Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleEwers RM, Cook J, Daniel OZ, et al., 2024,
New insights to be gained from a Virtual Ecosystem
, Ecological Modelling, Vol: 498, ISSN: 0304-3800The myriad interactions among individual plants, animals, microbes and their abiotic environment generate emergent phenomena that will determine the future of life on Earth. Here, we argue that holistic ecosystem models – incorporating key biological domains and feedbacks between biotic and abiotic processes and capable of predicting emergent phenomena – are required if we are to understand the functioning of complex, terrestrial ecosystems in a rapidly changing planet. We argue that holistic ecosystem models will provide a framework for integrating the many approaches used to study ecosystems, including biodiversity science, population and community ecology, soil science, biogeochemistry, hydrology and climate science. Holistic models will provide new insights into the nature and importance of feedbacks that cut across scales of space and time, and that connect ecosystem domains such as microbes with animals or above with below ground. They will allow us to critically examine the origins and maintenance of ecosystem stability, resilience and sustainability through the lens of systems theory, and provide a much-needed boost for conservation and the management of natural environments. We outline our approach to developing a holistic ecosystem model – the Virtual Ecosystem – and argue that while the construction of such complex models is obviously ambitious, it is both feasible and necessary.
-
Journal articleOlivelli A, Maxence P, Xu H, et al., 2024,
Vertical transport of anthropogenic lead by reversible scavenging in the South Atlantic Ocean
, Earth and Planetary Science Letters, Vol: 646, ISSN: 0012-821XStable lead (Pb) isotopes have been regarded as tracers of ocean circulation, both in the present time and geological past. Here we present a new dataset of seawater Pb concentrations and isotope compositions for ten depth profiles from the South Atlantic Ocean (GEOTRACES cruises GA02 and GA10). By comparing Pb isotope data collected on the two cruises, and by modelling the distribution of Pb with an extended optimum multiparameter analysis, we find evidence of vertical transport of anthropogenic Pb pollution due to reversible scavenging. Surface to depth transfer of polluted Pb is aided by high suspended particulate matter loads at the Brazil – Malvinas Confluence and along ∼40°S in the South Atlantic. Overall, our findings caution the use of Pb isotope ratios as ventilation tracers in the South Atlantic and emphasize the importance of particle-seawater interaction for biogeochemical cycles.
-
Journal articleSaceanu MC, Paluszny A, Ivars DM, et al., 2024,
Thermo-mechanical modelling of spalling around the deposition boreholes in an underground nuclear waste repository during its thermal phase
, International Journal of Rock Mechanics and Mining Sciences, Vol: 183, ISSN: 1365-1609This paper presents a three-dimensional numerical analysis of multiple fracture growth leading to the development of excavation disturbed zones and spalling around deposition boreholes in a geological disposal facility. The development of fracture patterns is simulated with the Imperial College Geomechanics Toolkit, a finite-element based simulator that can model the simultaneous nucleation, growth, and coalescence of multiple fractures in quasi-brittle rock. In these simulations, fractures develop due to the stress concentrations around the borehole wall, caused by the local in situ stresses, and due to the thermal stresses caused by the radioactive decay of the waste. Fracture patterns, and the extent of the spalled zone, are computed after the borehole drilling, heating, and cooling stages, at the Forsmark repository site in Sweden. The effect of temperature on the nucleation and growth of spalling fractures, as well as on the reactivation of pre-existing fractures, is assessed qualitatively, by comparing fracture patterns, and quantitatively, in terms of the maximum spalling depth, width, and increase in the total fractured surface area. Overall, the simulations presented herein indicate that thermal spalling will increase the depths (away from the borehole) and angular widths of the spalled zone, but is not likely to lead to major increases in fracture aperture, and concomitant increases in hydraulic transmissivity and permeability of the spalled zone, above that which has already been caused by mechanical spalling.
-
Journal articleCarpenter A, Lawrence JA, Mason PJ, et al., 2024,
Drone SAR Imaging for Monitoring an Active Landslide Adjacent to the M25 at Flint Hall Farm
, Remote Sensing, Vol: 16, Pages: 1-25, ISSN: 2072-4292Flint Hall Farm in Godstone, Surrey, UK, is situated adjacent to the London Orbital Motorway, or M25, and contains several landslide systems which pose a significant geohazard risk to this critical infrastructure. The site has been routinely monitored by geotechnical engineers following a landslide that encroached onto the hard shoulder in December 2000; current in situ instrumentation includes inclinometers and piezoelectric sensors. Interferometric Synthetic Aperture Radar (InSAR) is an active remote sensing technique that can quantify millimetric rates of Earth surface and structural deformation, typically utilising satellite data, and is ideal for monitoring landslide movements. We have developed the hardware and software for an Unmanned Aerial Vehicle (UAV), or drone radar system, for improved operational flexibility and spatial–temporal resolutions in the InSAR data. The hardware payload includes an industrial-grade DJI drone, a high-performance Ettus Software Defined Radar (SDR), and custom Copper Clad Laminate (CCL) radar horn antennas. The software utilises Frequency Modulated Continuous Wave (FMCW) radar at 5.4 GHz for raw data collection and a Range Migration Algorithm (RMA) for focusing the data into a Single Look Complex (SLC) Synthetic Aperture Radar (SAR) image. We present the first SAR image acquired using the drone radar system at Flint Hall Farm, which provides an improved spatial resolution compared to satellite SAR. Discrete targets on the landslide slope, such as corner reflectors and the in situ instrumentation, are visible as bright pixels, with their size and positioning as expected; the surrounding grass and vegetation appear as natural speckles. Drone SAR imaging is an emerging field of research, given the necessary and recent technological advancements in drones and SDR processing power; as such, this is a novel achievement, with few authors demonstrating similar systems. Ongoing and future work includes repeat-pass SAR data collecti
-
Journal articleNathwani C, Blundy J, Large S, et al., 2024,
A zircon case for super-wet arc magmas
, Nature Communications, ISSN: 2041-1723 -
Journal articleMartínez-Hernández I, Euán C, Burr WS, et al., 2024,
Modelling particle number size distribution: a continuous approach
, Journal of the Royal Statistical Society Series C: Applied Statistics, ISSN: 0035-9254Particulate matter (PM) is well known to be detrimental to health, and it is crucial to apportion PM into the underlying sources to target policies. Particle number size distribution (PNSD) is the most accessible data to identify these sources, which provides information on the PM sizes. Here, we propose a new functional factor model for PNSD, which allows to disentangle PM into sources and contributions while considering the complex dependencies of the data across different sizes and periods. Through a simulation study, we show that this method is able to identify sources correctly, and we use it to analyse hourly PNSD data collected in London for 7 years, finding 6 well-defined sources. Our proposed methodology is fast, accurate, and reproducible.
