| 51. |
- Buder, Sven, et al.
(författare)
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The GALAH Survey : second data release
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966. ; 478:4, s. 4513-4552
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Tidskriftsartikel (refereegranskat)abstract
- The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic survey of the Milky Way, designed to deliver complementary chemical information to a large number of stars covered by the Gaia mission. We present the GALAH second public data release (GALAH DR2) containing 342 682 stars. For these stars, the GALAH collaboration provides stellar parameters and abundances for up to 23 elements to the community. Here we present the target selection, observation, data reduction, and detailed explanation of how the spectra were analysed to estimate stellar parameters and element abundances. For the stellar analysis, we have used a multistep approach. We use the physics-driven spectrum synthesis of Spectroscopy Made Easy (SME) to derive stellar labels (T-eff, log g, [Fe/H], [X/Fe], v(mic), vsin i, AKS) for a representative training set of stars. This information is then propagated to the whole sample with the data-driven method of The Cannon. Special care has been exercised in the spectral synthesis to only consider spectral lines that have reliable atomic input data and are little affected by blending lines. Departures from local thermodynamic equilibrium (LTE) are considered for several key elements, including Li, O, Na, Mg, Al, Si, and Fe, using 1D MARCS stellar atmosphere models. Validation tests including repeat observations, Gaia benchmark stars, open and globular clusters, and K2 asteroseismic targets lend confidence to our methods and results. Combining the GALAH DR2 catalogue with the kinematic information from Gaia will enable a wide range of Galactic Archaeology studies, with unprecedented detail, dimensionality, and scope.
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| 52. |
- Fronczek, Jakub, et al.
(författare)
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Relationship between the Clinical Frailty Scale and short-term mortality in patients ≥ 80 years old acutely admitted to the ICU : a prospective cohort study
- 2021
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Ingår i: Critical Care. - : BioMed Central (BMC). - 1364-8535 .- 1466-609X. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Clinical Frailty Scale (CFS) is frequently used to measure frailty in critically ill adults. There is wide variation in the approach to analysing the relationship between the CFS score and mortality after admission to the ICU. This study aimed to evaluate the influence of modelling approach on the association between the CFS score and short-term mortality and quantify the prognostic value of frailty in this context.METHODS: We analysed data from two multicentre prospective cohort studies which enrolled intensive care unit patients ≥ 80 years old in 26 countries. The primary outcome was mortality within 30-days from admission to the ICU. Logistic regression models for both ICU and 30-day mortality included the CFS score as either a categorical, continuous or dichotomous variable and were adjusted for patient's age, sex, reason for admission to the ICU, and admission Sequential Organ Failure Assessment score.RESULTS: The median age in the sample of 7487 consecutive patients was 84 years (IQR 81-87). The highest fraction of new prognostic information from frailty in the context of 30-day mortality was observed when the CFS score was treated as either a categorical variable using all original levels of frailty or a nonlinear continuous variable and was equal to 9% using these modelling approaches (p < 0.001). The relationship between the CFS score and mortality was nonlinear (p < 0.01).CONCLUSION: Knowledge about a patient's frailty status adds a substantial amount of new prognostic information at the moment of admission to the ICU. Arbitrary simplification of the CFS score into fewer groups than originally intended leads to a loss of information and should be avoided. Trial registration NCT03134807 (VIP1), NCT03370692 (VIP2).
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| 53. |
- Fronczek, Jakub, et al.
(författare)
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Short-term mortality or patients >= 80 years old admitted to European intensive care units: an international observational study
- 2022
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Ingår i: British Journal of Anaesthesia. - : ELSEVIER SCI LTD. - 0007-0912 .- 1471-6771. ; 129:1, s. 58-66
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Tidskriftsartikel (refereegranskat)abstract
- Background: Limited evidence suggests variation in mortality of older critically ill adults across Europe. We aimed to investigate regional differences in mortality among very old ICU patients. Methods: Multilevel analysis of two international prospective cohort studies. We included patients >= 80 yr old from 322 ICUs located in 16 European countries. The primary outcome was mortality within 30 days from admission to the ICU. Results are presented as n (%) with 95% confidence intervals and odds ratios (ORs). Results: Of 8457 patients, 2944 (36.9% [35.9-38.0%]) died within 30 days. Crude mortality rates varied widely between participating countries (from 10.1% [6.4-15.6%] to 45.1% [41.1-49.2%] in the ICU and from 21.3% [16.3-28.9%] to 55.3% [51.1-59.5%] within 30 days). After adjustment for confounding variables, the variation in 30-day mortality between countries was substantially smaller than between ICUs (median OR 1.14 vs 1.58). Healthcare expenditure per capita (OR=0.84 per $1000 [0.75-0.94]) and social health insurance framework (OR=1.43 [1.01-2.01]) were associated with ICU mortality, but the direction and magnitude of these relationships was uncertain in 30-day follow-up. Volume of admissions was associated with lower mortality both in the ICU (OR=0.81 per 1000 annual ICU admissions [0.71-0.94]) and in 30-day follow-up (OR=0.86 [0.76-0.97]). Conclusion: The apparent variation in short-term mortality rates of older adults hospitalised in ICUs across Europe can be largely attributed to differences in the clinical profile of patients admitted. The volume-outcome relationship identified in this population requires further investigation.
