Gravitational Attraction Fields for Population in Turkey

Inspired by the gravitational attraction of the masses in Physics, the gravitational pull between the settlements has been proven to be an important phenomenon in explaining potentials that arise among towns. Again inspired by the Electro-magnetic fields in Physics, in this paper, the gravitational attraction between the cities is assumed to be exerted on a city with a certain “charge” on a map of superimposing “charges” of different cities. Following this line, an attraction field has been presented for different census years on city basis in Turkey and possible implications have been evaluated. The values for the year 2000 on the other hand have been tested with other factors including the GNP per head, population and the literacy rate to see the impact of these forces on the tendencies to move in and out of the cities, that is the migrationary effects. The study is as well done seperating the country into a West and an East to see if there are striking differences in between.

Computerised Applications and Evaluation Methods in Land Zoning

Land Zoning is an important issue in urban & regional planning, requiring heavy computational burden. Another challenge ihaving to decide on the parameters to be used in the evaluation. This paper takes the transportation-communication frequency and the rent-inflator interactions between different zonetypes (with possible coefficients) as the major elements in zone-evaluation. For the type of evaluation on the other hand three alternative methods were used. One of these methods only considers one-way interactions in rent-inflator relations. Another one is developped to include a self-updating mechanism on the same interactions. The third of the methods meanwhile attempts to take in account the topological factors. A software was developped in C++ that uses the Manhattan Metric to calculate the distances. The program prompts the user to feed in the evaluation method, different interaction coefficients as well as different landtypes and different maps. The software, based on the preference can either use a steepest descent heuristic or an enumeration algorithm.

The Effect of the Employees of Participation Banks on the Performance of Organizational Commitment

The aim of this study is to determine the organizational performance level of employees and the relationship between them. The sample of the study consists of 309 participation bankers working in Istanbul. In the study, it was found that as the emotional and normative commitment of the employees in the participation bank increased, their work performance increased but decreased due to their attendance commitment. In addition, it was found that 7.8% of the study performance was positively explained by emotional commitment and negative by continuation commitment, and normative commitment did not make a significant contribution to performance. It was found that the organizational performance of the employees did not differ according to the gender, education, job position variable and there were significant differences according to age, marital status and year worked

Multi exciton generation and recombination of semiconductor nanocrystals : fundamental understanding and applications

Ankara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Science of Bilkent Univ., 2013.Thesis (Master's) -- Bilkent University, 2013.Includes bibliographical references leaves 83-95.Semiconductor nanocrystal quantum dots (QDs) have been found to be very promising for important application areas in optoelectronics and photonics. Their energy band-gap tunability, high performance band-edge emission, decent temperature stabilities, and easy material processing make the QDs attractive for these applications ranging from photovoltaic devices to photodetectors and lasers to light-emitting diodes. For these QDs, the concepts of multi exciton generation (MEG) and recombination (MER) have recently been shown to be important especially because they possibly enable efficiency levels exceeding unity using these QDs in various device configurations. However, understanding multi exciton kinetics in QD solids has been hindered by the confusion of MER with the recombination of carriers in charged QDs. This understanding lacks to date and the spectral-temporal aspects of MER still remain unresolved in solid QD ensembles. In this thesis, we reveal the spectral-temporal behavior of biexcitons (BXs) in the presence of photocharging using near-unity quantum yield core/shell CdSe/CdS QDs. The spectral behavior of BXs and that of excitons (Xs) were obtained for the QD samples with different core sizes, exhibiting the strength-tunability of the X-X interaction energy in these QDs. The extraction of spectrally resolved X, BX, and trion kinetics, which would be spectrally unresolved using conventional approaches, is enabled by our approach introducing the integrated time-resolved fluorescence. Besides the fundamental understanding of MEG and MER concepts, we also explored the possibility of utilizing multi excitons in these QDs for optical gain. In this part of the thesis, tunable, high performance, two-photon absorption (TPA) based amplified spontaneous emission (ASE) from the same QDs is presented. Here, for the first time, in addition to the absolute spectral tuning of the ASE, on the single material system of CdSe/CdS, the relative spectral tuning of ASE peak with respect to spontaneous emission was demonstrated. With the core and shell size adjustments, it was shown that Coulombic X-X interactions can be tuned to be either attractive leading to the red-shifted ASE peak or repulsive leading to the blue-shifted ASE peak and that non-shifting ASE can be achieved with the right core-shell combinations. It was further found here that it is possible to obtain ASE at a specific wavelength from both Type-I-like and Type-II-like CdSe/CdS QDs. In addition to the CdSe/CdS QDs, we showed ASE and Type-tunability features on CdSe/CdS nanorods (NRs), which are particularly promising with their extremely high TPA cross-sections and independent emission/absorption tunabilities. In the final part of the thesis, we report the observation of MEG on CdHgTe QDs, for the first time in the literature, and a novel application of MEG concept in a photosensor device, one of the first examples of real-life photosensing application of MEG concept. We believe that the results provided in this thesis do not only contribute to the fundamental understanding of MEG and MER concepts in the QDs, but also pave the way for the utilization of these concepts in the QD-based lasers, photodetectors and photovoltaic devices.Cihan, Ahmet FatihM.S

