| 1. |
- Bécoulet, A., et al.
(författare)
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Science and technology research and development in support to ITER and the Broader Approach at CEA
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10
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Tidskriftsartikel (refereegranskat)abstract
- In parallel to the direct contribution to the procurement phase of ITER and Broader Approach, CEA has initiated research & development programmes, accompanied by experiments together with a significant modelling effort, aimed at ensuring robust operation, plasma performance, as well as mitigating the risks of the procurement phase. This overview reports the latest progress in both fusion science and technology including many areas, namely the mitigation of superconducting magnet quenches, disruption-generated runaway electrons, edge-localized modes (ELMs), the development of imaging surveillance, and heating and current drive systems for steady-state operation. The WEST (W Environment for Steady-state Tokamaks) project, turning Tore Supra into an actively cooled W-divertor platform open to the ITER partners and industries, is presented.
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| 2. |
- Adam, A, et al.
(författare)
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Abstracts from Hydrocephalus 2016.
- 2017
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Ingår i: Fluids and Barriers of the CNS. - : Springer Science and Business Media LLC. - 2045-8118. ; 14:Suppl 1
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Saliba-Gustafsson, P., et al.
(författare)
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Subclinical atherosclerosis and its progression are modulated by PLIN2 through a feed-forward loop between LXR and autophagy
- 2019
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 286:6, s. 660-675
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Tidskriftsartikel (refereegranskat)abstract
- Background Hyperlipidaemia is a major risk factor for cardiovascular disease, and atherosclerosis is the underlying cause of both myocardial infarction and stroke. We have previously shown that the Pro251 variant of perilipin-2 reduces plasma triglycerides and may therefore be beneficial to reduce atherosclerosis development. Objective We sought to delineate putative beneficial effects of the Pro251 variant of perlipin-2 on subclinical atherosclerosis and the mechanism by which it acts. Methods A pan-European cohort of high-risk individuals where carotid intima-media thickness has been assessed was adopted. Human primary monocyte-derived macrophages were prepared from whole blood from individuals recruited by perilipin-2 genotype or from buffy coats from the Karolinska University hospital blood central. Results The Pro251 variant of perilipin-2 is associated with decreased intima-media thickness at baseline and over 30 months of follow-up. Using human primary monocyte-derived macrophages from carriers of the beneficial Pro251 variant, we show that this variant increases autophagy activity, cholesterol efflux and a controlled inflammatory response. Through extensive mechanistic studies, we demonstrate that increase in autophagy activity is accompanied with an increase in liver-X-receptor (LXR) activity and that LXR and autophagy reciprocally activate each other in a feed-forward loop, regulated by CYP27A1 and 27OH-cholesterol. Conclusions For the first time, we show that perilipin-2 affects susceptibility to human atherosclerosis through activation of autophagy and stimulation of cholesterol efflux. We demonstrate that perilipin-2 modulates levels of the LXR ligand 27OH-cholesterol and initiates a feed-forward loop where LXR and autophagy reciprocally activate each other; the mechanism by which perilipin-2 exerts its beneficial effects on subclinical atherosclerosis.
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| 4. |
- Frisk, U., et al.
(författare)
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The Odin satellite - I. Radiometer design and test
- 2003
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Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 402:3, s. L27-L34
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Tidskriftsartikel (refereegranskat)abstract
- The Sub-millimetre and Millimetre Radiometer (SMR) is the main instrument on the Swedish, Canadian, Finnish and French spacecraft Odin. It consists of a 1.1 metre diameter telescope with four tuneable heterodyne receivers covering the ranges 486-504 GHz and 541-581 GHz, and one fixed at 118.75 GHz together with backends that provide spectral resolution from 150 kHz to 1 MHz. This Letter describes the Odin radiometer, its operation and performance with the data processing and calibration described in Paper II.
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| 5. |
- Hillairet, J., et al.
