| 1. |
- Rosén, Tomas, 1985-, et al.
(författare)
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Cross-Sections of Nanocellulose from Wood Analyzed by Quantized Polydispersity of Elementary Microfibrils
- 2020
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 14:12, s. 16743-16754
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Tidskriftsartikel (refereegranskat)abstract
- Bio-based nanocellulose has been shown to possess impressive mechanical properties and simplicity for chemical modifications. The chemical properties are largely influenced by the surface area and functionality of the nanoscale materials. However, finding the typical cross-sections of nanocellulose, such as cellulose nanofibers (CNFs), has been a long-standing puzzle, where subtle changes in extraction methods seem to yield different shapes and dimensions. Here, we extracted CNFs from wood with two different oxidation methods and variations in degree of oxidation and high-pressure homogenization. The cross-sections of CNFs were characterized by small-angle X-ray scattering and wide-angle X-ray diffraction in dispersed and freeze-dried states, respectively, where the results were analyzed by assuming that the cross-sectional distribution was quantized with an 18-chain elementary microfibril, the building block of the cell wall. We find that the results agree well with a pseudosquare unit having a size of about 2.4 nm regardless of sample, while the aggregate level strongly depends on the extraction conditions. Furthermore, we find that aggregates have a preferred cohesion of phase boundaries parallel to the (110)-plane of the cellulose fibril, leading to a ribbon shape on average.
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| 2. |
- Abarenkov, Kessy, et al.
(författare)
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The UNITE database for molecular identification and taxonomic communication of fungi and other eukaryotes: sequences, taxa and classifications reconsidered
- 2024
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Ingår i: Nucleic Acids Research. - 0305-1048 .- 1362-4962. ; 52:D1, s. D791-D797
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Tidskriftsartikel (refereegranskat)abstract
- UNITE (https://unite.ut.ee) is a web-based database and sequence management environment for molecular identification of eukaryotes. It targets the nuclear ribosomal internal transcribed spacer (ITS) region and offers nearly 10 million such sequences for reference. These are clustered into similar to 2.4M species hypotheses (SHs), each assigned a unique digital object identifier (DOI) to promote unambiguous referencing across studies. UNITE users have contributed over 600 000 third-party sequence annotations, which are shared with a range of databases and other community resources. Recent improvements facilitate the detection of cross-kingdom biological associations and the integration of undescribed groups of organisms into everyday biological pursuits. Serving as a digital twin for eukaryotic biodiversity and communities worldwide, the latest release of UNITE offers improved avenues for biodiversity discovery, precise taxonomic communication and integration of biological knowledge across platforms. Graphical Abstract
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| 3. |
- Abdalla, H., et al.
(författare)
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Gamma-ray blazar spectra with HESS II mono analysis : The case of PKS2155-304 and PG1553+113
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 600
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Tidskriftsartikel (refereegranskat)abstract
- Context. The addition of a 28 m Cherenkov telescope (CT5) to the H.E.S.S. array extended the experiment's sensitivity to lower energies. The lowest energy threshold is obtained using monoscopic analysis of data taken with CT5, providing access to gamma-ray energies below 100 GeV for small zenith angle observations. Such an extension of the instrument's energy range is particularly beneficial for studies of active galactic nuclei with soft spectra, as expected for those at a redshift >= 0.5. The high-frequency peaked BL Lac objects PKS 2155-304 (z = 0.116) and PG 1553 + 113 (0.43 < z < 0.58) are among the brightest objects in the gamma-ray sky, both showing clear signatures of gamma-ray absorption at E > 100 GeV interpreted as being due to interactions with the extragalactic background light (EBL). Aims. The aims of this work are twofold: to demonstrate the monoscopic analysis of CT5 data with a low energy threshold, and to obtain accurate measurements of the spectral energy distributions (SED) of PKS 2155-304 and PG 1553 + 113 near their SED peaks at energies approximate to 100 GeV. Methods. Multiple observational campaigns of PKS 2155 304 and PG 1553 + 113 were conducted during 2013 and 2014 using the full H.E.S.S. II instrument (CT1-5). A monoscopic analysis of the data taken with the new CT5 telescope was developed along with an investigation into the systematic uncertainties on the spectral parameters which are derived from this analysis. Results. Using the data from CT5, the energy spectra of PKS 2155 304 and PG 1553 + 113 were reconstructed down to conservative threshold energies of 80 GeV for PKS 2155 304, which transits near zenith, and 110 GeV for the more northern PG 1553 + 113. The measured spectra, well fitted in both cases by a log-parabola spectral model ( with a 5.0 similar to statistical preference for non-zero curvature for PKS 2155 304 and 4.5 sigma for PG 1553+113), were found consistent with spectra derived from contemporaneous Fermi-LAT data, indicating a sharp break in the observed spectra of both sources at E approximate to 100 GeV. When corrected for EBL absorption, the intrinsic H.E.S.S. II mono and Fermi-LAT spectrum of PKS 2155 304 was found to show significant curvature. For PG 1553+113, however, no significant detection of curvature in the intrinsic spectrum could be found within statistical and systematic uncertainties.
