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Forecasting the volatility of bist 100 index return with linear and nonlinear time series models
No full textThe successful modeling and forecasting of volatility, which is the most important element of risk indicators, minimizes financial uncertainties. Classical volatility models are insufficient to forecast structural changes in economic variables. Hybrid models that integrate the benefits of several model architectures have become more significant as the amount of neural network-based research has increased recently. The purpose of the research is to show that mixed models are more accurate and consistent when it comes to predicting variable volatility. For this purpose, the return volatility of the Borsa Istanbul 100 index was modeled, and forecasting performance results were compared with hybrid models. According to the findings, the best forecasting performance was achieved with hybrid structures containing the exponential GARCH-Artificial Neural Networks (MSEGARCH-ANN) combination. It can be said that hybrid models are superior in the risk analysis of volatile financial instruments and in the estimation of macroeconomic variables in general
The effects of e-health and artificial intelligence literacy levels on disease self-management in patients with diabetes
No full textBackground: This study was conducted to examine the effects of eHealth and artificial intelligence literacy on disease self-management in patients with diabetes. Methods: The cross-sectional study was conducted with 212 patients with diabetes who were followed up in Endocrinology clinics and outpatient clinics of a hospital between October 2024 and June 2025. Data were collected through face-to-face interviews using a Personal Information Form, the eHealth Literacy Scale, the Artificial Intelligence (AI) Literacy Scale, and the Diabetes Self-Management Questionnaire. Data were analysed using the SPSS-27 software, and p = 0.05 was considered statistically significant. Results: The mean age of the 212 patients was 52.09 f 17.02, and their mean disease duration was 9.66 f 8.47 years. The patients had mean Diabetes Self-Management Questionnaire, eHealth Literacy Scale, and AI Literacy Scale scores of 6.47 f 1.50, 27.87 f 8.83, and 48.12 f 11.26, respectively. Diabetes self-management was significantly and positively correlated with eHealth literacy (r = 0.505; p = 0.000) and AI literacy (r = 0.499; p = 0.000). Additionally, a positive significant relationship was found between general eHealth literacy and AI literacy (r = 0.865; p = 0.000). Conclusions: The results of this study suggest that general eHealth and AI literacy play a significant role in supporting diabetes self-management
Turkish medical students' perspectives on the advantages and disadvantages of telemedicine: Scale development and psychometric evaluation
No full textBackground The rise of digital technology and the COVID-19 pandemic have accelerated the adoption of telemedicine, yet its integration into medical education remains limited. Understanding the perceptions of future physicians is vital for the sustainable implementation of these services and for developing evidence-based telemedicine training programs. This study aims to assess the awareness and perception of telemedicine among medical students in T & uuml;rkiye and provide empirical evidence to inform curriculum development. Methods This nationwide survey included 810 medical students from six universities in T & uuml;rkiye. A valid and reliable 19-item questionnaire was developed to measure participants' perceptions of telemedicine. The questionnaire used a 5-choice Likert-type scale. The data were analyzed using exploratory and confirmatory factor analysis to determine the scale's validity and reliability. Results The final 11-item scale demonstrated strong validity and reliability, with a two-factor structure: "Advantages of Telemedicine" and "Disadvantages of Telemedicine." The results showed that students largely perceive telemedicine as beneficial, particularly for preventive health services. However, they also expressed concerns, with the highest-rated disadvantage being that telemedicine might create a distance between the doctor and patient. The students rated "increased health inequalities" as the lowest concern. These findings reveal specific competency gaps and training needs that should be addressed in medical curricula. Conclusion The findings suggest that medical students in T & uuml;rkiye hold a generally positive view of telemedicine, recognizing its potential advantages in healthcare. While they are aware of some ethical concerns, such as the potential for a distant doctor-patient relationship, they see telemedicine as a tool to reduce health inequalities. This validated scale provides a foundation for designing targeted telemedicine training programs, assessing educational outcomes, and identifying specific competencies that require emphasis in medical school curricula. We propose a competency-based framework and specific pedagogical approaches to prepare future physicians for effective telemedicine practice
