| 1. |
- Arnardottir, E. S., et al.
(författare)
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The Sleep Revolution project: the concept and objectives
- 2022
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Ingår i: Journal of Sleep Research. - : Wiley. - 0962-1105 .- 1365-2869. ; 31:4
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Tidskriftsartikel (refereegranskat)abstract
- Obstructive sleep apnea is linked to severe health consequences such as hypertension, daytime sleepiness, and cardiovascular disease. Nearly a billion people are estimated to have obstructive sleep apnea with a substantial economic burden. However, the current diagnostic parameter of obstructive sleep apnea, the apnea-hypopnea index, correlates poorly with related comorbidities and symptoms. Obstructive sleep apnea severity is measured by counting respiratory events, while other physiologically relevant consequences are ignored. Furthermore, as the clinical methods for analysing polysomnographic signals are outdated, laborious, and expensive, most patients with obstructive sleep apnea remain undiagnosed. Therefore, more personalised diagnostic approaches are urgently needed. The Sleep Revolution, funded by the European Union's Horizon 2020 Research and Innovation Programme, aims to tackle these shortcomings by developing machine learning tools to better estimate obstructive sleep apnea severity and phenotypes. This allows for improved personalised treatment options, including increased patient participation. Also, implementing these tools will alleviate the costs and increase the availability of sleep studies by decreasing manual scoring labour. Finally, the project aims to design a digital platform that functions as a bridge between researchers, patients, and clinicians, with an electronic sleep diary, objective cognitive tests, and questionnaires in a mobile application. These ambitious goals will be achieved through extensive collaboration between 39 centres, including expertise from sleep medicine, computer science, and industry and by utilising tens of thousands of retrospectively and prospectively collected sleep recordings. With the commitment of the European Sleep Research Society and Assembly of National Sleep Societies, the Sleep Revolution has the unique possibility to create new standardised guidelines for sleep medicine.
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| 2. |
- Hreinsdottir, S., et al.
(författare)
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Volcanic plume height correlated with magma-pressure change at Grimsvotn Volcano, Iceland
- 2014
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 7:3, s. 214-218
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Tidskriftsartikel (refereegranskat)abstract
- Magma flow during volcanic eruptions causes surface deformation that can be used to constrain the location, geometry and internal pressure evolution of the underlying magmatic source(1). The height of the volcanic plumes during explosive eruptions also varies with magma flow rate, in a nonlinear way(2,3). In May 2011, an explosive eruption at Grimsvotn Volcano, Iceland, erupted about 0.27 km(3) dense-rock equivalent of basaltic magma in an eruption plume that was about 20 km high. Here we use Global Positioning System (GPS) and tilt data, measured before and during the eruption at Grimsvotn Volcano, to show that the rate of pressure change in an underlying magma chamber correlates with the height of the volcanic plume over the course of the eruption. We interpret ground deformation of the volcano, measured by geodesy, to result from a pressure drop within a magma chamber at about 1.7 km depth. We estimate the rate of magma discharge and the associated evolution of the plume height by differentiating the co-eruptive pressure drop with time. The time from the initiation of the pressure drop to the onset of the eruption was about 60 min, with about 25% of the total pressure change preceding the eruption. Near-real-time geodetic observations can thus be useful for both timely eruption warnings and for constraining the evolution of volcanic plumes.
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| 3. |
- Mattsson, H B, et al.
