Preprints
Filtering by Subject: Physical Sciences and Mathematics
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 [...]
Trees and Life, Heat and Death: Integrating Temperature and Green Spaces with Social Determinants of Health in Hamilton, Ontario, Canada.
Published: 2025-10-01
Subjects: Medicine and Health Sciences, Physical Sciences and Mathematics
Objectives Climate change has wide-reaching implications for planetary and human health; one of its rising impacts is deaths related to extreme heat. This study attempts to integrate remotely sensed measures of temperature and greenness into the methodology of Code Red, a study examining the relationship between health and a variety of social determinants in Hamilton, Ontario, Canada, initially [...]
Development of a Coupled Hydro-Economic Model to Support Groundwater Irrigation Decisions
Published: 2025-09-30
Subjects: Physical Sciences and Mathematics
Groundwater sustains global agriculture but faces significant pressure from overexploitation, threatening long-term water security. Achieving a balance between agricultural productivity and sustainable groundwater use requires decision-support tools that are both practical and robust. This study develops an accessible farm-level hydro-economic model that integrates groundwater dynamics with [...]
Integrating Environmental Variables and Machine Learning for Wildfire Susceptibility Prediction in Portugal
Published: 2025-09-29
Subjects: Life Sciences, Physical Sciences and Mathematics
Wildfires constitute a significant ecological disturbance within Mediterranean ecosystems, exerting profound effects on forest dynamics, biodiversity, and land management practices. The development of precise susceptibility mapping is essential to inform prevention strategies, optimize resource allocation, and promote sustainable forest management by increasing fire pressure. This study employed [...]
Do Coupled Megathrusts Rupture?
Published: 2025-09-28
Subjects: Physical Sciences and Mathematics
Megathrust earthquakes are among the most destructive and least predictable natural hazards. Kinematic geodetic coupling models, which identify regions of the plate interface where interseismic strain accumulates, are essential for seismic and tsunami hazard assessment. Yet their reliability remains debated: geodetic records are short, offshore resolution remains poor, and earthquake ruptures may [...]
Surface tension estimation of bubble nuclei in magma using spinodal pressure and nonclassical nucleation theory
Published: 2025-09-24
Subjects: Physical Sciences and Mathematics
Efforts to estimate the magma decompression rate from the vesicular texture of volcanic products have progressed through the development of theoretical models and laboratory experiments. The theoretical model is based on nucleation theory, with the surface tension between the melt and bubble nucleus being the parameter that most strongly governs nucleation. Since direct measurement of surface [...]
SWOT Satellite Altimetry Observations and Source Model for the Tsunami from the 2025 M8.8 Kamchatka Earthquake
Published: 2025-09-24
Subjects: Physical Sciences and Mathematics
On 29 July 2025 a Mw 8.8 earthquake struck off Kamchatka, Russia generating a Pacific-wide tsunami and marking the largest earthquake since the launch of the SWOT satellite in 2022. We analyze tsunami observations from SWOT together with three nearby DART buoys to resolve the source of the event. SWOT provided the first high-resolution spaceborne track of a great subduction-zone tsunami, [...]
Community Heat Flow Recommendations: Suitable Basal Boundary Conditions for Greenland and Antarctica in ISMIP7
Published: 2025-09-23
Subjects: Physical Sciences and Mathematics
Geothermal heat flow (GHF) influences ice-sheet thermal conditions, affecting ice flow by sliding and deformation. However, GHF distribution under polar ice-sheets remains poorly constrained, with few direct borehole-derived estimates and large discrepancies between glaciological and geophysical models caused by methodological differences and data limitations. As a result, many ice-sheet models [...]