363 research outputs found
CO2 Storage Modelling and Capacity Estimation for the Trøndelag Platform, Offshore Norway - using a Basin Modelling Approach
AbstractThere are several approaches to estimate possible storage capacities for aquifers and traps in sedimentary basins, ranging from static theoretical capacities estimates to more detailed methods involving dynamic modelling. In this paper, we used a modified version of the basin modelling software SEMI [1,2] which applies a ray tracing technique to migrate CO2 within a carrier bed below a sealing cap-rock. We present a modelling strategy for a systematic modelling of maximum trap storage capacities and a mapping of possible “safe” injection localities for a storage unit. Two end-member models regarding the influence of faults were tested. The basin modelling results are compared and validated with results obtained from an reservoir simulation software.Simulations were carried out for the Trøndelag Platform, offshore Norway covering an area of ca. 15,000 km2. The slightly north-westwards dipping Middle Jurassic Garn Formation (Fm.) is considered as a good candidate for CO2 storage. It is widely deposited at the Trøndelag Platform, with a thickness around 120 m and shallow buried (<2 km). It is overlain by a thick shale- mudstone sequence (the Middle Jurassic Viking Group), and thick Cretaceous shales favouring a low risk for caprock leakage.Two simulation approaches were tested. First, injection in the Garn Fm. over the whole study area were simulated, to get the maximum total trap storage capacity. The modelling showed a storage capacity of 2.0 Gt with no faults and 5.2 Gt using interpreted faults at top Garn Fm. level as input to the simulations. Secondly, simulations were carried out with 38 CO2 injection sites. From these, the injection sites which caused migration out of the study area (e.g. upward to the rim of the storage unit, with only Quaternary coverage), where removed. Finally, 7 sites with very low probability for migration out of the area were selected. These “safe” injection sites were mainly mapped in the centre of the Trøndelag Platform where only a few faults are mapped
Gause's exclusion principle revisited: artificial modified species and competition
Gause's principle of competition between two species is studied when one of
them is sterile. We study the condition for total extinction in the niche,
namely, when the sterile population exterminates the native one by an optimal
use of resources. A mathematical Lotka-Volterra non linear model of interaction
between a native and sterile species is proposed. The condition for total
extinction is related to the initial number of sterile individuals
released in the niche. In fact, the existence of a critical sterile-population
value is conjectured from numerical analysis and an analytical
estimation is found. When spatial diffusion (migration) is considered a
critical size territory is found and, for small territory, total extinction
exist in any case. This work is motived by the extermination agriculture
problem of fruit flies in our region.Comment: 11 pages. Published in Jour.Phys.A Math.Gen. 33, 4877 (2000
Immunomodulatory therapies for the treatment of SARS-CoV-2 infection: an update of the systematic literature review to inform EULAR points to consider
OBJECTIVE: To update the EULAR 2020 systematic literature review (SLR) on efficacy and safety of immunomodulatory agents in SARS-CoV-2 infection. METHODS: As part of a EULAR taskforce, a systematic literature search update was conducted from 11 December 2020 to 14 July 2021. Two reviewers independently identified eligible studies and extracted data on efficacy and safety of immunomodulatory agents used therapeutically in SARS-CoV-2 infection at any stage of disease. The risk of bias (RoB) was assessed with validated tools. RESULTS: Of the 26 959 records, 520 articles were eligible for inclusion. Studies were mainly at high or unclear RoB. New randomised controlled trials (RCTs) on tocilizumab clarified its benefit in patients with severe and critical COVID-19, mainly if associated with glucocorticoids. There are emergent data on the usefulness of baricitinib and tofacitinib in severe COVID-19. Other therapeutic strategies such as the use of convalescent plasma and anti-SARS-CoV-2 monoclonal antibodies showed efficacy in subjects not mounting normal anti-SARS-CoV-2 antibody responses. CONCLUSION: This new SLR confirms that some immunomodulators (tocilizumab and JAK inhibitors) have a role for treating severe and critical COVID-19. Although better evidence is available compared with the previous SLR, the need of RCT with combination therapy (glucocorticoids+anti-cytokines) versus monotherapy with glucocorticoids still remains alongside the need for standardisation of inclusion criteria and outcomes to ultimately improve the care and prognosis of affected people. This SLR informed the 2021 update of the EULAR points to consider on the use of immunomodulatory therapies in COVID-19
Pathophysiology of acute respiratory syndrome coronavirus 2 infection: a systematic literature review to inform EULAR points to consider
BACKGROUND: The SARS-CoV-2 pandemic is a global health problem. Beside the specific pathogenic effect of SARS-CoV-2, incompletely understood deleterious and aberrant host immune responses play critical roles in severe disease. Our objective was to summarise the available information on the pathophysiology of COVID-19. METHODS: Two reviewers independently identified eligible studies according to the following PICO framework: P (population): patients with SARS-CoV-2 infection; I (intervention): any intervention/no intervention; C (comparator): any comparator; O (outcome) any clinical or serological outcome including but not limited to immune cell phenotype and function and serum cytokine concentration. RESULTS: Of the 55 496 records yielded, 84 articles were eligible for inclusion according to question-specific research criteria. Proinflammatory cytokine expression, including interleukin-6 (IL-6), was increased, especially in severe COVID-19, although not as high as other states with severe systemic inflammation. The myeloid and lymphoid compartments were differentially affected by SARS-CoV-2 infection depending on disease phenotype. Failure to maintain high interferon (IFN) levels was characteristic of severe forms of COVID-19 and could be related to loss-of-function mutations in the IFN pathway and/or the presence of anti-IFN antibodies. Antibody response to SARS-CoV-2 infection showed a high variability across individuals and disease spectrum. Multiparametric algorithms showed variable diagnostic performances in predicting survival, hospitalisation, disease progression or severity, and mortality. CONCLUSIONS: SARS-CoV-2 infection affects both humoral and cellular immunity depending on both disease severity and individual parameters. This systematic literature review informed the EULAR 'points to consider' on COVID-19 pathophysiology and immunomodulatory therapies
