Long-term shoreline change on tropical islands is spatially heterogeneous, but alongshore contrasts remain insufficiently resolved. We quantified shoreline change along the 151.1 km eastern sandy coast of Hainan Island, China, from 1987 to 2025 using Landsat-derived visually interpreted shoreline proxies and the Digital Shoreline Analysis System across 1413 transects. The coast was broadly stable to accretional, with a mean linear regression rate (LRR) of 0.49 m/yr and a mean net shoreline movement (NSM) of 17.72 m. Under the uncertainty-aware classification, 28.0% of transects were stable, 42.1% accretional, 8.2% erosional, and 21.7% indeterminate. For descriptive comparison, the eight sectors were grouped into three broad alongshore zones: a stable northern zone (Beaches A–B), an accretion-dominated central zone (Beaches C–E), and a heterogeneous southern zone (Beaches F–H). The strongest accretion occurred at Beach D (LRR = 7.63 m/yr), whereas the strongest erosion occurred south of the offshore artificial island at Beach F (LRR = −3.97 m/yr). These contrasts show that coast-wide stability or accretion can mask localized erosion. The observed patterns were spatially associated with differences in headland-bay morphology, nearshore seagrass beds, engineering structures, estuarine processes, and lagoon-inlet settings. The findings support beach-sector monitoring and differentiated coastal management.
This paper reviews the application of Life Cycle Assessment (LCA), Life Cycle Cost Assessment (LCCA), and ship design optimisation methods and examines the extent to which these approaches have been integrated to support sustainable electric ship design. The main goal is to understand how these methods have been applied and where the key gaps remain. The review analyses current practices in environmental and cost assessments of ship systems and design, along with ship design optimisation methods aimed at improving energy efficiency and reducing emissions. Overall, the reviewed literature shows that LCA, LCCA, and ship design optimisation are generally applied as separate processes rather than parts of an integrated framework. Key gaps include the lack of models that account for time-varying costs, changes in technology and energy systems. Additionally, this paper highlights the need for integrated and adaptive frameworks, supported by open and standardised data and digital tools, to better connect environmental and economic considerations across a vessel’s life cycle, for more practical and sustainable ship design.
Abstract Black carbon (BC) in marine sediments provides a unique archive of combustion history and a reservoir for long-term carbon storage. However, the distinct roles of char BC (CBC) and soot BC (SBC) in combustion-source tracing and carbon-cycle assessment remain poorly resolved in marginal seas. Here, we analyze four sediment cores from the Beibu Gulf, South China Sea, using benzene poly(carboxylic acid) (BPCA) and chemothermal oxidation at 375 °C (CTO-375) methods to resolve subtype-specific BC records. CBC accounted for 52–57% of the estimated total BC burial across all settings, consistent with sustained biomass-burning contributions. SBC exhibited higher spatiotemporal variability and sensitivity to fossil fuel expansion, particularly near industrial zones. Estimated BC burial fluxes varied spatially, largely reflecting differences in representative sedimentation rates rather than BC content. Notably, nearshore sites exhibited higher burial despite lower BC content. Centennial-scale profiles revealed that SBC effectively traced regional transitions from biomass to fossil fuel combustion, while CBC preserved the long-term fire legacy. These findings highlight the complementary roles of CBC and SBC in reconstructing combustion histories and assessing BC burial in marginal seas. Burial of biomass-derived BC can contribute to net atmospheric CO2 sequestration, whereas fossil-derived BC burial represents the transfer of fossil carbon into long-term sedimentary storage.
High-resolution range profile (HRRP) reconstruction is essential for extracting range-direction scattering characteristics in wideband radar remote sensing, particularly in synthetic aperture radar (SAR) and inverse synthetic aperture radar (ISAR) imaging. Coded interrupted sampling (CIS) can improve radar low probability of intercept (LPI) performance by controlling signal transmission with a binary sequence. However, the reduced number of valid echo samples may degrade HRRP reconstruction, especially under low-duty-ratio and low signal-to-noise ratio (SNR) conditions. Conventional orthogonal matching pursuit (OMP) processes each frame independently and ignores the inter-frame continuity of scattering-center positions, which may lead to false selections and missed detections. To address this problem, this paper proposes a candidate-interval-assisted orthogonal matching pursuit (CI-OMP) algorithm based on multi-frame sequential priors. Stable scattering-center positions are extracted from historical reconstruction results and expanded into candidate intervals to guide atom matching in the current frame. Simulation results show that CI-OMP outperforms standard OMP in terms of normalized mean squared error (NMSE), tolerant support recovery rate (Tol-SRR), and peak-to-sidelobe ratio (PSLR). At a duty ratio of 0.20, CI-OMP reduces the NMSE by 1.71 dB and improves the PSLR by 7.56 dB compared with OMP. In addition, the candidate-interval strategy reduces the atom-search range by approximately 54–75% under different duty ratios and by approximately 50–83% under different SNRs, demonstrating improved search efficiency. These results demonstrate that CI-OMP improves the accuracy, robustness, and search efficiency of HRRP reconstruction for CIS radar echoes, particularly under low-duty-ratio and low-to-medium-SNR conditions.
