| 1. |
- Johansson, Madelaine, et al.
(författare)
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Individual Reflection Paper : Supporting Student's Learning in the Critical Phase of Self-directed Learning in PBL
- 2019
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Ingår i: Journal of Problem Based Learning in Higher Education. - : Aalborg Universitetsforlag. - 2246-0918. ; 7:1, s. 97-106
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Tidskriftsartikel (refereegranskat)abstract
- Supporting and assessment of students’ preparation and learning process in problem-based learning (PBL) tutorials has long been a challenge. We present a modified PBL model focussing on the specific critical phase in the PBL process, the self-directed learning phase in between tutorial meetings. The modified seven step PBL model including an Individual reflection paper (IRP) is presented as well as students’ perspectives on the implementation of IRP and information literacy, knowledge gathering, and PBL tutorial work. The assessment of PBL work is complex, and the ways in which IRPs support the tutor’s role as an examiner is beyond the scope of the current study. However, it seems that the students experienced assessment of the IRPs as part of their as a positive driving force in their learning process.
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| 2. |
- Montelius, Malin, 1984-, et al.
(författare)
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Radiotracer evidence that the rhizosphere is a hot-spot for chlorination of soil organic matter
- 2019
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Ingår i: Plant and Soil. - : Springer. - 0032-079X .- 1573-5036. ; 443:1-2, s. 245-257
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Tidskriftsartikel (refereegranskat)abstract
- AimsThe ubiquitous and extensive natural chlorination of organic matter in soils, leading to levels of chlorinated soil organic matter that often exceed the levels of chloride, remains mysterious in terms of its causes and regulation. While the composition of plant species and the availability of labile organic matter was recently shown to be important, the physical localization of chlorination in soils remains unclear but is a key for understanding regulation and patterns observed. Here we assess the relative importance of organic matter chlorination in (a) bulk soil, (b) the plant roots plus the rhizosphere zone surrounding the roots, and (c) above-ground plant biomass, in an experimental plant-soil system.MethodsA radiotracer, 36Cl, was added to study translocation and transformations of Cl− and Clorg in agricultural soil with and without wheat (Triticum vulgare) over 50 days.ResultsThe specific chlorination rates (the fraction of the added 36Cl− converted to 36Clorg per day) in soil with plants was much higher (0.02 d−1) than without plants (0.0007 d−1) at peak growth (day 25). The plant root and rhizosphere showed much higher formation of 36Clorg than the bulk soil, suggesting that the rhizosphere is a hotspot for chlorination in the soil. In addition, the treatment with plants displayed a rapid and high plant uptake of Cl−.ConclusionsOur results indicate that the rhizosphere harbour the most extensive in-situ chlorination process in soil and that root-soil interaction may be key for terrestrial chlorine cycling.
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| 3. |
- Svensson, Teresia, 1975-
(författare)
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Measurements and fluxes of volatile chlorinated organic compounds (VOCl) from natural terrestrial sources : Measurement techniques and spatio-temporal variability of flux estimates
- 2019
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Volatile organic compounds (VOCs) and especially chlorinated VOCs (VOCls) are regarded as en viron mental risk substances in water bodies due to their toxic characteristics. Even in the atmosphere they highly impact atmospheric chemistry, e.g. degrading the ozone layer. Several studies have convincingly identified a number of natural VOCl sources thereby challenging the view of VOCls as only produced by humans. Yet, fundamental knowledge is still missing concerning the emission, distribution and the natural abundance of VOCls, especially regarding the high spatial and temporal variability of emissions from terrestrial sources. In the nuclear industry, Cl36 is a dosedominating radionuclide in some waste, and this adds to the need to better understand the processes, transport and fate of chlorine in the bio sphere. In this report 38 studies on VOCl flux measurement estimates were reviewed to summarize the current knowledge on spatiotemporal variations of different VOCls and various measurement tech niques.Chloromethane is the most studied VOCl compound and chloroform, the second most studied. A few other studies have estimated fluxes of additional VOCls such as tetrachloromethane (CCl4), methyl chloroform (CH3CCl3), tetrachloroethane (C2H2Cl4), freons (CFCs), chloroethane (C2H5Cl), bromodichloromethane (CHBrCl2). Studies were conducted in climates and terrestrial ecosystems ranging from arctic tundra to tropical rainforest but most studies focus on the temperate climate region. Wetlands and coastal systems dominate the studied ecosystems. Flux chambers are the most common method for investigation of the soilatmosphere exchange of VOCls, but a few studies used soil gas profiles and one the Relaxed Eddy Accumulation (REA) technique. Methodological uncertainties are mainly related to sample contamination, few replicates, chamber design, and chamber deployment (the time of measurement) effects on the soilatmosphere exchange itself. Despite the many challenges in measuring VOCls and estimating the fluxes, a substantial part of the chlorine in terrestrial ecosystems, and especially from wetlands and coastal areas, is emitted to the atmosphere as VOCls. In inland forested ecosystems, the release of Cl to the atmosphere could be as much as 0.1 g m–2, which is 40 % of the wet deposition and there are studies that suggest that freshwater wetlands are much larger source of chlorine in the atmosphere than previously understood.
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| 4. |
- Svensson, Teresia, 1975-, et al.
(författare)
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Miljövetenskaplig undervisning i högre utbildning
- 2016
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Ingår i: Pedagogik för högskolelärare. - Möklinta : Gidlunds förlag. - 9789178449378 ; , s. 262-288
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Det finns didaktiska utmaningar och möjligheter relaterade till ett tvärdisciplinärtämnesområde som det miljövetenskapliga. En central fråga är hur miljövetenskapligutbildning kan utformas för att ge studenterna förutsättningaratt handskas med komplexa, idag möjligen okända, miljöfrågor i en kommandeyrkesverksamhet. I en svensk definition av didaktik är frågeorden Vad, Huroch Varför är centrala, vad bör en miljövetenskaplig utbildning innehålla,hur ska undervisningen genomföras och varför organiseras den som den gör?Det miljövetenskapliga ämnets framväxt har skapat läraktiviteter såsom: case,rollspel, debatt, och projekt. Alla har olika syfte vad gäller bearbetning av innehålloch färdighetsträning. Verklighetsanknuten undervisning är ett viktigt målinom det miljövetenskapliga utbildningsområdet och genom en genomtänktdesign kan studenterna få stöd för lärande inför de arbetsuppgifter de kommeratt möta i teori och i praktik.
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