(författare)
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Recent progress on lower hybrid current drive and implications for ITER
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:7
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Tidskriftsartikel (refereegranskat)abstract
- The sustainment of steady-state plasmas in tokamaks requires efficient current drive systems. Lower hybrid current drive is currently the most efficient method to generate a continuous additional off-axis toroidal plasma current and to reduce the poloidal flux consumption during the plasma current ramp-up phase. The operation of the Tore Supra ITER-like lower hybrid (LH) launcher has demonstrated the capability to couple LH power at ITER-like power densities with very low reflected power during long pulses. In addition, the installation of eight 700 kW/CW klystrons at the LH transmitter has allowed increasing the total LH power in long-pulse scenarios. However, in order to achieve pure stationary LH-sustained plasmas, some R&D is needed to increase the reliability of all the systems and codes, from radio-frequency (RF) sources to plasma scenario prediction. The CEA/IRFM is addressing some of these issues by leading a R&D programme towards an ITER LH system and by the validation of an integrated LH modelling suite of codes. In 2011, the RF design of a mode converter was validated at a low power. A 500 kW/5 s RF window is currently under manufacture and will be tested at a high power in 2012 in collaboration with the National Fusion Research Institute. All of this work aims to reduce the operational risks associated with the ITER steady-state operations.
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| 6. |
- Stephens, Philip A., et al.
(författare)
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Consistent response of bird populations to climate change on two continents
- 2016
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 352:6281, s. 84-87
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Tidskriftsartikel (refereegranskat)abstract
- Global climate change is a major threat to biodiversity. Large-scale analyses have generally focused on the impacts of climate change on the geographic ranges of species and on phenology, the timing of ecological phenomena. We used long-term monitoring of the abundance of breeding birds across Europe and the United States to produce, for both regions, composite population indices for two groups of species: those for which climate suitability has been either improving or declining since 1980. The ratio of these composite indices, the climate impact indicator (CII), reflects the divergent fates of species favored or disadvantaged by climate change. The trend in CII is positive and similar in the two regions. On both continents, interspecific and spatial variation in population abundance trends are well predicted by climate suitability trends.
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| 7. |
- Agic, Heda, et al.
(författare)
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Late Ediacaran occurrences of the organic-walled microfossils Granomarginata and flask-shaped Lagoenaforma collaris gen. et sp. nov.
- 2022
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Ingår i: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1071-1092
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Tidskriftsartikel (refereegranskat)abstract
- New occurrences of flask-shaped and envelope-bearing microfossils, including the predominantly Cambrian taxon Granomarginata, are reported from new localities, as well as from earlier in time (Ediacaran) than previously known. The stratigraphic range of Granomarginata extends into the Cambrian System, where it had a cosmopolitan distribution. This newly reported Ediacaran record includes areas from Norway (Baltica), Newfoundland (Avalonia) and Namibia (adjacent to the Kalahari Craton), and puts the oldest global occurrence of Granomarginata in the Indreelva Member (< 563 Ma) of the Stahpogieddi Formation on the Digermulen Peninsula, Arctic Norway. Although Granomarginata is rare within the assemblage, these new occurrences together with previously reported occurrences from India and Poland, suggest a potentially widespread palaeogeographic distribution of Granomarginata through the middle-late Ediacaran interval. A new flask-shaped microfossil Lagoenaforma collaris gen. et sp. nov. is also reported in horizons containing Granomarginata from the Stahpogieddi Formation in Norway and the Dabis Formation in Namibia, and flask-shaped fossils are also found in the Gibbett Hill Formation in Newfoundland. The Granomarginata-Lagoenaforma association, in addition to a low-diversity organic-walled microfossil assemblage, occurs in the strata postdating the Shuram carbon isotope excursion, and may eventually be of use in terminal Ediacaran biostratigraphy. These older occurrences of Granomarginata add to a growing record of body fossil taxa spanning the Ediacaran-Cambrian boundary.
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| 8. |
- Agic, Heda, et al.