Abstract Causal inference plays a central role in sustainability studies, providing the foundation for evidence-based scientific discovery and policy evaluation. However, uncovering credible causal relationships in complex real-world settings often relies heavily on the judgment of domain experts and extensive contextual knowledge. With the emergence of large language models (LLMs), an open question arises as to whether these models can meaningfully support causal reasoning for sustainability research. This study systematically evaluates the capacity of LLM to infer causal hypotheses and methodological structures from contextual descriptions of empirical research. We construct a benchmark based on five high-quality, peer-reviewed sustainability studies and design structured prompts that replicate the informational context available to human researchers prior to estimation. LLM outputs are evaluated against expert-validated ground truth in terms of causal edge recovery, scope expansion, and alignment with identification strategies, allowing for a quantitative assessment of conceptual causal reasoning rather than numerical estimation. Our findings indicate that GPT-5 recovers core causal edges with moderate accuracy (0.33-0.85), and assigns causal direction with high reliability (0.87-1.00). However, the scope expansion rate achieves roughly 0.58-0.93 of the causal edges proposed by the model, indicating a strong tendency toward over-connection between variables. Overall, our findings contribute to a deeper understanding of the potential and limitations of LLMs as tools for causal reasoning and methodological support in empirical sustainability research.
Marine mammal mass stranding events (MSEs) are complex phenomena that require detailed investigation into their causes and behavioural precursors. In July 2023, Scotland experienced a large MSE involving 55 long-finned pilot whales ( Globicephala melas ), offering a rare opportunity to examine their pre-stranding feeding ecology and, by extension, habitat use using stable isotopes. We analysed carbon ( δ 13 C) and nitrogen ( δ 15 N) stable isotopes in matched samples of liver, skin, and muscle from 39 individuals to assess resource use patterns across different tissue integration timescales, as recent changes in feeding might indicate a change in habitat. Liver, representing the most recent dietary integration, showed lower δ 13 C values than skin and muscle. While δ 15 N values were higher in liver, TEF-corrected δ 15 N values did not differ across tissues, providing no detectable bulk-isotope evidence for major trophic level shifts across the sampled dietary integration windows represented by the different tissues. We applied the Stable Isotope Trajectory Analysis (SITA) framework in R for the first time to multi-tissue data from marine mammals. Trajectories revealed minimal net change across and between individuals, and the direction and magnitude of isotopic changes were consistent with shared temporal patterns in resource use. We found no consistent detectable bulk-isotope evidence of recent dietary or habitat shifts across the stranded group and no evidence for a coherent systematic directional shift in isotopic space over the time represented by the tissues analysed. Importantly, in a broader context, our findings highlight the potential of multi-tissue isotope analysis as a cost-effective tool for reconstructing short- to medium-term foraging history in stranded cetaceans, providing important insights into habitat and resource use of cryptic cetacean species.
Since heavy clutter seriously restricts the ability of radar to detect targets, it is significant to build the target detector under heavy clutter. For practical situations without the secondary data or prior knowledge of target and clutter, this paper proposes a polarization-space-time detector. First, a general radar model is constructed for multiple pulses, multiple arrays, and multiple polarizations. Based on the theory of ternary hypothesis, the secondary data free (SDF) GLRT detector is proposed, which can maintain the constant false alarm probability (CFAR) in inhomogeneous clutter. Then, this paper proposes a matrix transform operator and an adaptive detection method using sliding window. These two approaches do not need to know the steering vector of radar and the noncentral parameter of clutter in advance, so the SDF-GLRT detector can adapt to different application scenarios. In addition, this paper optimizes the polarization waveform of the radar system by constructing a projection matrix. This method yields closed-form solutions of the optimal polarization and worst polarization, rather than relying on numerical solution. Finally, the performances of the SDF-GLRT detector and three other detectors are compared by simulated and real data. The proposed SDF-GLRT maintains PFA of 5.4×10−3 and 2.6×10−3 on two IPIX datasets (#54 and #310) at a design PFA=10−3, whereas the other detectors deviate to 0.0249–0.7405. The optimal polarization yields a detection-probability gain of more than 0.22 over the worst polarization at SCR=0 dB.
