Mode choice and shopping mall parking

In this thesis, I analyze individuals' mode choice decisions and shopping mall's parking space pricing behavior. Individuals have three choices: first they may come to the mall by car in which case they have to park, second they may come by public transportation, or they do not visit the mall and go for their outside option. The mall determines the price of the good and the parking fee after the government sets public transportation fare. I find that the equilibrium parking fees are always less than the marginal cost of providing parking spaces and more importantly they are two of the many parking fees that lead to the social optimum. The mall can be thought as using parking as a loss leader to increase its profits, and implicitly employing mixed bundling in which the good is sold either alone or bundled with parking

An empirical analysis of macroeconomic and bank-specific factors affecting liquidity of banks: The case of Turkey

Bu çalışmanın amacı, 2005-2015 döneminde Türkiye’de faaliyette bulunan bankalarının likidite düzeyini etkileyen makroekonomik ve bankaya özgü faktörlerin araştırılmasıdır. Panel veri analiz tekniklerinin kullanıldığı çalışmadan elde edilen ampirik bulgular, bankalar tarafından tutulan likit varlıkların düzeyi ile banka sermayesi, aktif kalitesi ve mevduat düzeyi arasında pozitif yönlü ve istatistiksel olarak anlamlı bir ilişki olduğunu göstermektedir. Bununla birlikte, banka büyüklüğü ile likidite düzeyi arasında ters-U şeklinde doğrusal olmayan bir ilişkinin varlığı tespit edilmiştir. Ayrıca makroekonomik faktörlerden ekonomik büyüme, işsizlik oranı ve küresel kriz değişkenlerinin bankaların likidite düzeyini negatif yönde etkiledikleri tespit edilmiştir

Pharyngocutaneous Fistula after Total Laryngectomy: Risk Factors with Emphasis on Previous Radiotherapy and Heavy Smoking

Objective:In this retrospective cohort study, we aimed to determine the incidence of pharyngocutaneous fistula (PCF) after total laryngectomy (TL) and to define the possible predictors for PCF formation.Methods:The medical records of 198 patients with laryngeal squamous cell carcinoma who underwent TL were reviewed. After the exclusion of patients with history of free flap reconstruction, previous laryngeal surgery, and previous radiotherapy (RT) for other primary cancers, the risk factors for PCF were analyzed in 183 patients who were included in the study.Results:The overall incidence of PCF was 20.2%. A history of heavy smoking and previous RT were detected as independent risk factors in both univariate (p=0.004 and p=0.007, respectively) and multivariate (p=0.005) analyses. Preoperative tracheotomy (PT) longer than 14 days was a risk factor for PCF among patients with PT in the univariate analysis (p=0.031). Overall three- and five-year survival rates were statistically indifferent between the PCF and non-PCF groups (p>0.05). However, the overall five-year survival rate was lesser in the persistent PCF group (47%) than in the non-persistent PCF group (83%) (p=0.038).Conclusion:Heavy smoking and previous RT are independent risk factors for PCF, and the persistence of PCF decreases survival rates. Preventable measures should be taken to decrease the incidence and persistence of this complication of TL in the management of patients with possible risk factors

Role of Elective Neck Dissection in Early Stage Lip Cancers

Objective:To date, the management of the neck in early stage lower lip cancers remains controversial. The aim of this study is to investigate if prophylactic neck dissection is necessary in early stage lower lip cancers.Methods:Charts of 11 patients who underwent surgery of the primary site and neck because of T1–2N0 lower lip cancer between 1997 and 2011 were retrospectively examined. Clinical stages, surgeries, histopatological examination results, and loco-regional recurrences were evaluated.Results:Of the 11 patients, 10 were male (90.9%) and 1 was female (9.09%). The follow-up time of these patients was between 24-168 months (mean, 56.6 months). There were 5 patients with clinically diagnosed T1N0 tumors and 6 patients with clinically diagnosed T2N0 tumors. Suprahyoid neck dissection was performed in 4/5 T1N0 patients and supraomohyoid neck dissection was performed in the remaining 1 patient. For T2N0 tumors, 4 suprahyoid, 1 supraomohyoid, and 1 comprehensive neck dissection was performed. Histopathological examination revealed no occult metastasis in any of the patients. In 1 patient who had lower lip resection and suprahyoid neck dissection for T1N0 lower lip cancer, a contralateral neck metastasis was detected 22 months postsurgery, and a comprehensive neck dissection was performed.Conclusion:Our results show that in patients with T1N0 lower lip tumors, neck dissection may not be necessary; however, close follow-up is mandatory. Further researches with larger series dividing T2N0 tumors into subgroups for tumor size and thickness are necessary to determine neck treatment in these tumors