Fgo-tuned 2-dof pi controller for pressure regulation in centrifugal fans driven by induction motors using an experimentally validated model
No full textThis study proposes a novel pressure control strategy for a centrifugal fan driven by an induction motor, using a two-degree-of-freedom (2-DOF) proportional-integral (PI) controller optimized via the fungal growth optimizer (FGO). Built upon a validated nonlinear model, the FGO algorithm tunes the controller parameters to minimize a cost function reflecting overshoot and tracking error. Comparative evaluations are performed against genetic algorithm (GA), L-SHADE, and the Newton-Raphson-based optimizer (NRBO), as well as classical methods such as Cohen-Coon and Rovira techniques. The FGO-based controller demonstrates superior dynamic response, robustness, and noise immunity. Statistical validation using the Wilcoxon signed-rank test confirms the performance improvements. These results highlight the effectiveness of FGO in real-world pressure regulation and establish a benchmark for modern industrial fan control systems.RCUK's Energy Programme
EP/P003605/
Lumpy skin disease threat in europe: Current situation, transmission dynamics and future prospects
No full textLumpy skin disease (LSD), caused by Lumpy Skin Disease Virus (LSDV, genus Capripoxvirus), is an emerging transboundary disease of cattle and water buffalo. Although rarely fatal, it results in severe economic losses due to decreased productivity, hide damage, infertility, and trade limitations. This review summarizes the etiology, susceptible hosts, modes of transmission, and advances in control, vaccination, and treatment strategies, with a particular focus on Europe, where spread into previously unaffected areas has recently been reported. Since its first identification in Zambia in 1929, LSD remained endemic in Africa for six decades before spreading into the Middle East, Asia, and Europe. Major outbreaks have subsequently occurred in T & uuml;rkiye, the Balkans, Russia, Asian territories, and, most recently, in Italy, France, and Spain in 2025. Transmission is primarily vector-borne through blood-feeding arthropods, while animal movements and inadequate farm-level biosecurity further exacerbate the spread. Control measures such as vaccination with homologous live-attenuated vaccines, quarantine, and movement restrictions have proven effective in limiting outbreaks. LSD poses a significant threat to livestock health and trade globally. Coordinated surveillance, improved biosecurity, and vaccination remain the cornerstones of control. Continued research into antiviral and alternative therapeutic strategies to complement existing prevention measures is warranted. Killed vaccines may currently help to protect animals in pre-epidemic areas and slow the rate of epidemics
Association of imp3 and cd10 expression with clinicopathological features and outcomes in phyllodes tumors: A retrospective single-center study
No full textBackground/Objectives: Phyllodes tumors (PTs) are rare fibroepithelial breast neoplasms with highly variable clinical behavior. Identifying predictive immunohistochemical markers is crucial for early detection of lesions with malignant potential and appropriate treatment selection. This study aimed to evaluate the association of insulin-like growth factor II mRNA-binding protein 3 (IMP3) and cluster of differentiation 10 (CD10) expression with histopathological grade and survival outcomes in PTs. Methods: We retrospectively analyzed sixty-eight female patients with PTs at Uludag University Faculty of Medicine Hospital, between 2000 and 2024. Histopathological features, IMP3 and CD10 expression, and clinical outcomes were evaluated. Disease-free survival (DFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared using the log-rank test. Results: Among the 68 patients (median age: 39.0 years), 60.3% had benign PTs, 14.7% had borderline PTs, and 25.0% had malignant PTs. Histopathological parameters differed significantly across grades (all p 0.05). Conclusions: IMP3 expression is strongly associated with malignant histology and poorer overall survival in PTs; however, its independent prognostic value could not be conclusively established due to the limited number of outcome events. While IMP3 may serve as a promising marker in routine pathological assessment, validation in larger, prospective cohorts with sufficient event numbers is warranted
The trend of monthly mean streamflow values and regimes in the Susurluk basin (Türkiye) with mountain and semi-arid climates
