Search Results (11,927)

This study investigates the effects of financial market instability, national security, and foreign direct investment (FDI) on economic growth in Sub-Saharan Africa from 1991 to 2023, while examining the moderating role of institutional quality. The study employs a panel autoregressive distributed lag (ARDL) model as the baseline estimator, complemented by fully modified ordinary least squares (FMOLS) and dynamic ordinary least squares (DOLS) for robustness analysis. The results reveal that financial market instability constrains economic growth primarily through sovereign bond market instability and vulnerability to earnings manipulation, whereas stock price volatility exerts no significant long run effect. Improved peace conditions and domestic military expenditure promote growth, while terrorism undermines economic performance. Government effectiveness and control of corruption enhance growth, whereas foreign direct investment exerts a negative long-run effect in the absence of supportive domestic conditions. The interaction results show that institutional quality significantly conditions the effects of financial market conditions, national security, and foreign investment on growth. Stronger institutions reduce the adverse consequences of financial and security-related disturbances and improve the growth-enhancing capacity of foreign capital. The FMOLS and DOLS estimates largely confirm the baseline results. The study concludes that institutional quality constitutes a critical transmission mechanism through which financial stability, national security, and foreign investment influence long run economic growth in Sub-Saharan Africa. Full article

The transition toward decentralized renewable energy systems creates monitoring problems that current digital infrastructures do not solve: sustainability claims are produced by the same actors they evaluate, environmental evidence is reported periodically rather than observed continuously, and the communities most affected by deployment cannot inspect the data used to represent their territories. Existing integrated platforms combine subsets of the blockchain, Internet of Things (IoT) sensing and life cycle assessment (LCA) at the data layer, but they do not organize that integration through an explicit governance structure. This paper contributes a cybernetic governance framework in which the Viable System Model (VSM) supplies the organizing structure of a blockchain–IoT–LCA monitoring architecture, so that sensing, distributed trust, strategic intelligence and participatory governance are recursively coupled rather than sequentially chained. The framework was developed and evaluated under the Design Science Research paradigm, and instantiated in the IMPACT Energy.CO platform across two technology routes, wind and solar, in La Guajira, Cesar, Atlántico and Magdalena, Colombia. Evaluation against six pre-declared criteria reports 45 executed test cases with a 100% pass rate, 90% unit and 87% integration code coverage, load tests up to 5000 concurrent users with zero errors and sub-second mean response, an operating hash-chained provenance layer issuing verifiable LCA certificates, 14 participatory validation workshops, 199 users trained and 166 technicians certified. We use traceability in a deliberately narrow sense throughout: the property whereby a committed record can be linked to the ingested data series, model version and computation that produced it, and its integrity and ordering checked by a party that does not trust the producer. It is provenance and integrity traceability from the point of ingestion onward, and it is not metrological traceability: the architecture cannot verify that an original sensor measurement corresponds to the physical quantity it purports to represent. We accordingly make explicit what the architecture does not guarantee: a ledger protects records after commitment but cannot certify measurement at the point of capture, and we present a threat model, a set of implemented controls and the residual risk that remains. This study contributes an architecture, a reproducible development and evaluation method, and a calibrated account of what verifiable environmental monitoring can and cannot deliver in contested Global-South territories. Full article

