| 1. |
- Högberg, Peter, et al.
(författare)
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Factors determining the 13C abundance of soil-respired CO2 in Boreal forests
- 2005
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Ingår i: Stable isotopes and biosphere-atmosphere interactions. - : Elsevier. - 9780120884476 ; , s. 47-68
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Bokkapitel (refereegranskat)abstract
- Analysis of the isotopic composition of the CO2 respired from soils may reveal information about the important component of the ecosystem C balance. This is crucial, since a large terrestrial sink for atmospheric CO2 has been located in the northern hemisphere, and the vast boreal forests may be largely responsible. At the same time, boreal and arctic ecosystems have large amounts of C stored in the soil, and could potentially become a source of CO2 in a warmer climate promoting more rapid decomposition of soil organic matter. Furthermore, the northern hemisphere has complex dynamics in terms of annual fluctuations in both the concentration of CO2 in the atmosphere and its δl3C. It is of utmost importance to understand the causes of this variability, since it interferes with the partitioning between the ocean and the terrestrial contributions in global models. This chapter aims to provide an update on the reviews by Flanagan and Ehleringer and Ehleringer et al. on the causation of the δ13C of the soil CO2 efflux and, in doing this, focuses on the boreal forests.
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| 2. |
- Agåker, Marcus, et al.
(författare)
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Novel instruments for ultra-soft X-ray emission spectroscopy
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 601:1-2, s. 213-219
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Tidskriftsartikel (refereegranskat)abstract
- Two alternative instrument designs to the traditional Rowland grating spectrometer for high resolution ultra-soft X-ray spectroscopy are presented. The first instrument is a plane grating spectrometer using off-axis parabolic mirrors for collection and refocusing, and with a spatially resolving multichannel detector with delay line read-out. The instrument offers substantially higher performance in terms of resolution and sensitivity than traditional instruments. The second instrument is a Fourier transform spectrometer based on a grazing incidence Mach-Zehnder interferometer using wavefront dividing beamsplitters. The path length difference can be scanned over 0.1 mm, which corresponds to a resolution of 12 meV. (C) 2009 Elsevier B.V. All rights reserved.
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| 3. |
- Dekker, Cornelis, 1970-
(författare)
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Judging in the Public Realm : A Kantian Approach to the Deliberative Concept of Ethico-Political Judgment and an Inquiry into Public Discourse on Prenatal Diagnosis
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis discusses how to enhance the public discussion of moral and political questions. Enhancing public ‘deliberation’ is desirable since it provides citizens with influence, it enables coming to an understanding, and it ensures legitimacy. The concept of ethico-political judgment, with its two conditions, is elaborated on as an ideal that suggests how we should deliberate. In order to understand how we actually deliberate, an empirical inquiry into the public discourse on prenatal diagnosis and screening in the Netherlands and Sweden is conducted. On the basis of Kant’s ethics and his theory of the faculty of judgment, the two conditions for public deliberation are developed. These conditions are the giving of and asking for normative reasons as well as aiming at impartiality of judgment. Normative reasons are prescriptive, universal, and internal and these are related to Kant’s ethics. Impartiality is related to Kant’s ‘enlarged thought’, to think from the standpoint of others, as well as Kant’s practical philosophy. We need to think from the standpoints of others in order to consider whether or not the principle of our action applies to all. Four thematic foci in the public discourse on prenatal diagnosis are investigated – the unborn life, attitudes toward the disabled, implications of new choices, and the limits of medicine. The conclusion is that – if we wish to enhance public deliberation on the basis of the two conditions of ethico-political judgment – we should deal with both interpretive differences over universal principles (such as respect for autonomy and human dignity) and varying representations of ‘the other’ (such as the fetus, disabled persons, mothers-to-be, and future parents).
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| 4. |
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| 5. |
- Duda, Laurent, et al.
(författare)
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Resonant Inelastic X-Ray Scattering at the Oxygen K Resonance of NiO: Nonlocal Charge Transfer and Double-Singlet Excitations
- 2006
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 96:067402
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Tidskriftsartikel (refereegranskat)abstract
- We report high-resolution polarization-dependent resonant inelastic x-ray scattering (RIXS) at the O K resonance of NiO showing a rich excitation spectrum. We perform multisite Ni6O19 cluster model calculations, revealing that solid state effects are substantial. We identify a nonlocal charge transfer excitation at 4–5 eV and double-singlet creation at 1.75 eV, both exhibiting significant scattering geometry dependence. Apart from an intense band of local charge transfer excitations (above 5 eV) also dd excitations at 1 eV are observed. Finally, we point out that O K RIXS of correlated metal oxides allows a quantitative and consistent determination of the charge transfer energy and the Hund coupling energy JH.