(författare)
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Life through an Ediacaran glaciation : Shale- and diamictite-hosted organic-walled microfossil assemblages from the late Neoproterozoic of the Tanafjorden area, northern Norway
- 2024
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 635
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Tidskriftsartikel (refereegranskat)abstract
- New organic-walled microfossil (OWM) assemblages are reported from upper Neoproterozoic glacial and interglacial siliciclastic deposits in Finnmark, northern Norway. A nearly continuous sedimentary succession of the Vestertana Group contains two glaciogenic units, the Smalfjorden and Mortensnes formations, interpreted as end-Cryogenian Marinoan and Ediacaran glaciations, respectively. We investigated the OWM record in the Nyborg, Mortensnes, and St ' ahpogieddi formations to assess the impact of a glacial interval on the diversity of microscopic eukaryotes. A modified acid-extraction technique was applied to recover OWM from the diamictite matrix. The upper Nyborg Formation contains morphologically complex Doushantuo-Pertatataka acritarchs (DPA), restricting the age of the Nyborg Formation to early-mid Ediacaran. DPA occur below the dolostones that record a negative carbon isotope excursion correlated with the Shuram anomaly and below a glacial diamictite. A decline in species richness and compositional change is observed in the Mortensnes glacial assemblage. DPA are replaced by bacterial filaments and cell aggregates. The overlying Indreelva Member, St ' ahpogieddi Formation contains Ediacara-type biota and palaeopascichnids, but only a depauperate OWM assemblage of leiosphaerids and flask-shaped microfossils characteristic of the late Ediacaran.The succession of assemblages in the Vestertana Group demonstrates a turnover from large eukaryotic OWM to a microbial community in the glacial interval, to a low diversity post-glacial assemblage during the rise of macroscopic life. We compared the Vestertana record to global DPA occurrences. Although one DPA assemblage zone postdates the Shuram excursion, no DPA occur above Ediacaran glacial diamictites in successions where those deposits are present. Considering this, and the community changes in the Vestertana succession, we suggest that DPA were affected by the onset of an Ediacaran glaciation. Lastly, we combined the biostratigraphic markers in the Vestertana Group to constrain the age of the Mortensnes diamictite.
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| 9. |
- Agic, Heda, et al.
(författare)
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Life through the 'Varanger ice ages' : microfossil record of late Neoproterozoic glacial-interglacial units from arctic Norway
- 2018
-
Ingår i: Geological Society of America <em>Abstracts with Programs</em>. - : Geological Society of America.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The late Neoproterozoic strata in Finnmark (Arctic Norway) provide a good sedimentary record of Neoproterozoic glaciations on the Baltica paleocontinent. The lower Vestertana Group exposed on the Digermulen Peninsula contains two glaciogenic units, the Smalfjord and Mortensnes formations. Chemostratigraphic correlation dated the Smalfjord diamictite to the Marinoan glaciation (650-635 Ma), yet its age was also proposed to be older, per correlation to glacial units in central and southern Scandinavia. The diamictites are bracketing shales and siltstones of the interglacial Nyborg Formation. Stratigraphic, paleontological, and sedimentological data are presented from the interglacial-glacial succession, investigated by the Digermulen Early Life Research Group. Palynological analysis yielded well-preserved organic-walled microfossils (OWM) from the Nyborg Fm., and from fine-grained diamictite matrix in the Mortensnes Fm. via a modified extraction method.The interglacial Nyborg Fm. hosts a moderate diversity assemblage of prokaryotic and eukaryotic OWM, as well as acanthomorphic acritarchs such as Ceratosphaeridium, ?Cavaspina, and a novel process-bearing form. Organically preserved, enigmatic multicellular eukaryotic fossils occur in the upper Nyborg Fm. The Mortensens glacial assemblage is less diverse and contains bacterial filaments, leiosphaerids, toroidal forms, and Micrhystridium-type minute acanthomorphs.The presence of Doushantuo-Pertatataka type acritarchs in the Nyborg Fm., and small acanthomorphs in the Mortensnes diamictite corroborate an early Ediacaran age for the interglacial-glacial succession on Digermulen. In addition to the trace fossil and body-fossil record of Ediacara-biota in the overlying Stáhpogieddi Formation, the microfossil biostratigraphy suggests Marinoan and Gaskiers glaciation equivalent ages of the Varanger glaciations in Finnmark. Protistan diversity in the succession declined through and following the glaciation, until late Ediacaran.
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| 10. |
- Agić, Heda, 1989-, et al.
(författare)
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Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with differentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have benefitted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water filtration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise affinity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular differentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstatten.
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| 11. |
- Arahal, David, et al.
