| 1. |
- van de Vegte, Yordi, et al.
(författare)
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Genetic insights into resting heart rate and its role in cardiovascular disease
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The genetics and clinical consequences of resting heart rate (RHR) remain incompletely understood. Here, the authors discover new genetic variants associated with RHR and find that higher genetically predicted RHR decreases risk of atrial fibrillation and ischemic stroke. Resting heart rate is associated with cardiovascular diseases and mortality in observational and Mendelian randomization studies. The aims of this study are to extend the number of resting heart rate associated genetic variants and to obtain further insights in resting heart rate biology and its clinical consequences. A genome-wide meta-analysis of 100 studies in up to 835,465 individuals reveals 493 independent genetic variants in 352 loci, including 68 genetic variants outside previously identified resting heart rate associated loci. We prioritize 670 genes and in silico annotations point to their enrichment in cardiomyocytes and provide insights in their ECG signature. Two-sample Mendelian randomization analyses indicate that higher genetically predicted resting heart rate increases risk of dilated cardiomyopathy, but decreases risk of developing atrial fibrillation, ischemic stroke, and cardio-embolic stroke. We do not find evidence for a linear or non-linear genetic association between resting heart rate and all-cause mortality in contrast to our previous Mendelian randomization study. Systematic alteration of key differences between the current and previous Mendelian randomization study indicates that the most likely cause of the discrepancy between these studies arises from false positive findings in previous one-sample MR analyses caused by weak-instrument bias at lower P-value thresholds. The results extend our understanding of resting heart rate biology and give additional insights in its role in cardiovascular disease development.
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| 2. |
- Aquila, Andrew, et al.
(författare)
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Time-resolved protein nanocrystallography using an X-ray free-electron laser
- 2012
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Ingår i: Optics Express. - 1094-4087. ; 20:3, s. 2706-2716
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate the use of an X-ray free electron laser synchronized with an optical pump laser to obtain X-ray diffraction snapshots from the photoactivated states of large membrane protein complexes in the form of nanocrystals flowing in a liquid jet. Light-induced changes of Photosystem I-Ferredoxin co-crystals were observed at time delays of 5 to 10 µs after excitation. The result correlates with the microsecond kinetics of electron transfer from Photosystem I to ferredoxin. The undocking process that follows the electron transfer leads to large rearrangements in the crystals that will terminally lead to the disintegration of the crystals. We describe the experimental setup and obtain the first time-resolved femtosecond serial X-ray crystallography results from an irreversible photo-chemical reaction at the Linac Coherent Light Source. This technique opens the door to time-resolved structural studies of reaction dynamics in biological systems.
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| 3. |
- Jansson, John-Olov, 1954, et al.
(författare)
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Body weight homeostat that regulates fat mass independently of leptin in rats and mice.
- 2018
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 115:2, s. 427-432
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Tidskriftsartikel (refereegranskat)abstract
- Subjects spending much time sitting have increased risk of obesity but the mechanism for the antiobesity effect of standing is unknown. We hypothesized that there is a homeostatic regulation of body weight. We demonstrate that increased loading of rodents, achieved using capsules with different weights implanted in the abdomen or s.c. on the back, reversibly decreases the biological body weight via reduced food intake. Importantly, loading relieves diet-induced obesity and improves glucose tolerance. The identified homeostat for body weight regulates body fat mass independently of fat-derived leptin, revealing two independent negative feedback systems for fat mass regulation. It is known that osteocytes can sense changes in bone strain. In this study, the body weight-reducing effect of increased loading was lost in mice depleted of osteocytes. We propose that increased body weight activates a sensor dependent on osteocytes of the weight-bearing bones. This induces an afferent signal, which reduces body weight. These findings demonstrate a leptin-independent body weight homeostat ("gravitostat") that regulates fat mass.
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| 4. |
- Johansson, Linda C, 1983, et al.
(författare)
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Lipidic phase membrane protein serial femtosecond crystallography.
- 2012
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Ingår i: Nature methods. - : Springer Science and Business Media LLC. - 1548-7105 .- 1548-7091. ; 9:3, s. 263-265
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Tidskriftsartikel (refereegranskat)abstract
- X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. Here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-FEL beam using a sponge phase micro-jet.
