| 11. |
- Akiyama, Kazunori, et al.
(författare)
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First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
- 2022
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 930:2
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A*, as observed by the EHT in 2017 April at a wavelength of 1.3 mm. We find that the Sgr A* data exhibit variability that exceeds what can be explained by the uncertainties in the data or by the effects of interstellar scattering. The magnitude of this variability can be a substantial fraction of the correlated flux density, reaching similar to 100% on some baselines. Through an exploration of simple geometric source models, we demonstrate that ring-like morphologies provide better fits to the Sgr A* data than do other morphologies with comparable complexity. We develop two strategies for fitting static geometric ring models to the time-variable Sgr A* data; one strategy fits models to short segments of data over which the source is static and averages these independent fits, while the other fits models to the full data set using a parametric model for the structural variability power spectrum around the average source structure. Both geometric modeling and image-domain feature extraction techniques determine the ring diameter to be 51.8 +/- 2.3 mu as (68% credible intervals), with the ring thickness constrained to have an FWHM between similar to 30% and 50% of the ring diameter. To bring the diameter measurements to a common physical scale, we calibrate them using synthetic data generated from GRMHD simulations. This calibration constrains the angular size of the gravitational radius to be 4.8(-0.7)(+1.4) mu as, which we combine with an independent distance measurement from maser parallaxes to determine the mass of Sgr A* to be 4.0(-0.6)(+1.1) x 10(6) M-circle dot.
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| 12. |
- Brodén Gyberg, Veronica, 1978-, et al.
(författare)
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Framing and Responding to Climate-related Security Risks in Swedish Development Cooperation
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Societies worldwide are increasingly facing security challenges posed by climate change. The impacts of climate change exacerbate existing vulnerabilities and undermine human security, and the most detrimental effects are seen in already fragile contexts. Development organizations are key in addressing and mitigating climate-related security risks due to the importance of preventive measures. Such organizations are conceptualizing and integrating security risks posed by climate change, but the work is often done in silos. This paper contributes to the burgeoning research on the integration of climate-related security risks by organizations, with a case study on how the Swedish International Development Cooperation Agency (Sida) is framing and developing its responses. The study shows that although Sida prioritizes the integration of environment and climate with conflict on a general policy level, there are some challenges when translating the policy into practice. The analysis identifies ambiguities with regard to concepts used and tensions between expert and general knowledge. There are several initiatives at Sida on different levels with the aim to integrate climate and conflict. However, there seems to be room for increased collaboration on operationalization, which could enable even deeper levels of integrated work.
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| 13. |
- Dellgran, Peter, 1954, et al.
(författare)
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The academisation of social work: Sweden – a case study
- 2016
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Ingår i: Taylor I, et al.(eds.) Routledge International Handbook of Social Work Education. - New York : Routledge. - 9781138890237 ; , s. 51-59
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Bokkapitel (refereegranskat)
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| 14. |
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| 15. |
- Huang, R., et al.
(författare)
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Prediction and Optimization of WAG Flooding by Using LSTM Neural Network Model in Middle East Carbonate Reservoir
- 2021
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Ingår i: Society of Petroleum Engineers - Abu Dhabi International Petroleum Exhibition and Conference, ADIP 2021. - : Society of Petroleum Engineers.
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Konferensbidrag (refereegranskat)abstract
- Production prediction continues to play an increasingly significant role in reservoir development adjustment and optimization, especially in water-alternating-gas (WAG) flooding. As artificial intelligence continues to develop, data-driven machine learning method can establish a robust model based on massive data to clarify development risks and challenges, predict development dynamic characteristics in advance. This study gathers over 15 years actual data from targeted carbonate reservoir and establishes a robust Long Short-Term Memory (LSTM) neural network prediction model based on correlation analysis, data cleaning, feature variables selection, hyper-parameters optimization and model evaluation to forecast oil production, gas-oil ratio (GOR), and water cut (WC) of WAG flooding. In comparison to traditional reservoir numerical simulation (RNS), LSTM neural networks have a huge advantage in terms of computational efficiency and prediction accuracy. The calculation time of LSTM method is 864% less than reservoir numerical simulation method, while prediction error of LSTM method is 261% less than RNS method. We classify producers into three types based on the prediction results and propose optimization measures aimed at the risks and challenges they faced. Field implementation indicates promising outcome with better reservoir support, lower GOR, lower WC, and stabler oil production. This study provides a novel direction for application of artificial intelligence in WAG flooding development and optimization.
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| 16. |
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| 17. |
- Israelsson-Skogsberg, Åsa, et al.
(författare)
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Young adults’ narratives about living with home mechanical ventilation – a phenomenological hermeneutical study
- 2023
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Ingår i: Disability and Rehabilitation. - 0963-8288 .- 1464-5165.
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Tidskriftsartikel (refereegranskat)abstract
- PurposeAn increasing number of children and young adults with complex medical conditions and respiratory failure are treated with home mechanical ventilation (HMV). The current study aimed to describe how young adults using HMV experience their everyday life with the ventilator, their physical impairments and their opportunities for an educational and professional career.Materials and methodsData were collected via narrative interviews with nine young HMV users (3 females and 6 males, aged 18–31 years) in their homes. Two were ventilated invasively, six were ventilated non-invasively and one was treated with continuous positive airway pressure (CPAP) via facemask. Data were analysed using a phenomenological hermeneutical method.ResultA multi-professional team contributed to participants’ safety and ability to participate in society through higher education and professional work. A good and valuable life, mostly feeling healthy were experienced but also prejudice and stiffened social society structures.ConclusionThe findings of this study prove the importance of having long-standing access to a competent and supportive available multi-professional healthcare team when living with a long-term complex condition. These teams provided well-functioning human and technological support in everyday lives.Implications for Rehabilitation· An increasing number of children and young adults are treated with home mechanical ventilation due to respiratory failure.· The home mechanical ventilation treatment provided rest from breathing and improved sleep quality in such a way that work and higher studies could be managed.· Longstanding access to a supportive multi-professional healthcare team provided feelings of being safe, which in turn boosted self-confidence in life and preparedness to meet new challenges.
