| 1. |
- Bentley, Michael J., et al.
(författare)
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A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum
- 2014
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 100, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- A robust understanding of Antarctic Ice Sheet deglacial history since the Last Glacial Maximum is important in order to constrain ice sheet and glacial-isostatic adjustment models, and to explore the forcing mechanisms responsible for ice sheet retreat. Such understanding can be derived from a broad range of geological and glaciological datasets and recent decades have seen an upsurge in such data gathering around the continent and Sub-Antarctic islands. Here, we report a new synthesis of those datasets, based on an accompanying series of reviews of the geological data, organised by sector. We present a series of timeslice maps for 20 ka, 15 ka, 10 ka and 5 ka, including grounding line position and ice sheet thickness changes, along with a clear assessment of levels of confidence. The reconstruction shows that the Antarctic Ice sheet did not everywhere reach the continental shelf edge at its maximum, that initial retreat was asynchronous, and that the spatial pattern of deglaciation was highly variable, particularly on the inner shelf. The deglacial reconstruction is consistent with a moderate overall excess ice volume and with a relatively small Antarctic contribution to meltwater pulse la. We discuss key areas of uncertainty both around the continent and by time interval, and we highlight potential priorities for future work. The synthesis is intended to be a resource for the modelling and glacial geological community.
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| 2. |
- Jane, Stephen F., et al.
(författare)
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Widespread deoxygenation of temperate lakes
- 2021
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 594:7861, s. 66-70
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Tidskriftsartikel (refereegranskat)abstract
- The concentration of dissolved oxygen in aquatic systems helps to regulate biodiversity(1,2), nutrient biogeochemistry(3), greenhouse gas emissions(4), and the quality of drinking water(5). The long-term declines in dissolved oxygen concentrations in coastal and ocean waters have been linked to climate warming and human activity(6,7), but little is known about the changes in dissolved oxygen concentrations in lakes. Although the solubility of dissolved oxygen decreases with increasing water temperatures, long-term lake trajectories are difficult to predict. Oxygen losses in warming lakes may be amplified by enhanced decomposition and stronger thermal stratification(8,9) or oxygen may increase as a result of enhanced primary production(10). Here we analyse a combined total of 45,148 dissolved oxygen and temperature profiles and calculate trends for 393 temperate lakes that span 1941 to 2017. We find that a decline in dissolved oxygen is widespread in surface and deep-water habitats. The decline in surface waters is primarily associated with reduced solubility under warmer water temperatures, although dissolved oxygen in surface waters increased in a subset of highly productive warming lakes, probably owing to increasing production of phytoplankton. By contrast, the decline in deep waters is associated with stronger thermal stratification and loss of water clarity, but not with changes in gas solubility. Our results suggest that climate change and declining water clarity have altered the physical and chemical environment of lakes. Declines in dissolved oxygen in freshwater are 2.75 to 9.3 times greater than observed in the world's oceans(6,7) and could threaten essential lake ecosystem services(2,3,5,11).
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| 3. |
- Maier, O., et al.
(författare)
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ISLES 2015-A public evaluation benchmark for ischemic stroke lesion segmentation from multispectral MRI
- 2017
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Ingår i: Medical Image Analysis. - : Elsevier BV. - 1361-8415 .- 1361-8423. ; 35, s. 250-269
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Tidskriftsartikel (refereegranskat)abstract
- Ischemic stroke is the most common cerebrovascular disease, and its diagnosis, treatment, and study relies on non-invasive imaging. Algorithms for stroke lesion segmentation from magnetic resonance imaging (MRI) volumes are intensely researched, but the reported results are largely incomparable due to different datasets and evaluation schemes. We approached this urgent problem of comparability with the Ischemic Stroke Lesion Segmentation (ISLES) challenge organized in conjunction with the MICCAI 2015 conference. In this paper we propose a common evaluation framework, describe the publicly available datasets, and present the results of the two sub-challenges: Sub-Acute Stroke Lesion Segmentation (SISS) and Stroke Perfusion Estimation (SPES). A total of 16 research groups participated with a wide range of state-of-the-art automatic segmentation algorithms. A thorough analysis of the obtained data enables a critical evaluation of the current state-of-the-art, recommendations for further developments, and the identification of remaining challenges. The segmentation of acute perfusion lesions addressed in SPES was found to be feasible. However, algorithms applied to sub-acute lesion segmentation in SISS still lack accuracy. Overall, no algorithmic characteristic of any method was found to perform superior to the others. Instead, the characteristics of stroke lesion appearances, their evolution, and the observed challenges should be studied in detail. The annotated ISLES image datasets continue to be publicly available through an online evaluation system to serve as an ongoing benchmarking resource (www.isles-challenge.org).
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| 4. |
- Artigas, J., et al.
