| 11. |
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| 12. |
- Wik, Preben, et al.
(författare)
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Contrastive analysis through L1-L2map
- 2011
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Ingår i: TMH-QPSR. - 1104-5787. ; 51:1, s. 49-52
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This paper describes the CALST project, in which the primary aim is to developVille-N, a computer assisted pronunciation training (CAPT) system for learners ofNorwegian as a second language. Ville-N makes use of L1-L2map, a tool for multilingualcontrastive analysis, to generate a list of language-specific features. Thesecan be used to tailor pronunciation and listening exercises. The tool can also beused for other target languages.
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| 13. |
- Aharonian, Felix, et al.
(författare)
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Solar abundance ratios of the iron-peak elements in the Perseus cluster
- 2017
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 551:7681, s. 478-
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Tidskriftsartikel (refereegranskat)abstract
- The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae(1). Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to investigate the nature of supernova explosions integrated over cosmic time. In particular, the abundance of the iron-peak elements (chromium, manganese, iron and nickel) is key to understanding how the progenitors of typical type Ia supernovae evolve and explode(2-6). Recent X-ray studies of the intracluster medium found that the abundance ratios of these elements differ substantially from those seen in the Sun(7-11), suggesting differences between the nature of type Ia supernovae in the clusters and in the Milky Way. However, because the K-shell transition lines of chromium and manganese are weak and those of iron and nickel are very close in photon energy, highresolution spectroscopy is required for an accurate determination of the abundances of these elements. Here we report observations of the Perseus cluster, with statistically significant detections of the resonance emission from chromium, manganese and nickel. Our measurements, combined with the latest atomic models, reveal that these elements have near-solar abundance ratios with respect to iron, in contrast to previous claims. Comparison between our results and modern nucleosynthesis calculations(12-14) disfavours the hypothesis that type Ia supernova progenitors are exclusively white dwarfs with masses well below the Chandrasekhar limit (about 1.4 times the mass of the Sun). The observed abundance pattern of the iron-peak elements can be explained by taking into account a combination of near-and sub-Chandrasekhar-mass type Ia supernova systems, adding to the mounting evidence that both progenitor types make a substantial contribution to cosmic chemical enrichment(5,15,16).
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| 14. |
- Caja, Laia, et al.
(författare)
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Snail regulates BMP and TGF beta pathways to control the differentiation status of glioma-initiating cells
- 2018
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Ingår i: Oncogene. - : Springer Science and Business Media LLC. - 0950-9232 .- 1476-5594. ; 37:19, s. 2515-2531
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Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma multiforme is a brain malignancy characterized by high heterogeneity, invasiveness, and resistance to current therapies, attributes related to the occurrence of glioma stem cells (GSCs). Transforming growth factor beta (TGF beta) promotes self-renewal and bone morphogenetic protein (BMP) induces differentiation of GSCs. BMP7 induces the transcription factor Snail to promote astrocytic differentiation in GSCs and suppress tumor growth in vivo. We demonstrate that Snail represses stemness in GSCs. Snail interacts with SMAD signaling mediators, generates a positive feedback loop of BMP signaling and transcriptionally represses the TGFB1 gene, decreasing TGF beta 1 signaling activity. Exogenous TGF beta 1 counteracts Snail function in vitro, and in vivo promotes proliferation and re-expression of Nestin, confirming the importance of TGFB1 gene repression by Snail. In conclusion, novel insight highlights mechanisms whereby Snail differentially regulates the activity of the opposing BMP and TGF beta pathways, thus promoting an astrocytic fate switch and repressing stemness in GSCs.
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| 15. |
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| 16. |
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| 17. |
- Emerson, Joanne B., et al.
