices was 3.76 mm larger than the narrowest size of the PDA. Spontaneous embolization occurred in one patient in whom smaller device implanted due to his short ductus. All patients attained complete occlusion and there were no complications encountered during follow-up. Conclusion: The retrograde wire-guided technique is an effective approach and offers an alternative to access the PDA antegradely in adult patients. Larger than recommended size ADO device can be used safely in all adult patients with feasible ductal ampulla and may prevent device migration. [ABSTRACT FROM AUTHOR]

Objective: There have been numerous investigations demonstrating protective effects of a well- grown coronary collateral circulation (CCC) on left ventricular systolic function. N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) is released by ventricular myocardium as a result of increased myocardial wall stress. The aim of the study was to evaluate the relationship between CCC and plasma NT-pro-BNP levels. Methods: Study group was retrospectively selected from patients who had a coronary angiography at our center between January 2008 and December 2009. One hundred and thirty patients having at least one totally occluded main coronary artery were included in this study. Collateral circulation was graded according to Rentrop score. Grade 0 and 1 are regarded as poor, and grade 2 and 3 - good CCC. Plasma NT-pro-BNP levels were measured by electro chemiluminescence immuno assay method and left ventricular ejection fraction (LVEF) were measured by modified Simpson method. We used Chi-square, Student t and Mann-Whitney-U tests for statistical analysis. Results: Overall 57 patients were found to have poor CCC and 73 patients have good CCC. Plasma NT-pro-BNP levels (pg/ml)-median (minimum maximum)- were 1319 (48-9753) in poor CCC group and 847 (16-5529) in good CCC group (p=0.004). LVEF was found to be -median (minimum maximum)- 45% (30-55%) in poor CCC group and 50% (30-60%) in good CCC group (p=0.003). Correlation analysis demonstrated that collateral grade was negatively correlated with NT-pro-BNP levels (r=-0.252, p=0.004). Conclusion: We found that plasma NT-pro-BNP levels were more elevated in patients with poor CCC than in patients with good CCC. This finding may be explained with the protective effect of good CCC on LVEF. [ABSTRACT FROM AUTHOR]

In this paper, we calculate the different goodness of fit measures for both logit and probit model and compare the results. The findings of the study indicate that there are large numerical differences between the different measures. The results show that it is obviously important to ensure it is the same measure when comparing the goodness of fit values from the same estimation method on different data sets and models. [ABSTRACT FROM AUTHOR]

In accordance with regenerated Turkish teaching programmes in 2004-2005, it has been aimed to bring up individuals who are "using language clearly, effectively, thinking as critically and examined knowledges". Critical thinking ability has provided to individuals a "doubt-based approach, interpreting and decisioning with this approach". While converting this ability to acqusition for learners, Turkish teachers' critical thinking attitudes are very important. For this reason, it must be examined that what Turkish teachers' and candidates' critical thinking attitude and what they are impressed by difference variable. This study have been aimed that Turkish teacher candidates' critical thinking attitudes' changing according to difference variables. 144 students who are in Gazi University Gazi Education Faculty Department of Turkish Teaching has been constituted this research's exemplify. For data gathering, Likert-based critical thinking attitude scale has been used in this research. For data analysis, t-tests in independence group, ANOVA and descriptive statistics have been used in this research. According to research conclusion, in terms of critical thinking ability, Turkish teacher candidates are in middle level. Also, conclusions showed that their attitudes are not impressed by their gender, age, school, parents' education, yearly income, high school type, reading book and newspaper. [ABSTRACT FROM AUTHOR]