| 311. |
- Karimi, Shirin
(författare)
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Peatland hydrology in boreal Sweden: Modelling, long-term data analysis, and experimental rewetting
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Peatlands are the dominant type of wetland in boreal ecosystems and they are thought to play a major role in moderating hydrological extremes such as floods and droughts. Despite the valuable ecosystem services that they provide, a large proportion of peatlands around the globe has been degraded by human activity. Notably, in Sweden, peatlands have been subjected to drainage for the purposes of forestry. As awareness of the detrimental effects of climate change on boreal ecosystems has grown, the rewetting of drained peatlands has emerged as a naturebased solution for mitigating floods and droughts. However, the science behind this strategy is scant and the question of whether its potential benefits, in terms of alleviating extreme weather impacts, outweigh the costs of rewetting remains unanswered. Using a unique collection of hydrological field observations and modelling, this thesis provides a comprehensive analysis of the hydrological functioning of peatlands, at both local and stream network scale, within a heterogeneous boreal landscape (Paper I and Paper II) and addresses the question of whether peatland rewetting is more effective at mitigating both flooding events and low flow conditions than leaving historically drained peatlands as they are (Paper III and Paper IV). Our findings indicate that the moderating effect of peatlands on flow responses can primarily be found at the local scale. We also demonstrated that peatland rewetting successfully raised the groundwater table level, increased baseflow, and enhanced the overall storage capacity within the study site. During storm events, peatland rewetting effectively attenuated peak flow, reduced the runoff coefficient, and mitigated hydrograph flashiness. In conclusion, peatland rewetting is shown to be an effective tool for moderating hydrological extremes. However, given the dynamic nature of hydrological systems, continuous long-term monitoring of peatland processes following rewetting is required.
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| 312. |
- Korp, Helena, 1967-, et al.
(författare)
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Exploring multi-sited ethnography as an approach for studying good practice in the L2 classroom
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- IntroductionThis paper explores multi-sited ethnography (Marcus, 2011) as a research strategy in L2 classroom research in regard to a specific project: Bridging the Gap between in and out-of-school English: Learning from good practice (hence forth BTG). Using an online survey, we aim to identify English teachers in Swedish lower secondary schools (grades 6-9) who in their teaching are committed to exploring and drawing on students’ experiences and use of English in their free-time. After establishing contact and reaching agreements with selected teachers, we plan to do in-depth classroom studies through observations, interviews with teachers and students, collected instructional materials and student work, and other possible sources. We will also collect data from students in these classes about their use of English outside of school. The classroom studies will be carried out by three or four researchers, each spending about three weeks with four teachers which means that we will get data from the classrooms of about 16 teachers (which means approximately 48 weeks of classroom studies). Such a design, where a phenomenon is elicited based on the analysis of observational and other kinds of data from several settings has been termed “multi-sited ethnography” Coleman & von Hellermann, 2011).With this design we hope to combine many of the benefits of classic ethnography, based on rich data from the extensive study of one case, with the opportunity to explore the complex interplay between learning tasks, processes, teaching and classroom culture in various pedagogic contexts. We also intend to examine what kind of tasks that are motivating for different students, and which students get the opportunity to feel that their cognitive and cultural resources are recognized and drawn upon in class. Realizing that we can never predict how a pedagogical action or task would be interpreted and work out in a new context or from all students’ point of view (Willis & Trondman, 2000), our hope is still that we will be able to convey the results of BTG in such a way that teachers could use them, not as a manual, but as a starting point for reflecting on how such processes could develop in their classrooms, with their students.The purpose of the current paper is to discuss how ethnography, and particularly multi-sited ethnography could be applied in our project, given the purpose and theoretical framing of the study as well as practical concerns. We will do this through a review of literature on methodology in classroom ethnography and of second language (L2) studies in the same vein as our project.The review is not based on a systematic selection of readings, but is an effort to outline a map of the methodological and theoretical landscape where we, at this moment, see it as relevant to place and discuss our study. Another purpose of this paper is to provide it as a point of departure for critical and creative discourse with experienced ethnographers in OEC about design and methods, and thus help us work these out soundly. Willis & Trondman (2000, p. 12) argue concerning theory in ethnography thatthe criterion for relevance is maximum power in relation to the data for purposes of illumination, not theoretical adequacy or sophistication for its own sake. ‘Analytic points’ can be made without recourse to a full account of the whole intellectual history of the traditions from which theory is drawn: the necessity is for sufficient, perhaps quite brief, account of the specific theoretical work that a concept or view can bring to the subject of study, its usefulness in context.The paper is organised as follows: a presentation of the purpose and theoretical framing of the project, the literature review, an outline in more concrete detail of our planned design of the project BTG (based on our application for grants, and inspired by the accounted readings and by other empirical L2 studies in the same vein). We conclude with some ideas and questions regarding our research project.