The study of exposure times and dose-escalation of tick saliva on mouse embryonic stem cell proliferation

The saliva of ticks contains numerous bioactive molecules with anti-hemostatic and immunomodulatory properties. Due to their abilities of self-renewal and pluripotency, stem cells hold considerable promise in the regenerative medicine and biomedical fields. The present study examines the viability and proliferation of mouse embryonic stem cells (mESCs) following the addition of tick salivary gland extracts obtained from three tick species (Dermacentor marginatus, Rhipicephalus bursa and Hyalomma marginatum) to the mESC medium in different quantities (0.2, 2, 20, 40, 80, and 160 µg/ml). On days 2, 5 and 7 of the treatment, the vitality and proliferation of the cells were determined with CellTiter-Glo and morphological tests. The results showed that the culture supplemented with D. marginatus salivary gland extract at a concentration of 80 µg/ml positively affected the proliferation rate of mESC. It was further shown that all concentrations of the salivary gland extracts derived from H. marginatum and R. bursa had a negative effect on the proliferation rate of mESC when compared to the controls

Jute and luffa fiber-reinforced biocomposites: Effects of sample thickness and fiber/resin ratio on sound absorption and transmission Loss Performance

The acoustic properties of natural fiber-reinforced composites should be identified before using these materials in various engineering applications including sound and vibration isolation. This study investigates the effects of sample thickness and fiber/resin ratio on the acoustic performance of jute and luffa fiber-reinforced biocomposites. For this purpose, jute and luffa composite samples with different thicknesses and fiber/epoxy ratios are manufactured and their sound absorption coefficients (SACs) and transmission losses (TLs) are determined using impedance tube method. Thickness-dependent tendencies of the SACs and TLs of jute and luffa composites for low-, medium-, and high-frequency ranges are identified. The effect of fiber/epoxy ratio on the acoustic properties of jute and luffa composites as a function of frequency are determined. Furthermore, the SACs and TLs of some natural fiber-based samples with different thicknesses are predicted using mathematical models and the theoretical and experimental results are compared and evaluated.TUBITAK (The Scientific and Technological Research Council of Turkey) under Grant 119M115.WOS:000638569100001Scopus - Affiliation ID: 60105072Science Citation Index ExpandedQ1Article; Early AccessUluslararası işbirliği ile yapılmayan - HAYIRNisan2021YÖK - 2020-2

Congenital left main coronary artery aneurysm

Left main coronary artery aneurysm (LMCAA) is an uncommon coronary abnormality seen in 0.1% of patients during routine diagnostic coronary angiographies. The most common etiology is atherosclerosis in acquired cases. However, it can also be a congenital malformation. We present the case of a 26 year-old female with a large LMCAA. She was diagnosed with tetralogy of Fallot initially. (Cardiol J 2011; 18, 4: 430–433

The Use of Human Epididymis 4 and Cancer Antigen 125 Tumor Markers in the Benign or Malignant Differential Diagnosis of Pelvic or Adnexal Masses

Background: Ovarian cancer is one of the highest mortality cancers in gynaecology. Discrimination of benign masses from malignant ones may sometimes become a challenge for the clinician since there is not a reliable tumour marker, thus some unnecessary, highly morbid operations can be performed. Aims: To explore the efficacy of human epididymis 4 (HE 4) and cancer antigen 125 (CA 125) markers in differentiating malignant and benign pelvic masses of ovarian origin and to identify the cut-off points for those markers. Study Design: Prospective study. Methods: Fifty-one patients who were diagnosed and planned to undergo surgery for ovarian mass between June 2008 and December 2008 were enrolled into this study. Preoperative venous blood samples were taken and frozen for marker investigation and final diagnoses were concluded by histopathological examination. After recruitment of all cases CA 125 and HE 4 levels were evaluated. Results: The statistical analysis did not indicate any statistically significant difference between the CA 125 levels of the patients with malignant and benign adnexal masses (p=0.105). The HE 4 levels of the patients with malignant adnexal masses were higher at a statistically significant level compared to the patients with benign adnexal masses (p=0.002). For HE 4 tumour marker and at the cut-off point of >25 pM, sensitivity was 1, specificity 0.40, positive cut-off value 0.19, negative cut-off value 1, accuracy 0.47 and positive likelihood ratio 1.65. Conclusion: Human epididymis 4 is a better diagnostic tool than CA 125 in benign-malignant discrimination of adnexal masses. The cut-off value of 25 pmol/L for human epididymis 4 will contribute to providing proper guidance to patients with adnexal masses and applying the proper treatment method