(författare)
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The best of both worlds: a proposal for further integration of Candidatus names into the International Code of Nomenclature of Prokaryotes
- 2024
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Ingår i: International Journal of Systematic and Evolutionary Microbiology. - 1466-5026 .- 1466-5034. ; 74:1
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Tidskriftsartikel (refereegranskat)abstract
- The naming of prokaryotes is governed by the International Code of Nomenclature of Prokaryotes (ICNP) and partially by the International Code of Nomenclature for Algae, Fungi and Plants (ICN). Such codes must be able to determine names of taxa in a universal and unambiguous manner, thus serving as a common language across different fields and activities. This unity is undermined when a new code of nomenclature emerges that overlaps in scope with an established, time-tested code and uses the same format of names but assigns different nomenclatural status values to the names. The resulting nomenclatural confusion is not beneficial to the wider scientific community. Such ambiguity is expected to result from the establishment of the ‘Code of Nomenclature of Prokaryotes Described from DNA Sequence Data’ (‘SeqCode’), which is in general and specific conflict with the ICNP and the ICN. Shortcomings in the interpretation of the ICNP may have exacerbated the incompatibility between the codes. It is reiterated as to why proposals to accept sequences as nomenclatural types of species and subspecies with validly published names, now implemented in the SeqCode, have not been implemented by the International Committee on Systematics of Prokaryotes (ICSP), which oversees the ICNP. The absence of certain regulations from the ICNP for the naming of as yet uncultivated prokaryotes is an acceptable scientific argument, although it does not justify the establishment of a separate code. Moreover, the proposals rejected by the ICSP are unnecessary to adequately regulate the naming of uncultivated prokaryotes. To provide a better service to the wider scientific community, an alternative proposal to emend the ICNP is presented, which would result in Candidatus names being regulated analogously to validly published names. This proposal is fully consistent with previous ICSP decisions, preserves the essential unity of nomenclature and avoids the expected nomenclatural confusion.
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| 12. |
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| 13. |
- Devos, David, et al.
(författare)
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Trial of Deferiprone in Parkinson’s Disease
- 2022
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 387:22, s. 2045-2055
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUNDIron content is increased in the substantia nigra of persons with Parkinson's disease and may contribute to the pathophysiology of the disorder. Early research suggests that the iron chelator deferiprone can reduce nigrostriatal iron content in persons with Parkinson's disease, but its effects on disease progression are unclear.METHODSWe conducted a multicenter, phase 2, randomized, double-blind trial involving participants with newly diagnosed Parkinson's disease who had never received levodopa. Participants were assigned (in a 1:1 ratio) to receive oral deferiprone at a dose of 15 mg per kilogram of body weight twice daily or matched placebo for 36 weeks. Dopaminergic therapy was withheld unless deemed necessary for symptom control. The primary outcome was the change in the total score on the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS; range, 0 to 260, with higher scores indicating more severe impairment) at 36 weeks. Secondary and exploratory clinical outcomes at up to 40 weeks included measures of motor and nonmotor disability. Brain iron content measured with the use of magnetic resonance imaging was also an exploratory outcome.RESULTSA total of 372 participants were enrolled; 186 were assigned to receive deferiprone and 186 to receive placebo. Progression of symptoms led to the initiation of dopaminergic therapy in 22.0% of the participants in the deferiprone group and 2.7% of those in the placebo group. The mean MDS-UPDRS total score at baseline was 34.3 in the deferiprone group and 33.2 in the placebo group and increased (worsened) by 15.6 points and 6.3 points, respectively (difference, 9.3 points; 95% confidence interval, 6.3 to 12.2; P<0.001). Nigrostriatal iron content decreased more in the deferiprone group than in the placebo group. The main serious adverse events with deferiprone were agranulocytosis in 2 participants and neutropenia in 3 participants.CONCLUSIONSIn participants with early Parkinson's disease who had never received levodopa and in whom treatment with dopaminergic medications was not planned, deferiprone was associated with worse scores in measures of parkinsonism than those with placebo over a period of 36 weeks.
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| 14. |
- Drilon, Alexander, et al.
