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- Valenti, S., et al.
(författare)
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PESSTO spectroscopic classification of La Silla-Quest Transients
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- PESSTO is the "Public ESO Spectroscopic Survey of Transient Objects" (http://www.pessto.org) using the ESO New Technology Telescope (NTT) at La Silla and the EFOSC2 (optical) and SOFI (near-IR) spectrographs. It is one of two currently running public spectroscopic surveys at ESO. The survey details are as follows: - PESSTO has 90 nights per year on the NTT: 9 lunations (August to April), 10 nights per lunation (we are not observing May-July).
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| 2. |
- Prentice, S. J., et al.
(författare)
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Investigating the properties of stripped-envelope supernovae; what are the implications for their progenitors?
- 2019
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 485:2, s. 1559-1578
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Tidskriftsartikel (refereegranskat)abstract
- We present observations and analysis of 18 stripped-envelope supernovae observed during 2013-2018. This sample consists of five H/He-rich SNe, sixH-poor/He-rich SNe, three narrow lined SNe Ic, and four broad lined SNe Ic. The peak luminosity and characteristic time-scales of the bolometric light curves are calculated, and the light curves modelled to derive Ni-56 and ejecta masses (M-Ni and M-cj). Additionally, the temperature evolution and spectral line velocity curves of each SN are examined. Analysis of the [O I] line in the nebular phase of eight SNe suggests their progenitors had initial masses < 20 M-circle dot. The bolometric light curve properties are examined in combination with those of other SE events from the literature. The resulting data set gives the M-ej distribution for 80 SE-SNe, the largest such sample in the literature to date, and shows that SNe Ib have the lowest median M-ej, followed by narrow-lined SNe Ic, H/He-rich SNe, broad-lined SNe Ic, and finally gamma-ray burst SNe. SNe Ic-6/7 show the largest spread of M-ej ranging from similar to 1.2-11 M-circle dot, considerably greater than any other subtype. For all SE-SNe = 2.8 +/- 1.5 M-circle dot which further strengthens the evidence that SE-SNe arise from low-mass progenitors which are typically <5 M-circle dot at the time of explosion, again suggesting M-ZAMS < 25 M-circle dot. The low and lack of clear bimodality in the distribution implies < 30 M-circle dot progenitors and that envelope stripping via binary interaction is the dominant evolutionary pathway of these SNe.
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| 3. |
- Ventura, P., et al.
(författare)
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Gas and dust from extremely metal-poor AGB stars
- 2021
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 655
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Tidskriftsartikel (refereegranskat)abstract
- Context. The study of stars that evolve through the asymptotic giant branch (AGB) proves crucial in several astrophysical contexts because these objects provide important feedback to the host system in terms of the gas that is poured into the interstellar medium after being exposed to contamination from nucleosynthesis processes, and in terms of the dust that forms in their wind. Most of the studies conducted so far have been focused on AGB stars with solar and sub-solar chemical composition, whereas the extremely metal-poor domain has been poorly explored. Aims. We study the evolution of extremely metal-poor AGB stars with metallicities down to [Fe/H] = -5 to understand the main evolutionary properties and the efficiency of the processes able to alter their surface chemical composition, and to determine the gas and dust yields. Methods. We calculated two sets of evolutionary sequences of stars in the 1-7.5M(circle dot) mass range that evolved from the pre-main sequence to the end of the AGB phase. To explore the extremely metal-poor chemistries, we adopted the metallicities Z= 3 x 10(-5) and Z= 3 x 10(-7), which correspond to [Fe/H]= -3 and [Fe/H]= -5, respectively. The results from stellar evolution modelling were used to calculate the yields of the individual chemical species. We also modelled dust formation in the wind to determine the dust produced by these objects. Results. The evolution of AGB stars in the extremely metal-poor domain we explored proves highly sensitive to the initial mass of the star. M <= 2 M-circle dot stars experience several third-dredge-up events, which favour the gradual surface enrichment of C-12 and the formation of significant quantities of carbonaceous dust, similar to 0.01 M-circle dot. The C-13 and nitrogen yields are found to be significantly smaller than in previous explorations of low-mass metal-poor AGB stars because the proton ingestion episodes experienced during the initial AGB phases are weaker. M >= 5 M-circle dot stars experience hot bottom burning, and their surface chemistry reflects the equilibria of a very advanced proton-capture nucleosynthesis; little dust production takes place in their wind. Intermediate-mass stars experience both third dredge-up and hot bottom burning: they prove efficient producers of nitrogen, which is formed by proton captures on C-12 nuclei of primary origin dredged up from the internal regions.
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| 4. |
- Magrini, L., et al.
(författare)
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The Gaia -ESO Survey : radial distribution of abundances in the Galactic disc from open clusters and young-field stars
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 603
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Tidskriftsartikel (refereegranskat)abstract
- Context. The spatial distribution of elemental abundances in the disc of our Galaxy gives insights both on its assembly process and subsequent evolution, and on the stellar nucleogenesis of the different elements. Gradients can be traced using several types of objects as, for instance, (young and old) stars, open clusters, HII regions, planetary nebulae. Aims. We aim to trace the radial distributions of abundances of elements produced through different nucleosynthetic channels - the α-elements O, Mg, Si, Ca and Ti, and the iron-peak elements Fe, Cr, Ni and Sc - by use of the Gaia-ESO IDR4 results for open clusters and young-field stars. Methods. From the UVES spectra of member stars, we have determined the average composition of clusters with ages > 0.1 Gyr. We derived statistical ages and distances of field stars. We traced the abundance gradients using the cluster and field populations and compared them with a chemo-dynamical Galactic evolutionary model. Results. The adopted chemo-dynamical model, with the new generation of metallicity-dependent stellar yields for massive stars, is able to reproduce the observed spatial distributions of abundance ratios, in particular the abundance ratios of [O/Fe] and [Mg/Fe] in the inner disc (5 kpc
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| 12. |
- Timmermans, EJ, et al.
