Preprints
Filtering by Subject: Physical Sciences and Mathematics
Calcareous nannofossil assemblages from El Kef (Tunisia) reveal strong regional and bathymetric controls on Northern Hemisphere recovery patterns following the Cretaceous/Paleogene (K/Pg) mass extinction
Published: 2025-10-12
Subjects: Earth Sciences, Physical Sciences and Mathematics
The Cretaceous-Paleogene (K-Pg) mass extinction event ~66.0 million years ago (Ma), led to the elimination of over 75% of species on Earth and drove large-scale ecological reorganization in both the marine and terrestrial realms. In particular, the nearly complete extinction of calcareous nannoplankton-the most dominant phytoplankton group at the end of the Cretaceous- led to a shift in community [...]
Dense neural network outperforms other machine learning models for scaling-up lichen cover maps in Eastern Canada
Published: 2025-10-12
Subjects: Environmental Sciences, Natural Resource Economics, Natural Resources Management and Policy, Physical Sciences and Mathematics, Sustainability
Lichen mapping is vital for caribou management plans and sustainable land conservation. Previous studies have used random forest, dense neural network, and convolutional neural network models for mapping lichen coverage. However, to date, it is not clear how these models rank in this task. In this study, these machine learning models were evaluated on their ability to predict lichen percent [...]
Variational numerical-modelling strategies for the simulation of driven free-surface waves
Published: 2025-10-11
Subjects: Engineering, Physical Sciences and Mathematics
A new tool is developed for simulating three-dimensional (3D) water-wave motion using the first fully variational 3D discretisation in space and time of Luke's variational principle (VP), with additional focus on the formation and analysis of extreme waves generated within in-house experimental wavetanks. The resulting ``numerical wavetank'' is able to emulate laboratory sea states in which [...]
Toward Greater Clarity: Reanalyzing Solomon’s Depiction of the Ross Ice Shelf Atmospheric Dynamic
Published: 2025-10-10
Subjects: Education, Physical Sciences and Mathematics, Social and Behavioral Sciences
In her book The Coldest March, Dr. Susan Solomon’s influential interpretation of the meteorological conditions surrounding Captain Scott’s South Pole expedition emphasizes the role of extreme weather. However, a reassessment of her characterization of atmospheric dynamics over the Ross Ice Shelf—particularly regarding katabatic winds and airstream structure—reveals discrepancies with established [...]
Curlew 1.0: Spatio-temporal implicit geological modelling with neural fields in python
Published: 2025-10-10
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
We present curlew, an open-source python package for structural geological modelling using neural fields. This modelling framework incorporates various local constraints (value, gradient, orientation and (in)equalities) and tailored global loss functions to ensure data-consistent and geologically realistic predictions. Random Fourier Feature (RFF) encodings are used to improve model convergence [...]
Vegetable supply to Tokyo disrupted by 2023 and 2024 summer heatwaves
Published: 2025-10-09
Subjects: Physical Sciences and Mathematics
Understanding the impacts on urban food supply from extreme climate events is a first step towards building climate-resilient agri-food systems. Here, we report on vegetable supply disruptions in the Tokyo metropolitan area due to the summer heatwaves of 2023 and 2024, using the governmental survey on wholesale market arrival volumes and prices. Fifteen vegetables (broccoli, cabbage, carrot, [...]
No evidence for a 10-m historical tectonic uplift at Mangalia, (Romanian Black Sea coast): Comment on Drăgușin et al. (2025)
Published: 2025-10-09
Subjects: Physical Sciences and Mathematics
Drăgușin et al. (2025) interpreted deposits at Mangalia (Romania) as evidence of a two-phase tectonic event (~14 m subsidence and uplift) during the 18th–19th centuries. Based on multi-proxy data from the same site, we show that this scenario is inconsistent with regional tectonics, stratigraphy, and archaeology. The deposits instead record the gradual infill of a coastal depression episodically [...]
