411 research outputs found
Patch for till flux in the Parallel Ice Sheet Model (PISM)
No full textPISM tillflux
This is a set of patches for the Parallel Ice Sheet Model (PISM) https://www.pism.io/
The patches extend PISM to include a dynamical and empirical model for modeling subglacial till flux, where the flux alters the subglacial topography. The dynamical model is the Cohesive Non-local Granular Fluidity model with Pore Fluid (CNGF-PF), developed by Anders Damsgaard (https://src.adamsgaard.dk/cngf-pf). The empirical model is developed from calibration between CNGF-PF and laboratory shear results by Hansen & Zoet 2022 "Characterizing sediment flux of deforming glacier beds", doi:10.1029/2021JF006544.
If you use these patches, directly or indirectly, please cite the following publication in addition to citing this repository:
A. Damsgaard, L. Goren and J. Suckale 2020 “Water pressure fluctuations control variability in sediment flux and slip dynamics beneath glaciers and ice streams”. Commun. Earth Environ. 1(66), 1–8. doi: 10.1038/s43247-020-00074-7
This repository also contains a mirror of PISM, with the patches already applied.
Option 1: Applying the patch to PISM from official sources
Clone PISM and apply the patch with the following commands:
git clone https://github.com/pism/pism
cd pism
git checkout dev
# copy pism-cngf-pf.patch to the current directory with PISM source code
git am -S pism-cngf-pf.patch
Option 2: Using alternate source with patches already applied
Alternatively, use the PISM version in pism-cngf-pf.tar.gz:
tar xvfz pism-cngf-pf.tar.gz
cd pism
or clone the actively developed PISM version maintained by Anders Damsgaard:
git clone --recurse-submodules git://src.adamsgaard.dk/pism
cd pism
git checkout tillflux
In both versions, the "tillflux" branch already has the patches applied.
License
Creative Commons Attribution 4.0 International, unless noted in source code files and LICENSE files.
Author and funding
Anders Damsgaard
Department of Geoscience, Aarhus University
This dataset is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 897967
Simulation scripts for ridging experiments with Granular.jl v0.3.4
No full text# `riding/`
Experiments with two elastic ice floes, two elastoplastic ice foes,
and an elastic sheet. The `generate_pbs_scripts_*.sh` scripts set up
various experiments by passing parameters to the simulation driver script
`ridging_simulation.jl`. The script `ridging_plots.jl` is afterwards
called for generating all figures
# `ridging-bulk/`
Experiments with many ice floes that use the ridging parameterization. The
`Makefile` runs all simulations and plotting. Alternatively, the
simulations can be run with `generate_pbs_scripts_ridging_bulk-seed1.sh`.
# `ridging-bulk-shear/`
Run `simulation_init.jl`, `simulation_cons.jl`, `simulation_shear.jl`,
and the plotting scripts in turn. The script `simulation_benchmark.jl`
compares the performance of the parameterization vs. output from a
compression experiment.
# Author
Anders Damsgaard https://adamsgaard.dk
doi:10.5281/zenodo.3471354</p
PISM MISMIP experiment with sediment transport
No full text<p>The original repository is hosted at [0] and includes a modified version of the PISM[1] MISMIP example included with upstream PISM[1]. All scripts here should be run with a modified version of PISM[2] that supports modeling of subglacial till advection.</p>
<p>Author:<br>
Anders Damsgaard <[email protected]></p>
<p>License:<br>
See LICENSE file</p>
<p>Funding:<br>
This dataset is part of a project that has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 897967.</p>
<p>References:<br>
0: https://src.adamsgaard.dk/pism-exp-gsw<br>
1: https://github.com/pism/pism<br>
2: https://src.adamsgaard.dk/pism (tillflux branch)</p>
European Economic History: From Mercantilism to Maastricht and Beyond. By E. Damsgaard Hansen. Copenhagen: Copenhagen Business School Press, 2001. Pp. 528. $54.00.