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| 5. |
- Kool, Erik C., et al.
(författare)
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A radio-detected type Ia supernova with helium-rich circumstellar material
- 2023
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 617:7961, s. 477-482
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Tidskriftsartikel (refereegranskat)abstract
- Type Ia supernovae (SNe Ia) are thermonuclear explosions of degenerate white dwarf stars destabilized by mass accretion from a companion star1, but the nature of their progenitors remains poorly understood. A way to discriminate between progenitor systems is through radio observations; a non-degenerate companion star is expected to lose material through winds2 or binary interaction3 before explosion, and the supernova ejecta crashing into this nearby circumstellar material should result in radio synchrotron emission. However, despite extensive efforts, no type Ia supernova (SN Ia) has ever been detected at radio wavelengths, which suggests a clean environment and a companion star that is itself a degenerate white dwarf star4,5. Here we report on the study of SN 2020eyj, a SN Ia showing helium-rich circumstellar material, as demonstrated by its spectral features, infrared emission and, for the first time in a SN Ia to our knowledge, a radio counterpart. On the basis of our modelling, we conclude that the circumstellar material probably originates from a single-degenerate binary system in which a white dwarf accretes material from a helium donor star, an often proposed formation channel for SNe Ia (refs. 6,7). We describe how comprehensive radio follow-up of SN 2020eyj-like SNe Ia can improve the constraints on their progenitor systems.
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| 6. |
- Alvarez Vadillo, Ines, et al.
(författare)
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Centralised Architecture for the Automatic Self-Configuration of Industrial Networks
- 2023
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Ingår i: IEEE Int. Conf. Emerging Technol. Factory Autom., ETFA. - : Institute of Electrical and Electronics Engineers Inc.. - 9798350339918
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Konferensbidrag (refereegranskat)abstract
- Novel production paradigms aim at increasing the efficiency and flexibility of production systems. Nonetheless, traditional industrial infrastructures lack the mechanisms needed to support these new paradigms. One of the main limiting factors is the architecture, which follows the automation pyramid in which subsystems are divided in layers depending on their functionalities. This allowed to meet the timing and dependability requirements of the production subsystems, however at the cost of limiting the exchange of information required to provide increased flexibility to the system. For this reason, in this paper we propose a new industrial architecture with a single network infrastructure to connect all the devices that conform to the industrial systems. On top of that, we design an Automatic Network Configurator to support the automatic configuration of the system. To assess the feasibility of our design and evaluate its performance, we implement the first instance of the architecture capable of supporting changes in the traffic requirements during run-time, i.e., without stopping or disrupting the system's operation. Furthermore, we use the implemented instance to measure the time required for reconfigurations.
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| 7. |
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| 8. |
- Basu, K., et al.
(författare)
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Non-parametric modeling of the intra-cluster gas using APEX-SZ bolometer imaging data
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 519:Article Number: A29
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We aim to demonstrate the usability of mm-wavelength imaging data obtained from the APEX-SZ bolometer array to derive the radial temperature profile of the hot intra-cluster gas out to radius r(500) and beyond. The goal is to study the physical properties of the intra-cluster gas by using a non-parametric de-projection method that is, aside from the assumption of spherical symmetry, free from modeling bias. Methods. We use publicly available X-ray spectroscopic-imaging data in the 0.7-2 keV energy band from the XMM-Newton observatory and our Sunyaev-Zel'dovich Effect (SZE) imaging data from the APEX-SZ experiment at 150 GHz to de-project the density and temperature profiles for a well-studied relaxed cluster, Abell 2204. We derive the gas density, temperature and entropy profiles assuming spherical symmetry, and obtain the total mass profile under the assumption of hydrostatic equilibrium. For comparison with X-ray spectroscopic temperature models, a re-analysis of recent Chandra observation is done with the latest calibration updates. We compare the results with that from an unrelaxed cluster, Abell 2163, to illustrate some differences between relaxed and merging systems. Results. Using the non-parametric modeling, we demonstrate a decrease of gas temperature in the cluster outskirts, and also measure gas entropy profiles, both of which are done for the first time independently of X-ray spectroscopy using the SZE and X-ray imaging data. The gas entropy measurement in the central 100 kpc shows the usability of APEX-SZ data for inferring cluster dynamical states with this method. The contribution of the SZE systematic uncertainties in measuring T-e at large radii is shown to be small compared to XMM-Newton and Chandra systematic spectroscopic errors. The total mass profile obtained using the hydrostatic equilibrium assumption is in agreement with the published X-ray and weak lensing results; the upper limit on M-200 derived from the non-parametric method is consistent with the NFW model prediction from weak lensing analysis.
