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| 2. |
- Franchini, Mariagrazia, et al.
(författare)
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The Gaia-ESO Survey : Carbon Abundance in the Galactic Thin and Thick Disks
- 2020
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Ingår i: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 888:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on carbon, which is one of the most abundant elements in the universe and is of high importance in the field of nucleosynthesis and galactic and stellar evolution. The origin of carbon and the relative importance of massive and low- to intermediate-mass stars in producing it is still a matter of debate. We aim at better understanding the origin of carbon by studying the trends of [C/H], [C/Fe], and [C/Mg] versus [Fe/H] and [Mg/H] for 2133 FGK dwarf stars from the fifth Gaia-ESO Survey internal data release (GES iDR5). The availability of accurate parallaxes and proper motions from Gaia DR2 and radial velocities from GES iDR5 allows us to compute Galactic velocities, orbits, absolute magnitudes, and, for 1751 stars, Bayesian-derived ages. Three different selection methodologies have been adopted to discriminate between thin- and thick-disk stars. In all the cases, the two stellar groups show different [C/H], [C/Fe], and [C/Mg] and span different age intervals, with the thick-disk stars being, on average, older than the thin-disk ones. The behaviors of [C/H], [C/Fe], and [C/Mg] versus [Fe/H], [Mg/H], and age all suggest that C is primarily produced in massive stars. The increase of [C/Mg] for young thin-disk stars indicates a contribution from low-mass stars or the increased C production from massive stars at high metallicities due to the enhanced mass loss. The analysis of the orbital parameters R-med and supports an "inside-out" and "upside-down" formation scenario for the disks of the Milky Way.
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| 3. |
- Franchini, Mariagrazia, et al.
(författare)
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The Gaia-ESO Survey : Oxygen Abundance in the Galactic Thin and Thick Disks*
- 2021
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Ingår i: Astronomical Journal. - : Institute of Physics Publishing (IOPP). - 0004-6256 .- 1538-3881. ; 161:1
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Tidskriftsartikel (refereegranskat)abstract
- We analyze the oxygen abundances of a stellar sample representative of the two major Galactic populations: the thin and thick disks. The aim is to investigate the differences between members of the Galactic disks and contribute to the understanding of the origin of oxygen chemical enrichment in the Galaxy. The analysis is based on the [O i] = 6300.30 A oxygen line in high-resolution spectra (R similar to 52,500) obtained from the Gaia-ESO public spectroscopic Survey (GES). By comparing the observed spectra with a theoretical data set computed in LTE with the SPECTRUM synthesis and ATLAS12 codes, we derive the oxygen abundances of 516 FGK dwarfs for which we have previously measured carbon abundances. Based on kinematic, chemical, and dynamical considerations, we identify 20 thin and 365 thick disk members. We study the potential trends of both subsamples in terms of their chemistry ([O/H], [O/Fe], [O/Mg], and [C/O] versus [Fe/H] and [Mg/H]), age, and position in the Galaxy. The main results are that (a) [O/H] and [O/Fe] ratios versus [Fe/H] show systematic differences between thin and thick disk stars with an enhanced O abundance of thick disk stars with respect to thin disk members and a monotonic decrement of [O/Fe] with increasing metallicity, even at metal-rich regime; (b) there is a smooth correlation of [O/Mg] with age in both populations, suggesting that this abundance ratio can be a good proxy of stellar ages within the Milky Way; and (c) thin disk members with [Fe/H] 0 display a [C/O] ratio smaller than the solar value, suggesting a possibly outward migration of the Sun from lower Galactocentric radii.
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| 4. |
- Iovino, Maria Rosa, et al.
(författare)
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Archaeological volcanic glass from the site of Rocchicella (Sicily, Italy)
- 2008
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Ingår i: Archaeometry. - : Wiley-Blackwell. - 0003-813X .- 1475-4754. ; 50:3, s. 474-494
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Tidskriftsartikel (refereegranskat)abstract
- The site of Rocchicella, near Catania, in eastern Sicily, has yielded important archaeological evidence from prehistoric times to the Middle Ages. Extensive archaeological investigations of cultural layers dating from the Palaeo-Mesolithic to the Copper Age have recently been undertaken, and volcanic glass, mainly obsidian, has been collected in the course of excavation. To determine the provenance of this volcanic glass, a non-destructive elemental analysis was carried out to measure the concentration of characteristic trace elements. The analysis was carried out using a new XRF spectrometer equipped with a beam stability controller and a quantitative method developed at the LANDIS laboratory of the INFN–CNR Institutes of Catania. In addition to the obsidian, it was demonstrated for the first time that a local vitreous material similar to obsidian, but displaying a completely different composition, was used during all the investigated periods. This material was identified as a basaltic glass, characterized by a superficial product of devitrification called palagonite. Analysis of the obsidians has led to the identification of the island of Lipari as the provenance source. High- and low-power microscopic use-wear analysis on obsidian and basaltic glass artefacts indicated that soft wood and plant matter might have been processed at the site.
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| 5. |
- Roederer, Ian U., et al.
(författare)
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The discovery space of ELT-ANDES. Stars and stellar populations
- 2024
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Ingår i: Experimental Astronomy. - : Springer. - 0922-6435 .- 1572-9508. ; 57:2
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Tidskriftsartikel (refereegranskat)abstract
- The ArmazoNes high Dispersion Echelle Spectrograph (ANDES) is the optical and near-infrared high-resolution echelle spectrograph envisioned for the Extremely Large Telescope (ELT). We present a selection of science cases, supported by new calculations and simulations, where ANDES could enable major advances in the fields of stars and stellar populations. We focus on three key areas, including the physics of stellar atmospheres, structure, and evolution; stars of the Milky Way, Local Group, and beyond; and the star-planet connection. The key features of ANDES are its wide wavelength coverage at high spectral resolution and its access to the large collecting area of the ELT. These features position ANDES to address the most compelling questions and potentially transformative advances in stellar astrophysics of the decades ahead, including questions which cannot be anticipated today.
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| 6. |
- Tziraki, Chariklia, et al.
(författare)
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Rethinking palliative care in a public health context : addressing the needs of persons with non-communicable chronic diseases
- 2020
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Ingår i: Primary Health Care Research and Development. - : Cambridge University Press. - 1463-4236 .- 1477-1128. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- Non-communicable chronic diseases (NCCDs) are the main cause of morbidity and mortality globally. Demographic aging has resulted in older populations with more complex healthcare needs. This necessitates a multilevel rethinking of healthcare policies, health education and community support systems with digitalization of technologies playing a central role. The European Innovation Partnership on Active and Healthy Aging (A3) working group focuses on well-being for older adults, with an emphasis on quality of life and healthy aging. A subgroup of A3, including multidisciplinary stakeholders in health care across Europe, focuses on the palliative care (PC) model as a paradigm to be modified to meet the needs of older persons with NCCDs. This development paper delineates the key parameters we identified as critical in creating a public health model of PC directed to the needs of persons with NCCDs. This paradigm shift should affect horizontal components of public health models. Furthermore, our model includes vertical components often neglected, such as nutrition, resilience, well-being and leisure activities. The main enablers identified are information and communication technologies, education and training programs, communities of compassion, twinning activities, promoting research and increasing awareness amongst policymakers. We also identified key 'bottlenecks': inequity of access, insufficient research, inadequate development of advance care planning and a lack of co-creation of relevant technologies and shared decision-making. Rethinking PC within a public health context must focus on developing policies, training and technologies to enhance person-centered quality life for those with NCCD, while ensuring that they and those important to them experience death with dignity.
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