Search Results (209,014)

A significant fraction of the HF waves is absorbed by the lowest ionospheric layer, the D-region. This region is perturbed by solar flares, which notably cause fast increases in the Sun’s X-ray flux. We present here a new chemistry model, the "Lower Ionosphere Region–Absorption and Chemistry Modelling" (LIR-ACheM), to study the D-region behaviour. It is based on the Mitra–Rowe scheme and takes into account four distinct sources (EUV, Lyman-$\alpha$, X-rays and cosmic rays) and seven species (electrons, $N{O}^{+}$, $O_2^{+}$, $O_4^{+}$, positive cluster ions, $O_2^{-}$ and other negative ions). It thus offers a compromise between accuracy and computing time. The D-region’s sluggishness and its recovery time after a flare are analysed, highlighting the importance of detachment at low altitudes and soft X-ray fluxes above 80 km. Full article

Semaglutide represents a unique therapeutic option for patients with type 2 diabetes mellitus (T2DM), being the first and currently only glucagon-like peptide-1 receptor agonist (GLP-1RA) available in both subcutaneous and oral formulations. This study aimed to compare the effectiveness of oral versus subcutaneous (sc) semaglutide on metabolic parameters and cardiovascular risk factors in T2DM patients. This is a retrospective real-world study including adult patients with T2DM taking oral or sc semaglutide followed at the ASUGI Diabetes Center. We analyzed data from 434 patients (median age 70 years, diabetes duration 13 years), treated with oral (n = 232) or sc (n = 202) semaglutide. The oral formulation had a higher discontinuation rate. Among these patients, 130 patients in the oral group and 145 in the sc group had an 18-month follow-up. When comparing these groups, patients taking sc semaglutide had a significantly higher baseline BMI. However, multivariate linear regression models suggested that both formulations were comparably effective in reducing HbA1c and BMI, with baseline values being the primary predictors of response. To address BMI imbalances, propensity score matching was performed, identifying 55 matched pairs. Both oral and sc semaglutide reduced HbA1c and BMI and there were no significant differences in the median change in HbA1c and BMI between groups. Interestingly, oral semaglutide was associated with a significantly greater reduction in diastolic blood pressure compared to the sc formulation. Furthermore, concomitant therapy with SGLT2 inhibitors significantly enhanced the reduction in total and LDL cholesterol. Oral and subcutaneous semaglutide show comparable effectiveness in lowering HbA1c and BMI in a real-world setting. Full article

Off-grid electric vehicle (EV) charging infrastructure powered by hybrid solar–wind systems address critical adoption barriers in developing countries, where grid unreliability and sparse charging networks constrain transportation electrification. Despite growing research interest, no comprehensive review has systematically synthesized the interplay between hybrid renewable architectures, intelligent energy management strategies, and techno-economic viability specifically for off-grid EV charging in resource-constrained settings. This systematic review applies the PRISMA methodology to analyze 94 peer-reviewed publications (2013–2026), examining system architectures, intelligent control strategies, power electronics, battery storage, and deployment frameworks for standalone hybrid solar–wind EV charging stations. Key findings indicate that hybrid solar–wind configurations achieve 30–50% reductions in battery storage requirements and 15–25% lower levelized cost of energy (LCOE) (USD 0.08–0.15/kWh) compared with single-source systems, driven by diurnal and seasonal resource complementarity. Among intelligent control methods, the two-stage distributionally robust optimization (TSDRO) framework emerges as the most promising for data-scarce environments, outperforming conventional deterministic and stochastic approaches by 10–20% in managing renewable intermittency without requiring precise probability distributions. Wide-bandgap power semiconductors (SiC, GaN) enable 96–98% conversion efficiency, while lithium iron phosphate batteries provide 3000–5000 cycle lifetimes suited to tropical operating conditions. Critical gaps remain with field validation still predominantly simulation based, long-term operational data exceeding 24 months on equipment degradation and climate resilience are scarce, and scalable financing models for developing country contexts require further development. Nigeria is presented as an exemplar deployment context, with transferable insights for sub-Saharan Africa, South Asia, and Southeast Asia. Full article

To address the urgent need for electronics operable in extremely high-temperature environments, this paper presents a novel three-terminal, dual-gate, lateral 4H-SiC n-channel depletion-mode junction field effect transistor (JFET) without a backside electrode. Featuring a fully planar electrode layout, the device eliminates the back-gate effect and significantly improves integration compatibility. Experimental results demonstrate stable DC operation up to 500 °C, with an intrinsic gain of 9.79 at room temperature and 6.01 at 500 °C. Comparison with TCAD simulations confirms excellent agreement in the key physical trends of threshold voltage drift and mobility degradation, though quantitative discrepancies are observed and attributed to process-induced parasitic effects such as non-ideal ohmic contacts and interface states. Analysis shows that the new structure broadens the channel depletion layer by optimizing the depletion profile, thereby suppressing channel-length modulation and improving both output resistance and gate control. This work not only provides an effective device platform for high-temperature 4H-SiC analog integrated circuits (ICs) but also deepens the understanding of process-performance correlations, offering clear guidance for process-oriented device optimization. The proposed structure serves as a foundation for developing fully planar, high-temperature 4H-SiC analog ICs with promising potential in aerospace, automotive, and energy exploration systems. Full article