-
Journal articleSangkaew S, Sangkaew S, Dorigatti I, 2024,
Unveiling post-COVID-19 syndrome: incidence, biomarkers, and clinical phenotypes in a Thai population
, BMC Infectious Diseases, ISSN: 1471-2334SummaryBackground: Post-COVID-19 syndrome (PCS) significantly impacts the quality of life of survivors. There is, however, a lack of a standardized approach to PCS diagnosis and management. Our bidirectional cohort study aimed to estimate PCS incidence, identify risk factors and biomarkers, and classify clinical phenotypes for enhanced management to improve patient outcomes.Methods: A bidirectional prospective cohort study was conducted at five medical sites in Hatyai district in Songkhla Province, Thailand. Participants were randomly selected from among the survivors of COVID-19 aged ≥18 years between May 15, 2022, and January 31, 2023. The selected participants underwent a scheduled outpatient visit for symptom and health assessments 12 to 16 weeks after the acute onset of infection, during which PCS was diagnosed and blood samples were collected for hematological, inflammatory, and serological tests. PCS was defined according to the World Health Organization criteria. Univariate and multiple logistic regression analyses were used to identify biomarkers associated with PCS. Moreover, three clustering methods (agglomerative hierarchical, divisive hierarchical, and K-means clustering) were applied, and internal validation metrics were used to determine clustering and similarities in phenotypes.Findings: A total of 300 survivors were enrolled in the study, 47% of whom developed PCS according to the World Health Organization (WHO) definition. In the sampled cohort, 66.3% were females, and 79.4% of them developed PCS (as compared to 54.7% of males, p-value <0.001). Comorbidities were present in 19% (57/300) of all patients, with 11% (18/159) in the group without PCS and 27.7% (39/141) in the group with PCS. The incidence of PCS varied depending on the criteria used and reached 13% when a quality of life indicator was added to the WHO definition. Common PCS symptoms were hair loss (22%) and fatigue (21%), while mental health symptoms were less frequent (insomnia 3
-
ReportClarke B, Barnes C, Sparks N, et al., 2024,
Climate change key driver of catastrophic impacts of Hurricane Helene that devastated both coastal and inland communities
-
Journal articleLiu Y, Dajnak D, Assareh N, et al., 2024,
Impact of net zero policy scenarios on air pollution inequalities in England and Wales
, Environment International, ISSN: 0160-4120 -
Journal articleBlyth L, Graven HD, Manning AJ, et al., 2024,
Radiocarbon as a tracer of the fossil fraction of regional carbon monoxide emissions
, Environmental Research Letters<jats:title>Abstract</jats:title> <jats:p>Carbon monoxide (CO) is an atmospheric pollutant with a positive net warming effect on the climate. The magnitude of CO sources and the fraction of fossil vs biogenic sources are still uncertain and vary across emissions inventories. Measurements of radiocarbon (<jats:sup>14</jats:sup>C) in CO could potentially be used to investigate the sources of CO on a regional scale because fossil sources lack <jats:sup>14</jats:sup>C and reduce the <jats:sup>14</jats:sup>C/C ratio (Δ<jats:sup>14</jats:sup>C) of atmospheric CO more than biogenic sources. We use regional Lagrangian model simulations to investigate the utility of Δ<jats:sup>14</jats:sup>CO measurements for estimating the fossil fraction of CO emissions and evaluating bottom-up emissions estimates (United Kingdom Greenhouse Gas, UKGHG, and TNO Copernicus Atmosphere Monitoring Service, TNO) in London, UK. Due to the high Δ<jats:sup>14</jats:sup>CO in atmospheric CO from cosmogenic production, both fossil and biogenic CO emissions cause large reductions in Δ<jats:sup>14</jats:sup>CO regionally, with larger reductions for fossil than biogenic CO per ppb added. There is a strong seasonal variation in Δ<jats:sup>14</jats:sup>CO in background air and in the sensitivity of Δ<jats:sup>14</jats:sup>CO to fossil and biogenic emissions of CO. In the UK, the CO emissions estimate from TNO has a higher fraction from fossil fuels than UKGHG (72\% vs 67\%). This results in larger simulated decreases in Δ<jats:sup>14</jats:sup>C per ppb CO for TNO emissions. The simulated differences between UKGHG and TNO are likely to be easily detectable by current measurement precision, suggesting that Δ<jats:sup>14</jats:sup>CO measurements could be an effective tool to understand regional CO
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.
Join the network
If you’d like to join the network, just email us here.