Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Uzun, Sevda(11)
- Gül, Abdulkadir(10)
- Baltacı, Cemalettin(9)
- Kaya, Selim(9)
- Kurnaz, Muammer(9)
- Ozturk, Samet(9)
- Çelik, Necati(9)
- Tuncer, Metin(8)
- Altuner, Elif Esra(7)
- Aydin, Aydanur(7)
- Barut, Abdulkadir(7)
- Cin, Aynur(7)
- Günen, Mehmet Akif(7)
- Ozdes, Duygu(7)
- Zaman, Tolga(7)
- Araz, Onur(6)
- Baltaci, Cemalettin(6)
- Bayrakdaroglu, Serdar(6)
- Bozbeyoglu, Pinar(6)
- Demirağ, Hatice(6)
- Karpuz, Ömer(6)
- Liu, Shuxiang(6)
- Merdan, Mehmet(6)
- Yilmaz, Coskun(6)
- Duran, Celal(5)
- Gulcin, Ilhami(5)
- Koçak, Tevfik(5)
- Pala, Fahrettin(5)
- Pilatin, Abdulmuttalip(5)
- Söyler, Mehmet(5)
- Topal, Fevzi(5)
- Tuncer, Gülsüm Zekiye(5)
- Türkkan, Tuğba(5)
- Uysal, Turan(5)
- Yapici, Ismail(5)
- Zengin, Gokhan(5)
- Çam, Alper Veli(5)
- Öztürk, Serkan(5)
- Şan, Murat(5)
- Şimşek, Ahmet Bahadır(5)
Yayınlar
- MakaleAçık Erişim2026Solution of Time-Fractional Coupled Burgers Equations by the Yang Transform Adomian Decomposition Method
Ali, Mustafa Ahmed; Merdan, Mehmet
In this paper, the Yang transform Adomian decomposition method (YTADM) is employed in the solution of nonlinear time-fractional coupled Burgers equations. The technique solves the fractional and nonlinear terms successfully via the Adomian decomposition of the Yang transform. Illustrative examples are given, which show the accuracy and ease of implementation of the method. The results show that the YTADM method gives good, reliable results and is very accurate, so that its solutions agree well with the exact solution. Finally, tables and graphs are shown, which illustrate the behavior of the solutions found.
- Kitap BölümüYalnız künye2026Artificial Intelligence-Assisted Design and Optimization of BioNanocomposites for Biomedical and Environmental Applications
Bozbeyoglu, Pinar; Kostas, Rabia Yasa; Altuner, Elif Esra; Elmas, Muzaffer
Bio-nanocomposites, produced from renewable resources, stand out as one of the promising next-generation material classes for both biomedical and environmental applications due to their biocompatible and biodegradable structures.However, the vast and complex design space of these materials, which depends on numerous variables including the type of biopolymer matrix and the type and concentration of the nanostructured filler, makes their optimization quite challenging with traditional “trial-and-error” based research methods.This study provides a general overview of an artificial intelligence (AI)-based methodology that holds the potential to overcome this complexity.In this context, the limitations of the traditional “forward screening” approach are discussed, and the “inverse design” paradigm, based on the idea of “designing a material with desired properties,” is proposed as a solution.The study outlines the potential roles of various AI tools in this field, from supervised learning models to deep learning approaches and optimisation algorithms.This theoretical framework is substantiated by practical case studies that range from drug delivery to sustainable packaging.The case studies demonstrate how AI not only enables the prediction of properties but also facilitates strategically developing materials for a particular function, thereby accelerating the discovery process.Finally, current challenges, such as data scarcity and the interpretability of models, are addressed, and future visions to overcome these obstacles, including physics-informed AI, autonomous discovery platforms, and human-AI partnerships, are discussed.It is concluded that this synergy has the capacity to stimulate a new era of innovation in sustainable materials science.