Water erosion is a core issue that threatens the ecological integrity of the highland ecosystems in the Andes Mountains and the agricultural sustainability of the Ramis River basin. This study uses the Revised Universal Soil Loss Equation (RUSLE), which integrates five factors, rainfall erosivity (R), soil erodibility (K), topography (LS), cover and management (C), and support practices (P), to estimate the spatial distribution of potential water erosion rates in this basin. The results show that the very low and low erosion classes together cover 73.21% of the basin, while the high, very high, and extreme erosion classes account for 17.29% of the total area. Among these, the extreme erosion class, with an annual erosion volume exceeding 250 tons per hectare, covers 8.07% of the basin, equivalent to 1190.13 square kilometers. This extreme erosion is concentrated in steep headwater areas and five sub-basins including Cuenca Grande. Comparative model verification shows that the Ordinary Least Squares (OLS) model only identifies a positive correlation between slope gradient and potential soil loss, with an extremely low explanatory power (R² = 0.045). Its residuals exhibit significant spatial autocorrelation (Moran’s I = 0.204, p < 0.001). In contrast, the Geographically Weighted Regression (GWR) model greatly improves the model fit (R² = 0.359, RMSE = 148.288) and eliminates the spatial autocorrelation of residuals, proving that the slope-erosion relationship has spatial non-stationarity. Sensitivity analysis shows that the C factor has the highest sensitivity (0.980), followed by the LS factor (0.626). Based on these findings, this study proposes that cover and management measures such as vegetation restoration should be prioritized in high-risk headwater sub-basins. It should be noted that the values estimated in this study are potential soil loss amounts, rather than actually measured erosion values. Full article

Achieving integrated water resources management at all levels, as called for by Sustainable Development Goal (SDG) target 6.5, requires assessment tools that operate at the local administrative scale. However, watershed sustainability assessments are mostly conducted at the whole-basin or provincial scale, which masks the spatial disparities that matter for local water management. This study develops a sub-district-scale Watershed Sustainability Index (WSI) for the Nong Han Basin, Thailand, by integrating the HELP framework (Hydrology, Environment, Life, and Policy) with the Pressure–State–Response structure, a calibrated QSWAT hydrological model, and spatial analysis in a geographic information system, covering 25 sub-districts. The results show that the basin has a moderate-to-high level of sustainability, with a mean WSI of 0.620: 18 sub-districts are classified as high and 7 as moderate, and none fall into the low category. The Life and Hydrology dimensions are the strongest, whereas the Policy dimension is the limiting factor in most sub-districts. This limitation arises from a low Response component (0.19) rather than from a lack of institutional capacity, as confirmed by the finding that sub-districts with low and high policy scores differ only in the Policy dimension. The apparently uniform aggregate index, combined with the high disparity among dimensional scores, confirms the value of diagnosis at the sub-district scale. The proposed framework translates the assessment results into spatial prioritization, an agency-linked decision matrix, and an intervention typology, thereby supporting evidence-based water management by local administrative organizations. Full article

The Controllable Line-Commutated Converter (CLCC) integrates fully controlled and semi-controlled devices to mitigate commutation failure. However, its application in large-capacity HVDC systems is constrained by the limited current-carrying capability of fully controlled valves in the main branch. To address the HVDC requirements under high-current conditions, this paper proposes a high-reliability cascaded H-bridge CLCC (H-CLCC) valve topology. The proposed topology employs a dual-path conduction mode for H-bridge sub-valves, reducing electrical stress on devices and enabling modular scalability. A redundant configuration, in which cascaded H-bridges are paralleled with bypass thyristors, allows faulty sub-modules to be rapidly bypassed, ensuring continuous operation. An analytical model based on the Laplace transform is developed to reveal the relationship between capacitor voltage and turn-off current, providing guidance for capacitance design. PSCAD/EMTDC simulations verify that the H-CLCC valve effectively suppresses commutation failure via active commutation, even under severe AC-side faults with currents up to 8 kA. Device-failure simulations further demonstrate strong self-healing capability, ensuring sustained forced commutation under local faults. This work provides a foundation for high-reliability UHVDC converter valve design. Full article

Electric-shovel top sheave bearings with sensor-embedded slots operate under harsh service loads, making them prone to fatigue crack initiation and propagation. Accurate predictions of crack growth within the bearing body are therefore essential for intelligent bearing design and reliability assessments because the bearing integrity directly affects shovel service life and safety. This paper presents a sub-modeling-based method that embeds initial cracks while preserving actual roller-ring boundary conditions and ensuring computational efficiency via adaptive mesh refinement. A global model first identifies critical crack-prone zones, after which the sub-model systematically examines the effects of the initial crack angle and sensor-embedded slot depth on the propagation behavior. The results indicate that both factors significantly increased the stress intensity factor (SIF). Among the evaluated designs, the 15 mm -deep slot produced the highest SIFs and the shortest predicted crack-propagation life, indicating that slot depth was a key design parameter under the investigated conditions. The findings provide theoretical support for the structural design and fatigue evaluation of intelligent electric-shovel top sheave bearings. Full article

