Automated detection of lunar impact craters from digital elevation model (DEM) data is important for lunar geological analysis, landing-site selection, and crater catalog updating. However, this task remains challenging because lunar craters exhibit large scale variations, weak or degraded rims, ambiguous boundaries, and complex topographic backgrounds. In addition, large-scale lunar remote sensing applications require detection models to achieve a reasonable balance among accuracy, model complexity, and inference efficiency. To address these challenges, this study proposes FPW-YOLO11n, a frequency-perception crater detection method developed based on YOLO11n. First, a Frequency-Directional Attention Module (FDA-Module) is introduced into the shallow stage of the backbone. This module combines frequency-aware channel attention and direction-aware spatial attention to enhance the representation of crater rim structures, elevation variations, and directional topographic cues in DEM data. Second, a C2PSA-LRSA module is designed by embedding Local Region Self-Attention into the C2PSA framework, thereby improving local contextual feature interaction while reducing the excessive cost associated with global self-attention. Third, Inner-WIoU is adopted to replace the original CIoU loss in YOLO11n. By combining the auxiliary-box mechanism of Inner-IoU with the sample-quality-aware weighting strategy of WIoU, Inner-WIoU provides a more flexible bounding-box regression objective for craters with weak rims, scale variations, and uncertain boundaries. A DEM-based lunar crater dataset was constructed from the Moon LRO LOLA-SELENE Kaguya TC DEM Merge 60N60S 59m product and the Robbins lunar crater catalog, covering the non-polar region from 60° S to 60° N and containing 4760 image tiles. Under the random data-splitting strategy, FPW-YOLO11n achieves 78.3% Precision, 66.2% Recall, 75.1% mAP@0.5, and 50.2% mAP@0.5:0.95, outperforming the YOLO11n baseline by 1.2, 2.0, 1.6, and 4.0 percentage points, respectively. Additional experiments based on geographically disjoint data splitting further show that the proposed method consistently performs better than YOLO11n on DEM data, indicating that the proposed structural improvements remain effective under a more rigorous spatially independent evaluation setting. Although the computational cost increases from 6.3 to 24.0 GFLOPs, FPW-YOLO11n maintains a compact parameter size of 2.59 M and a high inference speed, demonstrating an improved accuracy-efficiency trade-off for lunar crater detection from DEM data.
Home to a lake around 4 billion years ago, Jezero Crater is a unique location to study the interplay between igneous processes and aqueous alteration on ancient Mars. The Máaz formation, rich in basaltic rock, is the highest stratigraphic unit on the crater floor and hosts a diversity of alteration phases that indicate multiple aqueous episodes affected the crater floor rocks. Using data from the Planetary Instrument for X-ray Lithochemistry aboard the Perseverance rover, we investigated manganese enrichments across the crater floor. We report on multiple distinct types of Mn-rich materials. The first, in the Guillaumes abrasion low in the Máaz formation, has been tentatively identified as the rare mineral despujolsite (Ca3Mn4+(SO4)2(OH)6·3H2O), which forms on Earth in hydrothermal and lacustrine deposits. In the Alfalfa abrasion patch, high in the Máaz formation, we find Mn-enriched magnetite spatially associated with a Ca-dominant sulfate that may contain minor Mn, which suggests a history of serpentinization followed by exposure to oxidizing acidic fluids. These findings underscore the complexity of aqueous alteration over the course of Jezero history. Future sample return missions could refine mineralogical interpretations and provide more information to improve our understanding of aqueous conditions and habitability in the crater.
Launching and landing spacecraft on the lunar surface mobilizes regolith at high velocities which will likely cause damage to nearby objects and infrastructure, a phenomenon known as plume surface interactions (PSIs) that must be mitigated for sustainable lunar surface exploration. While some mitigation strategies prescribe the construction of walls and landing pads using locally sourced regolith and additive manufacturing techniques, cheaper and more immediately available approaches may be required. We introduce a novel concept that uses small lunar craters (<1.5 km) as unprepared landing sites to mitigate the hazards posed by PSIs. We simulated the ballistic trajectories of regolith grains ejected by PSIs from the centers of 238 lunar craters and find that many could completely shield nearby areas from ejected regolith, with some of these protected "umbrella zones" being large enough to host either a 16 m-tall Blue Moon Mk. 2 lander or a lunar outpost. These examined craters are also conducive to safe landings as they retain sufficiently large and flat crater floors, as well as crater walls that are traversable by the Artemis program's proposed Lunar Terrain Vehicle. However, much work remains for this approach to be fully relied upon as a mitigation strategy.