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| 18. |
- Ji, Yuanhui, et al.
(författare)
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Modeling the transport of CO2 in porous media with aqueous solutions by Gibbs free energy gradient
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The concentration of CO2 in atmosphere has been increasing greatly because of the fossil fuel combustion, which leads to a significant climate changes. CO2 is one of the most important greenhouse gases being responsible for about 64% of the enhanced "greenhouse effect" [1], and the disposal of anthropogenic CO2 has become an important issue of worldwide concern. Geological sequestration, generally refers to the injection of CO2 into deep geological formations such as deep saline aquifers, depleted hydrocarbon reservoirs or deep coalbeds, is attracting great attention [2] because of the large capacity and long residence time [3]. To predict the sequestration potential, to study the long-term behavior of CO2, and to estimate the potential for CO2 leakage in the geologic reservoirs, it is necessary to study the transport rate of CO2 in porous media with aqueous solutions. In the present work, the transport rate of CO2 in porous media with aqueous solutions is described and predicted by the Gibbs free energy gradient modeling based on linear nonequilibrium thermodynamics, and the Statistical Associating Fluid Theory equation of state is used to calculate the Gibbs free energy of the components in the investigated systems. The effects of temperature and pressure are analyzed.
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| 19. |
- Lange, David, et al.
(författare)
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A Comparison of the Conditions in a Fire Resistance Furnace When Testing Combustible and Non-combustible Construction
- 2020
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Ingår i: Fire technology. - : Springer. - 0015-2684 .- 1572-8099. ; 56:4, s. 1621-1654
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on two experiments conducted in a fire resistance furnace to study the differences in the boundary conditions, the fire dynamics and the fuel required to run the furnace when a combustible timber specimen as opposed to a non-combustible concrete specimen is tested. In both experiments measurements were taken in the furnace to evaluate the difference in the environments of the furnace and the response of the elements being tested. These include non-control plate thermometers distributed throughout the furnace; O2, CO2 and CO gas measurements taken at different distances from the specimen surface and in the furnace exhaust; instrumentation of one of the bricks comprising the furnace lining with thermocouples at different depths from the exposed surface; and mass loss of the combustible timber specimen. Thermal exposure of elements in a furnace is discussed, as well as the impact of the different materials on the similarity of thermal exposure. This is done through analysis and discussion of the different measurements taken and the apparent influence of the specimen being tested on the boundary condition of the heat diffusion equation. We conclude that; (1) the fire dynamics in a furnace are dependent on the specimen being tested; (2) that the test with the combustible specimen requires less fuel flow to the burners such that the control plate thermometers follow the ISO 834 temperature–time curve compared to the non-combustible specimen, however that this is not only a result of the combustibility of the specimen but is also a consequence of the different thermal inertia of the two materials; (3) that the boundary condition for heat transfer to a test object in furnace tests is dependent on the properties of the specimen being tested; and (4) that the timber when placed on the furnace experiences smouldering combustion after the char layer has formed. A fire resistance test of combustible construction of a given period represents a significantly less onerous test in terms of energy absorbed or fuel made available than one of a non-combustible construction, implying that the existing fire resistance framework may not be appropriate for timber structures and that an alternative approach may be required.
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| 20. |
- Li, Yunlong, et al.
(författare)
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RcsB positively regulates the Yersinia Ysc-Yop type III secretion system by activating expression of the master transcriptional regulator LcrF
- 2015
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Ingår i: Environmental Microbiology. - : John Wiley & Sons. - 1462-2912 .- 1462-2920. ; 17:4, s. 1219-1233
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Tidskriftsartikel (refereegranskat)abstract
- The Rcs phosphorelay is a complex signaling pathway used by the family Enterobacteriaceae to sense, respond and adapt to environmental changes during free-living or host-associated lifestyles. In this study, we show that the Rcs phosphorelay pathway positively regulates the virulence plasmid encoded Ysc-Yop type III secretion system (T3SS) in the enteropathogen Yesinia pseudotuberculosis. Both the overexpression of the wild-type Rcs regulator RcsB or the constitutive active RscB(D56E) variant triggered more abundant Ysc-Yop synthesis and secretion, whereas the non-phosphorylatable mutant RcsB(D56Q) negated this. Congruently, enhanced Yops expression and secretion occurred in an in cis rscB(D56E) mutant but not in an isogenic rscB(D56Q) mutant. Screening for regulatory targets of RcsB identified the virG-lcrF operon that encodes for LcrF, the Ysc-Yop T3SS master regulator. Protein-DNA binding assays confirmed that RcsB directly bound to this operon promoter, which subsequently caused stimulated lcrF transcription. Moreover, active RcsB enhanced the ability of bacteria to deliver Yop effectors into immune cells during cell contact, and this promoted an increase in bacterial viability. Taken together, our study demonstrates the role of the Rcs system in regulating the Ysc-Yop T3SS in Yersinia and reports on RcsB being the first transcriptional activator known to directly control lcrF transcription.
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