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| 6. |
- Forsberg, Johan, et al.
(författare)
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System for in situ studies of atmospheric corrosion of metal films using soft x-ray spectroscopy and quartz crystal microbalance
- 2007
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 78:8
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Tidskriftsartikel (refereegranskat)abstract
- We present a versatile chamber (atmospheric corrosion cell) for soft x-ray absorption/emission spectroscopy of metal surfaces in a corrosive atmosphere allowing novel in situ electronic structure studies. Synchrotron x rays passing through a thin window separating the corrosion cell interior from a beamline vacuum chamber probe a metal film deposited on a quartz crystal microbalance (QCM) or on the inside of the window. We present some initial results on chloride induced corrosion of iron surfaces in humidified synthetic air. By simultaneous recording of QCM signal and soft x-ray emission from the corroding sample, correlation between mass changes and variations in spectral features is facilitated.
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| 7. |
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| 8. |
- Hugo, Karin, 1969-
(författare)
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Genmodifierade livsmedel och kommunikativ etik : En analys av etisk oenighet i debatten om genmodifierade livsmedel
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The purpose of this thesis is to analyse the Swedish debate regarding genetically modified food products. What does the moral disagreements within this debate entail? In which way would it be possible to obtain and maintain a true dialogue? Is consensus a plausible or even a desirable goal? Can communicative ethics contribute? These questions are analysed in this research project.The project focuses on three themes of the debate on genetically modified food 1990-2000 in Sweden. The first theme is in relation to the concepts: natural and unnatural. Within the debate on genetically modified food, there have been various wide ranging arguments on whether or not genetic modification is natural or unnatural. The second theme concerns the concepts of risk and benefit. Safety questions and possible risks and benefits have been subjects of discussion and debate for a long time. This analysis highlights the way risks or benefits are valued. What does it mean if something is a risk? The third theme concerns the argumentations regarding democracy, mostlyin relation to labelling discussions. Democracy is used to describe freedom of choice, another argumentation focuses on the right to be a part of the decision making process.The last part of the thesis discusses the question whether communicative ethics can contribute to obtain dialogue between various parties, and whether consensus is possible or even a desirable as a goal. How would this function in a debate where there is an ethical disagreement based on divergent ethical standpoints?
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| 9. |
- Högberg, Peter, et al.
(författare)
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Partitioning of soil respiration into its autotrophic and heterotrophic components by means of tree-girdling in old boreal spruce forest
- 2009
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 257, s. 1764-1767
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Tidskriftsartikel (refereegranskat)abstract
- Forests accumulate much less carbon than the amount fixed through photosynthesis because of an almost equally large opposing flux Of CO(2) from the ecosystem. Most of the return flux to the atmosphere is through soil respiration, which has two major sources, one heterotrophic (organisms decomposing organic matter) and one autotrophic (roots, mycorrhizal fungi and other root-associated microbes dependent on recent photosynthate). We used tree-girdling to stop the flow of photosynthate to the belowground system, hence, blocking autotrophic soil activity in a 120-yr-old boreal Picea abies forest. We found that at the end of the summer, two months after girdling, the treatment had reduced soil respiration by up to 53%. This figure adds to a growing body of evidence indicating (t-test, d.f. = 7, p < 0.05) that autotrophic respiration may contribute more to total soil respiration in boreal (mean 53 +/- 2%) as compared to temperate forests (mean 44 +/- 3%). Our data also suggests that there is a seasonal hysteresis in the response of total soil respiration to changes in temperature. We propose that this reflects seasonality in the tree below-ground carbon allocation. (C) 2009 Elsevier B.V. All rights reserved.
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| 10. |
- Kvashnina, Kristina, et al.
(författare)
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Changes in electronic structure of copper films in aqueous solutions
- 2007
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 19:22, s. 226002-
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Tidskriftsartikel (refereegranskat)abstract
- The possibilities for using x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) to probe the Cu oxidation state and changes in the electronic structure during interaction between copper and ground-water solutions were examined. Surface modifications induced by chemical reactions of oxidized 100 Å Cu films with Cl−, SO42− and HCO3− ions in aqueous solutions with various concentrations were studied in situ using liquid cells. Copper corrosion processes in ground water were monitored for up to nine days. By comparing Cu 2p–3d, 4s transitions for a number of reference substances previously measured, changes in electronic structure of the Cu films were analysed. The XAS and RIXS spectral shape at the Cu edge, the chemical shift of the main line for Cu2+, and the energy positions of the observed satellites served as a tool for monitoring the changes during the reaction. It was found that the pH value and the Cl− concentration in solutions strongly affect the speed of the corrosion reaction.
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