To investigate the underlying mechanisms of talent mobility in higher-education institutions influenced by factors such as the development environment, macroeconomic policies, and evaluation mechanisms, this paper proposes a nonlinear stochastic differential equation (SDE) dynamical model that incorporates time delays and multiplicative noise. We analyze the dynamic processes of talent mobility under varying conditions regarding the number of nodes, policy implementation cycles, and noise intensity. First, we employ central manifold theory and stochastic averaging methods to reduce the system to a one-dimensional averaged $It\widehat{o}$ equation. Subsequently, with $\tau$ as a parameter, we conduct an in-depth study of the system’s stochastic bifurcation behavior using the corresponding Fok–Planck–Kolmogorov equations. Finally, we validate the theoretical conclusions through numerical simulations. The results indicate that the number of nodes, policy delay, and noise intensity all have significant effects on system stability; an increasing delay induces random P-bifurcation in the system, and when $N\le 3$ and $N>3$, the system exhibits distinctly different steady-state behaviors. We also found that excessively high noise intensity disrupts system stability, whereas moderate noise intensity has a positive effect on stability. This study not only provides theoretical insights into the dynamic evolution mechanisms of talent mobility in regional universities but also offers valuable guidance for universities in formulating talent recruitment and evaluation policies. The methodology employed in this study opens up a promising avenue for analyzing complex dynamic problems in the field of sociology. Full article

Users encounter privacy and permission settings across digital platforms, yet often struggle to understand, locate, and manage them effectively. Despite regulatory efforts such as the General Data Protection Regulation (GDPR) and platform mechanisms like App Tracking Transparency, these challenges persist due to interface design limitations rather than solely user capability. This study evaluates the My Information and Data Access (MIDA) framework, a user-centred privacy interface designed to support users with different levels of expertise. A between-subjects usability study was conducted with 44 participants (novice n = 15, intermediate n = 14, advanced n = 15), combining System Usability Scale (SUS) scores, task completion rates, error rates, and think-aloud protocols. The results show high usability across all groups, with SUS scores of 80 (novice), 84 (intermediate), and 92 (advanced), all exceeding the acceptability threshold of 68. Task completion rates exceeded 80%, whilst error rates remained below 25% across most tasks. These findings indicate that MIDA can support users in understanding, configuring, and managing privacy settings across different levels of expertise. This study builds on prior HCI research linking privacy management challenges to interface design limitations and provides empirical evidence that an expertise-adaptive interface can improve users’ ability to understand and manage privacy settings. Full article

How older adults psychologically appraise their health while managing multiple chronic conditions is a behavioral-science question as much as a clinical one. This study estimated the weighted prevalence of favorable mental-health self-appraisal, identified its behavioral, social, and functional correlates, and compared the relative salience of diagnosed-condition burden and functional limitation among U.S. adults aged ≥ 50 years with multimorbidity. This retrospective cross-sectional secondary analysis used the 2023 Medical Expenditure Panel Survey (MEPS) Full Year Consolidated Data File (HC-251). Multimorbidity was defined as at least two diagnosed chronic priority conditions. The primary outcome represents favorable mental-health self-appraisal, derived from MNHLTH53 (excellent/very good/good vs. fair/poor). Covariates were organized using Andersen’s Behavioral Model and health-psychology concepts of adaptation, resources, and lived functional burden. Weighted prevalence estimates and survey-weighted logistic regression models were fitted using PERWT23F, VARSTR, and VARPSU. Robustness checks examined a stricter outcome threshold, proxy adjustment/non-proxy restriction, and a physical-health extension model. The analytic sample included 5523 respondents, representing approximately 77.9 million U.S. adults aged ≥ 50 years with multimorbidity. The weighted prevalence of favorable perceived mental-health self-appraisal was 86.6% (95% CI 85.4–87.7). In the fully adjusted core model (complete-case n = 5330), age 65–74 years (aOR 1.52, 95% CI 1.17–1.98) and age ≥ 75 years (aOR 1.79, 95% CI 1.36–2.36) were associated with higher odds of favorable appraisal. Lower odds were observed for Hispanic respondents, non-Hispanic Asian respondents, lower educational attainment, lower income, non-employment, ≥4 diagnosed conditions, and any functional limitation. The strongest inverse association was limitation status (aOR 0.32, 95% CI 0.27–0.39). Sensitivity analyses were directionally consistent. Favorable mental-health self-appraisal remained common in this medically complex older population, but it was socially and functionally patterned. Functional limitation appeared more behaviorally salient than diagnosis count alone. Because the analysis was cross-sectional and based on household-interview reported measures, these results should be interpreted as associations rather than causal effects. Full article