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| 9. |
- Bergsjö, Dag Henrik, 1980, et al.
(författare)
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Assessing product development efficiency at Volvo Powertrain Focus on systems engineering and lean principles at two global sites
- 2013
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Ingår i: 23rd Annual International Symposium of the International Council on Systems Engineering, INCOSE 2013. ; 2, s. Pages 1481-1492
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Konferensbidrag (refereegranskat)abstract
- Measuring the performance of a development process is highly difficult, especially before it has led to an outcome such as a product. Furthermore, even with a diagnosis at hand showing the strengths and weaknesses of the development process, the information can seldom be used to answer the paramount question: How should the organization allocate its process improvement resources to best support its objectives?This paper presents a survey-based method for identifying which areas for process improvement are likely to have the strongest impact on company objectives, called outcomes. The survey has been completed by respondents within the organization and uses the data to present three different analyses. The first analysis shows the perceived current fulfillment within the organization of a number of principles identified as important for successful development. The second analysis is a regression analysis commonly used in marketing research to measure the impact of each principle on five outcomes: Efficiency/Effectiveness, Lead-Time, Innovation, Satisfaction and Product Quality. The two first analyses are then combined to a third analysis that provides a pie chart for each outcome with the principles possessing the highest potential for further improving that particular outcome.A case study at the automotive company, Volvo Powertrain, shows how the method was used to assess and compare process improvement potential at two development sites. The results clearly show that the analyses provide different views of what principles deserve attention for process improvement activities at the case company. The two principles deemed to be most attractive, based on their impact on outcomes, were currently neither among the highest nor the lowest performing principles. As a result of the study, Volvo Powertrain chose to start several improvement activities to work with the high-potential principles. The improvement can then be measured using annual surveys to track improvements and manage deviations from the plan.
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| 10. |
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| 11. |
- Borgmästars, Emmy, et al.
(författare)
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Metabolomics for early pancreatic cancer detection in plasma samples from a Swedish prospective population-based biobank
- 2024
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Ingår i: Journal of Gastrointestinal Oncology. - : AME Publishing Company. - 2078-6891 .- 2219-679X. ; 15:2, s. 755-767
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Tidskriftsartikel (refereegranskat)abstract
- Background: Pancreatic ductal adenocarcinoma (pancreatic cancer) is often detected at late stages resulting in poor overall survival. To improve survival, more patients need to be diagnosed early when curative surgery is feasible. We aimed to identify circulating metabolites that could be used as early pancreatic cancer biomarkers.Methods: We performed metabolomics by liquid and gas chromatography-mass spectrometry in plasma samples from 82 future pancreatic cancer patients and 82 matched healthy controls within the Northern Sweden Health and Disease Study (NSHDS). Logistic regression was used to assess univariate associations between metabolites and pancreatic cancer risk. Least absolute shrinkage and selection operator (LASSO) logistic regression was used to design a metabolite-based risk score. We used receiver operating characteristic (ROC) analyses to assess the discriminative performance of the metabolite-based risk score.Results: Among twelve risk-associated metabolites with a nominal P value <0.05, we defined a risk score of three metabolites [indoleacetate, 3-hydroxydecanoate (10:0-OH), and retention index (RI): 2,745.4] using LASSO. A logistic regression model containing these three metabolites, age, sex, body mass index (BMI), smoking status, sample date, fasting status, and carbohydrate antigen 19-9 (CA 19-9) yielded an internal area under curve (AUC) of 0.784 [95% confidence interval (CI): 0.714–0.854] compared to 0.681 (95% CI: 0.597–0.764) for a model without these metabolites (P value =0.007). Seventeen metabolites were significantly associated with pancreatic cancer survival [false discovery rate (FDR) <0.1].Conclusions: Indoleacetate, 3-hydroxydecanoate (10:0-OH), and RI: 2,745.4 were identified as the top candidate biomarkers for early detection. However, continued efforts are warranted to determine the usefulness of these metabolites as early pancreatic cancer biomarkers.