The universal operator-growth hypothesis (OGH) states that, in a closed chaotic system, the Lanczos coefficients grow linearly, $b_n\simeq \alpha n$. We ask how this structure is modified when the system is coupled to a Markovian environment, so that the generator becomes non-Hermitian. Applying the Arnoldi recursion to the vectorized Lindbladian in the infinite-temperature Wightman inner product, we organize the resulting pair of growth rates ${\alpha }_{\mathbb{C}}\equiv {\alpha }_R+i{\alpha }_I$—defined as effective slopes of the sub-diagonal and diagonal Arnoldi coefficients over a pre-registered fit window—around two statements whose logical status we delimit precisely. First, whenever the dissipator acts as $\mathcal{D}=-2\gamma \widehat{G}$ with $\widehat{G}$, a Hermitian grading (all dephasing-type baths), the diagonal obeys the identity $\mathrm{Re}{a}_n=-2\gamma {⟨\widehat{G}⟩}_n$: the imaginary rate measures how fast the growing operator accumulates weight in the dissipation channels. Second, we prove a conditional parity theorem: if the Hamiltonian, jump operators, and seeds can be made simultaneously real in some basis (an antiunitary condition), then $b_n$ is even, and $\mathrm{Re}{a}_n$ is odd in $\gamma$ exactly, so ${\alpha }_R$ is renormalized only at $O\left({\gamma }^2\right)$, and ${\alpha }_I=2{\kappa }_0\gamma$ follows from closed-system data alone. We exhibit a one-qubit Lindbladian that satisfies the often-assumed generator symmetry ${\mathcal{G}}^{†}\left(\gamma \right)=-\mathcal{G}(-\gamma )$ yet violates parity ($b_1=|1-\gamma |$), showing that the extra condition is essential; all models studied here satisfy it bit-exactly. For large-q SYK, these ingredients predict ${\alpha }_{\mathbb{C}}=\mathcal{J}-2i(q-2)\gamma$, whose imaginary part is fixed solely by the interaction range; the first ladder step is exact, and the multi-step increments approach $q-2$ with system size ($1.92\pm 0.04$ at $N=12$, $q=4$). Under a common fit protocol, the closed-system rates saturate by $N=10$ (${\alpha }_R\left(0\right)\to 0.437$, $2{\kappa }_0\to 0.224$). The imaginary rate is not an independent observable at leading order—its content is its sign, which resolves how the growing operator meets its environment (opposite for spin chains and SYK). Full article

Mobile charging stations can deliver energy at the point of demand, but their isolated battery-to-battery DC–DC stages must accommodate independent source and load battery-voltage variation. This study develops a hierarchical, domain-wide analytical framework for a fixed-hardware 20 kW silicon-carbide phase-shifted full-bridge converter with a four-diode rectifier. The independently varied terminal domain spans 586–840 V at the source and 495–738 V at the load. The framework combines rated-power coverage, constraint-resolved derating, modeled semiconductor-loss screening, analytical commutation-capacitance budgeting, deterministic sensitivity assessment, and selected-point switching-level refinement. For four screened transformer turns ratios, nominal area-based rated-power can reach 95%. However, a three-point leakage-inductance sensitivity changes the nominal ordering at −10%, showing that the sub-one-percentage-point coverage separation does not establish a robust unique ratio. Selected-point commutation-cell and full-converter simulations show that the analytical added-capacitance screening bound is useful for rapid screening but can be optimistic near difficult high-source-voltage and light-load conditions. The full-converter results also retain high-capacitance light-load cases in which target power is not reachable at the phase-shift-domain boundary. The proposed evidence hierarchy therefore supports rapid candidate screening, identifies sensitive boundaries, and directs detailed switching refinement without claiming a universal transformer-ratio optimum or replacing hardware measurements. Full article