Most major crops in agricultural soils exhibit relatively low nutrient use efficiency for nitrogen (N), phosphorus (P), and potassium (K), often necessitating supplemental nutrient inputs to achieve sustainable yields. Furthermore, the increasing use of biowastes such as compost, manure, and biosolids, which frequently have nutrient ratios that do not match crop requirements, has contributed to excessive nutrient inputs and subsequent accumulation in soils. This situation has been further exacerbated by intensive farming practices involving multiple cropping cycles per season. Overuse of nutrients causes them to accumulate in the soil, creating a legacy nutrient pool. The application of biochar as soil amendment is considered a potential strategy to control legacy nutrients dynamics. The current review inspects the possible value of biochar in modulating legacy nutrient reserves in the soil, thereby increasing the bioavailability of nutrients and improving crop yield. This review discusses the search scope and synthesis approaches for the bibliometric methodological component through rigorous screening process (Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)), focusing on journal articles published in last 20 years that specifically address legacy nutrient management. The significance of the economic and environmental effects of legacy nutrients and the insufficient knowledge of how biochar application influences nutrient dynamics in soil highlight the necessity for additional research to address current gaps. Full article

The $\delta$-complement $G_{\delta }$ of a graph G, introduced by Pai et al., is a variant of the ordinary complement that toggles edges only between vertices of equal degree. Tangjai et al. recently established Nordhaus–Gaddum-type bounds for the ordinary domination number on G and $G_{\delta }$, raising the natural question of analogous bounds for stronger domination invariants. We prove a sharp Nordhaus–Gaddum-type bound on the Roman domination number of the form ${\gamma }_R\left(G\right)+{\gamma }_R\left(G_{\delta }\right)\le n+3k-2s_1-s_2$, where n is the order of G, k is the number of distinct vertex degrees, and $s_1,s_2$ count degree classes of size 1 and 2, respectively. The bound strictly refines the trivial estimate $2(n+k)$ and is attained on an explicit infinite family of graphs of the form $m{K}_2$. For the total domination number, we pose the corresponding conjecture ${\gamma }_t\left(G\right)+{\gamma }_t\left(G_{\delta }\right)\le n+2k$ whenever G and $G_{\delta }$ have no isolated vertices. We are able to settle this bound only in part: we prove it unconditionally on the subclass of graphs whose every degree-class subgraph and its complement are free of isolated vertices, and we verify it computationally for all orders $3\le n\le 8$, but a proof in full generality remains open, so the bound is stated as a conjecture. The Roman bound is likewise checked by exhaustive enumeration of all $13,595$ non-isomorphic simple graphs of orders $3\le n\le 8$, with zero violations and all 26 sharp instances identified. Full article

A study was conducted on the construction of sulfonated poly(aryl ether ketone) nanomicelles and their dispersion–displacement synergistic behavior in deep oil recovery. Unlike conventional surfactant systems, inorganic nanoparticle-based EOR materials, and polymeric nanofluids that mainly rely on interfacial tension reduction, wettability alteration, or viscosity regulation, this study constructs self-assembled sulfonated poly(aryl ether ketone) nanomicelles that integrate a rigid aromatic backbone, ionizable sulfonic acid groups, nanoscale dispersion, and interfacial regulation within one polymeric architecture. Sulfonated poly(aryl ether ketone) nanomicelles were prepared by combining polymer sulfonation with solvent-induced self-assembly, and their structural features, dispersion stability, interfacial behavior, porous-media transport, and displacement performance were systematically evaluated. Spectroscopic characterization confirmed the successful introduction of sulfonic acid groups into the polymer backbone. The resulting nanomicelles exhibited an average hydrodynamic diameter of 117.8 nm, a polydispersity index of 0.186, and a zeta potential of −38.6 mV in deionized water, while a value of −27.4 mV was still maintained at a salinity of 150,000 mg/L, indicating good electrostatic stability under highly mineralized conditions. Further evaluation showed that the 0.30 wt% system retained a transmittance of 97.4% after 15 d of static standing, and its particle size remained at 151.7 nm even under 120 °C and 150,000 mg/L, demonstrating favorable thermal–salinity tolerance. At the same concentration, the oil–water interfacial tension decreased to 6.9 mN/m at 1800 s, while the contact angle of oil-aged quartz was reduced from 118.4° to 58.7°, indicating effective regulation of both the oil–water interface and the solid surface wettability. During microscopic displacement, the residual oil area fraction decreased from 32.8% after water flooding to 14.6%, and cluster-like oil, corner oil, and film-like oil were reduced from 14.6%, 9.8%, and 8.4% to 5.9%, 4.2%, and 4.5%, respectively. In core flooding, the incremental oil recovery reached 13.2%, the final water cut decreased to 81.2%, and the injection pressure increased only from 0.42 MPa to 0.68 MPa. These results indicate that sulfonated poly(aryl ether ketone) nanomicelles promote deep residual-oil mobilization through the combined effects of stable dispersion, interfacial regulation, and effective transport, with 0.30 wt% identified as the preferred concentration range. The main scientific contribution of this work is to establish a structure–dispersion–interface–transport–displacement relationship for SPAEK nanomicelles under deep-reservoir conditions, providing a polymeric nanomicelle-based strategy distinct from conventional surfactant, sulfonated polymer, and nanoparticle flooding systems. Full article