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| 12. |
- Borgmästars, Emmy, et al.
(författare)
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Metabolomics for early pancreatic cancer detection in plasma samples from a Swedish prospective population-based biobank
- 2024
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Ingår i: Journal of Gastrointestinal Oncology. - : AME Publishing Company. - 2078-6891 .- 2219-679X. ; 15:2, s. 755-767
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Tidskriftsartikel (refereegranskat)abstract
- Background: Pancreatic ductal adenocarcinoma (pancreatic cancer) is often detected at late stages resulting in poor overall survival. To improve survival, more patients need to be diagnosed early when curative surgery is feasible. We aimed to identify circulating metabolites that could be used as early pancreatic cancer biomarkers.Methods: We performed metabolomics by liquid and gas chromatography-mass spectrometry in plasma samples from 82 future pancreatic cancer patients and 82 matched healthy controls within the Northern Sweden Health and Disease Study (NSHDS). Logistic regression was used to assess univariate associations between metabolites and pancreatic cancer risk. Least absolute shrinkage and selection operator (LASSO) logistic regression was used to design a metabolite-based risk score. We used receiver operating characteristic (ROC) analyses to assess the discriminative performance of the metabolite-based risk score.Results: Among twelve risk-associated metabolites with a nominal P value <0.05, we defined a risk score of three metabolites [indoleacetate, 3-hydroxydecanoate (10:0-OH), and retention index (RI): 2,745.4] using LASSO. A logistic regression model containing these three metabolites, age, sex, body mass index (BMI), smoking status, sample date, fasting status, and carbohydrate antigen 19-9 (CA 19-9) yielded an internal area under curve (AUC) of 0.784 [95% confidence interval (CI): 0.714–0.854] compared to 0.681 (95% CI: 0.597–0.764) for a model without these metabolites (P value =0.007). Seventeen metabolites were significantly associated with pancreatic cancer survival [false discovery rate (FDR) <0.1].Conclusions: Indoleacetate, 3-hydroxydecanoate (10:0-OH), and RI: 2,745.4 were identified as the top candidate biomarkers for early detection. However, continued efforts are warranted to determine the usefulness of these metabolites as early pancreatic cancer biomarkers.
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| 13. |
- Bujosa Mateu, Daniel, et al.
(författare)
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The Effects of Clock Synchronization in TSN Networks with Legacy End-Stations
- 2022
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present our ongoing work on proposing solutions to integrate legacy end-stations into Time-Sensitive Network (TSN) communication systems where the legacy end-stations are synchronized via their legacy clock synchronization protocol. To this end, we experimentally identify the effects of lacking synchronization or partial synchronization in TSN networks. In the experiments we show the effects of clock synchronization in different scenarios on jitter and clock drifts. Based on the experiments, we propose preliminary solutions to overcome the identified effects.
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| 14. |
- Goobar, Ariel, 1962-, et al.
(författare)
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Uncovering a population of gravitational lens galaxies with magnified standard candle SN Zwicky
- 2023
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Ingår i: Nature Astronomy. - 2397-3366. ; 7:9, s. 1098-1107
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Tidskriftsartikel (refereegranskat)abstract
- Detecting gravitationally lensed supernovae is among the biggest challenges in astronomy. It involves a combination of two very rare phenomena: catching the transient signal of a stellar explosion in a distant galaxy and observing it through a nearly perfectly aligned foreground galaxy that deflects light towards the observer. Here we describe how high-cadence optical observations with the Zwicky Transient Facility, with its unparalleled large field of view, led to the detection of a multiply imaged type Ia supernova, SN Zwicky, also known as SN 2022qmx. Magnified nearly 25-fold, the system was found thanks to the standard candle nature of type Ia supernovae. High-spatial-resolution imaging with the Keck telescope resolved four images of the supernova with very small angular separation, corresponding to an Einstein radius of only θE = 0.167″ and almost identical arrival times. The small θE and faintness of the lensing galaxy are very unusual, highlighting the importance of supernovae to fully characterize the properties of galaxy-scale gravitational lenses, including the impact of galaxy substructures.