(författare)
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Towards a renewed research agenda in ecotoxicology
- 2012
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491. ; 160, s. 201-206
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Tidskriftsartikel (refereegranskat)abstract
- New concerns about biodiversity, ecosystem services and human health triggered several new regulations increasing the need for sound ecotoxicological risk assessment. The PEER network aims to share its view on the research issues that this challenges. PEER scientists call for an improved biologically relevant exposure assessment. They promote comprehensive effect assessment at several biological levels. Biological traits should be used for Environmental risk assessment (ERA) as promising tools to better understand relationships between structure and functioning of ecosystems. The use of modern high throughput methods could also enhance the amount of data for a better risk assessment. Improved models coping with multiple stressors or biological levels are necessary to answer for a more scientifically based risk assessment. Those methods must be embedded within life cycle analysis or economical models for efficient regulations. Joint research programmes involving humanities with ecological sciences should be developed for a sound risk management. (C) 2011 Elsevier Ltd. All rights reserved.
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| 5. |
- Franke, A., et al.
(författare)
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Operationalizing Ocean Health : Toward Integrated Research on Ocean Health and Recovery to Achieve Ocean Sustainability
- 2020
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Ingår i: One Earth. - : Elsevier BV. - 2590-3330 .- 2590-3322. ; 2:6, s. 557-565
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Tidskriftsartikel (refereegranskat)abstract
- Protecting the ocean has become a major goal of international policy as human activities increasingly endanger the integrity of the ocean ecosystem, often summarized as “ocean health.” By and large, efforts to protect the ocean have failed because, among other things, (1) the underlying socio-ecological pathways have not been properly considered, and (2) the concept of ocean health has been ill defined. Collectively, this prevents an adequate societal response as to how ocean ecosystems and their vital functions for human societies can be protected and restored. We review the confusion surrounding the term “ocean health” and suggest an operational ocean-health framework in line with the concept of strong sustainability. Given the accelerating degeneration of marine ecosystems, the restoration of regional ocean health will be of increasing importance. Our advocated transdisciplinary and multi-actor framework can help to advance the implementation of more active measures to restore ocean health and safeguard human health and well-being.
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| 6. |
- Joling, Karlijn J., et al.
(författare)
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Quality indicators for community care for older people : A systematic review
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 13:1
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Forskningsöversikt (refereegranskat)abstract
- Background Health care systems that succeed in preventing long term care and hospital admissions of frail older people may substantially save on their public spending. The key might be found in high-quality care in the community. Quality Indicators (QIs) of a sufficient methodological level are a prerequisite to monitor, compare, and improve care quality. This systematic review identified existing QIs for community care for older people and assessed their methodological quality.Methods Relevant studies were identified by searches in electronic reference databases and selected by two reviewers independently. Eligible publications described the development or application of QIs to assess the quality of community care for older people. Information about the QIs, the study sample, and specific setting was extracted. The methodological quality of the QI sets was assessed with the Appraisal of Indicators through Research and Evaluation (AIRE) instrument. A score of 50% or higher on a domain was considered to indicate high methodological quality. Results Searches resulted in 25 included articles, describing 17 QI sets with 567 QIs. Most indicators referred to care processes (80%) and measured clinical issues (63%), mainly about follow-up, monitoring, examinations and treatment. About two-third of the QIs focussed on specific disease groups. The methodological quality of the indicator sets varied considerably. The highest overall level was achieved on the domain 'Additional evidence, formulation and usage' (51%), followed by 'Scientific evidence' (39%) and 'Stakeholder involvement' (28%).Conclusion A substantial number of QIs is available to assess the quality of community care for older people. However, generic QIs, measuring care outcomes and non-clinical aspects are relatively scarce and most QI sets do not meet standards of high methodological quality. This study can support policy makers and clinicians to navigate through a large number of QIs and select QIs for their purposes.
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| 7. |
- Quin, Jaclyn, et al.
(författare)
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Inhibition of RNA polymerase I transcription initiation by CX-5461 activates non-canonical ATM/ATR signaling
- 2016
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 7:31, s. 49800-49818
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Tidskriftsartikel (refereegranskat)abstract
- RNA polymerase I (Pol I)-mediated transcription of the ribosomal RNA genes (rDNA) is confined to the nucleolus and is a rate-limiting step for cell growth and proliferation. Inhibition of Pol I by CX-5461 can selectively induce p53-mediated apoptosis of tumour cells in vivo. Currently, CX-5461 is in clinical trial for patients with advanced haematological malignancies (Peter Mac, Melbourne). Here we demonstrate that CX-5461 also induces p53-independent cell cycle checkpoints mediated by ATM/ATR signaling in the absence of DNA damage. Further, our data demonstrate that the combination of drugs targeting ATM/ATR signaling and CX-5461 leads to enhanced therapeutic benefit in treating p53-null tumours in vivo, which are normally refractory to each drug alone. Mechanistically, we show that CX-5461 induces an unusual chromatin structure in which transcriptionally competent relaxed rDNA repeats are devoid of transcribing Pol I leading to activation of ATM signaling within the nucleoli. Thus, we propose that acute inhibition of Pol transcription initiation by CX-5461 induces a novel nucleolar stress response that can be targeted to improve therapeutic efficacy.