- MakaleYalnız künye2026Variable-speed retrofit of a legacy slurry pumping duty: Measured energy reduction with proxy-based operability assessment
Külekçi, Gökhan; Aygün, Muhammet; Göller, Zafer; Yildiz, Onur
Legacy ore beneficiation plants often operate slurry pumps at fixed speed despite variable sump inflow and slurry conditions, which can increase electricity demand and complicate level control. This study evaluates a variable-speed retrofit in which a variable frequency drive was integrated with level feedback and proportional-integral control for a legacy slurry pumping duty. Measured average operating power decreased from 25.6 kW before retrofit to 11.6 kW after implementation, documenting a substantial reduction in electrical demand under the observed operating regime. Because hydraulic-duty data were unavailable for both periods, this result is not presented as a duty-normalised specific-energy reduction. Process interpretation was supported by a bounded proxy framework based on a flowsheet-consistent solids band over 177 days. The proxy analysis linked solids variability to derived slurry density behaviour and operability implications. Overall, the study documents measured electrical-demand reduction and provides a framework for discussing retrofit performance where plant instrumentation is limited.
- MakaleAçık Erişim2026Green Transformational Leadership, Creativity, and Organizational Culture: A Structural Model of Pro-Environmental Behavior in an Emerging Cosmetics Market
Baltacı, Duygu Çınar; Büyükbeşe, Tuba
Understanding the behavioral foundations of green transformation within firms requires attention to both leadership processes and the motivational mechanisms that shape employee action. Drawing on transformational leadership theory, the resource-based view, and self-determination theory, this study investigates how green transformational leadership (GTL) relates to pro-environmental behavior (PEB) through the creative and contextual conditions that support intrinsic motivation. Survey data from 1063 employees in the Turkish cosmetics industry were analyzed using structural equation modeling. The results indicate that green creativity (GC) transmits the influence of GTL on PEB, whereas green organizational culture (GOC) strengthens the conditions under which this influence is expressed. These findings clarify how leadership, creativity, and cultural support jointly underpin employees' environmental engagement. The study contributes to research on organizational greening by highlighting the motivational and contextual pathways through which leadership encourages sustainable behavior in emerging market settings.
- MakaleAçık Erişim2026Post-Seismic Variation in Petrophysical Parameters and Heat Storage at the Tuzla Geothermal Field, Biga Peninsula (NW Anatolia) From Resistivity-Depth Model Using Differential Evolution Algorithm
Büyük, Ersin; Uzel, Bora; Sözbilir, Hasan; Baba, Alper
Electrical resistivity has been shown to offer significant insights into post-seismic changes in geothermal reservoirs; however, its interpretation is complicated by the fact that it is controlled not only by temperature, but also by porosity and clay content. In this study, we used a post-seismic electrical resistivity-depth model from magnetotelluric data to estimate the temperature changes following a seismic swarm in the vicinity of the Tuzla Geothermal Field in the Biga Peninsula of northwestern Anatolia. In the absence of pre-seismic resistivity data for the field, we attribute the characteristic part of the post-seismic model to the seismic swarm. Temperature changes were then evaluated using pre- and post-seismic wellhead temperature observations together with the post-seismic resistivity-depth model. In order to address the relationships between resistivity and petrophysical parameters, the present study combined the established equations for temperature, porosity and clay-related effects. The estimation of petrophysical parameters from combined equations was then conducted using the differential evolution algorithm (DEA), a method that has gained popularity due to its effectiveness in solving non-linear optimization problems. The main contribution of this study lies in the integrated use of a unified petrophysical framework and the DEA to jointly estimate post-seismic changes in temperature, porosity and clay content from the resistivity model. Furthermore, an estimation was made of the reduction in stored heat within the defined reservoir zone. The results indicate that the observed increase in resistivity is primarily associated with a decrease in reservoir temperature, which is consistent with the observed decrease in wellhead temperatures. In addition, changes in clay content and porosity contribute significantly to the resistivity response. The findings demonstrate the efficacy of models of resistivity-depth, obtained following seismic activities, in facilitating the inference of changes in petrophysical parameters and thermal state in geothermal systems.
