Performance Evaluation of Logistic Regression, Linear Discriminant Analysis, and Classification and Regression Trees Under Controlled Conditions

Logistic Regression (LR), Linear Discriminant Analysis (LDA), and Classification and Regression Trees (CART) are common classification techniques for prediction of group membership. Since these methods are applied for similar purposes with different procedures, it is important to evaluate the performance of these methods under different controlled conditions. With this information in hand, researchers can apply the optimal method for certain conditions. Following previous research which reported the effects of conditions such as sample size, homogeneity of variancecovariance matrices, effect size, and predictor distributions, this research focused on effects of correlation between predictor variables, number of the predictor variables, number of the groups in the outcome variable, and group size ratios for the performance of LDA, LR, and CART. Data were simulated with Monte Carlo procedures in R statistical software and a factorial ANOVA with follow-ups was employed to evaluate the effect of conditions on the performance of each technique as measured by proportions of correctly predicted observations for all groups and for the smallest group. In most of the conditions for the two outcome measures, higher performances of CART than LDA and LR were observed. But, in some conditions where there were a higher number of predictor variables and number of groups with low predictor variable correlation, superiority of LR to CART was observed. Meaningful effects of methods of correlation, number or predictor variables, group numbers and group size ratio were observed on prediction accuracy of group membership. Effects of correlation, group size ratio, group number, and number of predictor variables on prediction accuracies were higher for LDA and LR than CART. For the three methods, lower correlation and greater number of predictor variables yielded higher prediction accuracies. Having balanced data rather than imbalanced data and greater group numbers led to lower group membership prediction accuracies for all groups, but having more groups led to better predictions for the small group. In general, based on these results, researchers are encouraged to apply CART in most conditions except for the cases when there are many predictor variables (around 10 or more) and non-binary groups with low correlations between predictor variables, when LR might provide more accurate results

A rare manifestation of tuberculosis: Scrofuloderma

Scrofuloderma is a cutaneous manifestation of tuberculosis that results from direct extension of an underlying tuberculous focus, such as lymph node to the overlying skin. In this article, 16-year-old male patient, live in a child detention home, with a purulent, ulcerated lesion in his neck, diagnosed as Scrofuloderma was presented. The case presented in order to stress that Scrofuloderma, a rare form of tuberculosis, should be kept in mind in the differential diagnosis of chronic skin lesions

Yükseköğretimde Uluslararasılaşma: Uluslararası Öğrencilerin Bulunduğu Sınıflarda Ders Veren Öğretim Elemanlarının Öğretim Sürecinde Yaşadıkları Sorunlar ve Çözüm Önerileri / Internationalization of Higher Education: Instructional Problems Experienced by Instructors who teach International Students and Their Suggestions for Solutions

Abstract The aim of this study is to identify problems in the instruction process experienced by instructors teaching international students at English preparatory classes at tertiary level and their suggestions for the solution of the problems. To this end, data were obtained from 26 instructors, selected through criterion sampling, at the school of foreign languages at a state university to define problems experienced in the instruction of reading, writing, speaking and listening skills, the process of assessment and evaluation, classroom communication, behavior management and other related issues regarding international students. This is a qualitative and descriptive case study and a semi-structured interview form was used as data collection instrument, developed based on the research questions, consisting of six questions. The data were analyzed through descriptive analysis and reported with quotations. The research findings suggest that the highest number of problems are experienced in the issues of writing skill, speaking skill, assessment and evaluation, classroom management, reading skill and listening skill respectively. In addition, difference in the alphabet used, pronunciation problems, use of native tongue in lessons, problems in exam practices, discipline problems and absenteeism problems are mostly stated problem areas. Besides, the instructors also offered practical suggestions for the solution of the stated problems. It is expected that the results of the study will put forth the opinions of instructors at tertiary level who are significant stakeholders of the rapid internationalization process in higher education lately and who are also ignored in the literature and thereby contribute to development of practices in the field. Öz Bu araştırmada, uluslararası öğrencilerin bulunduğu İngilizce hazırlık sınıflarında ders veren öğretim elemanlarının, öğretim sürecinde yaşadıkları sorunların ve bu sorunlara ilişkin çözüm önerilerinin belirlenmesi amaçlanmaktadır. Bu amaçla öğretim elemanlarının uluslararası öğrenciler bağlamında okuma, yazma, dinleme ve konuşma becerilerinin öğretiminde, ölçme ve değerlendirme, sınıf içi iletişim, davranış yönetimi ve ilgili diğer konulardaki sorunları tespit etmek ve bu sorunlara ilişkin çözüm önerilerini belirlemek için, bir devlet üniversitesinin yabancı diller yüksekokulunda görev yapan ve ölçüt örnekleme yöntemine göre belirlenmiş 26 öğretim elemanından veri toplanmıştır. Nitel, betimsel bir durum çalışması olarak desenlenen bu araştırmada veri toplama aracı olarak araştırma amaçlarına dayalı olarak altı sorudan oluşan bir yarı yapılandırılmış görüşme formu kullanılmıştır. Elde edilen veriler betimsel analiz yöntemiyle analiz edilmiş ve doğrudan alıntılarla desteklenerek sunulmuştur. Araştırma bulgularına göre öğretim elemanlarının en çok sorun yaşadıkları alanlar sırasıyla yazma becerisi, konuşma becerisi, ölçme ve değerlendirme, sınıf yönetimi, okuma becerisi ve dinleme becerisidir. Ek olarak, alfabe farklılıklarından kaynaklanan sorunlar, telaffuz sorunları, derslerde anadil kullanımı, sınav uygulama sorunları, disiplin sorunları ve devamsızlık sorunları öne çıkan alt sorun alanlarıdır. Diğer yandan, öğretim elamanları sorunların çözümü için pratiğe dönük öneriler de geliştirmişlerdir. Araştırma sonuçlarının yükseköğretimde son dönemde gerçekleşen hızlı uluslararasılaşma sürecinin en önemli paydaşlarından birisi olan ve alanyazında ihmal edilen öğretim elemanlarının görüşlerini ortaya koyarak uygulama pratiklerinin geliştirilmesi için katkı sağlaması beklenmektedir