The thickness and volume of the stratigraphic sequence in Mars' northern lowlands remain poorly constrained, despite their key role in recording the planet's geological and paleoclimatic evolution. Reliable thickness estimates are essential because they directly control calculations of volcanic effusion, surface flooding, and associated climate forcing. Here we present a revised volumetric assessment of the lowland stratigraphy - dominated by volcanic infill - based on integrated geological mapping and crater-statistical modeling. Our approach combines crater size-frequency distributions with volumetric reconstructions of buried craters and intercrater plains across both lowland and Noachian highland reference terrains. The results indicate that the minimum cumulative stratigraphic volume is at least three times greater than previous estimates, implying a proportional increase in volcanic outgassing of CO2, H2O, and SO2. These new quantitative conservative bounds provide improved constraints on early Martian volatile budgets and on mid- to late-Noachian atmospheric evolution, with implications for transient climate warming and late-stage lowland flooding.
To investigate the fracture mechanism of impacted ureteral stones during laser lithotripsy (LL). Impacted 6 × 6 mm cylindrical BegoStone samples embedded in a hydrogel ureter model and a 100% calcium phosphate (CaP) stone (58 × 60 mm) were treated in saline using holmium:YAG (Ho:YAG) laser or thulium fiber laser (TFL) via three clinical strategies: "drill and core," contact, and near-contact modes. Laser pulses were delivered at 0.8 J/12 Hz, 1.0 J/10 Hz, and 1.2 J/8 Hz with a 3 s on/3 s off protocol under continuous irrigation (40 mL/min). Crater formation, surface crack development, and bubble dynamics were assessed via optical coherence tomography, ureteroscope video, high-speed photography, and hydrophone measurements. To delineate the contributions of different plausible damage mechanisms, bubble collapse was suppressed using the ureteroscope's proximity effect, and photothermal ablation was minimized by treating donut-shaped BegoStones with central tunnels. The role of bubble expansion in stone fracture was evaluated by varying either tunnel size or pulse energy. Surface cracks and stone fractures occurred only in Ho:YAG-treated BegoStone and CaP stone samples under the "drill and core" strategy. TFL produced deeper craters yet failed to induce significant cracks under any test conditions. Although Ho:YAG-induced bubble collapses generated stronger acoustic emissions than TFL, suppression of bubble collapse or photothermal ablation had minimal impact on crack growth beyond localized surface damage. Instead, the number and length of surface cracks correlated strongly with the maximum bubble lateral diameter and expansion rate - both substantially greater for Ho:YAG laser than TFL. Crack formation also correlated inversely with the initial crater or tunnel size. These observations have significant clinical implications for optimizing stone fragmenting in LL procedures. Intra-crater bubble expansion, rather than photothermal ablation or bubble collapse, is the primary mechanism driving the fracture of impacted ureteral stones in LL.
This paper provides experimental and numerical evidence supporting the occurrence of liposome congregation at the floors of meteor craters on Early Earth. This work builds on our earlier research, which demonstrated that liposomes submerged in a shallow Archean pond are protected from harmful UV radiation. This protection enables them to survive sufficiently long for autocatalytic amphiphile replication and for the mutation and selection of assemblies that enhance membrane stability. For liposomes to fuse, grow, exchange contents and membrane components, and divide, they must establish a population, i.e., form a dense conglomerate that enables close physical contact. The study demonstrates that such a congregation is feasible in bowl-shaped meteor craters on Early Earth, especially under periodic seismic disturbances.
Using a Raman spectrometer onboard the Perseverance rover, we report the heterogeneous distribution of organic carbon within mudstones located in an ancient river valley on Mars. Measurements of two mudstones show hundreds of organic detections, making this the most robust organic detection in Jezero crater thus far, and, to our knowledge, the only detection of macromolecular carbon on a natural rock surface on Mars. Spectra of the interior of one rock reveal an association of organics with secondary carbonate and sulfate minerals, whereas another rock exhibits an association of organics with primary silicate-dominated matrix. Although in situ Raman analyses cannot determine whether these organics denote abiotic or biotic sources, the organic association with both depositional and diagenetic minerals and the detection of organics on the martian surface suggests that the organics observed ubiquitously at the Bright Angel outcrop may be resistant to radiation and oxidation or have been relatively recently exposed.
