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Scope, Drivers and Manifestations of the Realist Turn in Turkish Foreign Policy: a Case of Delayed Strategic Adjustment
No full textTurkish foreign policy has been on a steep-learning curve since 2015, whereby reliance on hard power has come to undergird its external conduct. Through a levels-of-analysis framework, the article will delineate its meaning, boundaries, and limitations, and problematize how it fits into underlying trends in Turkish foreign policy and security culture. It will argue that while the literature highlights the quest for strategic autonomy, middle power activism, realist turn, and militarization as the main characteristics of the qualitative change, it was the convergence of these longer-term trends and especially the increased propensity to use coercive instruments as part of a realist turn that defined this period. The discussion section will offer a plausible account of the transformation, drawing on insights from neoclassical realism. It will argue that the post-2015 transformation of Turkish behaviour represents an adjustment failure, namely a delayed reaction to external-systemic contingencies by devising corresponding strategies. © 2025 Informa UK Limited, trading as Taylor ; Francis Group
Approximate Formulas for Renewal-Reward Process With Dependent Components and Normally Distributed Interference of Chance
No full textIn this study a modification of renewal-reward process with dependent components and normally distributed interference of chance are investigated. The approximate formulas for the ergodic distribution of the process and its moments are proposed.TOBB University of Economics and Technology (Turkey)STRONG> /STRONG>In addition, one of the authors (Aynura Poladova) would like to thank TOBB University of Economics and Technology (Turkey) and Saleh A. Kamel for financial support of her scientific research
Study on Ultrasonically Actuated Molding: Evaluating an Alternative Manufacturing Method for Enhanced Lightweight Structures
No full textThis study explores ultrasonic treatment (UT) as an alternative to conventional casting methods for lightweight, high-strength materials, with a focus on aerospace applications. The approach in this study integrates computational modeling and experimental validation to design and optimize a two-piece mold system. Ultrasonic energy was applied during the solidification of tin, selected for its low melting point, to evaluate its effects on material properties. The process exploited advanced modeling techniques in COMSOL Multiphysics, addressing key factors such as acoustic pressure and cavitation dynamics. The experimental results reveal significant improvements in mechanical properties, including an increase in tensile strength 13% and considerable improvements in ductility and yield strength compared to traditional casting methods. This work demonstrates the potential of UT to improve casting quality and mechanical properties, paving the way for its application to more complex or different variants of aerospace materials through compliance with a simulation model. Future research will focus on scaling the method for more complex alloys and industrial environments. First and foremost, the authors would like to express their thanks to everyone who helped make this study possible. The authors would like to express their special thanks to Asst. Prof. Yiğit Taşçıoğlu and Assoc. Prof. Arif Sanlı Ergün for their guidance and direction in this study. The authors would also like to thank technician Kamil Arslan for his assistance with the laboratory work. In addition, the authors would like to thank Eren Can Ergül and Fırat Memu for their dedication and assistance in this project, which was very much appreciated. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved
Strongyloides Stercoralis Infection in a Patient Initiating Corticosteroid Therapy for Hypereosinophilia: a Case Report
No full textStrongyloides stercoralis (S. stercoralis) is a soil-transmitted nematode that is endemic to tropical and subtropical regions. S. stercoralis has the ability to cause autoinfection, potentially leading to a chronic disease that can last for decades or result in severe hyperinfection especially in individuals who are taking corticosteroids or other immunosuppressive medications. Here, we report the case of a patient presenting a two-week history of symptoms including cough, fatigue, weight loss, pruritus, and rash. Due to a significant increase in the percentage of eosinophils, the patient was referred to the hematology clinic. The patient underwent a comprehensive evaluation that included an autoimmune panel, genetic testing, and imaging methods. The results of these investigations