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| 313. |
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| 314. |
- Bucaioni, Alessio, 1987-, et al.
(författare)
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Model-based Automation of Test Script Generation Across Product Variants: a Railway Perspective
- 2021
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Ingår i: 2nd ACM/IEEE International Conference on Automation of Software Test AST 2021. - 9781665435673 ; , s. 20-29
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Konferensbidrag (refereegranskat)abstract
- In this work, we report on our experience indefining and applying a model-based approach for the automaticgeneration of test scripts for product variants in software productlines. The proposed approach is the result of an effort leveragingthe experiences and results from the technology transfer activitieswith our industrial partner Bombardier Transportation. Theproposed approach employs metamodelling and model transfor-mations for representing different testing artefacts and makingtheir generation automatic. We demonstrate the industrial ap-plicability and efficiency of the proposed approach using theBombardier Transportation Aventra software product line. Weobserve that the proposed approach mitigates the developmenteffort, time consumption and consistency drawbacks typical oftraditional strategies.
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| 315. |
- Gonzalez Palmén, Lorena, 1970-
(författare)
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Homotrimeric dUTPases : Principles of Catalysis and Inhibitor Design
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ubiquitous enzyme dUTPase hydrolyzes dUTP into dUMP and pyrophosphate, preventing DNA fragmentation and cell death due to accumulation of dUTP. Inhibitors of dUTPase could serve as drugs in the treatment of cancers and infectious diseases. This thesis presents five studies. A mutational study on the Escherichia coli dUTPase (S72A) provides new insights about the catalytic principles of the homotrimeric dUTPases. A model is presented in which transition state formation is associated with a rotation of the conserved Ser72 side chain. The model can explain the strict order of deamination and hydrolysis catalyzed by the bifunctional dCTP deaminase:dUTPases. The S72A/D90N double mutant is currently investigated. Preliminary data indicate that this form preserves the binding properties of the S72A mutant but is completely inactive, making it attractive for structural studies. In the remaining studies we compare the binding of substrate analogues to the human, the E. coli and the equine infectious anemia virus (EIAV) homotrimeric dUTPases. One study concerns 2´,3´-dideoxy-UTP (ddUTP) and shows that removal of the 3´-hydroxyl group increases KM, ten times with the cellular dUTPases and fifty times with the viral dUTPase, but does not affect kcat with any of these enzymes. Another study concerns the inhibitory effects of 3´-azido-2´,3´-dideoxy-UTP. This derivative binds to the bacterial dUTPase but not to the other forms making it a potential lead for the development of antibacterial dUTPase inhibitors. Yet another study investigates two uracil derivatives. Both compounds are found to inhibit the human, the bacterial but not the viral dUTPase. The inhibition is shown to be competitive.
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| 316. |
- Zani, Lorenzo, et al.
(författare)
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Transition metal-catalyzed cross-coupling methodologies for the engineering of small molecules with applications in organic electronics and photovoltaics
- 2019
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Ingår i: Coordination chemistry reviews. - : Elsevier. - 0010-8545 .- 1873-3840. ; 392, s. 177-236
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Forskningsöversikt (refereegranskat)abstract
- Cross-coupling reactions have played a key role in producing numerous types of it-conjugated small molecules having appealing properties for practical applications in organic electronics, especially in the field of photovoltaics. The main advantages of such synthetic methodology are the compatibility with many types of functional groups and the flexibility which allows an easy way to introduce diversity and tune the electronic and photophysical properties of the target molecules. As a result, many semiconducting and photoactive organic compounds have been synthesized using this powerful tool. In this paper we will highlight a number of selected syntheses and optimized C-C bond formation processes described in the years 2000-2018 and related to this specific field, choosing those examples which can demonstrate the enormous power of the cross-coupling processes, but also the room for improvements of these methodologies.
