| 1. |
- Coxall, Helen K., et al.
(author)
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The Eocene-Oligocene transition in Nanggulan, Java : lithostratigraphy, biostratigraphy and foraminiferal stable isotopes
- 2021
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In: Journal of the Geological Society. - : Geological Society of London. - 0016-7649 .- 2041-479X. ; 178:6
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Journal article (peer-reviewed)abstract
- The Nanggulan section in south central Java comprises open marine sediments and volcanic deposits of Eocene-Oligocene age that accumulated in a marginal basin within the young Sunda Arc complex. A new borehole captures the stratigraphy and showcases the exceptional preservation of calcareous microfossils across an apparently complete Eocene-Oligocene Transition (EOT), a time interval significant for the initiation of continental-scale glaciation on Antarctica. Low-resolution benthic and planktonic foraminifera oxygen and carbon stable isotopes (delta O-18 and delta C-13) record increasing delta O-18 and delta C-13 in the basal Oligocene, allowing correlation to global records. Isotopic values imply warm temperatures and relatively high nutrients along the SE Java margin. The Nanggulan EOT is a valuable archive for reconstructing ocean-climate behaviour and plankton evolution and extinction in the Indo-Pacific Warm Pool. The borehole also adds to understanding of the early stages of Sunda Arc volcanism.
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| 2. |
- Filippou, Georgios, et al.
(author)
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The predictive role of ultrasound-detected tenosynovitis and joint synovitis for flare in patients with rheumatoid arthritis in stable remission. Results of an Italian multicentre study of the Italian Society for Rheumatology Group for Ultrasound : The STARTER study
- 2018
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In: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 77:9, s. 1283-1289
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Journal article (peer-reviewed)abstract
- Objective: To define the role of ultrasound (US) for the assessment of patients with rheumatoid arthritis (RA) in clinical remission, including joint and tendon evaluation. Methods: A multicentre longitudinal study has been promoted by the US Study Group of the Italian Society for Rheumatology. 25 Italian centres participated, enrolling consecutive patients with RA in clinical remission. All patients underwent complete clinical assessment (demographic data, disease characteristics, laboratory exams, clinical assessment of 28 joints and patient/physician-reported outcomes) and Power Doppler (PD) US evaluation of wrist, metacarpalphalangeal joints, proximal interphalangeal joints and synovial tendons of the hands and wrists at enrolment, 6 and 12 months. The association between clinical and US variables with flare, disability and radiographic progression was evaluated by univariable and adjusted logistic regression models. Results: 361 patients were enrolled, the mean age was 56.20 (±13.31) years and 261 were women, with a mean disease duration of 9.75 (±8.07) years. In the 12 months follow-up, 98/326 (30.1%) patients presented a disease flare. The concurrent presence of PD positive tenosynovitis and joint synovitis predicted disease flare, with an OR (95% CI) of 2.75 (1.45 to 5.20) in crude analyses and 2.09 (1.06 to 4.13) in adjusted analyses. US variables did not predict the worsening of function or radiographic progression. US was able to predict flare at 12 months but not at 6 months. Conclusions: PD positivity in tendons and joints is an independent risk factor of flare in patients with RA in clinical remission. Musculoskeletal ultrasound evaluation is a valuable tool to monitor and help decision making in patients with RA in clinical remission.
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| 3. |
- Hutchinson, David K., et al.
(author)
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The Eocene-Oligocene transition : a review of marine and terrestrial proxy data, models and model data comparisons
- 2021
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In: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 17:1, s. 269-315
-
Research review (peer-reviewed)abstract
- The Eocene-Oligocene transition (EOT) was a climate shift from a largely ice-free greenhouse world to an icehouse climate, involving the first major glaciation of Antarctica and global cooling occurring similar to 34 million years ago (Ma) and lasting similar to 790 kyr. The change is marked by a global shift in deep-sea delta O-18 representing a combination of deep-ocean cooling and growth in land ice volume. At the same time, multiple independent proxies for ocean temperature indicate sea surface cooling, and major changes in global fauna and flora record a shift toward more cold-climateadapted species. The two principal suggested explanations of this transition are a decline in atmospheric CO2 and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. Here we review and synthesise proxy evidence of palaeogeography, temperature, ice sheets, ocean circulation and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively compare proxy records of change to an ensemble of climate model simulations of temperature change across the EOT. The simulations compare three forcing mechanisms across the EOT: CO2 decrease, palaeogeographic changes and ice sheet growth. Our model ensemble results demonstrate the need for a global cooling mechanism beyond the imposition of an ice sheet or palaeogeographic changes. We find that CO2 forcing involving a large decrease in CO2 of ca. 40 % (similar to 325 ppm drop) provides the best fit to the available proxy evidence, with ice sheet and palaeogeographic changes playing a secondary role. While this large decrease is consistent with some CO2 proxy records (the extreme endmember of decrease), the positive feedback mechanisms on ice growth are so strong that a modest CO2 decrease beyond a critical threshold for ice sheet initiation is well capable of triggering rapid ice sheet growth. Thus, the amplitude of CO2 decrease signalled by our data-model comparison should be considered an upper estimate and perhaps artificially large, not least because the current generation of climate models do not include dynamic ice sheets and in some cases may be undersensitive to CO2 forcing. The model ensemble also cannot exclude the possibility that palaeogeographic changes could have triggered a reduction in CO2.
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| 4. |
- Hutchinson, David K., et al.
(author)
-
The Eocene-Oligocene transition: a review of marine and terrestrial proxy data, models and model-data comparisons
- 2021
-
In: Climate of the Past. - : European Geosciences Union (EGU). - 1814-9324 .- 1814-9332. ; 17:1, s. 269-315
-
Journal article (peer-reviewed)abstract
- The Eocene–Oligocene transition (EOT) was a climate shift from a largely ice-free greenhouse world to an icehouse climate, involving the first major glaciation of Antarctica and global cooling occurring ∼ 34 million years ago (Ma) and lasting ∼ 790 kyr. The change is marked by a global shift in deep-sea δ18O representing a combination of deep-ocean cooling and growth in land ice volume. At the same time, multiple independent proxies for ocean tempera- ture indicate sea surface cooling, and major changes in global fauna and flora record a shift toward more cold-climate- adapted species. The two principal suggested explanations of this transition are a decline in atmospheric CO2 and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. Here we review and synthesise proxy evidence of palaeogeography, temperature, ice sheets, ocean circulation and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively com- pare proxy records of change to an ensemble of climate model simulations of temperature change across the EOT. The simulations compare three forcing mechanisms across the EOT: CO2 decrease, palaeogeographic changes and ice sheet growth. Our model ensemble results demonstrate the need for a global cooling mechanism beyond the imposition of an ice sheet or palaeogeographic changes. We find that CO2 forcing involving a large decrease in CO2 of ca. 40 % (∼ 325 ppm drop) provides the best fit to the available proxy evidence, with ice sheet and palaeogeographic changes play- ing a secondary role. While this large decrease is consistent with some CO2 proxy records (the extreme endmember of decrease), the positive feedback mechanisms on ice growth are so strong that a modest CO2 decrease beyond a critical threshold for ice sheet initiation is well capable of triggering rapid ice sheet growth. Thus, the amplitude of CO2 decrease signalled by our data–model comparison should be consid- ered an upper estimate and perhaps artificially large, not least because the current generation of climate models do not in- clude dynamic ice sheets and in some cases may be under- sensitive to CO2 forcing. The model ensemble also cannot exclude the possibility that palaeogeographic changes could have triggered a reduction in CO2.
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