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| 8. |
- Rehkämper, Mark, et al.
(författare)
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Thallium isotope variations in seawater and hydrogenetic, diagenetic, and hydrothermal ferromanganese deposits
- 2002
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Ingår i: Earth and Planetary Science Letters. - 0012-821X .- 1385-013X. ; 197:1-2
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented for the first in-depth investigation of Tl isotope variations in marine materials. The Tl isotopic measurements were conducted by multiple collector-inductively coupled plasma mass spectrometry for a comprehensive suite of hydrogenetic ferromanganese crusts, diagenetic Fe-Mn nodules, hydrothermal manganese deposits and seawater samples. The natural variability of Tl isotope compositions in these samples exceeds the analytical reproducibility (±0.05‰) by more than a factor of 40. Hydrogenetic Fe-Mn crusts have ε205Tl of +10 to +14, whereas seawater is characterized by values as low as -8 (ε205Tl represents the deviation of the 205Tl/203Tl ratio of a sample from the NIST SRM 997 Tl isotope standard in parts per 104). This 2‰ difference in isotope composition is thought to result from the isotope fractionation that accompanies the adsorption of Tl onto ferromanganese particles. An equilibrium fractionation factor of α1.0021 is calculated for this process. Ferromanganese nodules and hydrothermal manganese deposits have variable Tl isotope compositions that range between the values obtained for seawater and hydrogenetic Fe-Mn crusts. The variability in ε205Tl in diagenetic nodules appears to be caused by the adsorption of Tl from pore fluids, which act as a closed-system reservoir with a Tl isotope composition that is inferred to be similar to seawater. Nodules with ε205Tl values similar to seawater are found if the scavenging of Tl is nearly quantitative. Hydrothermal manganese deposits display a positive correlation between ε205Tl and Mn/Fe. This trend is thought to be due to the derivation of Tl from distinct hydrothermal sources. Deposits with low Mn/Fe ratios and low ε205Tl are produced by the adsorption of Tl from fluids that are sampled close to hydrothermal sources. Such fluids have low Mn/Fe ratios and relatively high temperatures, such that only minor isotope fractionation occurs during adsorption. Hydrothermal manganese deposits with high Mn/Fe and high ε205Tl are generated by scavenging of Tl from colder, more distal hydrothermal fluids. Under such conditions, adsorption is
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| 9. |
- Thörn, Filip, 1992-, et al.
(författare)
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Contemporary intergeneric hybridization and backcrossing among birds-of-paradise
- 2024
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Ingår i: Evolution Letters. - 2056-3744.
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Tidskriftsartikel (refereegranskat)abstract
- Despite large differences in morphology, behavior and lek-mating strategies the birds-of-paradise are known to hybridize occasionally, even across different genera. Many of these bird-of-paradise hybrids were originally described as distinct species based on large morphological differences when compared to recognized species. Nowadays, these specimens are generally recognized as hybrids based on morphological assessments. Having fascinated naturalists for centuries, hybrid specimens of birds-of-paradise have been collected and the specimens kept in Natural History Collections. In the present study, we utilize this remarkable resource in a museomics framework and evaluate the genomic composition of most described intergeneric hybrids and some intrageneric hybrids. We show that the majority of investigated specimens are first-generation hybrids and that the parental species, in most cases, are in line with prior morphological assessments. We also identify two specimens that are the result of introgressive hybridization between different genera. Additionally, two specimens exhibit hybrid morphologies but have no identifiable signals of hybridization, which may indicate that minor levels of introgression can have large morphological effects. Our findings provide direct evidence of contemporary introgressive hybridization taking place between genera of birds-of-paradise in nature, despite markedly different morphologies and lek-mating behaviors.
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| 10. |
- Zhong, Yi, et al.
(författare)
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Humidification of Central Asia and equatorward shifts of westerly winds since the late Pliocene
- 2022
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Ingår i: Communications Earth and Environment. - : Springer Science and Business Media LLC. - 2662-4435. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- The production, transport, and deposition of mineral dust exert major influences on climate change and Earth’s biogeochemical cycles. Furthermore, their imprint, as recorded in pelagic sediments, provides an avenue for determining past changes in terrestrial aridity and atmospheric circulation patterns in response to global climate change. Here, by examining geochemical and magnetic data obtained from a ferromanganese crust in the western Pacific Ocean, we investigate the eolian dust source-region conditions and dust transport mechanisms from the Asian interior to the Pacific Ocean since the Pliocene. We identify a gradual provenance change in the dust source regions, from a dominant Gobi Desert source during the early Pliocene to a mixed Gobi-Taklimakan Desert source during the late Pliocene and Pleistocene, alongside increasing chemical weathering in those source areas. Climate model simulations suggest that these changes were related to an equatorward shift of the westerly jet and humidification of Central Asia during the gradual transition from a warm Pliocene climate to the cool Pleistocene.
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