Background and Clinical Significance: Cutaneous paraneoplastic phenomena are infrequently characterised in colorectal cancer (CRC), and chronic pruriginous inflammatory eruptions in particular have received limited attention. In older adults, persistent treatment-resistant dermatoses of unclear aetiology may represent overlooked extraintestinal diagnostic clues to occult malignancy, including potentially curable CRC. Faecal immunochemical testing (FIT) for occult bleeding is a low-cost, non-invasive tool whose role outside conventional alarm-symptom triage remains underexplored. Case presentation: A 72-year-old woman presented for outpatient evaluation with several months of pruriginous, pustular, and crusted symmetric eruption involving the dorsal aspects of the limbs, refractory to standard dermatologic treatment, and without gastrointestinal symptoms. A non-invasive systemic stool-based work-up demonstrated detectable faecal haemoglobin (iFOBT), mildly elevated faecal calprotectin (51.6 mg/kg, ULN 50 mg/kg), markedly elevated faecal alpha-1-antitrypsin (631 µg/mL; 2.3× ULN), and predominance of Escherichia coli on stool culture. Colonoscopy revealed a locally advanced rectal adenocarcinoma; staging classified the lesion as cT3N1M0. The patient received long-course neoadjuvant chemoradiotherapy (50 Gy, concurrent capecitabine) followed by low anterior resection with total mesorectal excision and pathological complete response (ypT0N0, R0), and adjuvant capecitabine. The cutaneous eruption resolved progressively in parallel with antineoplastic therapy without specific dermatologic intervention. The patient remains in remission at over 36 months. Conclusions: Persistent, unexplained, treatment-resistant pruriginous/pustular cutaneous eruptions may, in selected patients, coincide with an underlying malignancy, including colorectal cancer, and should prompt careful individualised clinical assessment, including review of age-appropriate colorectal cancer screening status. This single case raises the hypothesis that quantitative faecal immunochemical testing (FIT) may be prospectively evaluated as a low-cost, non-invasive triage tool in carefully selected patients aged ≥50 years with persistent dermatoses of unclear aetiology, even in the absence of gastrointestinal symptoms. Positive FIT results should be managed according to established local colorectal referral pathways. NICE diagnostics guidance DG56 supports FIT use in symptomatic adults with suspected lower gastrointestinal pathology; however, any extension of FIT to extraintestinal presentations remains investigational and requires formal validation through prospective studies assessing diagnostic yield, cost-effectiveness, and stage distribution. Full article

The rapid evolution of Large Language Models (LLMs) has exposed limitations of static, accuracy-oriented benchmarks and increased the need for evaluation frameworks that distinguish among capabilities and benchmark quality. This survey analyzes 63 LLM benchmarks spanning 2012–2026 and organizes them into a taxonomy of six capability dimensions and 20 operational subcategories. We also propose the Benchmark Quality Assurance Index (BQAI), an AHP-weighted composite framework for assessing the scientific quality of benchmarks across seven dimensions related to annotation, clarity, standardization, reproducibility, robustness, coverage, and fairness. The BQAI is applied to 30 representative benchmarks, corresponding to 48% of the 63-benchmark corpus, with three-evaluator blinded scoring, formal inter-rater reliability validation $\left(\mathrm{ICC}(2,k)\right.$ and quadratic-weighted Cohen’s $\left.\kappa \right)$, and Monte Carlo sensitivity analysis $\left(n=1000\mathrm{trials},\pm 10\%\mathrm{to}\pm 50\%\mathrm{weight}\mathrm{perturbation}\right)$. In addition, we synthesize public performance results for 16 models across 10 benchmarks to examine saturation trends and reporting gaps. The analysis indicates that benchmark usefulness varies substantially across evaluation settings, that several established benchmarks are becoming less discriminative for frontier models, and that important gaps remain in safety, agentic, and cross-cultural assessment. Together, the taxonomy, BQAI, and saturation analysis provide a structured perspective on the current LLM benchmark landscape and on priorities for more rigorous evaluation. Full article