The growing demand for sustainable biotechnological solutions has intensified interest in microorganisms inhabiting understudied and environmentally constrained ecosystems. Volcanic systems create ecological niches shaped by geochemical and physicochemical stressors, yet the culturable bacteria in many remain poorly characterized. Here, we investigated the culturable bacterial fraction in the soils of Al Wahbah Crater (Saudi Arabia), an underexplored volcanic ecosystem, and evaluated its members' hydrolytic enzyme production and the genome-encoded metabolic potential of the most-promising isolates. Using multiple media and incubation conditions, we isolated bacterial strains from three crater soil types, identifying 65 representative isolates through 16S rRNA gene sequencing. The culture collection was dominated by Bacillota, particularly Bacillus spp., reflecting selective pressures typical of mineral-rich, saline soils. All isolates were screened for six hydrolases: cellulase, xylanase, amylase, protease, lipase, and gelatinase. Twenty-three strains exhibited activities for all six, while only one (Paenibacillus sp. AWC54) showed no detectable enzymatic activity. Cellulase activity was most prevalent (61/65 isolates), followed by xylanase (59/65), amylase (57/65), protease (48/65), lipase (35/65), and gelatinase (31/65). Five high-performing strains, Bacillus spizizenii AWC2, B. cereus AWC16, B. vallismortis AWC57 and AWC81, and B. haynesii AWS14, were selected for whole-genome sequencing and genome mining. Genome annotations revealed diverse carbohydrate-active enzyme repertoires including glycoside hydrolases, glycosyl transferases, and polysaccharide lyases, as well as multiple biosynthetic gene clusters predicted to encode antimicrobial and antifungal metabolites. Together, these findings establish Al Wahbah Crater as a cultivable regional reservoir of metabolically versatile bacteria and provide a curated strain collection and genomic framework for future ecological, evolutionary, and biotechnological investigations of volcanic microbiomes in the Arabian Peninsula.
We investigate the roles of spin and packing fraction on the dynamics of cratering when a solid projectile impacts a granular bed at different incident angles. To do so, we carried out DEM (discrete element method) computations in which we varied the magnitude and direction of the projectile spin, the impact velocity, the bed packing fraction, and the incident angle. For a given incident velocity, we found that the projectile can rebound for small angles, or be completely or partially buried for larger angles, and that when buried, it can sometimes migrate large horizontal distances depending on the incident angle. We also found that increasing the packing fraction strengthens rebounds, and that the initial spin, depending on its direction and orientation, induces rebound, burying, or transverse deviations. The crater morphology also changes with the varying parameters, acquiring circular, elliptical, goutte-like, tadpole-like, and transitional shapes, correlating well with the projectile behavior. Finally, we propose diagrams to organize and classify the observed dynamics. Our results shed new light on the different shapes of craters found in nature and the fate of the impacting material.
Microorganisms present in the rhizosphere of plants from extreme environments have become a subject of great interest as an alternative to chemical fertilizers for sustainable agriculture. This study focused on the isolation, identification and characterization of extremophilic rhizospheric fungi strains present in a habitat with challenging environmental conditions in terms of temperature, pH, and heavy metal concentrations. Studies were conducted with the aim of finding new microorganisms for the development of novel, robust inoculants that meet the agricultural needs of Solanum lycopersicum, a crop consumed worldwide that, at least in Mexico can be exposed to heat shock in certain seasons. All the strains showed at least five plant growth promoting traits. Noticeably two of the isolated strains (R_34 and R_40) produced indole related compounds (probably indoleacetic acid (IAA)); others hydrolytic enzymes (cellulases, xylanases, and chitinases), as well as siderophores and showed the ability to solubilize inorganic phosphate. All strains reduced the progression of infection caused by Botrytis cinerea on S. lycopersicum leaves and fruits compared to the control, and they also inhibited the growth of various phytopathogenic fungi under in vitro conditions, suggesting an important role in biological control. The microorganisms were identified at the species level through phylogenetic analysis. The fungal strains belonged to the genus Trichoderma sp., Penicillium sp., and Aspergillus sp. In addition, these fungi demonstrated the ability to enhance germination rates, and overall plant growth in S. lycopersicum compared to controls. This research demonstrates that extremophilic fungi can serve as effective probiotics for crops in regions affected by climate variability and heatwaves.
