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| 2. |
- Franciosini, E., et al.
(författare)
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The Gaia-ESO Survey : Lithium measurements and new curves of growth
- 2022
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 668
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Tidskriftsartikel (refereegranskat)abstract
- Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey that was carried out using the multi-object FLAMES spectrograph at the Very Large Telescope. The survey provides accurate radial velocities, stellar parameters, and elemental abundances for ~115 000 stars in all Milky Way components.Aims. In this paper, we describe the method adopted in the final data release to derive lithium equivalent widths (EWs) and abundances.Methods. Lithium EWs were measured using two different approaches for FGK and M-type stars, to account for the intrinsic differences in the spectra. For FGK stars, we fitted the lithium line using Gaussian components, while direct integration over a predefined interval was adopted for M-type stars. Care was taken to ensure continuity between the two regimes. Abundances were derived using a new set of homogeneous curves of growth that were derived specifically for GES, and which were measured on a synthetic spectral grid consistently with the way the EWs were measured. The derived abundances were validated by comparison with those measured by other analysis groups using different methods.Results. Lithium EWs were measured for ~40 000 stars, and abundances could be derived for ~38 000 of them. The vast majority of the measures (80%) have been obtained for stars in open cluster fields. The remaining objects are stars in globular clusters, or field stars in the Milky Way disc, bulge, and halo.Conclusions. The GES dataset of homogeneous lithium abundances described here will be valuable for our understanding of several processes, from stellar evolution and internal mixing in stars at different evolutionary stages to Galactic evolution.
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| 3. |
- Rawshani, N., et al.
(författare)
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Association between use of pre-hospital ECG and 30-day mortality: A large cohort study of patients experiencing chest pain
- 2017
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Ingår i: International Journal of Cardiology. - : Elsevier BV. - 0167-5273 .- 1874-1754. ; 248, s. 77-81
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Tidskriftsartikel (refereegranskat)abstract
- Background: In the assessment of patients with chest pain, there is support for the use of pre-hospital ECG in the literature and in the care guidelines. Using propensity score methods, we aim to examine whether the mere acquisition of a pre-hospital ECG among patients with chest pain affects the outcome (30-day mortality). Methods: The association between pre-hospital ECG and 30-day mortality was studied in the overall cohort (n=13151), as well as in the one-to-one matched cohort with 2524 patients not examined with pre-hospital ECG and 2524 patients examined with pre-hospital ECG. Results: In the overall cohort, 21% (n=2809) did not undergo an ECG tracing in the pre-hospital setting. Among those who had pain during transport, 14% (n=1159) did not undergo a pre-hospital ECG while 32% (n=1135) of those who did not have pain underwent an ECG tracing. In the overall cohort, the OR for 30-day mortality in patients who had a pre-hospital ECG, as compared with those who did not, was 0.63 (95% CI 0.05-0.79; p < 0.001). In the matched cohort, the OR was 0.65 (95% CI 0.49-0.85; p < 0.001). Using the propensity score, in the overall cohort, the corresponding HR was 0.65 (95% CI 0.58-0.74). Conclusion: Using propensity score methods, we provide real-world data demonstrating that the adjusted risk of death was considerably lower among the cases in whoma pre-hospital ECG was used. The PH-ECG is underused among patients with chest discomfort and the mere acquisition of a pre-hospital ECG may reduce mortality. (C) 2017 Elsevier B.V. All rights reserved.