- MakaleAçık Erişim2026The impact of high voltage transmission lines (HVTL) on property value: A descriptive initial survey
Marabaoğlu, Seda Nur; Uzun, Bayram
Properties hosting High Voltage Transmission Lines (HVTL) generally have lower values in Turkey. Therefore, owners are compensated for the easement. However, due to the inadequacy of laws and regulations, easement prices (compensation) can be calculated incorrectly. In this study, a descriptive survey was conducted to obtain ideas and information on the solution of problems encountered in determining easement prices and practices in other countries were examined. As a result of the survey, the area covered by the easement on the property and the route of the line were identified as the most important factors that negatively affect property value. It emerges that the diagonal crossing of HVTL over properties is the factor that decreases property value the most (compared to other crossing methods). Additionally, it is observed that the easement price paid to property owners varies mostly according to the per square meter value of the property and secondly according to the area of the property.
- MakaleAçık Erişim2026Valorization of Moss biomass as a natural porous Matrix for shape-stable phase change material (PCM) composites
Can, Ahmet; Ganguly, Sauradipta; Gencel, Osman; Sarı, Ahmet; Erata, Hüseyin
Phase change materials (PCMs) are used to improve energy efficiency, particularly in building heat storage and passive thermal management applications. In this study, moss biomass ( Calliergonella cuspidata (Hedw.) Loeske) (Ca) was evaluated as a natural porous matrix, and a novel non leachable composite phase change material (PCM) was developed based on n-octadecane (n-OD). The moss biomass was impregnated with 60% n-OD by direct mixing method, and its structural stability was enhanced by the addition of Sodium silicate (SS) at 10% and 30% (by wt%) respectively. The morphological, chemical, and thermal properties of the composites were characterized by SEM, EDS, FTIR, DSC, TGA, XRD, and thermal conductivity analyses. SEM-EDS results showed that the moss biomass (Ca) had high porosity, with the addition of SS resulting in a more compact and homogeneous structure. FTIR analyses exhibited the formation of Si–O–Si bands, indicating successful integration of SS into the matrix. According to DSC analysis, the Ca/n-OD(60%) composite had a melting temperature of 26.1 °C and a melting enthalpy of 153.7 J/g whereas for the SS-added variants, these values were measured as 148.3 J/g (10%) and 144.2 J/g (30%), respectively. The enthalpy losses of only 2–3 J/g after 700 heating-cooling cycles indicated high thermal stability. TGA and XRD analyses showed that the addition of SS increased the thermal resistance of the composites, creating an amorphous network structure. The results indicate that moss-based Ca/n-OD/SS composites, with their compact, leak-free structure, high heat storage capacity, and excellent cyclic stability, hold promise as eco‑friendly materials for subsequent applications in: thermal energy storage for buildings, solar energy systems, and the thermal management of electronic components.
- Derleme MakaleYalnız künye2026Red mud as a source of scandium: A review
Kumaş, Cavit; Prasetia, Hendra; Astuti, Widi; Sumardi, Slamet; Mufakhir, Fika Rofiek; Fasya, Muhammad Rizki Firdaus
The residue produced during the extraction of aluminum from bauxite ore via the Bayer process is known as red mud (RM), with 0.5–2.5 t of RM generated for each ton of alumina produced. Due to its highly alkaline nature (pH = 10.0–12.5), RM poses significant environmental threats and requires large storage areas. To address this environmental concern and develop sustainable way to utilize RM, extensive research has been conducted in fields such as soil remediation, metal recovery, steel production, catalytic reactions, cheap adsorbents for pollutant removal, ceramics, brick production, and pigment and slag additives for paint production. While early studies on metal recovery from RM focused on the recovery of metals such as Fe and Al, recent years have seen an increase in research on Sc recovery from RM, as RM is now recognized as an important source for Sc. This review examines in detail methods such as direct acid leaching, bioleaching, acid baking, and water leaching used for Sc recovery from RM. Additionally, data on the recovery of not only Sc but also other metals from RM are presented.