(författare)
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Clinicopathologic Features and Response to Therapy of NRG1 Fusion-Driven Lung Cancers : The eNRGy1 Global Multicenter Registry
- 2021
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Ingår i: Journal of Clinical Oncology. - : LIPPINCOTT WILLIAMS & WILKINS. - 0732-183X .- 1527-7755. ; 39:25, s. 2791-2802
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE Although NRG1 fusions are oncogenic drivers across multiple tumor types including lung cancers, these are difficult to study because of their rarity. The global eNRGy1 registry was thus established to characterize NRG1 fusion-positive lung cancers in the largest and most diverse series to date. METHODS From June 2018 to February 2020, a consortium of 22 centers from nine countries in Europe, Asia, and the United States contributed data from patients with pathologically confirmed NRG1 fusion-positive lung cancers. Profiling included DNA-based and/or RNA-based next-generation sequencing and fluorescence in situ hybridization. Anonymized clinical, pathologic, molecular, and response (RECIST v1.1) data were centrally curated and analyzed. RESULTS Although the typified never smoking (57%), mucinous adenocarcinoma (57%), and nonmetastatic (71%) phenotype predominated in 110 patients with NRG1 fusion-positive lung cancer, further diversity, including in smoking history (43%) and histology (43% nonmucinous and 6% nonadenocarcinoma), was elucidated. RNA-based testing identified most fusions (74%). Molecularly, six (of 18) novel 5 ' partners, 20 unique epidermal growth factor domain-inclusive chimeric events, and heterogeneous 5 '/3 ' breakpoints were found. Platinum-doublet and taxane-based (post-platinum-doublet) chemotherapy achieved low objective response rates (ORRs 13% and 14%, respectively) and modest progression-free survival medians (PFS 5.8 and 4.0 months, respectively). Consistent with a low programmed death ligand-1 expressing (28%) and low tumor mutational burden (median: 0.9 mutations/megabase) immunophenotype, the activity of chemoimmunotherapy and single-agent immunotherapy was poor (ORR 0%/PFS 3.3 months and ORR 20%/PFS 3.6 months, respectively). Afatinib achieved an ORR of 25%, not contingent on fusion type, and a 2.8-month median PFS. CONCLUSION NRG1 fusion-positive lung cancers were molecularly, pathologically, and clinically more heterogeneous than previously recognized. The activity of cytotoxic, immune, and targeted therapies was disappointing. Further research examining NRG1-rearranged tumor biology is needed to develop new therapeutic strategies.
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| 15. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Biostratigraphy and palaeontology of the lower Cambrian Duolbagáisá Formation on the Digermulen Peninsula, Arctic Norway
- 2018
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Ingår i: International Conference on Arctic Margins.
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Konferensbidrag (refereegranskat)abstract
- The lower Cambrian sequence on the Digermulen Peninsula (Finnmark, Arctic Norway) is the northernmost extension of the Cambrian deposits along the Caledonian front. It is exceedingly thick compared to cratonal successions typical of most of Baltica. The Duolbagáisá Formation represents the youngest lower Cambrian unit on the peninsula with the first trilobite-bearing strata, a plethora of trace fossils including diverse arthropod traces and Plagiogmus arcuatus, and abundant and wellpreserved organic walled microfossils (OWM). Extensive field work by the Digermulen Early Life Research Group allows for the first time a detailed appreciation of the age and faunal composition of the unit. The lower member is ~250 m thick with thin-bedded siltstone, sandstone and mudstone. A single unidentifiable holmiid thorax region occurs alongside arthropod trace fossils. OWM indicate the S. ornata-F. membranacea Zone. The upper member is ~390 m thick and consist of several upward shallowing parasequences with fine-grained sandstone, siltstone and mudstone followed by thick mature quartzite. The trace fossil Syringomorpha occurs throughout the upper member and Cruziana and Rusophycus are especially abundant in the upper parts. The first identifiable olenellid trilobites occur in a thick mudstone/siltstone interval at the middle of the member, along with an elliptocephalid trilobite and other arthropods. Abundant OWM indicate the H. dissimilare-S. ciliosa Zone with the higher levels belonging to the Volkovia-Liepaina Zone. The entire sequence thus span the Cambrian Series 2, stages 3–5.