were found to be normal. The upper gastrointestinal system endoscopy revealed eosinophilic duodenitis and corticosteroid treatment was initiated. The commencement of corticosteroid therapy resulted in a worsening of the patient's symptoms. In the repeated endoscopy of the upper gastrointestinal tract, the presence of S. stercoralis larvae was observed between the crypts. Subsequently, stool tests for S. stercoralis diagnosis were also found to be positive. The patient was at risk of developing a hyperinfection syndrome. Corticosteroids are commonly used to reduce inflammation and manage symptoms associated with eosinophilic disorders. The immunosuppressive effects of corticosteroids are known to precipitate S. stercoralis hyperinfection syndrome, which can result in significant morbidity and mortality. This case highlights the importance of maintaining a high index of suspicion for S. stercoralis in patients undergoing immunosuppressive therapy, particularly when presenting with unexplained eosinophilia
Numerical and Experimental Investigation of Transversal Effective Thermal Conductivity of Sandwich Panel With Lattice Core Under Vacuum Environment
No full textThis study investigates the transversal effective thermal conductivity of an additively manufactured periodic body-centered cubic (BCC) lattice core sandwich panel, commonly used in space applications, under vacuum environment. Theoretical calculations are performed based on the approaches which utilize the relative density of BCC lattice structures to estimate thermal conductivity. Numerical simulations were done using solid finite element (FE) model of the BCC with face sheets to predict its effective thermal conductivity. FE model of the lattice panel was developed to represent the test procedure using effective thermal properties of the lattice core. An experimental setup was established in a thermal vacuum chamber to test the thermal conductivity of the additively manufactured lattice panel and provide validation of the simulation results. The lattice core sandwich panel was designed for a micro satellite and tested in a vacuum environment simulating space conditions as a contribution to literature. The numerical analyses conducted for the experimental setup showed good agreement with the temperatures measured by the thermocouples and remained within the measurement accuracy (±1.5°C) of the thermocouples. Thus, the study highlights the effectiveness of combining simulation and experimental techniques to accurately predict thermal behavior in space environments. The findings provide valuable insights for the design of lightweight, thermally efficient sandwich panels for future space missions. © The Author(s) 2025.Türk Havacılık ve Uzay Sanayii, TUSAS; Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TUBITAK, (20AG051); Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, TUBITA
Asymptotic Formulae for Modified Bernstein Operators Based on Regular Summability Methods
No full textIn this paper, we get new Voronovskaja-type asymptotic formulae for modified Bernstein operators by using regular summability methods. We also display some significant special cases of our results including the methods of Ces ; agrave;ro summability, Riesz summability, Abel summability and Borel summability. At the end, we also discuss the similar results for the Kantorovich version of the operators
Relationship Between Overall Right Pre-Frontal Cortex Activity and Learning and Retention of a Visuomotor Adaptation Task: a Continuous Analysis
No full textLearning a visuomotor adaptation task (VMA) is typically assessed by describing the behavioral changes during adaption (early-fast and late-slow phases) and retention (consolidation) tests. Few studies have concurrently examined behavioral and brain activity during this type of learning and therefore their time-dependent dynamics is unknown. It has been proposed that two distinct strategies can be used during such learning: a model-free and a model-based, which distinctively involved explicit and implicit learning strategies. It has also been proposed that prefrontal cortex (PFC) is more implicated when explicit processes are more relevant as it was observed in the early adaptation (Taylor ; Ivry, 2014; Wolpe et al., 2020). Additionally, an explicit model-based strategy has been inferred when prefrontal (PFC) activity increases. Therefore, the study's aims were: (1) to examine the continuous temporal dynamics of behavior and right PFC activity during adaptation and retention of a VMA, and (2) to infer the implication of explicit processes during the learning of a VMA derived from right PFC activity. Eighteen young adults (24.22 ± 3.12 years) took part in this study. Continuous measures of the performance (the