Climate change and variability pose serious threats to natural and human systems. The Mediterranean and North Africa (MNA) are among the world’s climate change hotspots. An in-depth understanding of the decadal climate variability in this region is critical to support planning and management, as well as adaptation in important sectors such as water resources. Therefore, in this study, fifth-generation ECMWF atmospheric reanalysis (ERA5) precipitation data and the outputs of the Coordinated Regional Downscaling Experiment-COmmon Regional Experiment (CORDEX-CORE) regional models were used to characterize the decadal precipitation variability in MNA and its sub-regions (Western North Africa: WNA, Sahara: SAH, southern Mediterranean: SMED, and northern Mediterranean: NMED). The models showed overestimation in most areas and underestimation in a few areas relative to the ERA5 data, with the magnitude varying by region and season. The positive biases obtained from the regional climate models (RCMs) were higher than the positive biases obtained from the general circulation models (GCMs). The wet biases were dominant during the annual, summer, and autumn seasons over MNA and its sub-regions. Negative biases were mostly associated with GCMs, mainly HadGEM2-ES and/or NorESM1-M; meanwhile, they were linked with RCMs such as CCLM5-0-15 and/or RegCM4_v7 and were mostly obtained in winter and spring. The multi-model mean (MME) was better at reproducing the decadal precipitation patterns over MNA, SMED, and NMED at all time scales, while REMO2015-NorESM1-M and the MME performed better than the remaining models at the annual time scale over WNA and SAH. These findings are useful for improving climate modeling, the water resources management and related sectors, and climate adaptation strategies in the region, especially in North Africa. The short-period coverage of the simulated data available for this study constitutes a limitation to the findings. Full article

Blisk, as a critical component of aero−engines, is prone to fatigue cracks that can severely impair its dynamic performance and operational safety. This paper develops a finite element model of a blisk with breathing cracks to investigate the effects of crack distribution (adjacent blades vs. separated blades) and blade twist angle on natural frequencies, frequency−veering and mode localization, and response localization under varying operating conditions. Resonance vibration tests are conducted on blisk and cracked blisk specimens using the frequency dwell method to obtain natural frequencies and vibration responses, thereby experimentally validating the numerical model. The results indicate that cracks reduce the global stiffness, leading to a decrease in natural frequencies and modal localization phenomena. Furthermore, in the frequency−domain responses, nonlinear components such as sub−harmonics, ultra−sub−harmonics, and super−harmonics are observed in addition to the harmonics of the excitation frequency. Moreover, the cracked blisk with a 45° blade twist angle exhibits typical nonlinear vibration behaviors and the most pronounced response localization. This study provides a basis for crack monitoring and resonance fatigue warning. Full article

