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| 2. |
- Hill, M. S., et al.
(författare)
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Reconstruction of Family-Level Phylogenetic Relationships within Demospongiae (Porifera) Using Nuclear Encoded Housekeeping Genes
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:1, s. e50437-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Demosponges are challenging for phylogenetic systematics because of their plastic and relatively simple morphologies and many deep divergences between major clades. To improve understanding of the phylogenetic relationships within Demospongiae, we sequenced and analyzed seven nuclear housekeeping genes involved in a variety of cellular functions from a diverse group of sponges. Methodology/Principal Findings: We generated data from each of the four sponge classes (i.e., Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha), but focused on family-level relationships within demosponges. With data for 21 newly sampled families, our Maximum Likelihood and Bayesian-based approaches recovered previously phylogenetically defined taxa: Keratosap, Myxospongiaep, Spongillidap, Haploscleromorphap (the marine haplosclerids) and Democlaviap. We found conflicting results concerning the relationships of Keratosap and Myxospongiaep to the remaining demosponges, but our results strongly supported a clade of Haploscleromorphap+Spongillidap+Democlaviap. In contrast to hypotheses based on mitochondrial genome and ribosomal data, nuclear housekeeping gene data suggested that freshwater sponges (Spongillidap) are sister to Haploscleromorphap rather than part of Democlaviap. Within Keratosap, we found equivocal results as to the monophyly of Dictyoceratida. Within Myxospongiaep, Chondrosida and Verongida were monophyletic. A well-supported clade within Democlaviap, Tetractinellidap, composed of all sampled members of Astrophorina and Spirophorina (including the only lithistid in our analysis), was consistently revealed as the sister group to all other members of Democlaviap. Within Tetractinellidap, we did not recover monophyletic Astrophorina or Spirophorina. Our results also reaffirmed the monophyly of order Poecilosclerida (excluding Desmacellidae and Raspailiidae), and polyphyly of Hadromerida and Halichondrida. Conclusions/Significance: These results, using an independent nuclear gene set, confirmed many hypotheses based on ribosomal and/or mitochondrial genes, and they also identified clades with low statistical support or clades that conflicted with traditional morphological classification. Our results will serve as a basis for future exploration of these outstanding questions using more taxon- and gene-rich datasets.
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| 3. |
- Cumming, Graeme S., et al.
(författare)
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Research priorities for the sustainability of coral-rich western Pacific seascapes
- 2023
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Ingår i: Regional Environmental Change. - 1436-3798 .- 1436-378X. ; 23:2
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Tidskriftsartikel (refereegranskat)abstract
- Nearly a billion people depend on tropical seascapes. The need to ensure sustainable use of these vital areas is recognised, as one of 17 policy commitments made by world leaders, in Sustainable Development Goal (SDG) 14 (‘Life below Water’) of the United Nations. SDG 14 seeks to secure marine sustainability by 2030. In a time of increasing social-ecological unpredictability and risk, scientists and policymakers working towards SDG 14 in the Asia–Pacific region need to know: (1) How are seascapes changing? (2) What can global society do about these changes? and (3) How can science and society together achieve sustainable seascape futures? Through a horizon scan, we identified nine emerging research priorities that clarify potential research contributions to marine sustainability in locations with high coral reef abundance. They include research on seascape geological and biological evolution and adaptation; elucidating drivers and mechanisms of change; understanding how seascape functions and services are produced, and how people depend on them; costs, benefits, and trade-offs to people in changing seascapes; improving seascape technologies and practices; learning to govern and manage seascapes for all; sustainable use, justice, and human well-being; bridging communities and epistemologies for innovative, equitable, and scale-crossing solutions; and informing resilient seascape futures through modelling and synthesis. Researchers can contribute to the sustainability of tropical seascapes by co-developing transdisciplinary understandings of people and ecosystems, emphasising the importance of equity and justice, and improving knowledge of key cross-scale and cross-level processes, feedbacks, and thresholds.
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| 4. |
- Bartoszak-Adamska, E, et al.