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| 54. |
- Hampton, Stephanie E., et al.
(författare)
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Ecology under lake ice
- 2017
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 20:1, s. 98-111
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Forskningsöversikt (refereegranskat)abstract
- Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer ‘growing seasons’. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass.
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| 55. |
- Koenig, Julian, et al.
(författare)
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Cortical thickness and resting-state cardiac function across the lifespan : A cross-sectional pooled mega-analysis
- 2021
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Ingår i: Psychophysiology. - : Wiley. - 0048-5772 .- 1469-8986 .- 1540-5958. ; 58:7
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the association between autonomic nervous system [ANS] function and brain morphology across the lifespan provides important insights into neurovisceral mechanisms underlying health and disease. Resting-state ANS activity, indexed by measures of heart rate [HR] and its variability [HRV] has been associated with brain morphology, particularly cortical thickness [CT]. While findings have been mixed regarding the anatomical distribution and direction of the associations, these inconsistencies may be due to sex and age differences in HR/HRV and CT. Previous studies have been limited by small sample sizes, which impede the assessment of sex differences and aging effects on the association between ANS function and CT. To overcome these limitations, 20 groups worldwide contributed data collected under similar protocols of CT assessment and HR/HRV recording to be pooled in a mega-analysis (N = 1,218 (50.5% female), mean age 36.7 years (range: 12–87)). Findings suggest a decline in HRV as well as CT with increasing age. CT, particularly in the orbitofrontal cortex, explained additional variance in HRV, beyond the effects of aging. This pattern of results may suggest that the decline in HRV with increasing age is related to a decline in orbitofrontal CT. These effects were independent of sex and specific to HRV; with no significant association between CT and HR. Greater CT across the adult lifespan may be vital for the maintenance of healthy cardiac regulation via the ANS—or greater cardiac vagal activity as indirectly reflected in HRV may slow brain atrophy. Findings reveal an important association between CT and cardiac parasympathetic activity with implications for healthy aging and longevity that should be studied further in longitudinal research.
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| 56. |
- Leclere, David, et al.
(författare)
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Bending the curve of terrestrial biodiversity needs an integrated strategy
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 585:7826, s. 551-556
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Tidskriftsartikel (refereegranskat)abstract
- Increased efforts are required to prevent further losses to terrestrial biodiversity and the ecosystem services that it provides(1,2). Ambitious targets have been proposed, such as reversing the declining trends in biodiversity(3); however, just feeding the growing human population will make this a challenge(4). Here we use an ensemble of land-use and biodiversity models to assess whether-and how-humanity can reverse the declines in terrestrial biodiversity caused by habitat conversion, which is a major threat to biodiversity(5). We show that immediate efforts, consistent with the broader sustainability agenda but of unprecedented ambition and coordination, could enable the provision of food for the growing human population while reversing the global terrestrial biodiversity trends caused by habitat conversion. If we decide to increase the extent of land under conservation management, restore degraded land and generalize landscape-level conservation planning, biodiversity trends from habitat conversion could become positive by the mid-twenty-first century on average across models (confidence interval, 2042-2061), but this was not the case for all models. Food prices could increase and, on average across models, almost half (confidence interval, 34-50%) of the future biodiversity losses could not be avoided. However, additionally tackling the drivers of land-use change could avoid conflict with affordable food provision and reduces the environmental effects of the food-provision system. Through further sustainable intensification and trade, reduced food waste and more plant-based human diets, more than two thirds of future biodiversity losses are avoided and the biodiversity trends from habitat conversion are reversed by 2050 for almost all of the models. Although limiting further loss will remain challenging in several biodiversity-rich regions, and other threats-such as climate change-must be addressed to truly reverse the declines in biodiversity, our results show that ambitious conservation efforts and food system transformation are central to an effective post-2020 biodiversity strategy. To promote the recovery of the currently declining global trends in terrestrial biodiversity, increases in both the extent of land under conservation management and the sustainability of the global food system from farm to fork are required.
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| 57. |
- Mehrtens, Nicola, et al.