initial directional error, IDE, and the root mean square error, RMSE) of a rotational visuomotor adaptation task during an adaptation (AD) and two retention sets at 1 h (RT1) and 24 h (RT24) were collected. Concurrently, measures of the right PFC activity (relative changes of the oxyhemoglobin concentration, [ΔO2Hb]) were registered via a three-channel functional near-infrared spectroscopy device. General linear mixed models were run to explore differences across adaptation and retentions. Also, cross-correlations between performance (IDE and RMSE) and PFC activity were conducted to observe their relation during sets. The main results indicated that (1) initial fast behavioral improvement (decrease of IDE and RMSE) did not occur simultaneously with the largest increase of the [ΔO2Hb] in the PFC during the AD, and (2) there was similar performance in the RT1 and RT24 but possibly involving the PFC differently. While in both retentions the errors improved after the first trials, in RT1, the [ΔO2Hb] decreased from the very beginning, whereas the PFC activity initially increased in RT24. Our observations would suggest that various cooperating learning strategies, including model-free (i.e., exploratory) and model-based explicit (i.e., strategy) and implicit (i.e., sensory prediction errors), are coordinated in different timings to cooperate during the sensorimotor adaptation and consolidation processes. Furthermore, the involvement of these strategies during the retention may depend on the time elapsed from the end of the adaptation to the re-introduction of the task. © 2025 Elsevier LtdHorizon 2020 Framework Programme, H2020; European Commission, EC; Institut Nacional d'Educacio Fisica de Catalunya, Generalitat de Catalunya, INEFC; Generalitat de Catalunya, (BDNS 420097); Generalitat de Catalunya; R+D+i, (PID2020-120453RB-I00
Efficient Channel Estimation With Shorter Pilots in Ris-Aided Communications: Using Array Geometries and Interference Statistics
No full textBjornson, Emil/0000-0002-5954-434X; Sanguinetti, Luca/0000-0002-2577-4091Accurate estimation of the cascaded channel from a user equipment (UE) to a base station (BS) via each reconfigurable intelligent surface (RIS) element is critical to realizing the full potential of the RIS's ability to control the overall channel. The number of parameters to be estimated is equal to the number of RIS elements, requiring an equal number of pilots unless an underlying structure can be identified. In this paper, we show how the spatial correlation inherent in the different RIS channels provides this desired structure. We first optimize the RIS phase-shift pattern using a much-reduced pilot length (determined by the rank of the spatial correlation matrices) to minimize the mean square error (MSE) in the channel estimation under electromagnetic interference. In addition to considering the linear minimum MSE (LMMSE) channel estimator, we propose a novel channel estimator that requires only knowledge of the array geometry while not requiring any user-specific statistical information. We call this the reduced-subspace least squares (RS-LS) estimator and optimize the RIS phase-shift pattern for it. This novel estimator significantly outperforms the conventional LS estimator. For both the LMMSE and RS-LS estimators, the proposed optimized RIS configurations result in significant channel estimation improvements over the benchmarks.This work was supported by Swedish Foundation for Strategic Research under Grant FFL18-0277. The work of Luca Sanguinetti was supported by Italian Ministry of Education and Research (MUR) in the Framework of the FoReLab Project (Departments of Excellence) and the Garden Project (PRIN 2022 Program). An earlier version of this paper was presented at the IEEE 12th Sensor Array and Multichannel Signal Processing Workshop (SAM) [DOI: 10.1109/SAM53842.2022.9827790].Swedish Foundation for Strategic Research [FFL18-0277]; Italian Ministry of Education and Research (MUR); Garden Project (PRIN 2022 Program
Yetişkin Bağlanma Stillerinin Ayrılık Sonrası Yasla İlişkisinde Eski Partnere Yönelik Bilgi Arayışının Aracı Rolü