- MakaleAçık Erişim2026Antibacterial Efficiency and Osteoblast Viability of Ag/AgO/Ag2O Nanoparticles on Microarc-Oxidized TiO2
Aktas, Sitki; Durdu, Salih; Bird, Toby W.; Ozcan, Kadriye; Yigitturk, Gurkan; Aktug, Salim Levent; Usta, Metin; Acet, Tuba; Pratt, Andrew
Infections associated with titanium-based medical and dental implants present a major clinical challenge, as they can compromise osseointegration and long-term implant stability. Silver-based nanoparticles (NPs) are widely recognized for their strong antimicrobial properties, and when combined with titanium, they hold significant promise for developing infection-resistant and biocompatible implant surfaces. In this study, Ag/AgO/Ag2O NPs were deposited onto highly porous TiO2 layers formed on the Ti6Al4V alloy by microarc oxidation (MAO), with the aim of simultaneously enhancing antibacterial performance and supporting osteoblast activity. The NPs exhibited a predominant size of 8.7 ± 0.1 nm, with smaller particles oxidized to AgO and Ag2O, and larger particles (∼10 nm) composed of metallic Ag. SEM evaluation revealed that the NPs were homogeneously dispersed across the oxide surfaces without altering the rough and porous morphology of TiO2. The MAO-treated surfaces initially showed hydrophobic behavior (contact angle of 94.1 ± 0.3°), which shifted to hydrophilic after Ag/AgO/Ag2O NP deposition due to increased hydroxyl group formation. Antibacterial assays against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) revealed a significant enhancement in antibacterial activity, particularly for surfaces with the highest Ag/AgO/Ag2O NP density. Meanwhile, osteoblast cell viability assays demonstrated no reduction in metabolic activity after 72 h, and SEM images confirmed cell adhesion and proliferation. Overall, these findings highlight the potential of Ag/AgO/Ag2O NP-modified TiO2 surfaces as multifunctional coatings that combine infection resistance with osteoblast compatibility, offering promising applications in dental and orthopedic implants.
- MakaleYalnız künye2026The Impact of Financial Stability, Globalization, and Economic Stability on Ecological Footprint From the Perspective of EKC Hypothesis: New Evidence From a Fourier Panel Data Analysis for BRICS-T Countries
Sancar, Canan; Akbaş, Yusuf Ekrem; Suluk, Seher; Atay Polat, Melike; Aslan, Alper
The Environmental Kuznets Curve hypothesis, which states that the increase in growth up to a certain income level increases environmental pollution and the increase in growth after reaching this income level decreases environmental pollution, has recently started to be investigated by including economic development and financial development in the framework of this hypothesis to better investigate the hypothesis. This study aims to investigate the impact of financial stability, economic stability, globalization, energy use, and growth on the ecological footprint in Brazil, Russia, India, China, South Africa, and Turkey. In addition, the Environmental Kuznets Curve hypothesis is also tested while examining this relationship. The Panel Fourier approach is applied to test these relationships in Brazil, Russia, India, China, South Africa, and Turkey over the period 1996–2022. The coefficient estimation results show that economic stability, economic globalization, growth, and energy use have a positive impact on the ecological footprint in Brazil, Russia, India, China, South Africa, and Turkey, but financial stability reduces the ecological footprint. Moreover, an inverted-N relationship was found between economic growth and pollution in these countries, which means that the Environmental Kuznets Curve is invalid in these countries in the relevant period. The results obtained from causality analysis support the results of coefficient estimation. Accordingly, a unidirectional causality was found from explanatory variables to the ecological footprint in most of Brazil, Russia, India, China, South Africa, and Turkey.
- MakaleAçık Erişim2026Predictors of citations: an analysis of highly-cited-papers in hospitality and tourism research using a machine learning approach
Polat, Eray; Çelik, Fatih; Arici, Hasan Evrim; Köseoglu, Mehmet Ali
In the dynamic nature of hospitality and tourism (H&T) research, it is increasingly difficult to distinguish highly-cited-papers (HCPs) due to the rapid proliferation of publications. This study employs machine learning techniques to identify the predictors of citation counts in H&T research over both short-term (5-year) and long-term (20-year) periods using HCPs. The analysis integrates a theoretical framework comprising normative theory and social constructivist theory. The findings indicate that international citation, PlumXmetrics, and early citations are the most effective determinants in both periods. Furthermore, while the importance of international citations is evident in both periods, the order of importance of the other two predictors changes. PlumXmetrics are more important in the long-term, while early citations are more important in the short-term. In conclusion, this comprehensive and up-to-date study of citation dynamics provides valuable insights for scholars and other stakeholders interested in enhancing the visibility and influence of H&T literature.