Land-use transformation driven by large-scale water conservancy projects profoundly reshapes regional ecosystem structures and the supply capacity of ecosystem services, yet targeted quantitative assessments linking land-use evolution to ecosystem service values (ESV) in the Xiaolangdi Reservoir resettlement zone remain insufficient, restricting scientific ecological management and territorial spatial governance for reservoir-affected counties and districts. This study draws on the latest ecosystem service valuation theories proposed by domestic and international scholars and applies the value equivalence method to quantify variations in land-use pattern changes and ESV across nine resettlement counties and districts (including the Sanmenxia urban area) affected by the Xiaolangdi Reservoir relocation project. Data collected included historical records (1995–2020), digital elevation models (DEM, 30 m resolution), and land-use information. By applying value equivalence theory and analyzing land-use change impacts, the study calculated changes in ESV and conducted sensitivity analyses across different land types. The findings reveal significant impacts on surrounding counties following the reservoir’s completion. Data indicate that the expansion of water areas drove the total ESV to rise from US$3.3261 billion in 1995 to a peak of US$3.6557 billion in 2010, followed by a decline to US$3.6128 billion in 2020. The most pronounced changes occurred during the first five years post-reservoir filling (2000–2005), marked by elevated water sensitivity indices. This research clarifies the differentiated responses of ecosystem service functions to land-use changes across reservoir-affected counties, provides quantitative decision-making support for coordinated ecological restoration, cultivated land protection, and sustainable land management in the resettlement area of the Xiaolangdi Reservoir, and offers a replicable technical framework for ecosystem service valuation of large sediment-laden river reservoir regions worldwide.
To investigate the influence of inlet structure optimization on pressure pulsation and energy transport characteristics in mixed-flow pumps, this study employed experimental and numerical calculation methods to analyze both original and optimized models. The SST-SAS turbulence model was selected for flow field computation. The experimental and numerical results showed that inlet optimization increased the head at the design condition by 1.52 m, improved the efficiency by 5.38%, and reduced the pressure pulsation amplitude by more than 90%. Analysis of energy transport term distribution characteristics within the pump revealed the mechanism behind pulsation intensity improvement: the pressure propulsion power distribution in the impeller became more stable, while the Lamb vector divergence dissipation regions and enstrophy dissipation regions substantially decreased, thereby increasing the proportion of pressure propulsion power contribution. The enhanced energy transport characteristics and improved flow field stability in the impeller region collectively optimized energy conversion performance within the impeller.
Ring-stiffened cylindrical shells are widely used as load-bearing components in submarine pressure-hull sections. Existing underwater explosion studies have mainly emphasized incident-face denting or global failure, leaving unresolved how circumferential shock-wave diffraction and internal structural load transfer produce different response sequences and plastic-strain accumulation at the incident, side, and rear faces. A mechanism-oriented underwater explosion model test was conducted using a 44 g TNT charge at a stand-off distance of 0.50 m, and a fluid–structure interaction model was established in MSC.Dytran using the general coupling method. The model incorporated the Cowper–Symonds strain-rate effect of 16MnR steel and was validated against the Cole empirical peak pressure and measured incident-face residual deformations. The calculated free-field peak pressure was 35.50 MPa, with an error of 0.65%, while the mean relative error of the six residual-deformation measurements was 13.50%. The shell plating between adjacent ring stiffeners exhibited higher velocity and acceleration peaks than the stiffeners, indicating the local constraint imposed by the ring stiffeners. The side-face nodes showed symmetric transverse expansion, and the corresponding elements exhibited no discernible equivalent plastic strain. The rear-face center displayed a delayed axial response, and its representative element reached a final equivalent plastic strain of approximately 1.32×10−3, compared with 0.40×10−3 for the incident-face element. These results identify distinct circumferential response modes and show that macroscopic motion amplitude is not simply correlated with local plastic deformation.
