Recep Tayyip Erdoğan Üniversitesi Kurumsal Akademik Arşivi
DSpace@RTEÜ, Recep Tayyip Erdoğan Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Taxonomic notes on persicaria lapathifolia (Polygonaceae/ Polygonoideae) focusing on Türkiye
(Istanbul University-Cerrahpasa, 2026) Gültepe, Mutlu; Kundakçı, Suzan; Makbul, Serdar; Coşkunçelebi, Kamil
Persicaria lapathifolia has exhibited significant variation in its external morphological characteristics (e.g., stem dotting, leaf shape, leaf and ocrea indumentum, perianth properties), leading to different classifications by many taxonomists. According to recent records, P. lapathifolia is represented by P. lapathifolia subsp. brittingeri, P. lapathifolia subsp. lapathifolia, and P. lapathifolia subsp. nodosa in Türkiye. In the present study, P. lapathifolia is evaluated, focusing on morphological and molecular evidence (internal transcribed spacer sequences) inferred from extensive examination of both authentic herbarium specimens (from national and international collections) and newly gathered field samples. Morphological observations revealed that members belonging to Turkish subspecies exhibited very similar characteristics that do not provide sufficiently diagnostic features to describe the infraspecific variation of P. lapathifolia. Also, phylogenetic analyses further support the morphological similarities, confirming the lack of clear genetic differentiation among the members of Turkish specimens. When the specimens belonging to subsp. brittingeri and subsp. nodosa collected from Türkiye were examined in detail, and it was determined that they clearly belong to subsp. lapathifolia. This morphological similarity is also highly supported by phylogenetic analyses based on internal transcribed spacer data. All these findings show that P. lapathifolia is represented by P. lapathifolia subsp. lapathifolia in Türkiye. Therefore, the extended description, chorology, and phylogenetic relationships of the P. lapathifolia subsp. lapathifolia are presented in detail for the first time in the present article.
Leonardo cartan numbers and related fibonacci–lucas structures
(Wiley, 2026) Çakır, Hasan; İskender, Ö.
This paper investigates the Leonardo Cartan numbers, defined as an extension of the classical Leonardo sequence through additional algebraic structures. The recurrence relations of these numbers are established, and various summation formulas are derived. Furthermore, key mathematical identities, including Catalan’s and Cassini’s identities, are obtained within the framework of Leonardo Cartan numbers. The relationships among Fibonacci, Lucas, and Leonardo sequences are also explored, thereby highlighting their interconnections. By employing Binet’s formula, several fundamental properties of Leonardo Cartan numbers are confirmed, contributing to a deeper understanding of their algebraic structure.
Multiscale analysis of mechanical strength and failure characteristics in cementitious waste rock–tailings backfill considering aggregate dosage
(Taylor and Francis Ltd., 2026) Qi, Yuhe; Xue, Gaili; Yılmaz, Erol
Driven by the global transition towards greener and more efficient mineral extraction, waste rock–cementitious tailings backfill (WRCTB) has gained prominence as an innovative solution for repurposing mining solid waste. The strength performance of WRCTB is strongly governed by the aggregate proportion of waste rock (R) to tailings (T). This study systematically evaluates the influence of R/T ratios (4:6, 5:5, 6:4, and 7:3) on mechanical behaviour and microstructural evolution using a multi-scale framework. An integrated multi-scale approach combining uniaxial compression, X-ray CT–based 3D reconstruction, and SEM was employed to evaluate mechanical properties, energy dissipation, pore architecture, and hydration characteristics. The results indicate that an equal rock-to-tailings proportion (R/T = 5:5) yields the optimal composite behaviour, maximising strength and stiffness while minimising pore volume and producing a substantially more compact microstructure. Increasing slurry concentration and prolonging age further enhance strength development. CT analysis indicates a uniform pore distribution at lower R/T ratios, whereas higher ratios lead to sedimentation stratification and pore clustering. SEM observations confirm that at R/T = 5:5, abundant C–S–H gel and ettringite (AFt) are formed, producing strong interfacial bonding and a dense microstructure. Overall, a clear ‘mix ratio–structure–property’ relationship is established, clarifying the intrinsic mechanism governing WRCTB performance.
The effect of değirmendere on hydrography and nutrient salt distribution in the southeastern Black Sea (Trabzon) coastal waters
(Istanbul University Faculty of Aquatic Sciences, 2026) Fidan, Dilek; Ağırbaş, Ertuğrul; Kalıpçı, Ömer; Yavuz, Meryem; Altınbaş, Mehmet; Örnek, Volkan; Aydın, Ayşe Nur
In this study, the physical properties and nutrient salt composition of coastal waters affected by Değirmendere along the Trabzon coast of the Southeastern Black Sea were compared with stations representing open sea conditions relatively independent of river influence. Fieldwork was planned for March and August 2025 to capture two contrasting hydrographic conditions; sampling was carried out at depths of 0–200 m along the river-influenced TM (Trabzon-Center; TM1–TM4) line and the reference TY (Trabzon-Yomra; TY1–TY4) line. Temperature, salinity, and density profiles of the water column were obtained using CTD; dissolved inorganic nitrogen species (nitrate, nitrite, ammonium), orthophosphate, reactive silicate, and total nitrogen and total phosphorus concentrations were measured using an auto-analyzer and statistically evaluated using the Month×Line approach. In March, a cold and vertically well-mixed water column of 9 °C was observed in both channels, while in August, a warmer and less dense layer developed at the surface and a distinct thermocline/pycnocline formed between 20 and 40 m. While no significant difference was observed between TM and TY in terms of salinity and density, nutrient salts showed a significant change from the coast to the open sea and from the surface to the depths. Near the coast, TM showed a higher tendency for ammonium and total nitrogen, while total phosphorus and silicate were relatively higher in TY in most cases. The effects of month, line, and interaction were pronounced on total nitrogen, with enrichment being more prominent in TY in March and in TM in August. DIN:PO43-ratios above the Redfield ratio generally indicate phosphorus limitation; although Değirmendere increases enrichment near the coast, this effect weakens within a few nautical miles, indicating that the trophic status of the region remains relatively balanced in terms of eutrophication. This study provides a local reference dataset that comparatively documents river effects during two distinct periods rather than representing an annual cycle.
Matrix domain of the second-order q-Cesàro matrix in classical sequence spaces
(American Institute of Mathematical Sciences, 2026) Ellidokuzoğlu, Hacer Bilgin; Demiriz, Serkan
In this paper, we study a second-order q-Cesàro matrix and its matrix domains in the spaces c0 and c. We establish basic structural results, including inclusion relations, connections with earlier Cesàro-type sequence spaces, the duals of these spaces, and the associated matrix transformations. Our approach extends known work on q-Cesàro operators and provides a starting point for further investigations of higher-order q-averaging methods in summability theory.