- MakaleYalnız künye2026Analytical Solution of Discontinuous Contact Problem in Functionally Graded Layer and Homogeneous Layer
Kaya, Yusuf; Polat, Alper; Şükrü Özşahin, Talat; Bora, Pınar
In the study, the problem of discontinuous contact in two layers, one of which is functionally graded is solved using the theory of elasticity. In this problem functionally graded (FG) layer resting on homogeneous layer and loaded with two different rigid flat blocks. In addition, homogeneous layer is resting on a rigid plane. Frictions on all surfaces are neglected. The heights of the FG layer and the homogeneous layer are h1 and h2, respectively. When solving the problem, displacement and stress equations are substituted in the boundary conditions. Then the problem is demained to singular integral equations. Wherein unknown functions are the contact stresses under the two rigid flat blocks and the slope of the separation. These singular integral equations are solved numerically using the Gauss- Chebyshev integration formulas. The analyzes were performed for different inhomogeneity parameter (βh1), shear modulus ratio (μ2/μ-h1). distance between the rigid blocks ((a3-a2)/h1) and density parameter (γh1). Consequently, the stress distributions and starting and ending points of the separation area between the FG layer and homogeneous layer are determined for several dimensionless quantities.
- MakaleAçık Erişim2026Dynamic and Mechanical Properties of Nanoparticle Doped Aramid/Glass Fiber Reinforced Interply Hybrid Composites
Sadik, Ayşegül Cansu; Karabudak, Filiz; Kula, Muhammed Emin
In this study, the mechanical and dynamic properties of glass/aramid interply hybrid composites reinforced with four different nanoparticles were investigated. Firstly, matrix modification was performed and composite plates were manufactured by hand lay-up technique. Silicon dioxide (SiO2), graphene (GNP), silver (Ag) and cerium oxide (CeO2) nanoparticles were added to the epoxy matrix as reinforcement. With the addition of nanoparticles, the highest tensile (16%) and flexural (67.3%) strengths were observed in Ag reinforced composites. Tensile (16.8%) and flexural (14.4%) strengths decreased with the addition of graphene nanoparticles. Tensile and flexural tests revealed delamination, matrix and fibre rupture in all plate types. As a result of modal analysis, the highest natural frequency values and the lowest damping ratios were determined in the FFBC boundary condition. The addition of nanoparticles improved the mechanical properties of the composites in general.
- MakaleAçık Erişim2026An Integrated MCDM Framework for Sensitivity of Weighting Methods and Ranking Aggregation: Evidence From Financial Performance Evaluation
Macit, Nazife Şahin
This study proposes an integrated framework for evaluating alternatives in Multi-Criteria Decision Making (MCDM) by addressing weight sensitivity and ranking integration. The aim is to examine the effects of different criteria-weighting methods on ranking results and to develop a more consistent decision-making structure by integrating the resulting rankings. Financial performance indicators of Derimod Konfeksiyon A.Ş., listed on Borsa Istanbul (BIST), were evaluated using the Entropy, WENSLO, and MPSI weighting methods, while the MACAD method was employed to rank the alternatives. The analysis was initially conducted for the 2018–2024 period; however, identical rankings obtained across all weighting methods limited the assessment of weight sensitivity. Therefore, the analysis period was extended to 2015–2024, resulting in ranking variations that enabled a more meaningful comparison of the weighting methods. In the final stage, the resulting rankings were integrated into a single consensus ranking using the CURLIA method. The findings indicate that the proposed framework reduces inconsistencies arising from the use of different weighting methods and produces more stable and reliable performance evaluations. Consequently, the study contributes to the MCDM literature by presenting an integrated methodological framework and demonstrating its applicability to financial performance evaluation.