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| 16. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Distribution and correlation of Sabellidites cambriensis (Annelida?) in the basal Cambrian on Baltica
- 2022
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Ingår i: Geological Magazine. - : Cambridge University Press. - 0016-7568 .- 1469-5081. ; 159:7, s. 1262-1283
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Tidskriftsartikel (refereegranskat)abstract
- Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran-Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stahpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran-Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Cambrian. In the Manndrapselva Member, Sabellidites co-occurs with the acritarch Granomarginata, indicative of the lowermost Cambrian Granomarginata Zone, whereas in the Breidvika Formation it co-occurs with Asteridium. Sabellidites is widely distributed in Baltica, through the Rovnian and Lontovan regional stages but confined to the Fortunian global stage. In its lower range, Sabellidites is associated with a Treptichnus pedum trace fossil association and a depauperate leiosphaerid acritarch assemblage, followed by a Granomarginata assemblage. In its upper range, Sabellidites co-occurs with acritarchs of the Asteridium-Comasphaeridium Zone and the tubular foraminiferan Platysolenites. In Baltica, Sabellidites is a useful index fossil.
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| 17. |
- Ebbestad, Jan Ove R., et al.
(författare)
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Distribution and correlation of Sabellidites cambriensis (Annelida?) in the basal Cambrian on Baltica
- 2021
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Ingår i: Geological Magazine. - Cambridge : Cambridge University Press (CUP). - 0016-7568 .- 1469-5081. ; 159:7, s. 1262-1283
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Tidskriftsartikel (refereegranskat)abstract
- Sabellidites cambriensis is a tubular non-mineralized metazoan that appears as compressed ribbon-shaped imprints with transverse wrinkling, thick walls and an even tube diameter of up to 3 mm. The distribution of Sabellidites is investigated in three Ediacaran–Cambrian sections on the Digermulen Peninsula in Arctic Norway, spanning the Manndrapselva Member of the Stáhpogieddi Formation and the lower member of the Breidvika Formation. Here, the Ediacaran–Cambrian boundary is located in the lower part of the upper parasequence (third cycle) of the Manndrapselva Member. Specimens of Sabellidites are rare but consistently present close to the lowest level of Treptichnus pedum and upsection, whereas the taxon is common and abundant in the lower part of the lower member of the Breidvika Formation, with an upper record at c. 55 m above the base. The range is comparable with that of the GSSP section in Newfoundland, Canada, establishing Sabellidites as an index fossil for the lowermost Cambrian. In the Manndrapselva Member, Sabellidites co-occurs with the acritarch Granomarginata, indicative of the lowermost Cambrian Granomarginata Zone, whereas in the Breidvika Formation it co-occurs with Asteridium. Sabellidites is widely distributed in Baltica, through the Rovnian and Lontovan regional stages but confined to the Fortunian global stage. In its lower range, Sabellidites is associated with a Treptichnus pedum trace fossil association and a depauperate leiosphaerid acritarch assemblage, followed by a Granomarginata assemblage. In its upper range, Sabellidites co-occurs with acritarchs of the Asteridium–Comasphaeridium Zone and the tubular foraminiferan Platysolenites. In Baltica, Sabellidites is a useful index fossil.
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| 18. |
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| 19. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Holmiid trilobites from the lower Cambrian of the Digermulen Peninsula, Arctic Norway
- 2017
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Ingår i: 6th International Conference on Trilobites and their Relatives. Tallinn, Estonia, 7-10 July 2017. - Tallinn : Libris Est OU. - 9789949818617
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Konferensbidrag (refereegranskat)abstract
- Lower Cambrian holmiid olenelloids are used for biozonation of lower Cambrian (Series 2) strata in Baltoscandia. About a dozen species have been named since the description of Holmia kjerulfi (Linnarsson, 1868), but except for the classical area in Mjøsa, Norway, the species traditionally occur in small numbers, are variably preserved, occur at one or a few localities only and usually with only one taxon present. Definitions of the biozones are therefore still problematic. One level in the lower Cambrian Duolbasgáissá Formation of the Digermulen Peninsula, Arctic Norway, has yielded more than 50 new specimens of holmiids, preliminarily assigned to Elliptocephala n. sp. and Kjerulfia n. sp. Acritarchs indicate the Heliosphaeridium dissimilare–Skagia ciliosa acritarch Zone which corresponds to the traditional Holmia kjerulfi Assemblage Zone. Elliptocephala n. sp. is known from about a dozen specimens. It is characterized by very long palpebral lobes, a parallel-sided glabella, a short anterior glabellar lobe and short genal spines. A node is developed on the occipital ring. Semi-complete specimens show up to 10 thoracic segments, but the full number of thoracic segments and the pygidium is unknown. The slightly older E. lundgreni (Moberg, 1892), known from the Schmidtiellus mickwitzi Zone of southern Sweden, differs in the proportions of the glabella, the length of the palpebral lobes and definition of the cephalic border. Both H. mobergi and H. sulcata from Sweden show similarities to Elliptocephala n. sp. in the weakly developed lateral border with an effaced anterior border furrow. Nikolaisen & Henningsmoen (1987) described Kjerulfia lata Kiær, 1917 from two fragmentary specimens from this locality in Digermulen. More than 20 new specimens from this site shows that the species differs from Kjerulfia lata from the type area in southern Norway in proportions and features of the glabella, the width of the genal field and the possession of a stout and high spine on the occipital ring, and it is tentatively assigned to Kjerulfia n. sp. The material from the Digermulen Peninsula adds to the diversity of the Baltoscandian holmiids and is tightly constrained stratigraphically.
