14 research outputs found
Evaluation of the ECOSSE model for simulating soil carbon under short rotation forestry energy crops in Britain
Understanding and predicting the effects of land-use change to short rotation forestry (SRF) on soil C is an important requirement for fully assessing the C mitigation potential of SRF as a bioenergy crop. There is little current knowledge of SRF in the UK and in particular a lack of consistent measured datasets on the direct impacts of land use change on soil C stocks.
The ECOSSE model was developed to simulate soil C dynamics and greenhouse gas (GHG) emissions in mineral and organic soils. The ECOSSE model has already been applied spatially to simulate land-use change impacts on soil C and GHG emissions. However, it has not been extensively evaluated under SRF.
Eleven sites comprising 29 transitions in Britain, representing land-use change from non-woodland land uses to SRF, were selected to evaluate the performance of ECOSSE in predicting soil C and soil C change in SRF plantations.
The modelled C under SRF showed a strong correlation with the soil C measurements at both 0-30 cm (R = 0.93) and 0-100 cm soil depth (R = 0.82). As for the SRF plots, the soil C at the reference sites have been accurately simulated by the model. The extremely high correlation for the reference fields (R ≥ 0.99) shows a good performance of the model spin-up. The statistical analysis of the model performance to simulate soil C and soil C changes after land-use change to SRF highlighted the absence of significant error between modelled and measured values as well as the absence of significant bias in the model.
Overall, this evaluation reinforces previous studies on the ability of ECOSSE to simulate soil C and emphasize its accuracy to simulate soil C under SRF plantations
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European butterfly populations vary in sensitivity to weather across their geographical ranges
Aim
The aim was to assess the sensitivity of butterfly population dynamics to variation in weather conditions across their geographical ranges, relative to sensitivity to density dependence, and determine whether sensitivity is greater towards latitudinal range margins.
Location
Europe.
Time period
1980–2014.
Major taxa studied
Butterflies.
Methods
We use long-term (35 years) butterfly monitoring data from > 900 sites, ranging from Finland to Spain, grouping sites into 2° latitudinal bands. For 12 univoltine butterfly species with sufficient data from at least four bands, we construct population growth rate models that include density dependence, temperature and precipitation during distinct life-cycle periods, defined to accommodate regional variation in phenology. We use partial R2 values as indicators of butterfly population dynamics' sensitivity to weather and density dependence, and assess how these vary with latitudinal position within a species' distribution.
Results
Population growth rates appear uniformly sensitive to density dependence across species' geographical distributions, and sensitivity to density dependence is typically greater than sensitivity to weather. Sensitivity to weather is greatest towards range edges, with symmetry in northern and southern parts of the range. This pattern is not driven by variation in the magnitude of weather variability across the range, topographic heterogeneity, latitudinal range extent or phylogeny. Significant weather variables in population growth rate models appear evenly distributed across the life cycle and across temperature and precipitation, with substantial intraspecific variation across the geographical ranges in the associations between population dynamics and specific weather variables.