Martian rocks are known to contain sulfur-bearing species, including sulfates and sulfides. These compounds record a sulfur cycle that operated over Mars' geological evolution. We used the Curiosity rover to investigate a deposit of light-toned stones in Gediz Vallis, within Gale crater on Mars. We find that the stones are composed of native sulfur. The sulfur deposit appears to have formed in place, within a sinuous entrenched canyon cut into the floor of Gediz Vallis. The presence of native sulfur implies that a sulfur enrichment pathway involving buoyant subsurface fluids operated on ancient Mars. We propose that the primary source of this sulfur was magmatic vapor, which cooled in the near subsurface cryosphere and was released by decompression during the erosion of Gediz Vallis.
Popocatepetl, Mexico's second-most active volcano, intensified to level two in May 2023. This study aimed to analyze morbidity related to this eruption in nearby Puebla municipalities. An interdisciplinary, ecological, and correlational study was conducted in communities 15 km from the volcano. The Study Group included conditions linked to increased ash exposure, while the Study Control (+) comprised other causes of morbidity. The independent variable was the level-two eruption, characterized by daily PM10 and PM2.5 exposure in May 2023. The Kriging method was employed to estimate ash dispersion due to the limited number of monitoring stations. Statistical analysis included the Shapiro-Wilk test, frequencies, and Spearman correlation coefficient. Fourteen percent of patients had conditions related to increased ash exposure, mainly noninfectious respiratory issues. The other 86% sought consultation for different situations, forming a positive control profile. Correlations between ash exposure and conditions were not statistically significant. Findings suggest potential biological adaptation among residents near Popocatepetl but no adaptation to its magmatic phenomena. Continued improvement of population care strategies against volcanic risks is necessary. The study provides valuable evidence and methodologies for atmospheric monitoring in areas without formal networks, enhancing care strategies against volcanic risks.
Impact cratering has played a fundamental role in Earth's geological history and has resulted in the formation of some of the world's most productive economic mineral deposits. Here, we investigate the crater architecture of one of the top three largest terrestrial impact structures: the unique 1.85-billion-year-old Sudbury basin (Canada), the richest crater-hosted mineral district in the world. The integration of two, recently completed ~ 3 km ultra-deep drill holes combined with high-resolution geophysical imaging provides new evidence for a concentric uplifted horst-like feature. This indicates that Sudbury is a peak-ring structure with at least two concentric fault systems internal to the collapsed crater rim; sharing similarities with the Schrödinger impact crater on the Moon. A radially-orientated crater-floor trench accommodates a recently discovered > 30-million-tonne nickel-copper-platinum group element ore body. Our proposed model provides a revised framework to evaluate cratering processes and related mineral resources associated with a terrestrial peak-ring impact structure.
The impact of polymer solution droplets on granular beds is relevant to powder processing, binder-jetting additive manufacturing, and environmental applications involving erosion control or spray deposition, yet most controlled studies of drop-grain interactions have focused on Newtonian liquids. In this study, we experimentally investigate the impact of viscoelastic polyethylene oxide (PEO) solution droplets on a dry granular bed and compare the resulting cratering dynamics with those of Newtonian liquids over a wide range of impact energies and Ohnesorge numbers. Crater morphology changes with impact energy, and this evolution occurs at lower energies for drops of polymer solution, consistent with their distinct liquid-grain interactions during impact. The crater diameter exhibits two distinct regimes: a low-energy plateau and a power-law increase at higher impact energies. We identify the transition between these regimes and show that, although the plateau size and the power-law scaling remain nearly unchanged, viscoelastic droplets reach the transition at a lower impact energy than Newtonian droplets. This suggests that the non-Newtonian response introduced by PEO modifies how the impact energy is partitioned among droplet deformation, liquid-grain coupling, and dissipation in the granular bed.