(författare)
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The XMM Cluster Survey : optical analysis methodology and the first data release
- 2012
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 423:2, s. 1024-1052
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Tidskriftsartikel (refereegranskat)abstract
- The XMM Cluster Survey (XCS) is a serendipitous search for galaxy clusters using all publicly available data in the XMMNewton Science Archive. Its main aims are to measure cosmological parameters and trace the evolution of X-ray scaling relations. In this paper we present the first data release from the XMM Cluster Survey (XCS-DR1). This consists of 503 optically confirmed, serendipitously detected, X-ray clusters. Of these clusters, 256 are new to the literature and 357 are new X-ray discoveries. We present 463 clusters with a redshift estimate (0.06 < z < 1.46), including 261 clusters with spectroscopic redshifts. The remainder have photometric redshifts. In addition, we have measured X-ray temperatures (TX) for 401 clusters (0.4 < TX < 14.7 keV). We highlight seven interesting subsamples of XCS-DR1 clusters: (i) 10 clusters at high redshift (z > 1.0, including a new spectroscopically confirmed cluster at z= 1.01); (ii) 66 clusters with high TX (>5 keV); (iii) 130 clusters/groups with low TX (<2 keV); (iv) 27 clusters with measured TX values in the Sloan Digital Sky Survey (SDSS) Stripe 82 co-add region; (v) 77 clusters with measured TX values in the Dark Energy Survey region; (vi) 40 clusters detected with sufficient counts to permit mass measurements (under the assumption of hydrostatic equilibrium); (vii) 104 clusters that can be used for applications such as the derivation of cosmological parameters and the measurement of cluster scaling relations. The X-ray analysis methodology used to construct and analyse the XCS-DR1 cluster sample has been presented in a companion paper, Lloyd-Davies et al.
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| 58. |
- Perley, Daniel A., et al.
(författare)
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The fast, luminous ultraviolet transient AT2018cow : extreme supernova, or disruption of a star by an intermediate-mass black hole?
- 2019
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 484:1, s. 1031-1049
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Tidskriftsartikel (refereegranskat)abstract
- Wide-field optical surveys have begun to uncover large samples of fast (t(rise) less than or similar to 5 d), luminous (M-peak < 18), blue transients. While commonly attributed to the breakout of a supernova shock into a dense wind, the great distances to the transients of this class found so far have hampered detailed investigation of their properties. We present photometry and spectroscopy from a comprehensive worldwide campaign to observe AT 2018cow (ATLAS 18qqn), the first fast-luminous optical transient to be found in real time at low redshift. Our first spectra (<2 days after discovery) are entirely featureless. A very broad absorption feature suggestive of near-relativistic velocities develops between 3 and 8 days, then disappears. Broad emission features of H and He develop after >10 days. The spectrum remains extremely hot throughout its evolution, and the photospheric radius contracts with time (receding below R < 10 (14) cm after 1 month). This behaviour does not match that of any known supernova, although a relativistic jet within a fallback supernova could explain some of the observed features. Alternatively, the transient could originate from the disruption of a star by an intermediate-mass black hole, although this would require long-lasting emission of highly super-Eddington thermal radiation. In either case, AT 2018cow suggests that the population of fast luminous transients represents a new class of astrophysical event. Intensive follow-up of this event in its late phases, and of any future events found at comparable distance, will be essential to better constrain their origins.
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| 59. |
- Quillen, Alice C., et al.
(författare)
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The GALAH survey : stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere, and metallicity
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966. ; 478:1, s. 228-254
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Tidskriftsartikel (refereegranskat)abstract
- Using GALAH (GALactic Archaeology with HERMES) survey data of nearby stars, we look at how structure in the planar (u, v) velocity distribution depends on metallicity and on viewing direction within the Galaxy. In nearby stars with distance d less than or similar to 1 kpc, the Hercules stream is most strongly seen in higher metallicity stars [Fe/H] > 0.2. The Hercules stream peak v value depends on viewed galactic longitude, which we interpret as due to the gap between the stellar stream and more circular orbits being associated with a specific angular momentum value of about 16.40 km s(-1) kpc. The association of the gap with a particular angular momentum value supports a bar resonant model for the Hercules stream. Moving groups previously identified in Hipparcos (High Precision Parallax COllecting Satellite) observations are easiest to see in stars nearer than 250 pc, and their visibility and peak velocities in the velocity distributions depends on both viewing direction (galactic longitude and hemisphere) and metallicity. We infer that there is fine structure in local velocity distributions that varies over distances of a few hundred pc in the Galaxy.
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| 60. |
- Su, Zhan, et al.
(författare)
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Common variants at the MHC locus and at chromosome 16q24.1 predispose to Barrett's esophagus.
- 2012
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:10
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Tidskriftsartikel (refereegranskat)abstract
- Barrett's esophagus is an increasingly common disease that is strongly associated with reflux of stomach acid and usually a hiatus hernia, and it strongly predisposes to esophageal adenocarcinoma (EAC), a tumor with a very poor prognosis. We report the first genome-wide association study on Barrett's esophagus, comprising 1,852 UK cases and 5,172 UK controls in the discovery stage and 5,986 cases and 12,825 controls in the replication stage. Variants at two loci were associated with disease risk: chromosome 6p21, rs9257809 (Pcombined=4.09×10(-9); odds ratio (OR)=1.21, 95% confidence interval (CI)=1.13-1.28), within the major histocompatibility complex locus, and chromosome 16q24, rs9936833 (Pcombined=2.74×10(-10); OR=1.14, 95% CI=1.10-1.19), for which the closest protein-coding gene is FOXF1, which is implicated in esophageal development and structure. We found evidence that many common variants of small effect contribute to genetic susceptibility to Barrett's esophagus and that SNP alleles predisposing to obesity also increase risk for Barrett's esophagus.
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