Search Results (8,719)

Natural hazards and their negative impacts on assets are increasing because of a variety of causes, including climate change, population expansion, and urbanization. Moreover, several areas are susceptible to multiple hazards that interact spatially and/or temporally, necessitating a multi-hazard assessment to adequately mitigate their effects. The goal of this study is to investigate the direct monetary losses produced by the simultaneous interaction of two independent hazards in Lisbon’s city centre, i.e., earthquake and pluvial flood. Seismic hazard has been assessed in terms of macro-seismic intensity, while flood scenario allows for the prediction of water depth for different return periods through a hydrologic-hydraulic model in HEC-RAS software. The seismic and flood vulnerability of the urban investigated compound was evaluated through MCDM methodology—specifically, AHP and TOPSIS methods. A framework for multi-hazard analysis was subsequently developed, explicitly accounting for the interaction between the two hazards and their joint occurrence probabilities based on historical data from the case study area. The results demonstrate that multi-hazard losses are 108 M€ for a 2-year return period and 232 M€ for a 475/500-year scenario, emphasizing that floods contribute more across all return periods in the research area; however, for longer return periods, the earthquake contribution increases significantly. Full article

Ensuring food security is a top priority for China, and non-grain production (NGP) of cropland can substantially reduce food production. As the core grain production base in Shaanxi Province and even Northwest China, the Guanzhong region’s evolution of NGP is very important. Based on the single-phase remote sensing data and the time-series curve, this study identifies explicit non-grain production (E-NGP) and implicit non-grain production (I-NGP) of cropland in the Guanzhong region from 2001 to 2020. Spatial analysis and gradient analysis are applied to characterize the spatiotemporal dynamics, differences in reversibility, grain loss, and driving factors of E-NGP and I-NGP. The results show that the area of cropland used for NGP in the Guanzhong region has gradually increased over the past two decades. In 2020, the area of E-NGP reached 4212.06 km², while that of I-NGP accounted for 8300.16 km². The total cumulative loss attributed to NGP in 2020 reached 11.58 million tons, and the grain loss caused by I-NGP was approximately twice that of E-NGP. Moreover, cropland used for I-NGP exhibits greater instability and reversibility, making it more susceptible to human intervention than that under E-NGP. The cropland used for E-NGP is mainly distributed around urban areas, where it is often converted into construction land. The cropland used for I-NGP gradually expands from north to south, with areas south of the Weihe River increasingly converted into economic fruit forests. E-NGP is driven by both terrain and socioeconomic factors, while I-NGP shows a stronger natural geographical dependence. This study defines the scale boundaries and driving factors of NGP in the Guanzhong region, reveals its substantial threat to grain production capacity, and provides theoretical support for regional policy implementation and the formulation of refined cropland protection policies in the Guanzhong region. Full article

Urban fire incidents in complex built environments pose severe threats to public safety. However, the unstructured nature of urban scenes presents substantial challenges for existing detection algorithms in reliably identifying incipient flames and diffuse smoke under dynamic visual interference. To address this issue, we propose YOLO-Fire, a lightweight and high-precision detection algorithm based on YOLOv11. Specifically, a Hybrid Feature Fusion Module (HFFM) adopts a parallel dual-stream architecture to structurally decouple high-frequency flame boundaries from low-frequency smoke textures. A Dual-Scale Contextual Diffusion (DCD) mechanism establishes global contextual constraints through an additive diffusion strategy, effectively suppressing fire-like background interference while enhancing semi-transparent smoke features. In addition, a Gaussian Spatial Pyramid Pooling Fast (GSPPF) module further improves multi-scale receptive field aggregation. Evaluated on a self-constructed large-scale urban fire dataset, YOLO-Fire achieves an mAP50 of 75.7%, mAP50-95 of 53.3%, and an F1-score of 73.7%, with only 10.02 M parameters, surpassing the YOLOv11 baseline by 2.4%, 4.5%, and 2.9%, respectively. Ablation studies confirm that each proposed module contributes both independently and synergistically to the overall performance gains. Comprehensive comparisons with mainstream detectors and specialized fire detection models further demonstrate that YOLO-Fire achieves superior overall performance, outperforming YOLO-FireAD and FireSmoke-YOLO by 2.7% and 2.4% in mAP50, respectively, while maintaining lower computational complexity. Furthermore, inference evaluation on a single-core CPU achieves 17.28 FPS, validating the practical deployment potential of YOLO-Fire in resource-constrained environments and offering an efficient, lightweight solution for real-time urban fire surveillance and early warning. Full article