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- Rocha Flores, Waldo
(författare)
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Establishment of Security Knowledge Sharing in Organisations: An Empirical Study
- 2013
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Ingår i: Proceedings of the European Information Security Multi-Conference. - 9781841023458
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Konferensbidrag (refereegranskat)abstract
- The purpose of the present study is to empirically investigate what drives the establishment of security knowledge sharing in organisations. Based on a theoretical understanding a research model was developed and tested by collecting and analysing data from 62 security executives from a diverse set of organisations located in different geographic regions in the world. The empirical tests of a structural model revealed that all proposed hypotheses are accepted, except the hypotheses proposing a positive link between business-based information security and the establishment of security knowledge sharing. Organisational structure has a major direct influence on the establishment of security knowledge sharing in organisations, while the effect of coordinating information security process is moderate. A mediation analysis revealed that the reason for the nonsignificant direct relation between business-based information security and security knowledge sharing is the fully mediating effect of coordinating information security process. Thus, coordinating information security process has an important role on security knowledge sharing by either partially or fully mediating the effects of both organisational structure and business-based information security on security knowledge sharing. Implications and recommendation for future research are further discussed.
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| 6. |
- Tobias, Waffenschmidt, et al.
(författare)
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Extremal states of energy of a double-layered thick-walled tube – application to residually stressed arteries
- 2014
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Ingår i: Journal of the Mechanical Behavior of Biomedical Materials. - : Elsevier BV. - 1751-6161. ; 29, s. 635-654
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Tidskriftsartikel (refereegranskat)abstract
- Various biological tissues are designed to optimally support external loads for complex geometries and mechanobiological structures. This results in complex microstructures of such materials. The design of, for instance, (healthy) arteries, which are in the focus of this work, is characterised by a residually stressed fibre-reinforced multi-layered composite with highly non-linear elastic response. The complex interaction of material properties with the geometry and residual stress effects enables the optimal support under different blood pressures, respectively blood flow, within the vessel. The fibres reinforcing the arterial wall, as well as residual stresses present in the vessel, strongly influence its overall behaviour and performance. Turn-over and remodelling processes of the collagenous fibres occurring in the respective layers – either resulting from natural growth phenomena or from artificially induced changes in loading condition such as stent deployment – support the optimisation of the multi-layered composite structure of arteries for the particular loading conditions present in the artery. Within this contribution, the overall energetic properties of an artery are discussed by means of the inflation, bending and extension of a double-layered cylindrical tube. Different states of residual stresses and different fibre orientations are considered so that, for instance, representative fibre angles that result in extremal states of the total potential energy can be identified. In view of turn-over and remodelling processes, these orientations are considered to constitute preferred directions of fibre alignment. In summary, the main goal of this work is to calculate optimal material, structural and loading parameters by concepts of energy-minimisation. Several numerical studies show that the obtained values – such as the fibre orientations, the residual axial stretch and the opening angle – are in good agreement with respective physiological parameters reported in the literature.
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- van Eldert, Jeroen, 1987-, et al.
(författare)
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Drill Monitoring for Rock Mass Grouting : Case Study at the Stockholm Bypass
- 2021
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Ingår i: Rock Mechanics and Rock Engineering. - : Springer. - 0723-2632 .- 1434-453X. ; 54:2, s. 501-511
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Tidskriftsartikel (refereegranskat)abstract
- In tunneling, rock mass grouting is a method applied to reduce water ingress. Grouting is influenced by rock mass conditions, especially apertures, frequency, and continuation of fracturing. These rock mass conditions can partly be determined by rock mass classification systems. At the Stockholm bypass, the Measurement While Drilling (MWD) Fracturing Index was applied to characterize the rock mass for grouting purposes, with a focus on adjusting the grout hole drill plan to minimize environmental impact. This study divided the rock mass in a 1.9 km tunnel into six categories based on rock mass conditions, identifying rock mass quality, apparent fracturing, and grout consumption. These categories were then compared with the mean fracturing index based on the coefficients of penetration rate and rotation pressure variations, as well as grout consumption at each grout umbrella. The fracturing index was 93% successful in assessing favorable and unfavorable rock mass conditions in the studied tunnel and 85% successful in determining grout consumption. Finally, a conceptual method was developed to reduce the grouting activities using the MWD fracturing index and water loss tests. The introduction of this conceptual method for grouting decisions could potentially reduce 59% of the umbrellas found in the case study.
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