Emerging industrial agglomeration drives green transformation through knowledge spillovers and economies of scale. However, its effects exhibit pronounced nonlinearity and heterogeneity, shaped by spatial externalities and development stages. This paper investigates 19 Chinese urban agglomerations over the period 2014 to 2023. Kernel density estimation based on enterprise-level Point-of-Interest (POI) data is used to characterize spatial agglomeration patterns across eight emerging sectors. A two-stage dynamic network super-efficiency SBM model decomposes Green Transition Efficiency (GTE) into resource utilization and pollution control sub-stages. An XGBoost-SHAP-GEO analytical framework, combined with partial dependence analysis, then identifies nonlinear driving mechanisms. The main findings are as follows: First, emerging industrial agglomeration intensifies and polarizes toward the eastern coast, whereas GTE displays a “high-west, low-east” pattern. This produces a significant spatial mismatch, rooted in the near-saturation of environmental carrying capacity in eastern regions, where congestion effects exceed knowledge spillover dividends. Second, geographic characteristics constitute the primary factor shaping GTE and operate through nonlinear interactions with industrial agglomeration and R&D investment. Notably, their moderation direction is reversible, suggesting that geographic endowments should be understood as “conditional assets” rather than fixed advantages. Third, nonlinear patterns across sectors are highly heterogeneous. The bio-industry is the only sector to achieve a J-shaped positive breakthrough. Information technology and new materials exhibit persistent inhibition, while related services display an extremely narrow threshold window with the deepest negative reversal. Thus, “moderate agglomeration” is a multidimensional concept that shifts dynamically with industry type and regional endowment. Fourth, driving mechanisms display stage-dependent evolution. The incubation stage relies on natural endowments and basic industrial pull, with the green bottleneck residing in resource utilization efficiency. The growth stage faces multiple tensions from coexisting positive and negative effects. The optimization stage shifts toward R&D innovation and industrial greening, marking a qualitative transformation from MAR externalities to Jacobs externalities. In addition, the non-significant linear coefficient in the 2SLS instrumental variable test is consistent with the inverted U-shaped nonlinear finding, further validating the necessity of a nonlinear analytical framework. These findings provide differentiated governance evidence for balancing industrial agglomeration with green sustainable development. Full article

Sustainable agriculture is critical to sustainable development and climate resilience, yet evidence of its multidimensional environmental, social and economic benefits and trade-offs remains limited, especially in regions most vulnerable to climate change. This study addresses this gap in Vietnam’s Mekong Delta (MKD), where decades of intensive rice farming has bolstered rice yields at the expense of environmental quality and farmers’ health. This study presents a multi-criteria analysis (MCA) comparing organic rice (OR) and conventional rice (CR) farming systems in the MKD. We applied a weighted sum model to evaluate the environmental, social and economic performance of the two production systems. The assessment drew on quantitative and qualitative primary data collected through stakeholder engagements and field measurements from Vinh Long province between 2023 and 2025, as part of the OrganoRice project. Overall, OR farming performed cumulatively better (0.663 and 0.695) than CR farming (0.496 and 0.484). OR scores were higher across most sub-criteria, particularly “farmers’ income” and “biodiversity”. However, CR outperformed OR for “rice yield” and “farmers’ workload”. Comparable water and soil quality scores, due to the presence of pesticide residues in both systems, suggest that the environmental performance of OR farming was likely dampened due to cross-contamination from surrounding or upstream non-organic farms. The expansion of OR farming in the MKD has the potential to enhance environmental, social and economic performance of rice production in the region. However, in order to achieve the full scope of these benefits, short-term measures should aim to reduce the financial risks of conversion for farmers, ensure access to affordable organic inputs, increase farmer training, ensure reliable premium contracts for rice producers and support them in accessing organic markets. Longer-term measures must improve irrigation water management and infrastructure to minimise cross-contamination risks. Coordinated marketing campaigns are needed to develop a trusted regional brand for organic rice from the MKD to create new opportunities in international and domestic markets. Moreover, long-term monitoring of post-transition outcomes is important to capture the full impacts of conversion. As OR cultivation continues to expand across the MKD, evidence on its benefits and trade-offs is essential to guide this transition effectively. This study provides that evidence, offering a context-specific, multidimensional evaluation to inform OR policy and practice in the region. Full article