Main conclusions
Range-edge populations appear more sensitive to changes in weather than those nearer the centre of species' distributions, but density dependence does not exhibit this pattern. Precipitation is as important as temperature in driving butterfly population dynamics. Intraspecific variation in the form and strength of sensitivity to weather suggests that there may be important geographical variation in populations' responses to climate change
Evaluation of the ECOSSE model for simulating soil organic carbon under Miscanthus and short rotation coppice-willow crops in Britain
Acknowledgements This work contributes to the ELUM (Ecosystem Land Use Modelling & Soil Carbon GHG Flux Trial) project, which was commissioned and funded by the Energy Technologies Institute (ETI). We acknowledge the E-OBS data set from the EU-FP6 project ENSEMBLES (http://ensembles-eu.metoffice.com) and the data providers in the ECA&D project (http://www.ecad.eu).Peer reviewedPublisher PD
Deeper Understandings: A trench through the Bronze Age deposits at Khirbat Hamra Ifdan
Il paper presenta i risultati degli scavi del Barqa Landscape Project, diretto da Russell Adams, a Khirbat Hamra Ifdan nel 2013 e discute l'evidenza di occupazione del sito nel Bronzo Antico II-III in relazione alle fasi e allo sviluppo dell'estrazione e della metallurgia del rame in questa regione della Giordania nelle fasi urbane del Bronzo Antico
Formation and characterisation of a modifiable soft macro-porous hyaluronic acid cryogel platform
<div><p>A facile method for the synthesis of cell supportive, highly macro-porous hyaluronic acid (HA) hydrogels via cryogelation is presented. Unmodified HA was chemically cross-linked via EDC/NHS zero-length cross-linking at sub-zero temperatures to yield cryogels with high porosity and high pore interconnectivity. The physical properties of the HA cryogels including porosity, average pore size, elasticity and swelling properties were characterised as a function of cryogelation conditions and composition of the precursor solution. The HA cryogels swell extensively in water, with the average porosities observed being ~90% under all conditions explored. The morphology of the cryogels can be controlled, allowing scaffolds with an average pore size ranging from 18 ± 2 to 87 ± 5 μm to be formed. By varying the cross-linking degree and HA concentration, a wide range of bulk elastic properties can be achieved, ranging from ~1 kPa to above 10 kPa. Preliminary cell culture experiments, with NIH 3T3 and HEK 293 cell lines, performed on biochemically modified and unmodified gels show the cryogels support cell proliferation and cell interactions, illustrating the biomedical potential of the platform.</p></div
Clinical Outcomes and Quantitative HBV Surface Antigen Levels in Diverse Chronic Hepatitis B Patients in Canada: A Retrospective Real-World Study of CHB in Canada (REVEAL-CANADA)
Background: Hepatitis B surface antigen (HBsAg) loss is associated with improved clinical outcomes for individuals with chronic hepatitis B (CHB); however, the effects of varying HBsAg levels on clinical outcomes in diverse cohorts are understudied. Methods: In this cross-sectional, multicentre, retrospective study, the data on adult subjects enrolled in the Canadian HBV Network with CHB seen from 1 January 2012 to 30 January 2021 with the treatment and virologic data within 1 year of HBsAg testing were analyzed. Patients were tested for HBsAg using qualitative (for HBsAg-negative samples) and/or commercial quantitative assays. Fibrosis or hepatic necroinflammation was determined by the liver stiffness measurement (LSM). The baseline data were summarized using descriptive statistics and compared by using univariable/multivariable analyses. Results: This study included 844 CHB patients, with a median age of 49.6 years (IQR 40.1–60.5), and 37% were female. In total, 751 patients (78.6%) had known ethnicity data, and 76.7% self-reported as Asian, 11.4% as Black, 6.8% as White, and 4.8% as other. Among the 844 patients, 237 (28.0%) were HBsAg (−) (<LLOQ), 190 (22.5%) had qHBsAg 1–100, 91 (10.8%) had qHBsAg 100–500, 54 (6.4%) had qHBsAg 500–1000, and 272 (32.2%) had qHBsAg >1000 IU/mL. Overall, 80% (682) had known HBeAg status at the last follow-up, and the majority (87.0%) were HBeAg-negative. In addition, 54% (461/844) had prior antiviral therapy, 19.7% of which (16.3, 23.7, n = 91) were HBsAg (−). The treated patients had a lower risk of cirrhosis (16.46, 95% CI 1.89–143.39, p = 0.01) or HCC (8.23, 95% CI 1.01–67.39, p = 0.05) than the untreated patients. A lower proportion of the HBsAg-loss group had cirrhosis (5.7% vs. 10.9%, p = 0.021) and HCC (0.9% vs. 6.2%, p = 0.001). Conclusion: In this retrospective, ethnically diverse cohort study, CHB patients who received antiviral therapy and/or had HBsAg loss were less likely to develop cirrhosis and HCC, confirming the results of the studies in less diverse cohorts. No association was found between the qHBsAg level and fibrosis determined with LSM. Individuals who achieved HBsAg loss had low-level qHBsAg within 1 year of seroclearance