As urban areas expand, the sustainable management of municipal water becomes a critical challenge, especially in arid and semi-arid regions facing severe water scarcity. Accurate assessment of urban plant water requirements (PWR) is essential for developing sustainable landscape architecture and resilient green infrastructure. In this study, a new quantitative equation (PWR_q) was developed as a regional proof of concept to adjust reference evapotranspiration estimates for hyper-arid conditions. A Tree Morphology Coefficient (K_tm) is introduced to combine canopy features (form, height) and leaf traits (size, density) with an updated drought-resistance coefficient (K_dr). Field measurements of 277 mature trees, representing 27 native and introduced species in Riyadh and Jeddah, Saudi Arabia, were analyzed. The framework explicitly includes an empirical multiplier to account for extreme urban heat island (UHI) effects and aerodynamic canopy scaling. Instead of direct empirical validation, the PWR_q model was benchmarked against established reference indices: Water Use Classification of Landscape Species (WUCOLS) and Simplified Landscape Irrigation Demand Estimation (SLIDE), showing strong alignment with established categorical indices and structural traits. The results confirm that the morphology-based method effectively makes previously subjective classifications objective. Notably, the quantitative assessment found that the dominant introduced species require about 3.5 times more water than native species. As a proof of concept, future research should empirically validate these findings against direct physical measurements, such as sap flow sensors or lysimeters. The proposed framework presents a practical, objective decision-support tool for municipal policymakers and landscape architects to optimize species selection, implement nature-based solutions (NBS), and achieve long-term sustainability in urban greening. Full article

Background: Public perception of environmental (natural background) radiation represents an important challenge for public health communication, as risk perception is often influenced more by information quality and institutional trust than by objective exposure levels. Methods: A cross-sectional survey was conducted among 481 respondents using a structured questionnaire assessing self-perceived knowledge, information sources, perceived radiation risk, institutional trust, and health-related attitudes. Results: Significant gender differences were observed in self-reported knowledge about radioactivity, with men more frequently reporting higher knowledge levels than women (p < 0.001), while no significant differences emerged between urban and rural respondents; logistic regression analysis showed that lower perceived risk was associated with lack of medical information (OR = 0.32, 95% CI: 0.14–0.71) and absence of avoidance behavior (OR = 0.23, 95% CI: 0.11–0.47), whereas low trust in medical institutions was associated with higher odds of perceiving natural background radiation as dangerous (OR = 1.84, 95% CI: 1.21–2.80). Conclusions: Effective radiation risk communication requires more than the dissemination of information; it must also address public concerns, enhance institutional trust, and provide clear, credible, and accessible health-related messages. Tailored communication strategies are essential to bridge the gap between expert knowledge and public perception. Full article

Biological invasions are among the main threats to freshwater biodiversity, yet ecological patterns associated with assemblage structure and high relative abundances of non-native fishes in spring ecosystems remain insufficiently documented. We evaluated seasonal variation in community composition, reproductive traits, and trophic interactions in La Zarcita springs, part of the Natural Protected Area Laguna de Zacapu, central Mexico. Bimonthly sampling was conducted, including stomach content analysis and reproductive trait assessment. A total of 14 fish taxa were recorded (seven native and seven non-native), with the assemblage numerically dominated by Oreochromis niloticus (30%), Pseudoxiphophorus bimaculatus (24%), and Xiphophorus hellerii (14%). Overall diet composition did not differ significantly between taxa classified as native and non-native (PERMANOVA, p > 0.05), consistent with overlap in resource use within the assemblage. Exploratory assemblage-level analyses detected differences in omnivory index values among taxa grouped according to species origin (LMM, p < 0.05). Reproductive analyses detected variation in fertility values (GLMM, p < 0.05), reproductive activity (Wilcoxon test, p < 0.05), gonadosomatic index values, and Fulton’s condition factor values (LMM, p < 0.01) among taxa within the assemblage. Physicochemical variables varied seasonally but were not significantly associated with trophic composition, condition factor values, or reproductive traits in the statistical analyses performed. Overall, the results document variation in reproductive characteristics and trophic patterns among taxa within this urbanized spring system and highlight the value of assemblage-level ecological studies for understanding fish community structure in small freshwater habitats. Full article