(författare)
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Crustal xenoliths in the 6220 BP Saefell tuff-cone, south Iceland : Evidence for a deep, diatreme-fonning, Surtseyan eruption
- 2005
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Ingår i: Journal of Volcanology and Geothermal Research. - : Elsevier BV. - 0377-0273 .- 1872-6097. ; 145:3-4, s. 234-248
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Tidskriftsartikel (refereegranskat)abstract
- Three types of xenoliths were collected from a 80 in high vertical section of the Refell tuff-cone on Heimaey, Iceland. These types are: alkali basaltic (Type I), sedimentary (Type II) and cpx-bearing basalts (Type III). They are distinct in hand specimen, thin section and geochemistry. Near the base of the eruptive succession only juvenile material and Type I xenoliths are present. The middle section has Type II xenoliths in addition to Type I. Xenoliths of Type III first appear in the uppermost xenolith-rich horizons, where they are found together with all other types. Juvenile Swfell clasts are present in various amounts throughout the investigated section. A downward migration of explosion foci during the eruption is established based on the distribution of the different types of xenoliths in the tuff-cone (i.e. the appearance of Type I-Type II-Type III xenoliths with increasing stratigraphic height) in combination with the observed relations in basement stratigraphy beneath Heimaey. In the beginning of the eruption a combination of high eruption rate and abundant seawater resulted in shallow-seated explosions depositing only juvenile material and Type I xenoliths. The downward migration of explosion foci is suggested to be the result of lowered influx of seawater (due to the formation of a cone that reached 50-75 in a.s.l.) in combination with lowered eruption rate. As the basement stratigraphy beneath Heimaey is well documented by a 1565 in deep drill-hole, the depth of the explosions can be constrained to vary between less than 170 in in the beginning of the eruption and exceeding 820 in in the final phases. This is much deeper than previously reported for any Surtseyan tuff-cone forming eruption and consistent with the downward penetration of a diatreme. (c) 2005 Elsevier B.V. All rights reserved.
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| 4. |
- Mattsson, H B, et al.
(författare)
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Eruption reconstruction, formation of flow-lobe tumuli and eruption duration in the 5900 BP Helgafell lava field (Heimaey), south Iceland
- 2005
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Ingår i: Journal of Volcanology and Geothermal Research. - : Elsevier BV. - 0377-0273 .- 1872-6097. ; 147:1-2, s. 157-172
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Tidskriftsartikel (refereegranskat)abstract
- The 5900 BP Helgafell eruption started with an intense fire-fountaining phase that deposited scoria and spatter near the vent. Spatter accumulated, agglutinated, and was subsequently emplaced. as clastogenic flows. The intense initial phase was followed by effusive emplacement of tube-fed pahoehoe. This type of lava emplacement makes up the bulk of the lava field, and contains abundant inflation features such as tumuli and pressure-ridges. We measured the depths of 358 inflation clefts in tumuli and the thicknesses of the upper-vesicular crust in flow-lobes from the Helgafell lava field. Measurements of altitude between a point-source of lava tubes and the depth of inflation clefts in tumuli suggest that the magmastatic pressure affects initial tumuli formation. The overall growth of tumuli is, however, more dependent on effusion rate and collapse/clogging of individual tubes than on the magmastatic head within tubes. Three areas with abundant tumuli are recognized in the Helgafell lava field, each of which was active for at least 47 days. The average time for tumuli formation is 32 days. Using the crustal measurements of inflation features we test the hypothesis that the total eruption duration can be estimated for a pre-historic volcanic eruption. We chose the Helgafell lava field to test this hypothesis because it has (1) abundant inflation features that are easily measured, and (2) the majority of lava flows emplaced during the eruption are well exposed. Our result shows that the duration of the Helgafell eruption can be estimated to 11-12 months, yielding an average volumetric effusion rate for the Helgafell eruption of 0.05-0.06 km(3)/month. This result is very similar to the effusion rates for two known eruptions in the same volcanic system (i.e. the 1963-1967 Surtsey and the 1973 Eldfell eruptions, with effusion rates of 0.02 and 0.04 km(3)/month, respectively). Given that all three eruptions occurred within the same volcanic system and that they have similar volumetric effusion rates, we suggest that our estimated eruption duration for Helgafell is reasonable. Our results, building on the suggestion by Hon et al. (1994) [Hon, K., Kauhikaua, J., Denlinger, R., MacKay, K., 1994. Emplacement and inflation of pahoehoe sheet flows: observations and measurements of active lava flows on Kilauea Volcano, Hawaii. Geol. Soc. Amer. Bull. 106, 351-370] that the duration of inflation can be estimated for individual flows by measuring inflation features, show that by combining abundant and measureable inflation features with a well-established stratigraphy the duration of an entire pre-historic eruption can be estimated. (c) 2005 Elsevier B.V. All rights reserved.
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