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Ground-based off-line aerosol measurements at Praia, Cape Verde, during the Saharan Mineral Dust Experiment: Microphysical properties and mineralogy
A large field experiment of the Saharan Mineral Dust Experiment (SAMUM) was performed in Praia, Cape Verde, in
January and February 2008. This work reports on the aerosol mass concentrations, size distributions and mineralogical
composition of the aerosol arriving at Praia. Three dust periods were recorded during the measurements, divided by
transitional periods and embedded in maritime-influenced situations. The total suspended particle mass/PM10/PM2.5
were 250/180/74μg/m3 on average for the first dust period (17–21 January) and 250/230/83μg/m3 for the second (24–26
January). The third period (28 January to 2 February) was the most intensive with 410/340/130 μg/m3. Four modes were
identified in the size distribution. The first mode (50–70 nm) and partly the second (700–1100 nm) can be regarded as
of marine origin, but some dust contributes to the latter. The third mode (2–4 μm) is dominated by advected dust, while
the intermittently occurring fourth mode (15–70 μm) may have a local contribution. The dust consisted of kaolinite
(dust/maritime period: 35%wt./25%wt.),K-feldspar (20%wt./25%wt.), illite (14%wt./10%wt.), quartz (11%wt./8%wt.),
smectites (6%wt./4%wt.), plagioclase (6%wt./1%wt.), gypsum (4%wt./7%wt.), halite (2%wt./17%wt.) and calcite
(2%wt./3%wt.)
Immunomodulatory therapies for the treatment of SARS-CoV-2 infection: an update of the systematic literature review to inform EULAR points to consider
Objective To update the EULAR 2020 systematic literature review (SLR) on efficacy and safety of immunomodulatory agents in SARS-CoV-2 infection.
Methods As part of a EULAR taskforce, a systematic literature search update was conducted from 11 December 2020 to 14 July 2021. Two reviewers independently identified eligible studies and extracted data on efficacy and safety of immunomodulatory agents used therapeutically in SARS-CoV-2 infection at any stage of disease. The risk of bias (RoB) was assessed with validated tools.
Results Of the 26 959 records, 520 articles were eligible for inclusion. Studies were mainly at high or unclear RoB. New randomised controlled trials (RCTs) on tocilizumab clarified its benefit in patients with severe and critical COVID-19, mainly if associated with glucocorticoids. There are emergent data on the usefulness of baricitinib and tofacitinib in severe COVID-19. Other therapeutic strategies such as the use of convalescent plasma and anti-SARS-CoV-2 monoclonal antibodies showed efficacy in subjects not mounting normal anti-SARS-CoV-2 antibody responses.
Conclusion This new SLR confirms that some immunomodulators (tocilizumab and JAK inhibitors) have a role for treating severe and critical COVID-19. Although better evidence is available compared with the previous SLR, the need of RCT with combination therapy (glucocorticoids+anti-cytokines) versus monotherapy with glucocorticoids still remains alongside the need for standardisation of inclusion criteria and outcomes to ultimately improve the care and prognosis of affected people. This SLR informed the 2021 update of the EULAR points to consider on the use of immunomodulatory therapies in COVID-19
Integrated management of a Swiss cropland is not sufficient to preserve its soil carbon pool in the long term
Croplands are involved in the exchange of carbon dioxide (CO2)
between the atmosphere and the biosphere. Furthermore, soil carbon (C) stocks
play an important role in soil fertility. It is thus of great interest to
know whether intensively managed croplands act as a net source or sink of
atmospheric CO2 and if soil C stocks are preserved over long
timescales. The FluxNet site CH-Oe2 in Oensingen, Switzerland, has been
operational since the end of 2003. This cropland is managed under the Swiss
framework of the Proof of Ecological Performance (PEP, a variant of
integrated management) with a crop rotation centred on winter wheat, which
also includes winter barley, winter rapeseed, peas, potato and intermediate
cover crops. In addition to eddy covariance measurements, meteorological and
soil measurements were available along with information on C imports and
exports from organic fertilisation, sowing and harvesting. This study
investigates cropland C budgets over 13 years and assesses whether the PEP
regulations resulted in a balanced C budget. The strongest CO2 uptake was
observed during cereal seasons. C export through harvest, however, offset the
strong uptake of the cereal crops. The largest net CO2 emissions to
the atmosphere were observed during pea and cover crop seasons. Net biome
production, representing the overall C budget (assuming carbon leaching to
groundwater to be negligible), typically ranged between close to C neutral to
C losses of up to 407 g C m−2 per season, with peas being the largest
source. Overall, the field lost 1674 g C m−2 over 13 years
(129 g C m−2 yr−1), which was confirmed by soil C stock
measurements at the beginning and the end of the study period. Although
managing the field under the regulations of PEP did not result in an overall
C sink, model simulations showed that the use of cover crops reduced the C
losses compared to leaving the field bare. The use of solid manure improved
the C budget by importing substantial amounts of C into the soil, while liquid
manure had only a small effect. We thus conclude that additional efforts are
needed to bring Swiss management practices closer to the goal of preserving
soil C in the long term.</p
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