No full textThis study diagnoses monthly trends in streamflow magnitude and regime for the Susurluk Basin (T & uuml;rkiye), which spans semi-arid and mountainous sub-climates. Monthly records from 1990 to 2019 were analyzed at 14 stream gauges and nine precipitation stations. Trends are assessed with the Mann-Kendall (MK) test alongside recent graphical approaches, Improved Visualization for Innovative Trend Analyses (IV-ITA) to resolve value class-based (low/high) behavior, and Innovative Polygon Trend Analysis (IPTA) with the Star Concept to quantify intra-annual transitions. Before the trend analyses, the stations were tested to determine whether their values were homogeneous, and any inhomogeneous stations were excluded from the study. The consistency between the trends of nine precipitation stations and the streamflow data in the basin was analyzed. Across the basin, the average streamflow increased by approximately 40-60% between January and March at many measurement points. However, it then decreased by around 80% in April, albeit at a more moderate rate in December. This suggests significant rebalancing occurred during the December-April period, when most of the annual streamflow occurs. IV-ITA exhibits broadly similar trends for both low and high streamflow classes, with notable exceptions in January-February. Precipitation-streamflow trend directions are largely consistent in the high-flow season (December-April), supporting the notion that climatic control influences the detected shifts. To contextualize these signals, basin-wide land-use/land-cover shifts (1990-2018), notably urban growth, forest expansion, and cropland reconfiguration, provide process context, indicating that a larger fraction of rainfall is routed as fast surface runoff while infiltration and base streamflow recharge decline, alongside seasonally modified water demand. Collectively, the MK+IV-ITA+IPTA framework reveals class-specific and intra-annual dynamics that are obscured by monolithic tests alone and provides decision-relevant evidence for allocation, drought-flood risk, and operations in an intensively managed basin
Lung function outcomes of cystic fibrosis patients after early-life pulmonary exacerbations: National registry analysis
No full textBackground Pulmonary exacerbations (PEs) are associated with a subsequent decline in lung function. We aim to evaluate lung function in cystic fibrosis (CF) patients with frequent PEs in their first 2 years of age using spirometry at age 6. Methods This retrospective cohort study included CF patients who were 6 years old from the CF registry of Turkey in 2019. According to the number of PEs, patients were classified: those who had two or fewer PEs in the first 2 years of age were defined as Group 1 and those who had more than two PEs were defined as Group 2. The patients' demographics and clinical characteristics were compared between Group 1 and Group 2. Results The study included 88 patients who had data on PE from their first 2 years and completed their sixth year by 2019. Fifty-nine patients were included in Group 1 and 29 in Group 2. The mean percent-predictive FEV1 (ppFEV1), percent-predictive FVC (ppFVC) values, and the mean age at first PE were lower in Group 2 than in Group 1 (p = 0.019, p = 0.017, p < 0.001). The patients with chronic Pseudomonas aeruginosa (PA) colonization had lower mean ppFEV1 and ppFVC values than those without (p = 0.001, p = 0.001). Patients with PA in respiratory-sample culture during their first PE had lower ppFEV1 and ppFVC values than those with SA (p = 0.046; 0.018). Conclusions This study showed that more frequent PEs in the first 2 years of age and chronic PA colonization were associated with poorer FEV1, FVC, and BMI values in CF patients
Design, production and characterization of nanofiber/cryogel hybrid biomaterials and evaluation of their hemostatic property
No full textBu tez çalışmasında, nanolif ve kriyojel katmanlardan oluşan iki ve üç katlı hibrit biyomalzemelerin tasarımı ve üretimi yapılarak yeni nesil hemostatik biyomalzemeler geliştirilmiştir. Kontrolsüz kanamalar, önlenebilir ölümlerin önde gelen nedenleri arasındadır. Bu yüzden, kanama kontrolü hayati önem taşımaktadır. Özellikle son yıllarda; hemostatik biyomalzemelerin geliştirilmesi, üzerinde durulan araştırma konularındandır. Tez çalışmasının ilk aşamasında poli(2-hidroksietil metakrilat) (PHEMA) polimerinden elektroçekim yöntemiyle nanolifli yüzey üretim parametreleri optimize edilmiş ve PHEMA optimizasyonu literatürde ilk defa bu kadar detaylı bir şekilde ele alınmıştır. Devamında PHEMA-polivinil alkol (PVA) polimerlerinden oluşan nanolifli yüzey katman katman üretilmiştir. En dış katmanlar PHEMA’dan oluşacak şekilde, tüm yapının maksimum miktarda PHEMA içermesi sağlanmıştır. Üretilen nanolifli yüzey, mekanik dayanımının arttırılabilmesi açısından çapraz bağlanmıştır. PHEMA esaslı bir yapı literatürdeki ilk defa gluteraldehit ile çapraz bağlanmıştır. Çapraz bağlanan nanolifli yüzey üzerinde polikaprolakton (PCL) polimerinden elektro püskürtme yöntemiyle boncuklu yüzeyler oluşturulmuş ve lotus etkisi sağlanmıştır. Böylece katmanlı nanolif üretiminde, daha önce çalışılmamış bir polimer