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| 20. |
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| 21. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Stratigraphy of the Ediacaran and basal Cambrian of the Digermulen Peninsula, Northern Norway
- 2015
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Ingår i: Geological Society of America Abstracts with Programs, vol 47.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The succession of the Digermulen Peninsula in Finnmark, northern Norway, is the only fossiliferous site inScandinavia with sedimentation across the Ediacaran–Cambrian transition without a significant hiatus. Geologicalinvestigations started in the 1930’s, but the Peninsula was first mapped in the 60’s. Ediacara-type fossils werefirst discovered in the late 80’s but recent discoveries will establish the Digermulen Peninsula as one of the mostsignificant Ediacaran sites in northern Europe. The parautochthonous strata are exposed in the Tanafjord areaalong the coast and in valleys on the east side of the Peninsula. The beds dip slightly to the west with the strikefollowing the coastline (ca. 045°). The Ediacaran succession is close to 1000 m thick and dominantly siliciclastic.It starts with interglacial sediments of the Nyborg Formation (tentatively the earliest Ediacaran), overlying astacked succession of diamictites of the Cryogenian Smalfjord Formation. After a hiatus follows the glaciogenicdiamictites of the Mortensnes Formation (~60 m thick), which is commonly seen to represent the ~582 Ma-oldGaskiers glaciation. Upwards, the contact to the overlying Stáhpogiedde Formation is not exposed locally, but hasbeen shown to represent a hiatus followed by transitional fluvial to marine sediments of the Lillevannet Member.Ediacaran-type fossils appear in the succeeding Innerelva Member. This is a two-cycle deepening upwardssuccession of laminated mudstone with intercalated sand bodies showing load structures. Preliminary microfossilssamples of the Member have so far proven almost barren, making dating more challenging. The basal part of thesucceeding Manndraperelva Member consists of three cycles; first a succession of reddish sandstone followed bytwo coarsening-upward cycles. Each starts with mudstone and fine sandstone and terminates in cross-beddedsandstone. The Ediacaran–Cambrian boundary is located within the third cycle, identified by the trace fossilTreptichnus pedum and associated trilobed trace fossils.The Digermulen Early Life Research Group has since2011 made significant new finds, and focused fieldwork aims to resolve tighter age constraints, provenance of thesediments and the range and diversity of the extended Ediacaran biota.
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| 22. |
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| 23. |
- Ebbestad, Jan Ove R., 1967-, et al.
(författare)
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Trilobites from the North: lower Cambrian olenelloids fromthe Digermulen Peninsula, Arctic Norway
- 2016
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Ingår i: 3. Trilobiten-Tagung [Berlin, 8. und 9. Oktober 2016] - Kurzfassungen der Vortrage. - Halle, Saale : Ampyx-Verlag. - 9783932795398
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Scandinavian lower Cambrian stratigraphy is largely trilobite based, defined by the occurrence of distincttrilobite assemblages with classic olenelloid trilobites like Holmia and Kjerulfia. Except for a few localities in Scandinavia where these taxa are fairly common, most occurrences are represented by a single or a fewincomplete specimens at the best. Since 2011 a collecting effort in the lower Cambrian strata on the Digermulen Peninsula, Arctic Norway has yielded close to 100 specimens of at least three different olenelloid trilobite taxa, including Kjerulfia lata, Kjerulfia sp. and Elliptocephalus sp., as well as an ellipsocephalid. These specimens are found in a narrow stratigraphical interval in the silty mudstone of the Duolbagaisa Formation,and are accompanied by rich material of organic walled microfossils and trace fossils. The age constraints onthe occurrence are therefore well established, placing the trilobites in the Holmia kjerulfi assemblage Zone.Compared to the classical T0mten locality in the Mjösa area, southern Norway, the Digermulen Peninsula assemblage lacks Holmia kjerulfi. Ellipsocephalids are found with the new material and also slightly higher in the succession. Although the occurrence of trilobites in the Duolbagaisa Formation have been known for along time, the new extensive trilobite material is both better preserved and more abundant, even compared tomost other places in Scandinavia. This ensures that this succession will be a major reference for lower Cambrian trilobite zonation in this part of the world.