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| 15. |
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| 16. |
- Horellou, Cathy, 1967, et al.
(författare)
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Sicken attans liten söt antenn!
- 2008
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Ingår i: Populär Astronomi. - 1650-7177. ; 9:4, s. 28-29
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Tidskriftsartikel (refereegranskat)
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| 17. |
- Jalkanen, Jukka-Pekka, et al.
(författare)
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Modelling of discharges from Baltic Sea shipping
- 2021
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Ingår i: Ocean Science. - : Copernicus GmbH. - 1812-0784 .- 1812-0792.
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the new developments of the Ship Traffic Emission Assessment Model (STEAM) which enable the modelling of pollutant discharges to water from ships. These include nutrients from black/grey water discharges as well as from food waste. Further, the modelling of contaminants in ballast, black, grey and scrubber water, bilge discharges, and stern tube oil leaks are also described as well as releases of contaminants from antifouling paints.Each of the discharges is regulated by different sections of the IMO MARPOL convention, and emission patterns of different pollution releases vary significantly. The discharge patterns and total amounts for the year 2012 in the Baltic Sea area are reported and open-loop SOx scrubbing effluent was found to be the second-largest pollutant stream by volume. The scrubber discharges have increased significantly in recent years, and their environmental impacts need to be investigated in detail.
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| 18. |
- Johansson, Daniel, 1980, et al.
(författare)
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A LABOCA survey of submillimeter galaxies behind galaxy clusters
- 2011
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 527:14
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Tidskriftsartikel (refereegranskat)abstract
- Context. Submillimeter galaxies are a population of dusty star-forming galaxies at high redshift. Measuring their properties will help relate them to other types of galaxies, both at high and low redshift. This is needed in order to understand the formation and evolution of galaxies.Aims. The aim is to use gravitational lensing by galaxy clusters to probe the faint and abundant submillimeter galaxy population down to a lower flux density level than what can be achieved in blank-field observations.Methods. We use the LABOCA bolometer camera on the APEX telescope to observe five clusters of galaxies at a wavelength of 870 μm. The final maps have an angular resolution of 27.5" and a point source noise level of 1.2–2.2 mJy. We model the mass distribution in the clusters as superpositions of spherical NFW halos and derive magnification maps that we use to calculate intrinsic flux densities as well as area-weighted number counts. We also use the positions of Spitzer MIPS 24 μm sources in four of the fields for a stacking analysis.Context. Submillimeter galaxies are a population of dusty star-forming galaxies at high redshift. Measuring their properties will help relate them to other types of galaxies, both at high and low redshift. This is needed in order to understand the formation and evolution of galaxies.Aims. The aim is to use gravitational lensing by galaxy clusters to probe the faint and abundant submillimeter galaxy population down to a lower flux density level than what can be achieved in blank-field observations.Methods. We use the LABOCA bolometer camera on the APEX telescope to observe five clusters of galaxies at a wavelength of 870 μm. The final maps have an angular resolution of 27.5" and a point source noise level of 1.2–2.2 mJy. We model the mass distribution in the clusters as superpositions of spherical NFW halos and derive magnification maps that we use to calculate intrinsic flux densities as well as area-weighted number counts. We also use the positions of Spitzer MIPS 24 μm sources in four of the fields for a stacking analysis.Results. We detected 37 submm sources, out of which 14 have not been previously reported. One source has a sub-mJy intrinsic flux density. The derived number counts are consistent with previous results, after correction for gravitational magnification and completeness levels. The stacking analysis reveals an intrinsic 870 μm signal of 390 ± 27 μJy at 14.5σ significance. We study the S24 μm–S870 μm relation by stacking on subsamples of the 24 μm sources and find a linear relation at S24 μm
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| 19. |
- Johansson, Daniel, et al.