- MakaleAçık Erişim2026Financial literacy and psychological vulnerability to financial exploitation: the roles of financial anxiety, self-confidence, and behavior
Çam, Alper Veli; Soydaş, Şafak Sönmez; Özbek, Adem; Çam, Handan
Background: Financial exploitation constitutes a significant psychological vulnerability shaped by cognitive resources, emotional regulation, and financial decision-making behaviors. While financial literacy is widely recognized as a protective factor, limited empirical evidence disentangles the distinct psychological roles of financial knowledge, attitudes, and behaviors in reducing vulnerability to financial exploitation. Methods: This cross-sectional study analyzed survey data from 565 adults in Türkiye. Financial literacy was conceptualized as a multidimensional construct comprising financial knowledge, financial attitude, and financial behavior. Vulnerability to financial exploitation was assessed through three psychosocial indicators: self-confidence, financial anxiety, and financial satisfaction. Structural Equation Modeling (SEM) was employed to examine the relationships among cognitive, behavioral, and emotional components. Results: Financial knowledge was significantly associated with lower financial anxiety and higher financial satisfaction but showed no direct effect on self-confidence. Financial behavior emerged as the most robust protective factor, significantly enhancing self-confidence and financial satisfaction while substantially reducing financial anxiety. Financial attitude was positively related to financial satisfaction but did not significantly influence anxiety or self-confidence. Financial anxiety demonstrated a strong negative association with both self-confidence and financial satisfaction. Conclusions: Financial exploitation vulnerability is driven by interconnected psychological mechanisms rather than cognitive factors alone. The findings highlight the central role of behavior-based financial competencies and emotional regulation in strengthening financial resilience. Interventions aimed at preventing financial exploitation should prioritize behavioral skill development and psychological risk screening alongside traditional financial education approaches.
- MakaleAçık Erişim2026Green Synthesis and Bioactivities of Silver Nanoparticles Derived from Mercurialis annua L. Extract
Salad, Aisha Mohamud; Akar, Zeynep
Biogenic synthesis using plant materials provides a sustainable alternative to classical nanoparticle fabrication, minimizing chemical hazards and decreasing energy input. In this study, silver nanoparticles (AgNPs) were prepared using an aqueous extract of Mercurialis annua and characterized. Physicochemical properties of the AgNPs were confirmed using ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), and transmission electron microscopy coupled with energy-dispersive X-ray (TEM–EDX), which collectively indicated crystalline, spherical silver nanoparticles stabilized by extract-derived functional groups. Subsequently, the biological activities of both the nanoparticles and the extract were comparatively evaluated using antioxidant tests, including cupric ion reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), total phenolic content (TPC), and total flavonoid content (TFC), as well as enzyme inhibition tests targeting α-glucosidase and carbonic anhydrase. Liquid chromatography-mass spectrometry profiling identified 31 phenolic constituents in the extract, with ferulic, caffeic, salicylic, and 4-hydroxybenzoic acids detected in high abundance. Overall, the biosynthesized AgNPs demonstrated higher antioxidant performance and stronger inhibitory effects on both enzymes compared with the crude extract. These results indicate that M. annua-based AgNPs hold considerable promise sustainable and effective bioactive agents for future biomedical and biotechnological applications.
- MakaleAçık Erişim2026Evaluation of Physicochemical Properties, Phytochemical Composition, Antioxidant Activity, Mineral Content, and Sensory Characteristics of Crackers Fortified with Olive Pomace
Altay, Kadriye; Akdoğan, Arda; Erdoğan, Selma Lubabe; Koç, Gülşah Çalışkan
Olive pomace (OP), a by-product of olive oil production, is a rich source of various bioactive compounds. OP can be used as a value-added product for the development of functional food. The research aimed to produce functional crackers incorporating different levels of OP powder (ranging from 0% to 20%). Subsequent analysis involved evaluating the physicochemical and phytochemical compositions, antioxidant activity, mineral content, and sensory characteristics of all samples. In light of the findings, the samples containing OP powder are rich in phytochemicals (total phenolic and flavonoid contents), with higher antioxidant activities (total antioxidant content, DPPH radical scavenging activity, ABTS radical scavenging activity, and ferric reducing power), as well as a high amount of minerals compared to the control sample (P<0.05). Moreover, as the concentration of OP increased, there was a decline in the moisture content, water activity, and color values of the crackers. Conversely, the ash, fat, total flavonoid, total phenolic, and mineral contents, as well as antioxidant activity and hardness values, exhibited an increase. Sensory analyses revealed that the addition of 10% OP powder produced highly acceptable crackers compared to the higher concentration of OP (15 and 20%). Overall results indicated that functional crackers can be produced by the addition of powder and a maximum of 10% OP powder fortification is recommended for consumer acceptability.