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| 317. |
- Amaudruz, P, et al.
(författare)
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Measurements of Rd-Rp and RCa-Rc in deep inelastic muon scattering
- 1992
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 294:1, s. 120-126
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented on the difference in R, the ratio of longitudinally to transversely polarised virtual photon absorption cross sections, for the deuteron and the proton. They are obtained by comparing the ratio of cross sections for the deep inelastic scattering of muons from deuterium and hydrogen targets at 90 and 280 GeV incident energy. The results cover the range x = 0.01 -0.30, at an average Q2 of 9 GeV2. The measured difference R(d)-R(p) shows no significant x dependence and is compatible with zero, as well as with expectations from perturbative QCD. We use the same method to obtain the difference R(Ca)-R(C) from cross section ratios measured on carbon and calcium targets at 90 and 200 GeV incident energy.
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| 318. |
- Linderholm, Carl Johan, 1976, et al.
(författare)
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Use of Manganese Ores as Oxygen Carriers in Chemical-Looping Combustors for Solid Fuels
- 2016
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Ingår i: 4th International Conference on Chemical Looping, September 26-28, 2016, Nanjing, China.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Manganese ores are highly promising oxygen-carrier candidates due to high reactivity and high availability. It has been observed that some manganese ores may be sensitive to attrition, and the challenge has thus become to find a highly reactive manganese ore, or combination of ores, with sufficient mechanical integrity. This study summarizes the operational experience with manganese ores achieved at Chalmers UT.In an early study using Buritirama manganese ore as oxygen carrier a in 10 kW unit for solid fuels, it was shown that the gas conversion using petcoke as fuel increased from 80% with ilmenite to 85% with Buritirama. Simultaneously, there was a four-fold increase in gasification rate resulting in much higher carbon capture efficiency. However, the mechanical stability of the Mn ore was inferior to ilmenite, judged by the production of fines. In a subsequent study, ilmenite was mixed with the Buritirama manganese ore during operation in a 100 kW unit. The mixture of ilmenite and manganese ore gave significant improvements in gas conversion in comparison to only ilmenite. The highest gas conversion observed during testing with bituminous coal was as high as 91.5%, as compared to 84% with only ilmenite during similar conditions in the 100 kW unit. Another three manganese ores were recently investigated in the 10 kW unit. These ores appeared to form less fines as compared to Buritirama ore. All oxygen carriers showed high performance and reached more than 90% gas conversion at relevant conditions, using wood char as fuel. The estimated lifetime of the oxygen carrier based on fines production was in the range of 100 to 300 hours – a considerable improvement compared to the Buritirama ore. The most promising of the three ores tested in the 10 kW unit, Sinfin, was selected for use in the 100 kW unit. 52 hours of operation with different fuels has been achieved with the new oxygen carrier, called Sinaus, which is similar but not identical in composition to Sinfin. Preliminary results show that gas conversion is higher, and solid-fuel conversion much higher than with ilmenite as oxygen carrier. The evaluation also shows that the lifetime is lower than for ilmenite.
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| 319. |
- Sridhar, Sanjeevi Prasath, et al.
(författare)
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Adsorption of Anionic Dyes Using a Poly(styrene-block-4-vinylpyridine) Block Copolymer Organogel
- 2021
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 37:13, s. 3996-4006
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Tidskriftsartikel (refereegranskat)abstract
- An organogel was prepared by chemically cross-linking a poly(styrene-block-4-vinylpyridine) diblock copolymer using dibromododecane in dimethylformamide. Analysis of the prominent structure peak in small-angle X-ray scattering along with the results of light scattering and rheological profile suggests the bridging of the spherical micelles to one another to form an interconnected network after gelation. The use of this organogel as a selective adsorbent for removing anionic dyes from individual aqueous dye solutions and in a mixture of cationic and anionic dye solutions has shown more than 90% removal of the anionic dyes within 2 h. The regeneration and reusability studies showed that even after 20 cycles, the adsorption property of the organogel holds extremely well still beyond 90%. These results are indicative of the potential use of poly(styrene-block-4-vinylpyridine) organogel for the anionic ions removal in wastewater treatment.
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| 320. |
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