Evolutionary divergence in body size is common in animal adaptive radiations and is often associated with differences in key ecological traits, including habitat use and prey consumption. Here we characterize a notable case of body size-associated adaptive radiation in a group of predatory open water cichlid fish species from the Lake Malawi catchment. Using whole-genome sequences, we show that body size differences have evolved multiple times in the focal genus, Rhamphochromis, and that the group possesses well-defined signals of ancient interspecific hybridization. We identify genetic variants strongly associated with body size and show that these variants are connected to genes enriched for functions in vertebrate skeletal and nervous system development. We focus our analyses on two species of Rhamphochromis endemic to Lake Kingiri, a small (600 m diameter) crater lake geographically isolated from the main body of Lake Malawi but within the catchment. We show that these two ecomorphologically divergent sympatric species-one small-bodied, the other larger-bodied-share a unique common ancestor and diverged from one another ∼2000 years ago. We demonstrate strong directional selection focused on the larger-bodied Kingiri species, specifically on genetic variants connected to genes with anatomical development and nervous system function. Collectively, these results are supportive of body size-associated speciation taking place rapidly in the Lake Malawi cichlid fish superradiation. We conclude that body size-associated genetic variants have been important targets of selection during large-scale cichlid fish diversification, including in a crater lake sympatric speciation context.
This study presents a calibrated modelling approach for predicting the abrasive wear of copper-free composite friction materials. Four formulations were analysed, including a copper-containing reference material and three experimental compositions in which copper was replaced by different aluminium/polytetrafluoroethylene ratios. Dry ball-cratering tests were performed to determine the apparent wear-rate coefficient under controlled laboratory conditions. The copper-containing reference material showed the lowest wear-rate coefficient, kc = 80.655 × 10-14 m2·N-1, whereas the copper-free formulations reached kc = 111.811 × 10-14 m2·N-1, 98.586 × 10-14 m2·N-1 and 90.579 × 10-14 m2·N-1 for S2, S3 and S4, respectively. Thus, copper replacement increased the apparent wear-rate coefficient by approximately 12-39%, depending on the Al/PTFE ratio. The obtained data were used to develop and compare four calibrated predictive models. Among them, the modified Hertz-Archard model, which included effective hardness and contact-related descriptors, provided the best agreement with the experimental data. This model achieved MAPE = 1.5%, RMSE = 2.181 × 10-14 m2·N-1 and a maximum absolute error of 4.3%, with all predictions within the ±5% error band. The results indicate that the proposed calibration framework can support preliminary screening and ranking of copper-free friction-material formulations under the adopted dry ball-cratering conditions.
Laser lithotripsy is the main surgical treatment for urinary stones, using Holmium: Yttrium-Aluminium-Garnet (Ho: YAG) and Thulium Fiber Laser (TFL) lasers. Despite technological advances, the stone fragmentation determinants remain unclear. A better understanding would optimize laser lithotripsy (LL) outcomes (efficacy and safety). We aimed to investigate, in vitro, laser-stone interactions. TFL and Ho: YAG lasers were tested using 270 μm fibers on hard synthetic stone samples under four experimental conditions (dry, wet, immersed in contact and at 2 mm distance). A single pulse (0.5-1 J) was delivered. Crater dimensions, carbonization, and temperature profiles were assessed using optical microscopy and thermocouples. Crater's maximum radius increased with pulse energy regardless to laser source, pulse mode and experimental condition. Crater's max depth was reported for immersed HSS, LF in contact. A peripheral carbonization halo was systematically reported with TFL, regardless to laser settings. The maximum contact temperature (Tmaxcontact) increased with the pulse energy regardless to laser source, settings or experimental conditions. No temperature above 60 °C underwater were reported. TFL (High Peak Power) showed significantly higher crater's maximum radius and depth than Ho: YAG (Long Pulse) for immersed HSS. TFL exhibited higher Tmaxcontact than Ho: YAG, significant only at 0.5 J dry HSS in air (101.3vs27.96 °C, p = 0.001) and at 0.5 J immersed HSS, LF in contact (49,6 vs. 29.73 °C, p = 0.04). These findings suggest that thermal effects play a major role in laser-stone interaction, although additional mechanisms as photomechanical may contribute. Further studies, including numerical modeling, are required to better characterize these interactions and optimize clinical outcomes.