(författare)
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The Influence of Weather Conditions on Joint Pain in Older People with Osteoarthritis: Results from the European Project on OSteoArthritis
- 2015
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Ingår i: The Journal of rheumatology. - : The Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 42:10, s. 1885-1892
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Tidskriftsartikel (refereegranskat)abstract
- This study examined whether daily weather conditions, 3-day average weather conditions, and changes in weather conditions influence joint pain in older people with osteoarthritis (OA) in 6 European countries.Methods.Data from the population-based European Project on OSteoArthritis were used. The American College of Rheumatology classification criteria were used to diagnose OA in older people (65–85 yrs). After the baseline interview, at 6 months, and after the 12–18 months followup interview, joint pain was assessed using 2-week pain calendars. Daily values for temperature, precipitation, atmospheric pressure, relative humidity, and wind speed were obtained from local weather stations. Multilevel regression modelling was used to examine the pain-weather associations, adjusted for several confounders.Results.The study included 810 participants with OA in the knee, hand, and/or hip. After adjustment, there were significant associations of joint pain with daily average humidity (B = 0.004, p < 0.01) and 3-day average humidity (B = 0.004, p = 0.01). A significant interaction effect was found between daily average humidity and temperature on joint pain. The effect of humidity on pain was stronger in relatively cold weather conditions. Changes in weather variables between 2 consecutive days were not significantly associated with reported joint pain.Conclusion.The associations between pain and daily average weather conditions suggest that a causal relationship exist between joint pain and weather variables, but the associations between day-to-day weather changes and pain do not confirm causation. Knowledge about the relationship between joint pain in OA and weather may help individuals with OA, physicians, and therapists to better understand and manage fluctuations in pain.
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| 13. |
- Timmermans, EJ, et al.
(författare)
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The Influence of Weather Conditions on Outdoor Physical Activity Among Older People With and Without Osteoarthritis in 6 European Countries
- 2016
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Ingår i: Journal of physical activity & health. - : Human Kinetics. - 1543-5474 .- 1543-3080. ; 13:12, s. 1385-1395
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Tidskriftsartikel (refereegranskat)abstract
- Older adults with osteoarthritis (OA) often report that their disease symptoms are exacerbated by weather conditions. This study examines the association between outdoor physical activity (PA) and weather conditions in older adults from 6 European countries and assesses whether outdoor PA and weather conditions are more strongly associated in older persons with OA than in those without the condition.Methods:The American College of Rheumatology classification criteria were used to diagnose OA. Outdoor PA was assessed using the LASA Physical Activity Questionnaire. Data on weather parameters were obtained from weather stations.Results:Of the 2439 participants (65–85 years), 29.6% had OA in knee, hand and/or hip. Participants with OA spent fewer minutes in PA than participants without OA (Median = 42.9, IQR = 20.0 to 83.1 versus Median = 51.4, IQR = 23.6 to 98.6; P < .01). In the full sample, temperature (B = 1.52; P < .001) and relative humidity (B = –0.77; P < .001) were associated with PA. Temperature was more strongly associated with PA in participants without OA (B = 1.98; P < .001) than in those with the condition (B = 0.48; P = .47).Conclusions:Weather conditions are associated with outdoor PA in older adults in the general population. Outdoor PA and weather conditions were more strongly associated in older adults without OA than in their counterparts with OA.
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| 15. |
- Trevisan, Caterina, et al.
(författare)
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Judgment Capacity, Fear of Falling, and the Risk of Falls in Community-Dwelling Older Adults : The Progetto Veneto Anziani Longitudinal Study
- 2020
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Ingår i: Rejuvenation Research. - : Mary Ann Liebert Inc. - 1549-1684 .- 1557-8577. ; 23:3, s. 237-244
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Tidskriftsartikel (refereegranskat)abstract
- Little is known of the factors that transform fear of falling (FOF) from a normal adaptive to a maladaptive response that could alter its impact on fall risk. Focusing on judgment capacity, we investigated whether it is associated with FOF and FOF-related activity restriction (AR), and whether it modifies the influence of FOF on fall risk. Data came from 2625 community-dwelling older adults enrolled in the Progetto Veneto Anziani. Baseline FOF and AR were assessed through personal interviews, and judgment capacity-high, moderate, or poor-through situational tests. At follow-up after 4.4 years, self-reported falls during the previous year were recorded. The associations between judgment and FOF/AR, and between FOF and the risk of at least one fall or recurrent falls (two or more falls), stratified by judgment capacity, were evaluated using multinomial logistic regressions. Compared with high-judgment participants, lower judgment participants were 20% more likely to report FOF; moderate judgment participants were 54% more likely and poor judgment participants twice as likely to report AR. After adjusting for potential confounders, including physical activity and physical performance, FOF increased the reporting of at least one fall only in the poor judgment group. The association between FOF and recurrent falls was stronger in individuals with poor (odds ratio [OR] = 3.66, 95% confidence interval [CI]: 2.10-6.36) than with moderate (OR = 2.81, 95% CI: 2.22-3.55) or high (OR = 1.65, 95% CI: 1.48-1.83) judgment. Poor judgment capacity increases the probability of FOF and AR in older adults, and may exacerbate the effect of FOF in increasing fall risk.
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