No full textGenç yetişkinler için oldukça önemli hale gelen romantik ilişkiler sona erdiğinde kayıp yaşayan bireyler ayrılık sonrası yas sürecine girebilmektedir. Bu çalışmada, yetişkin bağlanma stilleri ve eski partnere yönelik bilgi arayışının bu sürece etkisi incelenmiştir. Araştırma örneklemini Türkiye'de bulunan ve yaşları 18 ila 30 arasında değişen 168 kadın ve 43 erkek katılımcı oluşturmaktadır. Katılımcılar sırasıyla Sosyo-demografik Bilgi Formu, Bilgi Arayışı Anket Formu, Ayrılık Sonrası Yas Ölçeği ve İlişki Ölçekleri Anketi'ni çevrimiçi olarak doldurmuştur. Bu tez çalışmasında; ayrılık sonrası yas güvenli bağlanma stili ile negatif yönlü, saplantılı bağlanma stili ve bilgi arayışı ile pozitif yönlü ilişkili bulunmuştur. Bulgular, ayrılık sonrası daha sık bilgi arama davranışında bulunan kişilerin yas şiddetlerinin daha yüksek olma eğiliminde olduğunu göstermektedir. Ancak yapılan aracı değişken analizleri, ayrılık sonrası geçen süre ve ilişki ciddiyeti kontrol edildiğinde bile, bilgi arayışının bağlanma stilleri ve ayrılık sonrası yas arasındaki ilişkiye aracılık etmediğini göstermiştir. Ek olarak, yarı-yapılandırılmış görüşmelerle katılımcıların ayrılık sonrası sürece dair deneyimleri tematik analiz yardımıyla incelenmiştir. Buna göre; ayrılığın genç yetişkinler için kayda değer bir hadise olduğu, ayrılık sonrası geçen süre ve ilişki ciddiyetinin belirleyici olduğu, adaptasyonun zaman aldığı, bilgi arayışının bu adaptasyonu olumsuz etkileyebileceği ve bu süreçte katılımcıların başvurdukları baş etme yöntemleri ortaya konmuştur. Nitel ve nicel analiz sonuçları, alan yazın bulguları ışığında değerlendirilmiş; bu çalışmanın katkıları ve sınırlılıkları tartışılmış, klinik doğurguları ve gelecek çalışmalar için öneriler sunulmuştur.When romantic relationships, which have become very important for young adults, end, individuals who experience loss may enter a period of grief after the breakup. In this study, the effects of adult attachment styles and information seeking regarding the ex-partner on this process were examined. The research sample consisted of 168 female and 43 male participants in Turkey, aged between 18 and 30. Participants completed the Socio-demographic Information Form, Information Seeking Survey Form, Post-Breakup Grief Scale, and Relationship Scales Questionnaire online, respectively. In this thesis study, post-breakup grief was found to be negatively correlated with secure attachment style and positively correlated with preoccupied attachment style and information seeking. Findings suggest that individuals who engage in more frequent information seeking behavior after breakup tend to have higher grief severity. However, mediator analyses indicated that information seeking did not mediate the relationship between attachment styles and post-breakup grief, even when controlling for time since breakup and relationship seriousness. Additionally, participants' experiences of the post-breakup process were examined with the help of thematic analysis through semi-structured interviews. Accordingly, it has been revealed that breakup is a significant event for young adults, the time since breakup and the seriousness of the relationship are determinative, adaptation takes time, the seek for information can negatively affect this adaptation, and the coping methods that the participants resort to during this process. The results of the qualitative and quantitative analyses were evaluated in the light of literature findings; the contributions and limitations of this study were discussed, and clinical implications and suggestions for future studies were presented
Loyalty To Amateur Sellers in the Online Second-Hand Market
No full textPurposeThis study develops a scale to measure loyalty to second-hand sellers in online markets. The potential marketing outcomes are discussed based on the tested model.Design/methodology/approachA scale measuring loyalty to unprofessional second-hand sellers was developed in five stages. An experimental model was also developed using data from four different countries, where the level of product information was manipulated to observe its effects on loyalty dimensions.FindingsThe developed scale has two sub-dimensions: purchase loyalty and person loyalty. The results validate the use of a loyalty scale and conclude that a second-hand seller should provide sufficient information about the product, which would increase loyalty and generate repurchase intention.Practical implicationsIt is recommended that second-hand sellers follow potentially profitable customers and provide sufficient product information to enhance loyalty sales. Consumers may be able to establish regular streams of income through online second-hand sales.Social implicationsThe system potentially enables the creation of a consistent and systematic used-product and revenue cycle, maintaining an environment-friendly circulation of second-hand items.Originality/valueMost studies have focused on buyer behavior, largely ignoring the amateur seller's perspective. The absence of deliberate branding by second-hand sellers creates an interesting research opportunity to investigate the factors contributing to buyer loyalty.Scientific and Technological Research Council of Turkiye (TUBITAK) [221K112]This project was financially supported by the Scientific and Technological Research Council of Turkiye (TUBITAK) (No: 221K112)