Evaluation of Nasal Mucociliary Transport Rate by99mTc-Macroaggregated Albumin Rhinoscintigraphy in Woodworkers

Woodworkers in the furniture industry are exposed to wood dust in their workplaces. The aim of this study is to investigate the effect of occupational wood dust exposure on the nasal mucociliary transport rates (NMTRs) in woodworkers. Twenty five woodworkers and 30 healthy controls were included in this study. Wood dust concentration in workplaces was measured using the sampling device. 99m Tc-macroaggregated albumin (99mTc-MAA) rhinoscintigraphy was performed, and NMTR was calculated in all cases. In statistical analysis, an independent samples t-test was used to compare NMTR of woodworkers and control subjects. We found that the mean NMTR of the woodworkers was lower than that of the healthy controls. However, there was not a statistically significant difference between them (P = 0.066). In conclusion, our findings suggested that wood dust exposure may not impair nasal mucociliary transport rate in woodworkers employed in joinery workshops

Rosai-Dorfman Disease Originating from Nasal Septal Mucosa

Rosai-Dorfman disease is a rarely seen disease with unknown etiology. Extranodal involvement is most commonly seen in the head and neck region. Histopathologically, it is characterized by histiocytic cell proliferation. This paper presents a case of a 15-year-old male patient who presented with nasal obstruction and was surgically treated for a mass filling in the left nasal meatus that was diagnosed to be Rosai-Dorfman disease by histopathological examination

Association Between Anxiety, Depression, and Salivary Cortisol Levels in Patients with Recurrent Aphthous Stomatitis

Objective:Recurrent aphthous stomatitis (RAS) is the most common ulcerative disease of the oral mucosa that commonly affects the general population. The objective of this study was to conduct a research in assesing the relationship between psychological disorders including anxiety, depression and salivary cortisol levels in patients with RAS.Methods:Thirty-nine patients suffering from minor RAS were enrolled in the study after obtaining an informed consent. The control group consisted of 25 age and gender matched healthy individuals. All subjects were evaluated by using both psychological tests (Hamilton’s anxiety rating scale [HARS] and Hamilton’s depression rating scale [HDRS]) and physiological testing instrument (salivary cortisol level).Results:While no statistical difference was found between the patients with RAS and controls for both salivary cortisol levels and anxiety, there was statisticaly significant difference between the groups for depression.Conclusion:There was no significant increase in salivary cortisol levels in patients with active disease when compared to the healthy subjects. But we found that depression scale values were significantly higher in patients with RAS

Evaluation of the nasal mucociliary transport rate by rhinoscintigraphy before and after surgery in patients with deviated nasal septum

In this study, we have investigated the effect of nasal septal deviation (NSD) on nasal mucociliary activity and how does a septoplasty operation affecs the nasal mucociliary transport rate in the first and third months during the post-operative period. Twenty-two patients who were diagnosed with NSD and 22 healthy controls were studied using rhinoscintigraphy with Tc-99m-macroaggregated albumin (Tc-99m-MAA). On each case, the nasal mucociliary transport rate (NMTR) was measured pre-operatively only on five cases, on the first and third months of post-operative period. The NMTRs of patients with a deviated septum were significantly lower than the NMTRs of the healthy controls on both the convex and concave sides. Significant improvement was observed in the first post-operative month. On the concave and convex sides, the average postop third month post-operative NMTR value was higher than the first month post-operative NMTR values. It was concluded that the septoplasty operation improves reduced NMTRs after surgery. The effect of nasal surgery on nasal mucociliary activity may be more accurately evaluated in the third month than the first month of post-operative period

pwrss R Paketi ile İstatistiksel Güç Analizi

This study presents the theoretical foundations and computational approaches to statistical power analysis. Ten hypothesis tests and their derivatives are reviewed, including the test of one proportion against a constant, difference between two proportions, one mean against a constant, difference between two means (independent and matched samples), one correlation against a constant, difference between two correlations, R-squared deviation from zero in linear regression, difference between two R-squared values in hierarchical linear regression, analyses of variance/covariance (one-way, two-way and three-way ANOVA or ANCOVA) for comparing means of two or more groups, and repeated measures analysis of variance (one-way repeated measures ANOVA). The concept of statistical power and sample size calculations for these tests are consolidated with practical examples. The hypothesis tests of non-inferiority, superiority, and equivalence, which are widely used in medical and pharmaceutical research are also introduced, and their applications are demonstrated using examples from behavioral and educational research. Calculations were performed with the pwrss R package (https://pwrss.shinyapps.io/lang-en/)