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| 24. |
- Fanidi, Anouar, et al.
(författare)
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Circulating Folate, Vitamin B6, and Methionine in Relation to Lung Cancer Risk in the Lung Cancer Cohort Consortium (LC3)
- 2018
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 110:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Circulating concentrations of B vitamins and factors related to one-carbon metabolism have been found to be strongly inversely associated with lung cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC) study. The extent to which these associations are present in other study populations is unknown.Methods: Within 20 prospective cohorts from the National Cancer Institute Cohort Consortium, a nested case-control study was designed including 5364 incident lung cancer case patients and 5364 control subjects who were individually matched to case patients by age, sex, cohort, and smoking status. Centralized biochemical analyses were performed to measure circulating concentrations of vitamin B6, folate, and methionine, as well as cotinine as an indicator of recent tobacco exposure. The association between these biomarkers and lung cancer risk was evaluated using conditional logistic regression models.Results: Participants with higher circulating concentrations of vitamin B6 and folate had a modestly decreased risk of lung cancer risk overall, the odds ratios when comparing the top and bottom fourths (OR 4vs1 ) being 0.88 (95% confidence interval [CI] = 0.78 to 1.00) and 0.86 (95% CI = 0.74 to 0.99), respectively. We found stronger associations among men (vitamin B6: OR 4vs1 = 0.74, 95% CI = 0.62 to 0.89; folate: OR 4vs1 = 0.75, 95% CI = 0.61 to 0.93) and ever smokers (vitamin B6: OR 4vs1 = 0.78, 95% CI = 0.67 to 0.91; folate: OR 4vs1 = 0.87, 95% CI = 0.73 to 1.03). We further noted that the association of folate was restricted to Europe/Australia and Asia, whereas no clear association was observed for the United States. Circulating concentrations of methionine were not associated with lung cancer risk overall or in important subgroups.Conclusions: Although confounding by tobacco exposure or reverse causation cannot be ruled out, these study results are compatible with a small decrease in lung cancer risk in ever smokers who avoid low concentrations of circulating folate and vitamin B6.
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| 25. |
- Friberg, Magne, et al.
(författare)
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Extreme diversification of floral volatiles within and among species of Lithophragma (Saxifragaceae)
- 2019
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 116:10, s. 4406-4415
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Tidskriftsartikel (refereegranskat)abstract
- A major challenge in evolutionary biology is to understand how complex traits of multiple functions have diversified and codiversified across interacting lineages and geographic ranges. We evaluate intra- and interspecific variation in floral scent, which is a complex trait of documented importance for mutualistic and antagonistic interactions between plants, pollinators, and herbivores. We performed a large-scale, phylogenetically structured study of an entire plant genus (Lithophragma, Saxifragaceae), of which several species are coevolving with specialized pollinating floral parasites of the moth genus Greya (Prodoxidae). We sampled 94 Lithophragma populations distributed across all 12 recognized Lithophragma species and subspecies, and four populations of related saxifragaceous species. Our results reveal an unusually high diversity of floral volatiles among populations, species, and clades within the genus. Moreover, we found unexpectedly major changes at each of these levels in the biosynthetic pathways used by local populations in their floral scents. Finally, we detected significant, but variable, genus- and species-level patterns of ecological convergence in the floral scent signal, including an impact of the presence and absence of two pollinating Greya moth species. We propose that one potential key to understanding floral scent variation in this hypervariable genus is its geographically diverse interactions with the obligate specialized Greya moths and, in some species and sites, more generalized copollinators.
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