179 research outputs found

    Relationship between Emotional Labor, Perceived School Climate and Emotional Exhaustion: A Study on Public School Teachers

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    Teachers’ emotional labor strategies have increased their importance in recent years. Teaching as a profession requires the high level of emotional labor which is a new area of research and it needs to be examined in terms of causes and consequences. The aim of this study is to analyze the relationship between emotional labor, perceived school climate, and emotional exhaustion. The sample included 212 primary, middle and high school teachers in Istanbul. As a survey instrument questionnaire was used to learn the respondents’ perception of school climate, emotional labor strategies, and emotional exhaustion. Structural equation modeling was used to analyze if; school climate is an antecedent of emotional labor, emotional exhaustion is a consequence of emotional labor and there is a relationship between school climate and emotional exhaustion. Results indicated that Turkish school teachers’ emotional exhaustion was negatively affected by the school climate. In contrast, teachers’ perceptions of school climate did not have a significant effect on emotional labor strategies. On the other hand, teachers’ surface acting strategies had a positive and significant effect on emotional exhaustion but teachers’ deep acting behaviors had no significant effect on emotional exhaustion

    Characterization of an embedded RF-MEMS switch

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    An RF-MEMS capacitive switch for mm-wave integrated circuits, embedded in the BEOL of 0.25μm BiCMOS process, has been characterized. First, a mechanical model based on Finite-Element-Method (FEM) was developed by taking the residual stress of the thin film membrane into account. The pull-in voltage and the capacitance values obtained with the mechanical model agree very well with the measured values. Moreover, S-parameters were extracted using Electromagnetic (EM) solver. The data observed in this way also agree well with the experimental ones measured up to 110GHz. The developed RF model was applied to a transmit/receive (T/R) antenna switch design. The results proved the feasibility of using the FEM model in circuit simulations for the development of RF-MEMS switch embedded, single-chip multi-band RF ICs

    Three-dimensional modelling and morphometric investigation of computed tomography images of brown bear’s (Ursus arctos) ossa cruris (Zeugopodium)

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    Background: This study was aimed to examine the detailed morphometrical and morphological characteristics of the bone by creating three-dimensional images through multidetector computed tomography images of ossa cruris in brown bears.Materials and methods: Four brown bear ossa cruris were used in the study.Results: It was observed that tibia and fibula articulated at proximal and distal epiphysis and they combined, and ossa cruris were shaped in this way. Cochlea tibiae were determined to be sagittally oriented. The length of the tibia was determined to be 268.97 mm and 266.32 mm at right and left sides, respectively. The length of the fibula was determined to be 249.16 mm and 250.19 mm on average at the right and left sides, respectively. In consequence of the correlation analysis, statistical relationships at different rates were detected between themeasured values.Conclusions: Detailed anatomical examinations are very important in terms of determining the similarities and differences of bear bones with those of the other species in the order Carnivora. Therefore, it is thought that this study will reveal detailed characteristics of ossa cruris of bears and provide data for further studies on archaeological and forensic sciences

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

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    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

    Formation of different magnetic phases and high Curie temperature ferromagnetism in Fe57-implanted ZnO film

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    © 2014 Elsevier B.V. All rights reserved. We investigated magnetic properties of ZnO thin film implanted with Fe57 ions to the fluence of 1.00×1017 ions/cm2. Both vibrating sample magnetometry and magneto-optical Kerr effect measurements revealed strong room temperature ferromagnetism with similar hysteresis loops. Temperature dependent measurements showed a very high Curie temperature around 850 K. Conversion electron Mössbauer spectroscopy experiments proved the existence of paramagnetic Fe+3 and Fe+2 ions and also the presence of substitutional Fe atoms in the hexagonal ZnO crystal resulting in intrinsic ferromagnetic order

    Fundamentals, progress, and future directions of nitride-based semiconductors and their composites in two-dimensional limit: A first-principles perspective to recent synthesis

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    Potential applications of bulk GaN and AlN crystals have made possible single and multilayer allotropes of these III-V compounds to be a focus of interest recently. As of 2005, the theoretical studies have predicted that GaN and AlN can form two-dimensional (2D) stable, single-layer (SL) structures being wide band gap semiconductors and showing electronic and optical properties different from those of their bulk parents. Research on these 2D structures have gained importance with recent experimental studies achieving the growth of ultrathin 2D GaN and AlN on substrates. It is expected that these two materials will open an active field of research like graphene, silicene, and transition metal dichalcogenides. This topical review aims at the evaluation of previous experimental and theoretical works until 2018 in order to provide input for further research attempts in this field. To this end, starting from three-dimensional (3D) GaN and AlN crystals, we review 2D SL and multilayer (ML) structures, which were predicted to be stable in free-standing states. These are planar hexagonal (or honeycomb), tetragonal, and square-octagon structures. First, we discuss earlier results on dynamical and thermal stability of these SL structures, as well as the predicted mechanical properties. Next, their electronic and optical properties with and without the effect of strain are reviewed and compared with those of the 3D parent crystals. The formation of multilayers, hence prediction of new periodic layered structures and also tuning their physical properties with the number of layers are other critical subjects that have been actively studied and discussed here. In particular, an extensive analysis pertaining to the nature of perpendicular interlayer bonds causing planar GaN and AlN to buckle is presented. In view of the fact that SL GaN and AlN can be fabricated only on a substrate, the question of how the properties of free-standing, SL structures are affected if they are grown on a substrate is addressed. We also examine recent works treating the composite structures of GaN and AlN joined commensurately along their zigzag and armchair edges and forming heterostructures, δ-doping, single, and multiple quantum wells, as well as core/shell structures. Finally, outlooks and possible new research directions are briefly discussed. © 2018 Author(s)

    Gas and seismicity within the Istanbul seismic gap

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    Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain
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