The formation and size evolution of gas-phase nanoparticles (NPs) in laser ablation inductively coupled plasma mass spectrometry critically influence aerosol transport, plasma ionization efficiency, and ultimately analytical accuracy. Nevertheless, burst-mode laser ablation, as an efficient and versatile strategy for controlling gas-phase NP size, remains insufficiently explored. Here, we combine experimental investigations and theoretical analysis to elucidate the mechanisms of gas-phase nanoparticle formation and size control by tuning the interpulse interval in burst-mode femtosecond (fs) laser ablation. The mean nanoparticle size exhibits a non-monotonic dependence on interpulse spacing, decreasing with a narrowing size distribution as the interval increases from 0 to 300 ps, and then increasing with distribution broadening at longer delays up to 1000 ps, closely correlating with ablation-crater depth. A characteristic transition at ~300 ps is identified, where both nanoparticle size and crater depth reach a minimum, revealing a critical timescale in pulse-plume-surface interactions. Simulations show that the interpulse interval governs the redistribution of laser energy between the surface and plume, driving a transition from surface-dominated ablation to plume-dominated absorption and partial recovery of surface coupling. This delay-dependent framework provides a unified explanation for nanoparticle formation, where particle size is determined by the competition between plume-mediated fragmentation and surface-driven material supply, and offers a basis for tailoring NP size distributions via temporal pulse shaping.
Military conflicts constitute an increasingly important yet still insufficiently quantified source of environmental contamination in agricultural ecosystems. This study investigated soils affected by missile strikes during the Russian aggression in Ukraine, with particular emphasis on heavy metal accumulation, radionuclide occurrence, and associated phytotoxic effects on wheat (Triticum aestivum L.). Geochemical analyses using X-ray fluorescence spectroscopy revealed pronounced enrichment of Pb, Zn, Cu, Cr, Ni, and Mn in crater soils, frequently exceeding local geochemical background levels and environmental guideline thresholds. Elevated activity concentrations of ^137Cs were additionally detected, indicating contamination associated with explosive materials and projectile components. Despite locally increased radionuclide levels, the calculated radiological indices demonstrated that the investigated soils do not currently pose a significant radiological hazard to human health. The contamination was accompanied by soil acidification, compaction, and degradation of physical structure, suggesting long-term disturbance of soil functioning in affected agricultural areas. Among the detected contaminants, Pb was consistently enriched in crater soils and was therefore selected as a representative model toxicant to investigate the biological mechanisms linking field-observed contamination to crop responses under controlled conditions. Hydroponic experiments demonstrated that Pb exposure induced a clear, dose-dependent inhibition of plant growth, biomass accumulation, and stress tolerance indices, whereas low Pb concentrations produced a slight hormetic response. Anatomical analyses of wheat roots revealed substantial structural reorganisation, including reduced stele and xylem development, enhanced cortical porosity, increased endodermal suberisation and lignification, and reduced vessel diameter, potentially limiting water and nutrient transport. Strong correlations between Pb concentration, anatomical modifications, and morphophysiological responses indicate that root structural disruption represents a major mechanism of toxicity. The results demonstrate that missile-derived contamination may significantly affect soil quality and crop performance even outside active combat zones. Furthermore, the study highlights the usefulness of root anatomical traits as sensitive biomarkers for early detection of military-induced soil stress and provides new insight into the combined, radiological and mechanistic biological approaches for assessing post-conflict agricultural environments.
The search for organic matter on Mars has rapidly evolved in the past decade with simple aromatic, S-heterocycles, and aliphatic organic molecules detected in Gale crater. We report the in situ detection of >20 organic molecules from clay-bearing sandstones in the ~3.5-billion-year-old Knockfarrill Hill member of Glen Torridon, Gale crater, by the Sample Analysis at Mars instrument suite onboard the Curiosity rover. These molecules were liberated by the onboard tetramethylammonium hydroxide wet chemistry experiment. Diverse thermochemolysis products, including benzothiophene, methyl benzoate, and single and dicyclic aromatic molecules were released and detected by evolved gas analysis and gas chromatography-mass spectrometry. Results indicate the experiment successfully released molecules preserved in ancient macromolecular or free organic matter within Martian bedrock despite ~3.5 billion years of diagenesis and radiation exposure.