- MakaleYalnız künye2026Improved generalized ratio estimators of population mean using auxiliary variables
Yadav, Subhash Kumar; Arya, Diksha; Sharma, Prayas; Zaman, Tolga
The Quest for the improved estimators of population mean is a continuous process to estimate it more efficiently and more closely to the true population mean of the study variable. There are various estimators of population mean in the literature, which estimate it efficiently, but still there is space for more efficient estimators. For improved estimation of population mean of primary variable, we suggest six different searls type ratio estimators utilizing the known auxiliary parameters. We derive the expressions for the biases and the mean squared errors of the introduced estimators for an approximation of degree one. The optimal values of the Searls characterizing constants, which minimize the mean squared errors of the introduced estimators, are obtained. The least value of the mean squared error of the proposed estimators for these optimal values of the characterizing scalars is also acquired. The efficiency of the proposed estimators is compared theoretically with the competing estimators of population mean through their mean squared errors. We derive the efficiency conditions of the proposed estimator for which it is more efficient than the estimators of population mean in competition. These efficiency conditions of the proposed estimators are verified through empirical data and the improvement over the competing estimators is calculated based on the minimum values of the mean squared errors. It is evident from the numerical study that the proposed estimator has the least mean squared error and the highest percentage relative efficiency in comparison to competing estimators. Thus, the proposed estimators are recommended for applications in different areas of applications.
- MakaleYalnız künye2026Do special economic zones support regional development in transition economies? The case of Kazakhstan
Önder, Kübra; Şahin, Muhammet
This study examines the impact of Special Economic Zones (SEZs) in Kazakhstan between 2000 and 2023 on regional development, explicitly accounting for institutional and spatial heterogeneity. For causal identification, it employs a Forward Orthogonal Deviations-based GMMf (System GMMf) estimator to address endogeneity and reverse causality, complemented by an event-study framework to trace the dynamic evolution of policy effects. The results reveal strong path dependence in regional growth and show that the effectiveness of SEZ incentives is non-linear and systematically conditioned by the depth of regional production structures, proxied by the Value Added Index. Empirical evidence suggests that SEZ incentives stimulate growth in low value-added regions, while potentially distorting market signals and generating crowding-out effects in regions with high value-added production. Dynamic analyses indicate that the negative shock observed immediately after implementation reflects temporary adjustment costs and resource reallocation, with effects converging towards zero over time. Overall, the findings imply that SEZs are not automatic engines of growth but require careful calibration to local production structures to mitigate risks of policy saturation and adverse selection. The study provides an original contribution to the literature on the design and life-cycle management of next-generation industrial policies in transition economies.
- MakaleYayıncıda açık erişim2026Blinking without eyelids: first video-documented evidence of a blink-like reflex in Ophisops elegans (Reptilia: Lacertidae)
Çelebi, Turan Meriç; Çelikağı, Yusuf; Kınay, Tuana; Kuyucu, Arda Cem; Kurnaz, Muammer; Şahin, Mehmet Kürşat
Eyelids play a crucial role in protecting the eyes of vertebrates; however, certain reptile species, such as Ophisops elegans, completely lack movable eyelids. In this study, we present the first video-documented evidence of a blink-like reflex in O. elegans, captured through endoscopic field observations and corroborated by laboratory video analysis. The observed movement consisted of a brief convex deformation of the ocular surface, lasting approximately 0.3 s and resembling a blink despite the presence of a fixed transparent brille. This behavior was observed once in the field and twice under controlled laboratory conditions. We propose that O. elegans may employ subtle contractions of the ocular musculature to mimic the protective function of blinking. These findings indicate a novel compensatory mechanism in eyelidless lizards and underscore the need for further research into ocular adaptations among reptiles.