The circular economy offers a key pathway to achieve the joint improvement of resource conservation and carbon reduction, yet its causal effect on urban energy efficiency remains insufficiently examined. This paper takes China’s Zero-Waste City (ZWC) policy as a quasi-natural experiment and uses panel data from prefecture-level cities between 2006 and 2023. By applying staggered difference-in-differences and double machine learning methods, we evaluate the effect of urban circular economy transformation on energy efficiency. The results reveal four main findings: (1) The ZWC policy significantly improves energy efficiency in pilot cities. (2) The policy operates through three mechanisms: resource circulation, structural optimization, and innovation compensation. (3) Policy effects are stronger in environmentally regulated cities, large cities, and regions with higher artificial intelligence development. (4) The policy also generates broader benefits beyond energy savings, including coordinated fiscal, economic, and environmental gains. Overall, this paper highlights the spillover benefits of the circular economy from waste reduction to energy conservation and provides policy implications for coordinating waste management and energy transition at the urban level. Full article

Urbanisation has led to dramatic alterations in pre-existing natural environments, resulting in several subsequent phenomena, such as the disappearance of habitats suitable for many plant and animal species and the concurrent arrival of generalist and non-native species, contributing to environmental homogenisation. Towns and cities serve as crossroads for transport, people, and animals, making them susceptible to colonisation by many types of plant species, dispersed either intentionally or unintentionally by these biotic vectors. Abiotic vectors, such as wind and water, also influence the composition of vegetation assemblages. Urban spontaneous vegetation occurs in (1) undisturbed areas, including brownfield sites, commons, and marginal lots, and (2) disturbed sites, such as green areas, parks, lawns (not subject to weeding), ancient monuments and walls, peripheral and industrial areas, and railways. When disturbance occurs, vegetation remains at early successional stages. Within this framework, with the aim of comparing existing contradictions and identifying knowledge gaps, we reviewed the literature on the characteristics of spontaneous plants and vegetation in urban areas, the different habitats in which they grow, the ecosystem services they provide, and management strategies, considering human perception. Our results highlight that studies on spontaneous plants are well-developed in terms of botany and ecology; however, some gaps remain, particularly regarding their integration into urban design and maintenance practices. Concerning public perception and acceptance, cultural and geographical differences emerged that deserve further investigation. In conclusion, spontaneous plants can represent a valuable heritage for cities, helping to address the challenges posed by the climate crisis. Full article

International evidence has been positioning the built environment as an active component of the development of students with Autism Spectrum Disorder (ASD); nevertheless, a gap persists in the empirical quantification of that relationship and, above all, in its dimensional hierarchization, a gap that becomes more pronounced in urban educational contexts with limited infrastructure such as those in Latin America. Within this framework, and with the aim of contributing empirical evidence to guide design decisions in comparable contexts, the present study analyzed the association between multisensory architecture and the cognitive development of students with ASD at a Special Basic Education Center (CEBE) in San Miguel, Metropolitan Lima, organizing the findings into a dimensional hierarchy that makes it possible to compare the relative strength of each spatial criterion. To address this objective, a non-experimental, cross-sectional, and correlational design was adopted, in which cognitive development was assessed through proxy informants (specifically, immediate family members with daily and sustained contact with the students), given that students with ASD present limitations for standardized verbal self-reporting. On this basis, a sample of 101 proxy informants completed, through the QuestionPro platform, a structured questionnaire of 24 Likert-scale items previously validated by expert judgment, exploratory factor analysis, and internal consistency analysis; inferential analysis was then conducted using Spearman’s rho, in keeping with the non-normal nature of the data. The results revealed a positive and statistically significant association between multisensory architecture and cognitive development, and they further allowed that relationship to be dimensionally ordered: on the built-environment side, physical-spatial conditions reached the greatest magnitude of association, followed by environmental conditions and, lastly, functional conditions; on the cognitive side, concentration emerged as the dimension most sensitive to the environment, followed by self-regulation and accessibility. Taken together, this empirical hierarchization offers architects, educational administrators, and therapeutic teams a practical reference for prioritizing design decisions in contexts with limited infrastructure and, to that extent, contributes to the fulfillment of Sustainable Development Goals 3 and 11, which connect health with inclusive urban environments. Full article