(författare)
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Bulk-synchronous parallel computing on the CELL processor
- 2007
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Ingår i: PARS-2007 21. PARS - Workshop, Hamburg, Germany, May 31-Jun 1, 2007. GI/ITG-Fachgruppe Parallel-Algorithmen, -Rechnerstrukturen und -Systemsoftware PARS.,2007. - : GI Gesellschaft für Informatik e.V..
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Konferensbidrag (refereegranskat)abstract
- In order to ease programming of heterogeneous architectures with explicitly managed memory hierarchies such as the CELL processor, we propose a solution adopting the BSP model as implemented in the parallel programming language NestStep. This allows the programmer to write programs with a global address space and run them on the slave processors (SPEs) of CELL while keeping the large data structures in main memory. We have implemented the run-time system of NestStep on CELL and report on performance results that demonstrate the feasibility of the approach. The test programs scale very well as their execution time is mostly dominated by calculations, and only a fraction is spent in the various parts of the NestStep runtime system library. The library also has a relatively small memory footprint in the SPE's software managed local memory.
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| 20. |
- Johansson, Daniel, 1980-
(författare)
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Convergence in mixed reality-virtuality environments : facilitating natural user behavior
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis addresses the subject of converging real and virtual environments to a combined entity that can facilitate physiologically complying interfaces for the purpose of training. Based on the mobility and physiological demands of dismounted soldiers, the base assumption is that greater immersion means better learning and potentially higher training transfer. As the user can interface with the system in a natural way, more focus and energy can be used for training rather than for control itself. Identified requirements on a simulator relating to physical and psychological user aspects are support for unobtrusive and wireless use, high field of view, high performance tracking, use of authentic tools, ability to see other trainees, unrestricted movement and physical feedback. Using only commercially available systems would be prohibitively expensive whilst not providing a solution that would be fully optimized for the target group for this simulator. For this reason, most of the systems that compose the simulator are custom made to facilitate physiological human aspects as well as to bring down costs. With the use of chroma keying, a cylindrical simulator room and parallax corrected high field of view video see-though head mounted displays, the real and virtual reality are mixed. This facilitates use of real tool as well as layering and manipulation of real and virtual objects. Furthermore, a novel omnidirectional floor and thereto interface scheme is developed to allow limitless physical walking to be used for virtual translation. A physically confined real space is thereby transformed into an infinite converged environment. The omnidirectional floor regulation algorithm can also provide physical feedback through adjustment of the velocity in order to synchronize virtual obstacles with the surrounding simulator walls. As an alternative simulator target use, an omnidirectional robotic platform has been developed that can match the user movements. This can be utilized to increase situation awareness in telepresence applications.
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| 21. |
- Johansson, Daniel, 1980, et al.
(författare)
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Molecular gas and dust in the highly magnified z similar to 2.8 galaxy behind the Bullet Cluster
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 543, s. Article Number: A62 (pp. 1-10)
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Tidskriftsartikel (refereegranskat)abstract
- Context. The gravitational magnification provided by massive galaxy clusters makes it possible to probe the physical conditions in distant galaxies that are of lower luminosity than those in blank fields and likely more representative of the bulk of the high-redshift galaxy population. Aims. We aim to constrain the basic properties of molecular gas in a strongly magnified submm galaxy located behind the massive Bullet Cluster (1E 0657-56). This galaxy (SMM J0658) is split into three images, with a total magnification factor of almost 100. Methods. We used the Australia Telescope Compact Array (ATCA) to search for (CO)-C-12(1-0) and (CO)-C-12(3-2) line emission from SMM J0658. We also used the SABOCA bolometer camera on the Atacama Pathfinder EXperiment (APEX) telescope to measure the continuum emission at 350 mu m. Results. CO(1-0) and CO(3-2) are detected at 6.8 sigma and 7.5 sigma significance when the spectra toward the two brightest images of the galaxy are combined. From the CO(1-0) luminosity we derive a mass of cold molecular gas of (1.8 +/- 0.3) x 10(9) M-circle dot, using the CO to H-2 conversion factor commonly used for luminous infrared galaxies. This is 45 +/- 25% of the stellar mass. From the width of the CO lines we derive a dynamical mass within the CO-emitting region L of (1.3 +/- 0.4) x 10(10)(L/1 kpc) M-circle dot. We refine the redshift determination of SMM J0658 to z = 2.7793 +/- 0.0003. The CO(3-2) to CO(1-0) brightness temperature ratio is 0.56(-0.15)(+0.21), which is similar to the values found in other star-forming galaxies. Continuum emission at 350 mu m from SMM J0658 was detected with SABOCA at a signal-to-noise ratio of 3.6. The flux density is consistent with previous measurements at the same wavelength by the Herschel satellite and BLAST balloon-borne telescope. We study the spectral energy distribution of SMM J0658 and derive a dust temperature of 33 +/- 5 K and a dust mass of 1.1(-0.3)(+0.8) x 10(7) M-circle dot. Conclusions. SMM J0658 is one of the least massive submm galaxies discovered so far. As a likely representative of the bulk of the submm galaxy population, it is a prime target for future observations.