This study presents a systematic literature review of spatial planning frameworks for coastal hazard mitigation, conducted in accordance with the PRISMA 2020 guidelines. A structured search of two academic databases, Scopus and Web of Science, covering the period 2016 to 2026 identified 368 records, of which 27 peer-reviewed studies were included in the final synthesis. The review pursues four interrelated objectives: analyzing global publication trends in research on spatial planning for coastal hazard mitigation; identifying and describing coastal hazard typologies and their associated mitigation approaches; examining how spatial planning frameworks are integrated with hazard mitigation strategies; and synthesizing cross-cutting constructs that structure an integrative analytical model. Findings reveal a marked intensification of scholarly output over the final third of the review period, with Asia–Pacific and Europe as the most represented regions, while sub-Saharan Africa and small island developing states remain critically underrepresented. Coastal hazards are classified into four categories: slow-onset climate and hydro-geological processes, acute hydro-meteorological events, multi-risk systemic hazard interactions, and ecological and environmental degradation. Three analytically distinct integration families are identified: geospatial and technical modeling, NbS and ecosystem-planning integration, and participatory governance and institutional integration. From these, four cross-cutting constructs emerge inductively across the evidence base, namely spatial risk assessment and geospatial modeling, land-use governance and climate-proof planning, community-based resilience and participatory governance, and ecosystem-based adaptation and nature-based solutions, which together constitute an integrative analytical framework. The discussion demonstrates that governance capacity, rather than technical sophistication, is the primary moderator of implementation effectiveness, and that socio-spatial equity in hazard planning represents a cross-regional challenge irrespective of governance capacity level. Limitations include the geographic concentration of the evidence based in high-capacity planning contexts and the predominantly projected rather than implemented nature of effectiveness evidence. Full article

Background: Glioblastoma (GBM) is the most aggressive subtype of malignant glioma. Current therapeutic options remain limited, highlighting the need for the development of novel compounds capable of improving the efficacy of standard treatments. This study aimed to evaluate the biological activity of a series of pyrazolone-based hydrazone compounds (TPPs) in vitro GBM cell lines. Methods: The eight TPPs were synthesized by a nucleophilic addition reaction of different substituted hydrazines with 1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-2-phenylethan-1-one and tested on two human GBM cell lines, T98 and U87. The cytotoxic effects were evaluated via MTT assay. The most active compound was further investigated at IC₅₀ and IC₂₅ concentrations to evaluate mechanisms of cellular damage, including reactive oxygen species (ROS) production and mitochondrial membrane potential (ΔΨ_m) changes. Additional assays included colony formation, cell cycle analysis, and evaluation of DNA damage and apoptosis markers. Results: TPP25 exhibited the highest activity with IC₅₀ values of 11.01 μM (95% CI: 10.42 to 11.64) and 13.12 μM (95% CI: 10.23 to 16.87) on T98 and U87 lines, respectively. Treatment induced early ROS production and mitochondrial depolarization, along with a significant reduction in colony formation. Cell cycle analysis revealed accumulation in the sub-G0 phase, consistent with increased cell death, supported by propidium iodide uptake. Furthermore, the results suggest the involvement of an apoptotic-like mechanism as supported by Annexin V positivity, γ-H2AX upregulation and transient caspase-3 activation. Conclusions: TPP25 demonstrates significant in vitro cytotoxicity, likely driven by a pro-apoptotic mechanism. This profile positions it as a potential lead compound for further preclinical evaluation, supporting its future transition into in vivo GBM models. Full article

This paper presents an analytical compact DC current model and a numerical gate capacitance model for p-type cylindrical gate-all-around (GAA) nanowire metal–oxide–semiconductor field-effect transistors (MOSFETs). The models are formulated within the Landauer transport framework, incorporating source-to-drain tunneling (SDT) and quantum statistical charge analysis. The proposed current model is validated against non-equilibrium Green’s function (NEGF) simulations for different channel lengths, nanowire radii, and bias conditions, showing good agreement with the NEGF results in the ballistic limit. The model parameters are separated into physical parameters obtained or calibrated from the NEGF simulations and a single set of global empirical fitting parameters. The latter is extracted once and remains unchanged across the investigated device geometries and bias conditions, allowing its transferability to be evaluated. The compact model is implemented in Verilog-A, and its SPICE compatibility is verified through DC simulations of PMOS inverter circuits. All NEGF comparisons in this work are performed with a zero channel backscattering coefficient corresponding to the ballistic transport limit; validation of the quasi-ballistic regime is left for future work. Full article