LONG-LIVED TOPOGRAPHY ALONG RIFTED MARGINS: INSIGHTS FROM APARADOS DA SERRA ESCARPMENT, SOUTHEAST BRAZIL
Published: 2025-10-07
Subjects: Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure
The Brazilian margin is one of the longest elevated passive margins (EPMs) in the world. However, both the timing of uplift and the long-term evolution of this EPM remain highly debated. In this study, we present a new suite of apatite (U-Th-Sm)/He (AHe) and fission track (AFT) ages for the southern end of the Brazilian EPM, in the Aparados da Serra plateau. Our results reveal that mean AHe ages [...]
Methane and nitrous oxide concentrations and sea-air fluxes in western Long Island Sound, a seasonally hypoxic urban estuary: Hourly to seasonal variability
Published: 2025-10-06
Subjects: Physical Sciences and Mathematics
We report the first water column profiles of dissolved methane (CH4) and nitrous oxide (N2O) in western Long Island Sound, an urban estuary in which seasonal hypoxia occurs due to eutrophication and restricted exchange with the ocean. We collected samples at seven stations along an 18 km transect in August 2023, October 2023, and May 2024. CH4 concentrations and sea-air fluxes were highest in [...]
Geochronology of Taung and other southern African australopiths
Published: 2025-10-05
Subjects: Physical Sciences and Mathematics
One century after the Taung juvenile’s discovery, its age and that of many other southern African australopiths remains unknown. This lack of accurate geochronological constraints leaves important questions unanswered, including the temporal relationship between the South African fossil sites and their well dated eastern African counterparts. Previous age estimates for the Taung fossil range from [...]
A Field Study on Background Radiation Variability with Elevation in Eastern Nepal
Published: 2025-10-03
Subjects: Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics
This research investigates how environmental radioactivity varies with altitude in the diverse landscapes of Eastern Nepal. Employing two calibrated Geiger–Müller (GM) counters, background radiation was recorded as counts per minute (cpm) across selected sites in the districts of Dhankuta, Panchthar, Taplejung, and Ilam. Data were geo- referenced using GPS to correlate radiation levels with [...]
Unified Granular Intrusion Dynamics for Planetary Materials
Published: 2025-10-02
Subjects: Physical Sciences and Mathematics
Granular friction μ is a sensitive and poorly understood function of packing fraction ϕ. Every granular material has a distinct critical volume fraction ϕc that delineates two mechanical deformation modes – compaction for ϕ < ϕc, and dilation for ϕ > ϕc. Here we examine the relation(s) between friction and packing fraction, using quasi-static penetration tests in materials ranging from [...]
Rapid increase of climate extremes across northern Amazonia
Published: 2025-10-02
Subjects: Environmental Sciences, Physical Sciences and Mathematics
Amazonia’s exceptional biodiversity, cultural significance, and ecosystem services make it pivotal to global and regional sustainability. However, the region is increasingly threatened by climate extremes, which exacerbate the effects of land use change (Barlow et al., 2018) and bring about abrupt changes in social and ecological condition (Bennett et al., 2023; Berenguer et al., 2021; Campanharo [...]
Estimating Stability Constants and Entropy for Reactions Between Aqueous Metal Ions and Monovalent Oxygen-Bearing Ligands: Applications to Hydrothermal Metal–Organic Acid Systems
Published: 2025-10-02
Subjects: Life Sciences, Medicine and Health Sciences, Physical Sciences and Mathematics
Linear free energy relations were obtained from existing experimental data and used to estimate stability constants for over 16,000 metal complexes with monovalent oxygen-bearing ligands comprising 75 metal species and 220 ligands. Similar relationships for metal-ligand entropy of association were also obtained which facilitate computation of stability constants from 0 to 125°C for over 6000 [...]
Biomineralisation for Sustainable Ecotoxic Metal Immobilisation via Enzyme Induced Carbonate Precipitation
Published: 2025-10-02
Subjects: Engineering, Physical Sciences and Mathematics
Heavy metal contamination of water presents a critical global challenge driven by the persistence and toxicity of elements such as arsenic, cadmium and lead. Conventional remediation strategies, such as Enzyme-Induced Carbonate Precipitation (EICP), typically rely on commercial urease and a multi-step extraction process, which increases energy demand, generates ammonium byproducts, and requires [...]