(författare)
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Diverse sediment microbiota shape methane emission temperature sensitivity in Arctic lakes
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Northern post-glacial lakes are significant, increasing sources of atmospheric carbon through ebullition (bubbling) of microbially-produced methane (CH4) from sediments. Ebullitive CH4 flux correlates strongly with temperature, reflecting that solar radiation drives emissions. However, here we show that the slope of the temperature-CH4 flux relationship differs spatially across two post-glacial lakes in Sweden. We compared these CH4 emission patterns with sediment microbial (metagenomic and amplicon), isotopic, and geochemical data. The temperature-associated increase in CH4 emissions was greater in lake middles—where methanogens were more abundant—than edges, and sediment communities were distinct between edges and middles. Microbial abundances, including those of CH4-cycling microorganisms and syntrophs, were predictive of porewater CH4 concentrations. Results suggest that deeper lake regions, which currently emit less CH4 than shallower edges, could add substantially to CH4 emissions in a warmer Arctic and that CH4 emission predictions may be improved by accounting for spatial variations in sediment microbiota.
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| 18. |
- Stiernström, Sara, et al.
(författare)
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An ecotoxicological approach for hazard identification of energy ash
- 2011
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Ingår i: Waste Management. - : Elsevier BV. - 0956-053X .- 1879-2456. ; 31:2, s. 342-352
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Tidskriftsartikel (refereegranskat)abstract
- Within the EU, ash should be classified by its inherent hazardous effects under criterion H-14 (ecotoxic) in the Directive on waste (2008/98/EC). Today, however, there are no harmonized quantitative criterions for such a classification, but it is stated that biological test systems can be used. In this study seven ash materials were leached and characterized, both biologically and chemically. The objectives were to evaluate if (a) clear concentration-response relationships could be achieved for the selected toxicity tests (bacteria, algae, crustacean and fish). (b) some test(s) are generally more sensitive and (c) the toxic responses were consistent with the chemical analyzes. Interestingly, our results indicate that high concentrations of non-hazardous components (Ca, K) influenced the toxicity of almost all ash eluates, whereas hazardous components (e.g. Zn, Pb) only influenced the toxicity of the eluates ranked as most hazardous. If considering both hazardous and non-hazardous substances, the observed toxic responses were relatively consistent with the chemical analyzes. Our results further showed that the (sub)chronic tests were much more sensitive than the acute tests. However, the use of extrapolation factors to compensate for using the less sensitive acute tests will likely lead to either over- or underestimations of toxicity. Our recommendation is therefore that classification of waste according to H-14 should be based on (sub)chronic test data. Finally, given that treatment of the eluates prior to toxicity testing has a major significance on the concentration and speciation of released substances, further studies are needed in order to propose a relevant testing scheme.
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| 19. |
- Strandberg, Rebecka, 1982-, et al.
(författare)
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Conflict between reproductive gene trees and species phylogeny among heterothallic and pseudohomothallic members of the filamentous ascomycete genus Neurospora
- 2010
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Ingår i: Fungal Genetics and Biology. - : Elsevier BV. - 1087-1845 .- 1096-0937. ; 47:10, s. 869-878
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigated the genealogies of genes important for sexual identity, i.e. mating-type (mat) and pheromone-receptor (pre) genes, among heterothallic and peudohomothallic taxa of Neurospora. The resulting genealogies were compared with the species phylogeny derived from non-coding sequences. We found conflicting topologies between the reproductive genealogies and the species phylogeny, and these conflicts were supported by both node support analyses and likelihood tests on the relative fit of datasets to alternative phylogenetic hypotheses. We argue that reproductive genes are more permeable to gene flow, i.e. are more often introgressed between species of Neurospora, than other parts of the genome. Certain conflicts between the species phylogeny and both mat genealogies were observed, suggesting that the two mating-type idiomorphs were selectively introgressed into a species from a single ancestral source. Taken together, the results presented here highlight complex evolutionary trajectories of reproductive genes in the fungal kingdom, which may be of importance for reproductive behavior in natural populations.
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| 20. |
- Tapp, I, et al.
(författare)
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Homogenous scoring of single nucleotide polymorphism markers: The 5´-nuclease
- 2000
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Ingår i: Biotechniques. ; 28, s. 732-
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Tidskriftsartikel (refereegranskat)abstract
- An exceptional disposition of the elongation factor genes is observed in Rickettsia prowazekii, in which there is only one tuf gene, which is distant from the lone firs gene, In contrast, the closely related bacterium Agrobacterium tumefaciens has the nor
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