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| 4. |
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Aktörer och marknader i omvandling : studier i företagandets historia tillägnade Kersti Ullenhag
- 2011
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- This book is a Festschrift to professor emerita Kersti Ullenhag in honour of her 75th birthday. Kersti Ullenhag has been a teacher and researcher in economic history at Uppsala University since the mid 1960’s. Her research has focused on different aspects of business history, often combining micro-oriented empirical case studies with Schumpeterian theories on entrepreneurship. In 19 chapters this book deals with research topics such as the roots of business history,political economy, business and entrepreneurship, the development of financial markets and gender perspectives in business and society.
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| 5. |
- Bergström, Göran, 1977-
(författare)
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Från svensk malmexport till utländsk etablering : Grängesbergsbolagets internationalisering 1953-1980
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main purpose of this thesis is to analyze the internationalisation of the Grängesberg Company from 1953 to 1980. The strategies that the company used and the knowledge it gained by participating in international mining projects are studied. The first and largest mining activity abroad was the Lamco project in Liberia. By transferring the company’s competence and knowledge of mining activities to Liberia, the Grängesberg Company used an international strategy of horizontal integration. The company’s contacts were of importance to start the production in 1963. The main ambition was thereafter to negotiate new long-term contracts in order to create stability for the project in the 1960s and the 1970s. Through its involvement in the Lamco project, the Grängesberg Company also acquired shares in a Belgian steel company and became half-owner with the Liberian state in a foreign shipping company. The experience and knowledge that the company gained in the Lamco project was used to increase its internationalisation in the 1970s. Appointing a Mineral Project Group, it investigated existing mineral projects abroad and formulated new internationalisation strategies such as vertical integration and diversification. The main motive for the further expansion abroad in the mining area was a need for resources for its domestic production. The most important outcome was the acquisition of a Canadian copper company, and the company integrated backwards to gain access to copper. The Grängesberg Company also used its competence by doing prospecting work in New Caledonia, Peru and Canada and consultant work in mining projects in Iran and Saudi Arabia in the 1970s. The study has shown that further international expansion became limited because of the downturn of the international economy in the 1970s, but also because of the company’s cautious attitude towards the political risks that were associated with international mining projects.
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| 6. |
- Björn, Erik, et al.
(författare)
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Recent Advances in Mercury Speciation Analysis with Focus on Spectrometric Methods and Enriched Stable Isotope Applications
- 2007
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Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 36:6, s. 443–51-
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses some recent advances in spectrometric methods and approaches for mercury speciation analysis of environmental samples with focus on isotope dilution techniques for determination of mercury species' concentrations in gaseous samples and reaction rates in soils and sediments. Such analytical data is important inter alia in fundamental research on mercury biogeochemistry and for risk assessments of mercury-contaminated soils and sediments and for designing effective remedial actions. The paper describes how the use of enriched stable isotope tracers in mercury speciation analysis can improve the traceability and accuracy of results, facilitate rational method developments, and be useful for studying biogeochemical processes, i.e. rate of reactions and fluxes, of mercury species. In particular the possibilities to study and correct for unwanted species transformation reactions during sample treatment and to study “natural” transformations of species in environmental samples, or micro- and mesocosm ecosystems, during incubations are highlighted. Important considerations to generate relevant data in isotope tracer experiments as well as reliability and quality assurance of mercury speciation analysis in general are also discussed.
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| 7. |
- Boud, David, et al.
(författare)
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Creating a world class program : Reciprocity and constraints in global study.
- 2006
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Ingår i: International Journal of Lifelong Education. - : Informa UK Limited. - 0260-1370 .- 1464-519X. ; 25:6, s. 609-622
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Tidskriftsartikel (refereegranskat)abstract
- The article reflects on the construction of a common Master's programme across four universities located on four continents, in order to explore the role of networks in international educational collaboration. The study draws on the documented processes of the principal members of the programme team. It is presented as a case study of the development of the programme that uses ideas drawn from actor-network theory to draw attention to the conjunction of human and non-human actors that shaped the resulting web-based courses. Constraints arising from major institutional and systemic obstacles were addressed through the effects of the actor-network. The reciprocity of action and de-centring of individual activity made possible through the collaboration enabled the human actors to sustain a level of innovation within their own institutions that would not have been possible through them acting alone.
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| 8. |
- Boud, David, et al.
(författare)
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Making sense of new forms of practice : multiple perspectives in researching an intercultural programme across continents.
- 2006
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Ingår i: Standing Conference on University Teaching and Research in the Education of Adults,2006.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The focus of the symposium is on researching a programme with multiple sites of practice (in four conutries on four continents), learners distributed across the world and an emphasis on a pedagogy that embeds intercultural understanding. Studies from different perspectives are used to explore research issues in intercultural courses.
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| 10. |
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