Mevcut binalar için güçlendirme yöntemleri geliştirilmesi

TÜBİTAK MAG01.05.2005Bugün ülkemizde ve diğer ülkelerde yaygın olarak uygulanan "sistem iyileştirmesi" yöntemi, dayanımı ve rijitliği yetersiz çerçevelerin bazı gözlerinin betonarme dolgu ile doldurularak yeni bir yatay yük taşıyıcı sistemi olmuşturulması olarak tanımlanabilir. Ülkemizde bugün karşılaşılan en önemli sorunlardan biri de hasar görmemiş ve kullanılmakta olan çok sayıda zayıf binanın depreme dayanıklı duruma getirilmesidir. Bu binaların güçlendirilmesinde, "sistem iyileştirmesi" yönteminin kullanılması elbette mümkündür. Ancak sözü edilen yöntemde dolgu duvarların oluşturulmasında beton kullanılacağından, binaların boşaltılması gerekmektedir. Çok sayıda binanın boşaltılması ve binada yaşayanların eşyaları ile birlikte başka bir konuta yerleştirilmesi pratik bir çözüm değildir. Bu proje kapsamında, depreme dayanıklı olmayan ve halen kullanılmakta olan binaların boşaltılmadan güçlendirilmesini sağlayacak yöntemler geliştirilmiş ve bunların gerekli dayanım ve rijitliği sağladığı deneysel ve analitik olarak kanıtlanmıştır.In the system behavior improvement technique, the general philosophy is to introduce a new lateral load resisting system, which will increase the lateral strength and the lateral stiffness of the existing system, which is generally a non-ductile frame with inadequate lateral stiffness. Various techniques based on this principle have been developed and applied in the past. Among them, the most widely used technique is the formation of new stiff walls through infilling some bays of the existing frame with reinforced concrete infills. Use of infilled frames as a method of seismic behavior improvement for existing structures is presently a very common application in Turkey. All these techniques are applicable at the cost of a certain discomfort to the occupants and, the application of these techniques in the rehabilitation of undamaged buildings may not very practical. With this project, the development of new strengthening techniques was achieved. Experimental and anaylical studies have been done to proove the effectiveness of newly developed strengthening techniques. In this study, rapid and yet reliable rehabilitation methodologies for Turkey have be developed

Effect of Korean Red Ginseng on Noise-Induced Hearing Loss

Objective:Noise-induced hearing loss (NIHL) is one of the most important problems affecting both social and professional life of patients. There is no treatment method considered to be successful on the hearing loss that has become a permanent nature. Aim of this study is to evaluate protective effect of Korean Red Ginseng (KRG) against NIHL in an animal model.Methods:Twenty-eight rats were separated into four groups [control saline (group I), control KRG (group II), saline + noise (group III), KRG + noise (group IV)]. Rats in the saline and KRG groups were fed via oral gavage with a dose of 200 mg/kg/day throughout for 10 days. Fourteen rats (group III and IV) were exposed to 4 kHz octave band noise at 120 dB SPL for 5 hours. Hearing levels of rats were evaluated by distortion product otoacoustic emissions (DPOAE) and auditory brainstem responses (ABR) at 4, 8, 12, 16 and 32 kHz frequencies prior to and on days 1, 7 and 10 after the noise exposure. Rats were sacrificed on 10th day, after the last audiological test. Cochlea and spiral ganglion tissues were evaluated by light microscopy.Results:Audiological and histological results demonstrated that after noise the group IV showed better results than group III. In the noise exposed groups, the most prominent damage was seen at the 8 kHz frequency region than other regions. After the noise exposure, DPOAE responses were lost in 1st, 7th and 10th measurements in both group III and IV. Thus, we were not able to perform any statistical analyses for DPOAE results.Conclusion:Our findings suggest that KRG seems to be an efficient agent against NIHL. There is need for additional research to find out about the mechanisms of KRG’s protective effect

Turner syndrome and associated problems in turkish children: A multicenter study

Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology

The relationship between the board structure and bank profitability: Dynamic panel data analysis

Bu çalışmanın amacı, Türkiye’de mevduat bankalarının yönetim kurulu yapısı ile banka karlılığı arasındaki ilişkiyi incelemektir. Çalışma 2007-2013 dönemini kapsamaktadır ve analizlerde dinamik panel regresyon modelleri (Havuzlanmış EKK, sabit etkiler ve sistem GMM tahmincileri) kullanılmıştır. Yönetim kurulu değişkeni olarak, yönetim kurulunun büyüklüğü, bağımsız yönetici oranı, yabancı yönetici oranı ve liderlik yapısı değişkenleri kullanılmıştır. Çalışmadan elde edilen sonuçlara göre, yönetim kurulu büyüklüğü ile karlılık arasında istatistiksel olarak anlamlı bir ilişki bulunamamıştır. Hem yönetim kuruluna atanan bağımsız yönetici sayısı ile hem de yönetim kurulunda yer alan yabancı yönetici sayısı ile karlılık arasında negatif yönlü bir ilişki olduğu tespit edilmiştir. Genel müdürlük ve yönetim kurulu başkanlığı görevlerini aynı kişinin icra etmesi durumunun ise karlılığı artırdığı görülmüştür. Banka düzeyinde kullanılan kontrol değişkenlerinden banka büyüklüğü ve kredilendirme düzeyi değişkeni ile banka karlılığı arasında istatistiksel olarak anlamlı bir ilişki çıkmamıştır. Banka sermayesi değişkeni ile banka karlılığı arasında ise istatistiksel olarak anlamlı ve pozitif yönlü bir ilişki bulunmuştur.The aim of this study is to examine the relationship between board structure of commercial banks and their profitability in Turkey. The study covers the time period of 2007-2013 and dynamic panel regression models (Pooled OLS, fixed effects and system GMM estimators) are used in the analysis process. The variables such as board size, the proportion of independent directors, the proportion of foreign directors and the dual position of the chairman of the board and the general manager of the bank are used for the board characteristics. According to the results obtained from the study, there is no statistically significant association between board size and profitability. In addition, both the proportion of independent directors and the proportion of foreign directors are found to be negatively related to bank profitability. It has also been observed that the influence of dual position of the chairman of the board and general manager of the bank on profitability is positive. As for the control variables, there is no statistically significant link between bank size and lending level variables and profitability. However, the effect of bank capital on profitability is positive and statistically significant