Van Yüzüncü Yıl University is a university in Van, Turkey.
Effective management of radioactive nuclear waste is vital for a sustainable energy supply. However, challenges in the synthesis and design of ideal adsorbent materials with desired adsorption properties remain. Here, a novel graphitic carbon nitride-based adsorbent was developed for the removal of uranium(VI) and thorium(IV) from wastewater. For this, sulfur-doped graphitic carbon nitride (SCN) nanosheets were prepared through the calcination of thiourea, and their surfaces were modified with polyserotonin (PS) using a simple enzymatic polymerization process. The modification process enhanced the surface area, functionality, and dispersion stability of the SCN. Batch experiments were performed at various temperatures, contact times, pH levels, and initial solution concentrations to assess adsorption performance, kinetics, and thermodynamics. The experiments showed that SCN had an excellent Th(IV) adsorption capacity of 336.43 mg/g. The PS modification increased its Th(IV) adsorption by 1.5 times (565.83 mg/g) and enhanced U(VI) adsorption performance by more than 2.5 times (from 36.88 to 94.10 mg/g). Moreover, these adsorption performances were achieved at low adsorbent concentrations (1–5 mg) and low radionuclide concentrations (5–50 mg/L). This composite adsorbent (SCN@PS) exhibited relatively good reusability and strong anti-interference properties, highlighting its stability and practical application. The adsorption mechanisms were elucidated by XPS analysis. The findings indicated that U(VI) ions selectively coordinated mainly with the oxygen atoms of the composite material, whereas Th(IV) ions coordinated mainly with sulfur atoms.
This study primarily aimed to apply a novel, advanced stochastic volatility model incorporating leverage and an asymmetrically heavy-tailed distribution (ASV-GHskw) to 18 financial asset returns, including 10 Asia-Pacific and six European stock market returns and two crude oil market returns. The study employed a generalized hyperbolic skew student's t-distribution using the Bayesian approach. The study's secondary aim was to concentrate on one-day-ahead downside market risk measurement of the related financial asset returns under Basel IV regulations based on the ASV-GHskw model. For comparison, an asymmetric stochastic volatility model with a symmetric student's t-distribution (ASV-st) was also considered. The findings indicated that the proposed Bayesian Markov chain Monte Carlo (MCMC) approach was sufficiently efficient, especially when estimating the ASV-GHskw model parameters. Further, the ASV-GHskw model provided a better fit for all financial asset returns examined than its competing ASV-st model. Moreover, the results revealed that the financial institutions taking positions in the examined financial markets will be required to hold additional regulatory capital for market risk exposures under the latest Basel capital regulations. Lastly, the findings give valuable information for risk-averse investors interested in the examined financial markets, as they expect to receive higher-than-average returns by holding less-risky assets.
Geoheritage elements are generally recognised to possess various high-level values, including scientific, educational, economic, aesthetic, and touristic significance. Numerous studies have been conducted to quantify geoheritage values, and research in this area is ongoing. This study aims to present a quantitative approach to measuring the various values of geoheritage elements by extending an established geoheritage assessment method with Multi-Criteria Decision Making (MCDM) techniques. Therefore, five geoheritage sites from Tokat province in Türkiye were subjected to quantitative evaluation using the CRADIS (Compromise Ranking of Alternatives from Distance to Ideal Solution) method based on the IMF SWARA (Improved Fuzzy Stepwise Weight Assessment Ratio Analysis). The findings revealed that Ballıca Cave (G1) was the most significant geoheritage site across all dimensions. It has been determined that other heritage elements differ in terms of importance across various dimensions. It is anticipated that this study, along with the methodological framework used, will provide significant theoretical insights to the geoheritage assessment literature. Furthermore, five strategies were formulated, and a strategic management model was designed within the study’s framework of sustainable policy implications. This model and its outcomes will provide local stakeholders with the information needed to protect and manage geoheritage areas throughout the province.
The Van–Çatak gypsum succession exposed along the Bitlis–Zagros Suture Zone in Eastern Anatolia records evaporite deposition during the final stages of Neotethyan closure at the Arabia–Eurasia plate boundary. This study integrates sedimentological observations, petrography, SEM–EDS analyses, whole-rock major and trace element geochemistry, and Sr–S–O isotope systematics to constrain the origin, depositional environment and post-depositional evolution of these evaporites. The succession comprises laminated, massive, selenitic and nodular–chicken-wire gypsum associated with marl and carbonate units, reflecting progressive hydrological restriction within a shallow marginal basin periodically influenced by marine inflow and intense evaporation. Petrographic and SEM data indicate in-situ gypsum growth within soft sediments together with partial anhydritization, recrystallization, oxidation-related alteration, brecciation and fracture-controlled satin-spar veins, documenting multi-stage dehydration–rehydration cycles during burial, uplift and near-surface modification while preserving primary depositional signatures. Major and trace element systematics reveal alternating sulfate precipitation and siliciclastic dilution, detrital-element associations (K–Al–Ti–Zr), and redox-sensitive element distributions (Fe–Mn–U–Mo–Ni–Co) indicating fluctuating oxic to suboxic conditions and stratified brines. Elevated Sr concentrations and high Sr/Ca–Sr/Ba ratios reflect progressive brine concentration. Strontium isotope ratios (⁸⁷Sr/⁸⁶Sr = 0.70814–0.70991), together with uniform δ34S (17.2–18.9‰) and evaporation-enriched δ1⁸O values (14.3–15.7‰), confirm precipitation from marine-derived sulfate under restricted circulation. These results demonstrate formation within a restricted marginal-marine lagoon–sabkha system rather than a continental salina and provide new constraints on the marine versus continental origin of collision-zone evaporites during Neogene basin evolution along the Arabia–Eurasia convergence zone.
Planococcus ficus Signoret (Hemiptera: Pseudococcidae), commonly known as the vine mealybug, is a globally distributed species and stands out as one of the most destructive pests affecting grapevines. Sustainable approaches for suppressing P. ficus populations are needed. One of the crucial strategies for pest management without disrupting ecological balance is the creation of unfavorable conditions for pests through plant-mediated mechanisms. Plant nutrients and biostimulants applied during crop cultivation can enhance plant physiological status and defense capacity, thereby increasing resistance to diseases and insect pests. In this study, effects of seven different commercial mineral nutrient and biostimulant products were assed on the growth parameters of P. ficus. The life table data of P. ficus in grapevines, treated with key nutrients relevant to grape cultivation, were systematically collected to assess their impact on the population growth rate of P. ficus under controlled conditions. Among the different treatments, mealybugs fed on vines grown with the application of boron ethanolamine (Borfast) have the longest preadult development period, the lowest intrinsic rate of increase (r,0.0656 ± 0.004 d−1), the finite rate of increase (λ,1.067 ± 0.004 d−1), and the longest mean generation time (T, 55.49 ± 0.84 d). Among the tested treatments, Borfast, Fyllon Smart, and Idai Cu were grouped within the same statistical category for population suppression of P. ficus, although Borfast consistently produced more pronounced effects across multiple life table parameters. These findings suggest that these treatments hold significant potential for the successful control of P. ficus, thereby contributing to sustainable agricultural practices.