sistemi (PHEMA-PVA-PCL) kullanılmıştır. Geliştirilen nanolifli yüzeyler; taramalı elektron mikroskobu, temas açısı, fourier dönüşümlü kızılötesi spektroskopisi, termogravimetrik analiz, civa porozimetresi ile gözeneklilik analizi ve şişme çalışmalarıyla karakterize edilmiştir. Çalışmanın devamında, katmanlı nanolifli yapı üzerinde (iki katlı için) ve katmanlı nanolifli yapılar arasında (üç katlı için) PHEMA kriyojel sentezi gerçekleştirilerek katlı biyomalzemeler üretilmiştir. İki farklı morfolojide olan nanolifli yüzeyler ve kriyojellerin katman katman bir araya getirilmesi ilk defa bu tez çalışması kapsamında gerçekleştirilmiştir. Geliştirilen katlı biyomalzemelerin in vitro testlerle sitotoksik etkileri incelenmiştir. Ayrıca, tromboelastogram, agregasyon, hemogram ve pıhtılaşma ölçümleri gibi ex vivo testlerle kanama üzerindeki etkinlikleri değerlendirilmiştir. Elde edilen sonuçlarla, katlı biyomalzemelerin hemostatik malzeme olarak kullanım potansiyelleri ortaya konulmuştur.In this thesis study, new-generation hemostatic biomaterials were developed by designing and producing two and three-layered hybrid biomaterials consisting of nanofibers and cryogel layers. Uncontrolled bleeding is among the leading causes of preventable deaths. Therefore, bleeding control is of vital importance. In recent years, the development of hemostatic biomaterials has been a major focus of research. In the first part of the thesis, the surface production parameters of nanofibers were optimized using the electrospinning method with poly(2-hydroxyethyl methacrylate) (PHEMA) polymer, and the optimization of PHEMA was addressed in detail for the first time in the literature. Subsequently, a nanofiber surface composed of PHEMA-polyvinyl alcohol (PVA) polymers was produced layer by layer. The outermost layers were made of PHEMA to ensure that the entire structure contained the maximum amount of PHEMA. The produced nanofiber surface was cross-linked to increase its mechanical strength. PHEMA-based structure was cross-linked with glutaraldehyde for the first time in the literature. Beaded surfaces were created on the cross-linked nanofiber surface using the electrospraying method with polycaprolactone (PCL) polymer, and the lotus effect was achieved. Thus, a previously unexplored polymer system (PHEMAPVA-PCL) was used in the production of layered nanofibers. The developed nanofiber surfaces were characterized by scanning electron microscopy, contact angle, Fourier transform infrared spectroscopy, thermogravimetric analysis, mercury porosimetry for porosity analysis, and swelling studies. In the continuation of the study, layered biomaterials were produced by performing PHEMA cryogel synthesis on the layered nanofiber structure (for two layers) and between layered nanofiber structures (for three layers). The layered assembly of nanofiber surfaces and cryogels with two different morphologies was performed for the first time within the scope of this thesis. The cytotoxic effects of the developed layered biomaterials were examined through in vitro tests. Furthermore, their effectiveness on bleeding was evaluated through ex vivo tests such as thromboelastogram, aggregation, hemogram, and coagulation measurements. The results obtained revealed the potential of layered biomaterials for use as hemostatic materials
The logic of scientific explanation in the light of Hempel and Nagel in the history of modern science: A study on models of explanation in historical science
No full text“Neden?” sorusu ekseninde, olaylar ile olup biten süreçlerin sistematik bir dizge altında toplanarak açık kılınmasını ihtiva eden “bilimsel açıklama”, 20. yüzyılın ikinci yarısı itibariyle bilimsel araştırmaların önemli bir düşünsel açılımını yansıtmaktadır. Meta bilimsel bir kavram olarak açıklamanın niçin haklı olduğu sorusunu soran Hempel, o güne değin dağınık halde bulunan açıklayıcı dizgeleri, inşa ettiği kapsayıcı yasa açıklama teorisi aracılığıyla mantıksal yapısı, epistemik gereklilikleri ve özgün değeri bakımından karakterize etmiştir. Sadece doğa değil, aynı zamanda sosyal, beşerî ve daha özel olarak, “tarih” bilimlerine ilişkin açıklayıcı dizgelere de uygulanabilirliğinin soruşturulduğu kapsayıcı yasa açıklama teorisi, ardılları tarafından çoğu zaman açıklamanın standart modeli olarak anılmıştır. Zamanla birlikle “bilimsel açıklama/açıklama” nosyonu üzerine yapılan araştırmaların kapsamı git gide derinleşmiş, bundan payını alan kapsayıcı yasa açıklama teorisi ise üstün ve eksik yönleri bakımından tartışılmıştır. Farklı açıklama modelleri üzerine olan çalışmalarıyla öne çıkan teorisyenlerden Nagel, bilimsel araştırmaların mantığından bilimsel açıklamanın mantığına uzanan kapsamlı araştırmasıyla özel bir yere sahiptir. Onun doğa, sosyal ve beşerî bilimlerde açıklayıcı dizgelerin mantıksal yapısı ve epistemik gerekliliklerine yönelik analizi, bilimsel araştırmaların metodolojik kıstaslarına ilişkin görüşlerinin genel bir resmini vermektedir.