Background: Out-of-hospital cardiac arrest is a major cause of mortality, and survival depends heavily on rapid defibrillation. Automated external defibrillators (AEDs) can significantly improve outcomes when used before emergency medical services (EMS) arrive, yet access to and use of these devices remain uneven across communities. This study investigates racial and geographic disparities in AED use during EMS encounters in the United States, evaluating differences across racial groups, geographic settings, cardiac arrest status, and patient acuity, irrespective of whether a bystander or EMS personnel applied the device. Methods: This descriptive study used aggregated data from the National Emergency Medical Services Information System (NEMSIS) Public Release Data Cube to compare AED use across racial, geographic, cardiac arrest, and acuity categories. AED use was defined as any documented application during the EMS encounter. Results: The dataset included 106,246 EMS encounters across six racial and ethnic groups. AEDs were applied in 16,688 encounters (15.7%), with substantial variation across demographic and geographic categories. Asian, American Indian or Alaska Native, and Black or African American patients had the highest rates of AED use, while White patients had the lowest rate despite representing the largest share of encounters. Urban areas accounted for most AED deployments, whereas suburban and frontier regions showed markedly lower use, while rural AED use was similar to urban rates. AED application was strongly associated with cardiac arrest and high patient acuity, yet racial differences persisted even within these clinically severe categories. Conclusions: AED use generally aligns with clinical indicators such as cardiac arrest and critical acuity, but meaningful racial and geographic differences were observed, reflecting descriptive patterns rather than confirmed disparities. These patterns should be interpreted cautiously, as the aggregated nature of the dataset limits the ability to determine whether differences reflect inequities, incident characteristics, or EMS system factors. These findings highlight the need for targeted strategies to expand AED access, improve device placement, and strengthen community readiness in underserved areas. Integrating AED availability into broader EMS planning and community outreach may help reduce inequities and create conditions that support improved survival outcomes. Further research using individual-level data and geospatial methods is needed to clarify the drivers of these observed differences and inform equitable prehospital care policies. Full article

Enormous land exploitation is triggering strong urban growth, and this phenomenon is exacerbating the already existing problem of rising land surface temperatures. This leads to increased human activities and a disruption of the balance of natural ecosystems. The application of thermal remote sensing techniques is, in this context, helpful in learning about the condition of the earth’s surface and monitoring how it changes over time. This paper utilizes thermal data from 2000, 2010 and 2020, with supplementary data from 2024, to assess current trends in two different seasonal conditions (rainy period and low rainy period). Two different areas (urban and rural) of the central Vietnamese Province of Thua Thien-Hue have been analyzed to compare them. Processing Landsat-5 TM, Landsat-7 ETM+, Landsat-8 OLI/TIRS, and Sentinel-2 satellite images, a heat map of the study area was defined, considering hot spots and cold spots. As support for this analysis, spectral indexes have been developed for a better comprehension of the land cover change over the years and to provide a validation of the thermal analysis. This paper aims to assess the threat posed by the intensification of the urban heat island effect on cultural heritage sites. The case studies are represented by areas where there are urban growing and cultural heritage sites to be preserved, such as the UNESCO-listed Hue Citadel. Full article

Existing flood risk models have improved predictive accuracy, but they prioritize natural and hydrological factors while giving limited attention to fine-grained urban morphology. This study develops an interpretable deep learning framework to examine how high-resolution, three-dimensional urban form shapes two dimensions of flood risk: inundation risk, measured by grid-level inundated area, and infrastructure risk, measured by flood-related disruptions, including water supply interruption, power outage, road blockage, and collapse-related damage. Using Zhengzhou, China, as a case study, we combine multi-source spatial data, convolutional neural networks, ablation analysis, SHAP interpretation, and Gaussian Mixture Model classification to examine how fine-grained urban morphology affects these two risk dimensions. Incorporating urban morphology improved inundation risk prediction, reducing MSE from 0.0431 to 0.0371. The improvement was greater for infrastructure risk, with accuracy increasing from 0.7327 to 0.8218, and ROC-AUC from 0.83 to 0.95. SHAP results show that inundation risk is associated with vegetation, elevation, hydrological proximity, and localized spatial disorder, whereas infrastructure risk is amplified by vertical intensity, imperviousness, building concentration, porosity, and shape. Spatially, very high infrastructure-risk areas accounted for only 2.30% of the city but 12.88% of the central districts, while 74.62% of very high infrastructure-risk zones were concentrated in dense mid- to high-rise morphology. These findings suggest that flood-resilient planning should move beyond hydrology-sensitive flood management toward morphology-sensitive planning. Full article

