| 1. |
- Coppola, D., et al.
(författare)
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Shallow system rejuvenation and magma discharge trends at Piton de la Fournaise volcano (La Réunion Island)
- 2017
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Ingår i: Earth and Planetary Science Letters. - : Elsevier BV. - 1385-013X .- 0012-821X. ; 463, s. 13-24
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Tidskriftsartikel (refereegranskat)abstract
- Basaltic magma chambers are often characterized by emptying and refilling cycles that influence their evolution in space and time, and the associated eruptive activity. During April 2007, the largest historical eruption of Piton de la Fournaise (Île de La Réunion, France) drained the shallow plumbing system (>240×106 m3) and resulted in collapse of the 1-km-wide summit crater. Following these major events, Piton de la Fournaise entered a seven-year long period of near-continuous deflation interrupted, in June 2014, by a new phase of significant inflation. By integrating multiple datasets (lava discharge rates, deformation, seismicity, gas flux, gas composition, and lava chemistry), we here show that the progressive migration of magma from a deeper (below sea level) storage zone gradually rejuvenated and pressurized the above-sea-level portion of the magmatic system consisting of a vertically-zoned network of relatively small-volume magma pockets. Continuous inflation provoked four small (
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| 2. |
- Conteduca, V., et al.
(författare)
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Plasma tumour DNA as an early indicator of treatment response in metastatic castration-resistant prostate cancer
- 2020
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Ingår i: British Journal of Cancer. - : Springer Science and Business Media LLC. - 0007-0920 .- 1532-1827. ; 123, s. 982-987
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Tidskriftsartikel (refereegranskat)abstract
- Background Plasma tumour DNA (ptDNA) levels on treatment are associated with response in a variety of cancers. However, the role of ptDNA in prostate cancer monitoring remains largely unexplored. Here we characterised on-treatment ptDNA dynamics and evaluated its potential for early assessment of therapy efficacy for metastatic castration-resistant prostate cancer (mCRPC). Methods Between 2011 and 2016, 114 sequential plasma samples from 43 mCRPC abiraterone-treated patients were collected. Targeted next-generation sequencing was performed to determine ptDNA fraction. ptDNA progressive disease was defined as a rise in the fraction compared to the pre-treatment. Results A ptDNA rise in the first on-treatment sample (interquartile range (IQR) 2.6-3.7 months) was significantly associated with increased risk of early radiographic or any prostate-specific antigen (PSA) rise (odds ratio (OR) = 15.8, 95% confidence interval (CI) 3.5-60.2,p = 0.0002 and OR = 6.0, 95% CI 1.6-20.0,p = 0.01, respectively). We also identified exemplar cases that had a rise in PSA or pseudoprogression secondary to bone flare but no rise in ptDNA. In an exploratory analysis, initial ptDNA change was found to associate with the duration of response to prior androgen deprivation therapy (p < 0.0001) but not to prior taxanes (p = 0.32). Conclusions We found that ptDNA assessment for therapy monitoring in mCRPC is feasible and provides data relevant to the clinical setting. Prospective evaluation of these findings is now merited.
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| 3. |
- Harris, A. J L, et al.
(författare)
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Effusive crises at Piton de la Fournaise 2014–2015: a review of a multi-national response model
- 2017
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Ingår i: Journal of Applied Volcanology. - : Springer Science and Business Media LLC. - 2191-5040. ; 6:1
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Forskningsöversikt (refereegranskat)abstract
- Many active European volcanoes and volcano observatories are island-based and located far from their administrative “mainland”. Consequently, Governments have developed multisite approaches, in which monitoring is performed by a network of individuals distributed across several national research centers. At a transnational level, multinational networks are also progressively emerging. Piton de la Fournaise (La Réunion Island, France) is one such example. Piton de la Fournaise is one of the most active volcanoes of the World, and is located at the greatest distance from its “mainland” than any other vulnerable “overseas” site, the observatory being 9365 km from its governing body in Paris. Effusive risk is high, so that a well-coordinated and rapid response involving near-real time delivery of trusted, validated and operational product for hazard assessment is critical. Here we review how near-real time assessments of lava flow propagation were developed using rapid provision, and update, of key source terms through a dynamic and open integration of near-real time remote sensing, modeling and measurement capabilities on both the national and international level. The multi-national system evolved during the five effusive crises of 2014–2015, and is now mature for Piton de la Fournaise. This review allows us to identify strong and weak points in an extended observatory system, and demonstrates that enhanced multi-national integration can have fundamental implications in scientific hazard assessment and response during an on-going effusive crisis.