Bu çerçevede tez çalışmasının birinci bölümü, Antik Yunan düşün dünyasından modern bilimsel araştırmaların yükselişine kadar uzanan açıklama arayışının, metodolojik açıdan felsefi ve mantıksal köklerine odaklanmaktadır. Her ne kadar açıklayıcı dizgelerin mantıksal inşası, “bilimsel açıklama” nosyonunun meta bilimsel bir kavram olarak tasarlanmasıyla mümkün olsa da köklerinin, Antik Yunan dünyasında serpildiği açıktır. Üstelik bu izlerin, mantıkçı empirizmin son dönem takipçilerinden olan Hempel ve Nagel’ın açıklama anlayışlarına ton kazandıran şey olduğu düşünülmektedir. Buna istinaden çalışmanın ikinci ve üçüncü bölümleri, sırasıyla onların gözünden açıklayıcı dizgelerin ayırt edici karakterine ilişkin problemler üzerinde durmakta ve sistematik bir tartışma sunmaktadır. Tezin son bölümünde ise tarihsel araştırmalarda açıklayıcı dizgelerin inşasına yönelik bir sorgu bulunmaktadır. Burada bir kesişim noktası olarak tarihin, “doğa, “sosyal” ve “beşerî” bilimlerde ortak bir araştırma mantığını yansıttığı; daha genel olarak empirik bilimlerin, açıklamanın mantığı bakımından ortak bir metodolojik zemine sahip olduğu fikri öne çıkmaktadır.The question of “why?” reflects a significant intellectual breakthrough in scientific research in the second half of the 20th century, encompassing “scientific explanation” which involves systematically gathering events and processes under a coherent framework to clarify them. Hempel, who questioned why explanation is justified as a meta scientific concept, characterised the explanatory systems that had been scattered until then in terms of their logical structure, epistemic requirements, and intrinsic value through his covering-law explanation theory. The theory of covering-law explanation, which investigates the applicability of explanation not only to nature but also to the social, human, and more specifically, “historical” sciences, has often been regarded by its successors as the standard model of explanation. Over time, the scope of research on the notion of “scientific explanation/explanantion” has expanded; the covering-law explation theory has also been debated in terms of its strengths and weaknesses. Nagel, a theorist who stands out for his work on different models of explanation, occupies a special place with his comprehensive research spanning from the logic of scientific research to the logic of scientific explanation. His analysis of the logical structure and epistemic requirements of explanatory systems in the natural, social, and human sciences provides an overview of his views on the methodological criteria of scientific research.
In this context, the first part of the thesis focuses on the philosophical and logical roots of the quest for explanation, spanning from the ancient Greek world of thought to the rise of modern scientific research. Although the logical construction of explanation is made possible by the design of the notion of “scientific explanation” as a meta scientific concept, it is clear that its roots lie in the ancient Greek world. Moreover, it is thought that these traces are what give tone to the explanatory understandings of Hempel and Nagel, who were followers of logical empiricism in its final period. Accordingly, the second and third parts of the study focus on problems related to the distinctive character of explanation from their perspective and present a systematic discussion. The final section of the thesis poses a question regarding the construction of explanation in historical research. Here, as a point of intersection, the idea emerges that history reflects a common research logic in the “natural,” “social,” and “human” sciences; more generally, that the empirical sciences share a common methodological ground in terms of the logic of explanation