Under the dual pressures of global climate change and rapid urbanization, the spatial contradiction between urban expansion and flash flood disasters in mountainous dam areas is increasingly evident. However, the mechanisms by which the multi-dimensional characteristics of urban expansion affect regional flash flood susceptibility (FFS) remain unclear, limiting scientific guidance for source-level disaster prevention. This study uses Zhaotong City, a flash flood-prone area in the lower Jinsha River basin of southwestern China, as a case study. Using land use and multi-source remote sensing data from 2000 and 2025, we identify urban expansion patterns and morphological characteristics, apply the XGBoost-SHAP model to evaluate flash flood susceptibility and determine dominant factors, and employ the generalized additive model (GAM) to quantify the nonlinear responses of expansion dimensions to FFS. Results show the following: (1) Urban expansion in Zhaotong City is primarily edge (51%) and leapfrog (46%), clustering along river valleys, dam areas, and transportation corridors. (2) The XGBoost model performs well (AUC = 0.877). Elevation, slope, normalized difference vegetation index (NDVI), and precipitation are the primary natural factors influencing FFS. About 15.66% of the city falls within the high/very high FFS zones, mainly in the Zhaolu Dam area, riverbanks of main and tributary streams, and the urban built-up area. (3) Urban expansion-related indicators explain 28.6% of the spatial variation in FFS, with leapfrog expansion as the primary driver (contribution rate 32.75%). Disorderly urban growth and morphological imbalance significantly increase flash flood susceptibility. This study provides a scientific basis for spatial planning, flash flood prevention and control, and climate-adaptive urban development in similar mountainous dam areas in Southwest China and Asia, supporting regional sustainable development goals. Full article

The Niger Delta region of Nigeria experiences multiple environmental stresses due to intensive oil exploration and pervasive gas flaring, both of which contribute to local and regional climate changes, extreme weather events, and excessive and erratic rainfall. Consequently, flooding remains a recurrent natural disaster, disproportionately impacting the low-lying states of Delta, Bayelsa, and Rivers. This study employs remotely sensed geospatial data and a GIS-based weighted overlay analysis to delineate flood-prone areas on a regional scale in the central Niger Delta states. Flood susceptibility was determined through a weighted overlay of digital elevation model (DEM), slope, proximity to streams, rainfall, and LULC data, among others. Weights of criteria were derived through an analytical hierarchy process (AHP) with a very good consistency ratio of 2.5%. Land use and land cover (LULC) and rainfall data were further analyzed to detect trends of changes between 2012 and 2022. The results show that relatively 77% of the study region is prone to flooding. Areas prone to very high flooding are about 16%, high is 29%, moderate is 32%, while low and very low flood-prone areas cover 18% and 5% of the study region, respectively. There is also a notable increase in average annual rainfall and land cover changes. Average rainfall increased by 58.1% between 2012 and 2017, and by 11.5% between 2017 and 2022. Land cover change analysis further indicates that approximately 1.3% of the study area was converted predominantly to flooded zones and water bodies from 2017 to 2022. The results of this study could be useful for urban regional planning, flood mitigation, and resettlement policies aimed at reducing flood vulnerability and enhancing resilience in the central Niger Delta, as well as other places where similar challenges exist. Full article

This study examines the persistence, change, and discontinuity of human settlements in the northern Stig Plain along the Danube in Serbia. It examines how natural conditions, together with historical events and the strategic imperatives of specific periods, have shaped the establishment, development, decline, and abandonment of settlements in this landscape, as well as their change and transformation. Particular attention is given to the Roman city of Viminacium, now largely buried beneath fertile farmland and affected by mining activity. The research integrates theoretical perspectives on landscape, human–environment relations, and processes of discontinuity and change with insights into Roman urban planning and overall settlement dynamics, contextualised through the environmental and historical development of the landscape. It considers why Viminacium remained the only major urban centre in the plain and why no later settlement developed directly above it, reexamining whether this absence can be understood as a form of landscape discontinuity. The findings emphasise the strong influence of natural factors, while suggesting that the urban potential of the fertile Stig Plain could only be fully realised in the Roman period, through the establishment of a legionary fortress supported by advanced technology and organised labour, and guided by strategic objectives. From a heritage perspective, the study also examines the definition of landscape boundaries, highlighting Viminacium’s legacy as an integrative element that brings together remains from multiple periods into a unique and evolving cultural landscape worthy of preservation, though one that faces ongoing challenges in sustainable management. Full article