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| 4. |
- Tuktamyshev, A., et al.
(författare)
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Telecom-wavelength InAs QDs with low fine structure splitting grown by droplet epitaxy on GaAs(111)A vicinal substrates
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 118:13
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Tidskriftsartikel (refereegranskat)abstract
- We present self-assembly of InAs/InAlAs quantum dots by the droplet epitaxy technique on vicinal GaAs(111)A substrates. The small miscut angle, while maintaining the symmetries imposed on the quantum dot from the surface, allows a fast growth rate thanks to the presence of preferential nucleation sites at the step edges. A 100nm InAlAs metamorphic layer with In content >= 50% directly deposited on the GaAs substrate is already almost fully relaxed with a very flat surface. The quantum dots emit at the 1.3 mu m telecom O-band with fine structure splitting as low as 16 mu eV, thus making them suitable as photon sources in quantum communication networks using entangled photons.
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| 5. |
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| 6. |
- Thivet, Simon, et al.
(författare)
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Evidences of Plug Pressurization Enhancing Magma Fragmentation During the September 2016 Basaltic Eruption at Piton de la Fournaise (La Réunion Island, France)
- 2020
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Ingår i: Geochemistry, Geophysics, Geosystems. - 1525-2027. ; 21:2
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Tidskriftsartikel (refereegranskat)abstract
- In September 2016, Piton de la Fournaise volcano, well known for its effusive and Hawaiian fountaining activity, produced, at the end of the eruption, an unusual phase of pulsating ash and bomb emission. Integration of geophysical data, with textural and petrological analysis of the samples, allowed us to constrain the main factors that controlled this sudden shift in activity, potentially dangerous for the tourist population that usually approach these “gentle” eruptive sites. Volcanic tremor, lava discharge rates, fountain heights, and SO2 emission changed rapidly during the eruption. Grain size and componentry of the tephra beds evolved from unimodal all along the sequence to bimodal on the last day of the activity, reflecting the contribution of both Hawaiian fountaining at the main vent (Vent A) and transient explosive activity at the second vent (Vent B). Hawaiian fountaining produced highly vesicular and almost microlite-free tephra (golden pumice and fluidal scoria) while transient explosive activity emitted denser and crystal-rich tephra (sideromelane and tachylite scoria) sometimes mingled with vesicular fragments. Permeability measurements on lapilli and bomb-sized samples reveal that golden pumice and fluidal scoria were more gas-permeable than the sideromelane and tachylite ones, while textural and chemical analyses of the ash support the hypothesis that these sideromelane and tachylite components were inherited from the subsurface crystallization of the initial golden pumice and fluidal scoria components. We thus suggest that Vent B accumulated a plug of degassed, cooled, and low-permeable magma, which modulated overpressure pulses under the late input of ascending magma.
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| 7. |
- Verdurme, Pauline, et al.
(författare)
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Lava Volume from Remote Sensing Data: Comparisons with Reverse Petrological Approaches for Two Types of Effusive Eruption
- 2022
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Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Five effusive eruptions of Piton de la Fournaise (La Réunion) are analyzed to investigate temporal trends of erupted mass and sulfur dioxide (SO2) emissions. Daily SO2 emissions are acquired from three ultraviolet (UV) satellite instruments (the Ozone Monitoring Instrument (OMI), the Ozone Mapping and Profiler Suite (OMPS), and the Tropospheric Monitoring Instrument (TROPOMI)) and an array of ground-based UV spectrometers (Network for Observation of Volcanic and Atmospheric Change (NOVAC)). Time-averaged lava discharge rates (TADRs) are obtained from two automatic satellite-based hot spot detection systems: MIROVA and MODVOLC. Assuming that the lava volumes measured in the field are accurate, the MIROVA system gave the best estimation of erupted volume among the methods investigated. We use a reverse petrological method to constrain pre-eruptive magmatic sulfur contents based on observed SO2 emissions and lava volumes. We also show that a direct petrological approach using SO2 data might be a viable alternative for TADR estimation during cloudy weather that compromises hot spot detection. In several eruptions we observed a terminal increase in TADR and SO2 emissions after initial emission of evolved degassed magma. We ascribe this to input of deeper, volatile-rich magma into the plumbing system towards the end of these eruptions. Furthermore, we find no evidence of volatile excess in the five eruptions studied, which were thus mostly fed by shallow degassed magma.
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