(författare)
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The influence of (O, N)-deuteration on the crystal and molecular structure, thermal stability and spectroscopic properties of 1,3-propanediammonium hydrogenphosphate monohydrate
- 2000
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Ingår i: POLISH JOURNAL OF CHEMISTRY. - 0137-5083. ; 74:3, s. 393-408
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Tidskriftsartikel (refereegranskat)abstract
- Exchange of mobile hydrogen atoms in 1,3-propanediammonium hydrogenphosphate for deuterium (OH-->OD, NH-->ND) affects the thermal stability of the salt. Additionally, (O,N)-deuteration induces some unexpected changes in the -CH2- vibrations in the IR spec
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| 5. |
- Berggren, Gustav, et al.
(författare)
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Biomimetic assembly and activation of [FeFe]-hydrogenases
- 2013
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Ingår i: Nature. - : Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.. - 0028-0836 .- 1476-4687. ; 499:7456, s. 66-69
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Tidskriftsartikel (refereegranskat)
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| 6. |
- Demmig-Adams, Barbara, et al.
(författare)
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Modulation of PsbS and flexible vs sustained energy dissipation by light environment in different species
- 2006
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 127, s. 670-80
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Tidskriftsartikel (refereegranskat)abstract
- Contrasting acclimation strategies of photosynthesis and photoprotection were identified for annual mesophytes (spinach, pumpkin, and Arabidopsis) vs the tropical evergreen Monstera deliciosa. The annual species utilized full sunlight for photosynthesis to a much greater extent than the evergreen species. Conversely, the evergreen species exhibited a greater capacity for photoprotective thermal energy dissipation as well as a greater expression of the PsbS protein in full sun than the annual species. In all species, the majority of thermal energy dissipation [assessed as non-photochemical fluorescence quenching (NPQ)] was the flexible, ΔpH-dependent form of NPQ over the entire range of growth light environments. However, in response to a transfer of shade-grown plants to high light, the evergreen species exhibited a high level of sustained thermal dissipation (qI), but the annual species did not. This sustained energy dissipation in the evergreen species was not ΔpH-dependent nor did the low level of PsbS in shade leaves increase upon transfer to high light for several days. Sustained ΔpH-independent NPQ was correlated (a) initially, with sustained D1 protein phosphorylation and xanthophyll cycle arrest and (b) subsequently, with an accumulation over several days of PsbS-related one-helix proteins and newly synthesized zeaxanthin and lutein.
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| 7. |
- Gjestvang, D., et al.
(författare)
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Examination of how properties of a fissioning system impact isomeric yield ratios of the fragments
- 2023
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 108:6
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Tidskriftsartikel (refereegranskat)abstract
- The population of isomeric states in the prompt decay of fission fragments-so-called isomeric yield ratios (IYRs)-is known to be sensitive to the angular momentum J that the fragment emerged with, and may therefore contain valuable information on the mechanism behind the fission process. In this work, we investigate how changes in the fissioning system impact the measured IYRs of fission fragments to learn more about what parameters affect angular momentum generation. To enable this, a new technique for measuring IYRs is first demonstrated. It is based on the time of arrival of discrete gamma rays, and has the advantage that it enables the study of the IYR as a function of properties of the partner nucleus. This technique is used to extract the IYR of 134Te, strongly populated in actinide fission, from the three different fissioning systems: 232Th(n, f), 238U(n, f), at two different neutron energies, as well as 252Cf(sf). The impacts of changing the fissioning system, the compound nuclear excitation energy, the minimum J of the binary partner, and the number of neutrons emitted on the IYR of 134Te are determined. The decay code TALYS is used in combination with the fission simulation code FREYA to calculate the primary fragment angular momentum from the IYR. We find that the IYR of 134Te has a slope of 0.004 +/- 0.002 with increase in compound nucleus (CN) mass. When investigating the impact on the IYR of increased CN excitation energy, we find no change with an energy increase similar to the difference between thermal and fast fission. By varying the mass of the partner fragment emerging with 134Te, it is revealed that the IYR of 134Te is independent of the total amount of prompt neutrons emitted from the fragment pair. This indicates that neutrons carry minimal angular momentum away from the fission fragments. Comparisons with the FREYA+TALYS simulations reveal that the average angular momentum in 134Te following 238U(n, f) is 6.0 h over bar . This is not consistent with the value deduced from recent CGMF calculations. Finally, the IYR sensitivity to the angular momentum of the primary fragment is discussed. These results are not only important to help understanding the underlying mechanism in nuclear fission, but can also be used to constrain and benchmark fission models, and are relevant to the gamma -ray heating problem of reactors.
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