Heating and cooling of outdoor space steadily increased over the last years. The pull between economic growth and lessening the ecological footprint remains a major concern in the light of reaching sustainable development goals (SDGs). We looked at numbers and energy consumption of heating and outdoor cooling in gastronomic outdoor spaces during one heating period in two Vienna districts (Austria) and investigated citizens' perspectives on climate change, outdoor heating and cooling with an online and in-person questionnaire ( N = 72, N = 79). We found more outside heaters than officially registered in one district (59 visible heaters, 0 registered) which indicates a high number of heaters used in private gastronomic outdoor spaces. The calculated total ( N = 901) could supply up to 2500 two-person households with electricity for one year. Radiant heaters influenced the decision to visit a gastronomic establishment for 40% of participants and altered the choice of seating for 63%. Our results reflect a cognitive dissonance and a trade-off between environmental behaviour and ever-increasing human development on societal and economic level. The lax registration policy in Vienna requires action and the lack of research in the outdoor heating area remains a blind spot in the context of urban sustainability: in times of global warming using fossil fuels to heat outdoor spaces seems questionable in itself.
Abstract Per- and polyfluoroalkyl substances (PFASs) are globally detected in humans, yet regional variations in PFAS exposure remain insufficiently characterized. Herein, by utilizing target and nontarget analysis with machine learning, differences in PFAS exposure were assessed based on 1088 serum samples of the population from SX, GD, HeB, and HuB regions in China. Nontarget analysis identified 49 PFASs, among which bis(trifluoromethane)sulfonimide (Ntf2), C8 per- and polyfluoroalkyl ether carboxylic acid, C12 hydrogen-substituted polyfluoroalkyl (linear) carboxylic acid, 8:2 fluorotelomer unsaturated carboxylic acid, 1-hydroxy-6:2 fluorotelomer sulfonic acid, haloxyfop, and leflunomide were reported in human serum for the first time. Target analysis indicated total PFAS concentrations of 9.4, 17, 25, and 29 ng/mL in the SX, GD, HeB, and HuB regions, respectively, with compositional profiles differing in the proportions of specific PFAS classes. Machine learning classifiers achieved an accuracy of 0.89 in distinguishing samples from the four regions, revealing significant interregional disparity. Furthermore, PFNA, Ntf2, PFOA, and 6:2 Cl-PFESA were identified as distinctive exposure biomarkers for SX, GD, HeB, and HuB, respectively, each being closely associated with local industrial activities. Overall, this study elucidates the region-specific characteristics of human PFAS exposure in China, providing a scientific basis for regionally tailored health risk assessment and pollution control strategies.
Localized sediment siltation poses a major engineering challenge that restricts the operational safety of water-related infrastructure, such as coastal ports and pile-supported wharfs. Pneumatic jet desilting technology provides a new solution for this problem. By combining stratified suspended sediment sampling with high fidelity particle image velocimetry (PIV) measurements, four transient dynamic stages of bed sediment suspension are identified. Furthermore, the vertical distribution characteristics of non-uniform sediment are quantified. The results show an energy saturation effect during the transfer of gas kinetic energy to the water body. The vertical flow velocity in the core region follows a power-law relationship with the incident gas flow rate. In the multiphase flow field, the distribution of non-uniform particles is governed by the mechanical competition between turbulent entrainment in the bubble wake and gravity settling. This competition leads to vertical spatial sorting. Based on the multiphase kinetic energy dissipation mechanism, a dimensionless generalized suspension index is constructed. Consequently, a predictive equation for the vertical concentration distribution of suspended sediment under pneumatic jets is derived. This equation theoretically reveals the spatial distribution laws of sediment under submerged gas jets. The equation provides an analytical basis for parameter optimization and energy control in pneumatic desilting engineering.
Ponds in urban green spaces, including those in private gardens and public areas, are important biodiversity refuges in otherwise ecologically constrained landscapes, and are significant nodes in the UK’s freshwater biome network. These ponds also represent diverse instances of complex ecosystems created and managed by people who have decisive roles in their construction and maintenance. The GenePools project was a multi-year community science project, initiated by the Defra DNA Centre of Excellence and subsequently led by Natural England as part of the Natural Capital and Ecosystem Assessment (NCEA), which sought to directly involve community scientists in molecular genetic biodiversity assessment, engaging community scientists in each stage of the experimental process, from pond sampling through to multiple, iterative presentations and interpretations of results. Metabarcoding and taxonomic annotation of genetic marker regions targeting multiple taxonomic groups (vertebrates, invertebrates, microbial eukaryotes, plants, green algae and fungi, and prokaryotes) revealed extensive diversity associated with sampled ponds, including representatives of nearly all major branches of the eukaryote tree of life. The species lists generated were presented to community scientists via a specifically developed interactive dashboard in multiple formats, including sequence tables and interactive plots. Here we report on the findings of the final iteration of the project, conducted between April 2024 and March 2025, including community scientist-facing results, and a selection of further analyses demonstrating the strength of the generated dataset for exploring urban pond diversity and community composition.