No full textDamsgaard Hansen s textbook is a study of twentieth-century Europe with a long historical background. About three-fifths of it covers the period since 1914, with special focus on the creation and development of the European Union, and the remaining two-fifths the years from the Middle Ages to the twentieth century. The author explains his focus: A leading theme is the development of international economic cooperation in the 1900s However, to fulfil the requirements of the CEMS-programme (Community of European Management Schools), the period of the first breakthrough of early industrialism has been included (p. 6).
Whole-blood culture is a valid low-cost method to measure monocytic cytokines - a comparison of cytokine production in cultures of human whole-blood, mononuclear cells and monocytes
No full textWhole-blood and peripheral blood mononuclear cell (PBMC) cultures are used as non-validated surrogate measures of monocytic cytokine production. The aim of this investigation was to compare ex vivo cytokine production from human whole-blood and PBMC with that from isolated monocytes. We also assessed the intra- and inter-individual variation in cytokine production. In 64 healthy men (age 19–40 years) IL-6, TNF and IL-10 were measured by enzyme-linked immunosorbent assay in supernatants from whole-blood, PBMC and monocytes cultured 24 h with lipopolysaccharide (LPS) or UV-killed L. acidophilus. Cytokines produced from whole-blood was found to be more strongly correlated with monocytic cytokines than cytokines from PBMC, particularly after LPS-stimulation: r = 0.57, P < 0.001 versus r = 0.33, P = 0.01 for IL-6 and r = 0.43, P < 0.001 versus r = 0.30, P = 0.02 for TNF-?. Adjustment for a preceding 8-week dietary fatty acid-intervention did not change any of the associations. Based on measurements at three time-points 8 weeks apart the intra-individual variation was ? 50% smaller than the inter-individual variation (P < 0.05) in most whole-blood cytokine responses and LPS-stimulated IL-6 from PBMC. We conclude that whole-blood cultures are well-suited low-cost proxy-measures of monocytic cytokine production. Moreover, large inter-individual variation in cytokine production was demonstrated whereas the individual responses in whole-blood were reproducible even over long time-periods
Colloidal Fe nanocrystals for CH4 decomposition: role of the support
No full textMetal-supported nanoparticles play a crucial role in heterogeneous catalysis, with their activity governed by size, composition, and metal-support interactions. Conventional preparation methods often lack precise control of nanoparticle descriptors or introduce secondary metallic phases, limiting insights into intrinsic catalytic properties. In this study, colloidal iron nanoparticles (FeNPs) were used as pre-formed active sites to investigate CH4 decomposition, a reaction that yields high-purity H2 and carbon nanotubes (CNTs). FeNPs were supported on SiO2, MgO, Si3N4 and MgAl2O4, to systematically assess the influence of support materials on catalytic activity and the nature and morphology of carbon products. Characterization via ex situ TEM, STEM-EDS, SEM, XPS, Raman spectroscopy, and in situ XRD revealed distinct support-dependent behaviors. Fe/SiO2 exhibited deactivation due to severe sintering and encapsulation. Nevertheless, Fe3C species were identified as a stable phase under reaction conditions. Fe/MgO showed high stability against sintering but severe FeNPs encapsulation. Surprisingly, FeNPs on Si3N4 retained their nanometric size, probably due to strong anchoring in the support. Nevertheless, the support partially reacts with CH4 leading to C3N3 species. In contrast, Fe/MgAl2O4 demonstrated the highest activity towards carbon nanostructures formation, producing abundant CNTs via the tip growth and base growth mechanisms. Beam-enhanced in situ TEM confirmed a base growth process, with FeNPs remaining attached to the spinel support. The results evidenced the oxophylic nature of the support as an important descriptor of the stability of preformed FeNPs. This study provides a systematic comparison of colloidal FeNPs on various supports for CH4 decomposition to form CNTs and CO2-free H2, offering insights into active phase formation, CNTs growth mechanisms, and optimal support selection for efficient CNTs production
Reduced ex vivo interleukin-6 production by dietary fish oil is not modified by linoleic acid intake in healthy men.