The “Kashmir Seismic Gap” is located between the epicentral regions of the 1905 Kangra and the 2005 Kashmir earthquakes. The area corresponds to the Jhelum basin and encompasses the Kashmir Valley. The geodetic measurements indicate that the Kashmir Himalaya accommodates ∼12 mm/yr of India-Asia convergence and ∼5 mm/yr of dextral shear. However, except for the known Karakoram Fault, which is further north of the area under investigation, there are no convincing reports of any prominent dextral faulting from the region. In this article, we have carried out remote sensing and GIS based geomorphic investigation including topographic derivatives such as drainage geometry, basin divide offsets, and elevation-χ analysis that consistently indicate an active accommodation of the missing dextral shear. The dextral slip is manifested in the deformed (offset) lateral divides of the Kashmir Valley (KV) and preferential deflection of the drainage along the Central Kashmir Fault (CKF). The χ-metric, which is used to examine the divide stability, also shows a change in its nature corresponding to the Central Kashmir Fault. The drainage on the SE lateral divide displays the most conspicuous evidence of the dextral shearing, which has resulted in the capture of through-going drainage within Kashmir Valley, and the beheaded stream continues to flow southwards. This event of drainage reorganisation has left a ‘wind-gap’ in the divide near Banihal. Furthermore, the hypothesis of dextral shearing is tested in the larger tectonic context together with the ∼ N-S oriented Jhelum Fault (JF) and Kishtwar Fault (KF). Both the Jhelum Fault and Kishtwar Fault are active sinistral faults and can impart anti-clockwise rotation to the region in between. The rotation between blocks of the Kashmir Himalaya can induce the observed dextral shear, which is consistent across the entire Kashmir Himalaya and the Kashmir Valley. Both of which, when calculated with the ∼ 4–6 Ma age of the Kashmir Valley, imply ∼ 5–7 mm/yr of dextral shear, similar to the estimates from geodesy.
Abstract Per- and polyfluoroalkyl substances (PFAS) accumulate in breast milk and pose a distinct hazard to breastfed infants, whose immature renal clearance substantially prolongs internal PFAS half-lives. We developed a two-compartment physiologically based pharmacokinetic (PBPK) model incorporating a postnatal glomerular filtration rate (GFR) maturation function to estimate individual-level infant blood PFAS concentrations from breast milk ingestion, and applied it to two prospective Korean birth cohorts (Cohort A: n = 221, 2018; Cohort B: n = 204, 2023). Five PFAS─perfluorodecanoic acid (PFDeA), perfluorohexanesulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctanesulfonate (PFOS)─were quantified by LC–MS/MS. Age-adjusted ANCOVA revealed compound-specific temporal shifts: PFHxS declined 66.7% (adjusted ratio: 0.33; p < 0.001), while PFNA and PFDeA increased 161.5% and 135.1% (both p < 0.001), evidencing regrettable substitution. PFOA and PFOS remained unchanged (both p > 0.69). Global sensitivity analysis confirmed that breast milk concentration and daily intake volume dominated model output uncertainty (|PRCC| = 0.82–0.91), whereas pharmacokinetic clearance parameters (elimination half-life and GFR maturation) had negligible influence on peak concentration (|PRCC| ≤ 0.05), reflecting accumulation-dominated kinetics over the first six months. External benchmarking against Fromme et al. (2010) yielded predicted-to-observed ratios of 0.67 and 0.61, respectively, within the prespecified acceptable range of 0.5–2.0. PBPK-estimated four-compound daily intake exceeded the EFSA (2020) TWI daily equivalent of 0.63 ng/kg/day (median multiples: 61× and 77×). These findings demonstrate that compound-specific regulatory action has not reduced aggregate infant fluorinated burden and highlight the urgent need for infant-specific PFAS reference values accounting for GFR immaturity.
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