No full textFish oil (FO) is considered antiinflammatory, but evidence regarding its effect on human cytokine production is conflicting. High linoleic acid (LA) intake may impair any effects of FO. The aim of this study was to investigate how FO combined with high or low LA intake affected ex vivo cytokine production from cultures of whole blood, peripheral blood mononuclear cells (PBMC), and monocytes in healthy men. The study was a double-blinded, controlled, 2 x 2 factorial 8-wk intervention. Sixty-four healthy men were randomized to 5 mL/d FO or olive oil (OO) provided in capsules and to spreads and oils with high or low LA content, resulting in LA intakes of 7 ± 2% and 4 ± 1% energy, respectively. We measured eicosapentaenoic acid (EPA) in PBMC and stimulated cytokine production in whole blood and PBMC 24-h cultures before and immediately after intervention and after an 8-wk wash-out period, and in monocyte cultures immediately after intervention. PBMC-EPA was markedly increased by FO (P < 0.001). LA intake did not modify the incorporation of FO and tended to have only a slight effect on PBMC-EPA by itself (P = 0.06). Lipopolysaccharide (LPS)-stimulated whole-blood interleukin (IL)-6 production immediately after intervention was lower with FO than OO (P = 0.02) but did not correlate with PBMC-EPA in the FO groups (r = –0.12; P = 0.53; n = 31). The LA intake did not modify IL-6 production or the effect of FO. Neither FO nor LA intake affected the production of tumor necrosis factor-{alpha}, IL-10, or interferon-{gamma} in any of the cultures. In conclusion, FO intake reduced IL-6 production from LPS-stimulated whole blood in healthy men compared with OO, but the effect was not modified by the LA intake
Document and author promotion strategies in the secure wiki model
No full textWiki systems form a subclass of the more general Open Collaborative Authoring Systems, where content is created by a user community. The ability of anyone to edit the content is, at the same time, their strength and their weakness. Anyone can write documents that improve the value of the wiki-system, but this also means that anyone can introduce errors into documents, either by accident or on purpose. A security model for wiki-style authoring systems, called the Secure Wiki Model, has previously been proposed to address this problem. This model is designed to prevent corruption of good quality documents, by limiting updates, to such documents, to users who have demonstrated their ability to produce documents of similar or better quality. While this security model prevents all user from editing all documents, it does respect the wiki philosophy by allowing any author who has produced documents of a certain quality to edit all other documents of similar or poorer quality. Moreover, authors who consistently produce top quality documents will eventually be allowed to edit all documents in the wiki. Collaborative filtering is used to evaluate the quality of documents that an author has contributed to the system, thus determining what other documents that the author can edit. This collaborative filtering mechanism, determines the promotion and demotion of documents and authors in the Secure Wiki Model. The original Secure Wiki Model only considers explicit promotion and demotion of documents, authors are implicitly promoted/demoted depending on the promotion/demotion of the documents that they contribute. In this paper, we revisit the question of promotion of documents and authors and propose a new security policy with explicit promotion of authors. This policy also incorporates a new collaborative filtering mechanism with a higher degree of parametrisation, so that the new policy can be adapted to the specific needs of a particular wiki. © 2012 IFIP International Federation for Information Processing
A Trust Evaluation Method Based on Logic and Probability Theory
No full textAbstract We introduce a trust evaluation method applicable in a decentralized set-ting, in which no universally trusted authority exists. The method makes simulta-neous use of logic and probability theory. The result of the qualitative part of the method are logical arguments for and against the reliability of an entity. The quan-titative part returns the probability that the reliability of an entity can be deduced under the given assumptions and pieces of evidence, as well a corresponding prob-ability for the counter-hypothesis. Our method is a true generalization of existing methods, in particular the Credential Networks. It relies on digital signatures for authenticating messages and accounts for many-to-many relationships between en-tities and public keys. Moreover, it includes eight different types of trust relations, namely the assumption or the statement that an entity is honest, competent, reliable, or malicious, and their corresponding negations.
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