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| 22. |
- Johansson, Daniel, 1980
(författare)
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Observations of submillimeter galaxies and of the Sunyaev-Zeldovich effect toward clusters of galaxies
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes observations of a population of high-redshift, dusty star-forming galaxies: thesubmillimeter (submm) galaxies. The submm galaxies detected so far are very massive and lumi-nous systems, with huge star-formation-rates (SFR>100Myr−1), large reservoirs of moleculargas (Mgas∼1×1010M) and large dynamical masses (Mdyn>1010M). The median redshiftof detected submm galaxies isz∼2.2, which corresponds to a look-back time of 10 Gyr.We have used the LABOCA bolometer camera mounted on the APEX telescope in Chile tosearch for gravitationally lensed submm galaxies behind massive galaxy clusters (with a total massMclust>5×1014M). The gravitational magnification induced by the galaxy clusters boosts theobserved flux densities of the background submm galaxies and allows us to probe deeper intothe faint galaxy population. The number counts of submm galaxies show that there are manymore faint galaxies than bright ones, and thus the properties of the bright submm galaxies mainlystudied so far may not be representative of the bulk of the population.In two papers we present our results of the observations toward galaxy clusters. In paperI, we discuss a merging galaxy cluster: the Bullet Cluster at redshiftz∼0.3. The huge massconcentration provides large magnification factors, and one of the background galaxies detectedwith LABOCA is gravitationally magnified∼100times. The number of galaxies detected towardthe Bullet Cluster is consistent with previously published number counts, and we probed thenumber counts to some of the lowest flux density levels so far. Paper I also includes a studyof the multi-wavelength-properties of the LABOCA galaxies, where we identified counterparts ininfrared Spitzer maps.In paper II the study of submm galaxies lensed by clusters was extended with four additionalclusters. The number of detected galaxies was more than doubled compared to paper I. A more so-phisticated method was used to determine the magnification factors for each galaxy, and to correctthe number counts for the effect of magnification differences across the map. The number countsagree with previous work but may indicate a flattening towards low flux densities. A study of thefaint, unresolved background population was also included, via the stacking technique. We usedthe positions of all sources detected in Spitzer 24μmmaps across the observed LABOCA fields.The LABOCA flux was extracted at each 24μmposition and when added together this yieldeda14.5σdetection, and a signal 5 to 10 times lower than the adopted flux limit for extraction ofsignificant sources in the maps. In combination with gravitational magnification, stacking makesit possible to probe deeper into the submm population, although only mean properties of the faintgalaxies can be derived.Having studied the observational properties of a sample of submm galaxies in paper III wefocused on one particular galaxy behind the Bullet Cluster, SMMJ0658, gravitationally magnifiedup to 100 times in total. The strong lensing caused by the total cluster potential and an ellipticalgalaxy within the cluster gives rise to three images of the same background galaxy. In ouriobservations with a radio/mm interferometer, the Australia Telescope Compact Array (ATCA),we detected two rotational transitions of the carbon monoxide (CO) molecule in SMMJ0658.CO is commonly used as a tracer of the more abundant moleculeH2, which constitutes a largefraction of the molecular gas in galaxies. Because of the large magnification factor of this galaxyit is possible to probe the physical conditions in a system with ten times less molecular gas anda lower star formation rate than the bright submm galaxy population studied so far.Finally, I have participated in the APEX-SZ project. APEX-SZ is a bolometer camera oper-ating at 2 mm wavelength, designed with the aim of detecting the Sunyaev–Zeldovich decrementin clusters of galaxies. The Sunyaev–Zeldovich effect is a secondary anisotropy to the Cosmic Mi-crowave Background (CMB) radiation. It is due to inverse Compton scattering of CMB photonsby hot electrons in the cluster gas. At 2 mm the SZ effect gives rise to a lower temperature whencompared to the 2.7 K radiation. I participated in six observing runs in Chile between 2008 and2010. The scientific studies with APEX-SZ focus on the physical state of the intra-cluster gasin galaxy clusters. In two of the papers summarized in this thesis the APEX-SZ detection wasused together with XMM-Newton X-ray observations to constrain non-parametric models for thedistribution and temperature of the hot gas. The existence of dusty galaxies within high-redshiftgalaxy clusters is a possible explanation as to why several high-redshift galaxy clusters have eludeddetection in Sunyaev–Zeldovich experiments.
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| 23. |
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| 24. |
- Johansson, Daniel, 1980, et al.
(författare)
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Submillimeter galaxies behind the Bullet cluster (1E 0657-56)
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 514:12
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Tidskriftsartikel (refereegranskat)abstract
- Context. Clusters of galaxies are effective gravitational lenses able to magnify background galaxies and making it possible to probe the fainter part of the galaxy population. Submillimeter galaxies, which are believed to be star-forming galaxies at typical redshifts of 2 to 3, are a major contaminant to the extended Sunyaev-Zeldovich (SZ) signal of galaxy clusters. For a proper quantification of the SZ signal the contribution of submillimeter galaxies needs to be quantified. Aims. The aims of this study are to identify submillimeter sources in the field of the Bullet cluster (1E 0657-56), a massive cluster of galaxies at z similar or equal to 0.3, measure their flux densities at 870 mu m, and search for counterparts at other wavelengths to constrain their properties. Methods. We carried out deep observations of the submillimeter continuum emission at 870 mu m using the Large APEX BOlometer CAmera (LABOCA) on the Atacama Pathfinder EXperiment (APEX) telescope. Several numerical techniques were used to quantify the noise properties of the data and extract sources. Results. In total, seventeen sources were found. Thirteen of them lie in the central 10 arcmin of the map, which has a pixel sensitivity of 1.2 mJy per 22 '' beam. After correction for flux boosting and gravitational lensing, the number counts are consistent with published submm measurements. Nine of the sources have infrared counterparts in Spitzer maps. The strongest submm detection coincides with a source previously reported at other wavelengths, at an estimated redshift z similar or equal to 2.7. If the submm flux arises from two images of a galaxy magnified by a total factor of 75, as models have suggested, its intrinsic flux would be around 0.6 mJy, consistent with an intrinsic luminosity below 10(12) L-circle dot.
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| 25. |
- Johansson, Linda C, 1983, et al.
(författare)
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Structure of a photosynthetic reaction centre determined by serial femtosecond crystallography.
- 2013
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Serial femtosecond crystallography is an X-ray free-electron-laser-based method with considerable potential to have an impact on challenging problems in structural biology. Here we present X-ray diffraction data recorded from microcrystals of the Blastochloris viridis photosynthetic reaction centre to 2.8Å resolution and determine its serial femtosecond crystallography structure to 3.5Å resolution. Although every microcrystal is exposed to a dose of 33MGy, no signs of X-ray-induced radiation damage are visible in this integral membrane protein structure.
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| 26. |
- Kasari, Villu, et al.
(författare)
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A role for the Saccharomyces cerevisiae ABCF protein New1 in translation termination/recycling
- 2019
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Ingår i: Nucleic Acids Research. - : Oxford University Press. - 0305-1048 .- 1362-4962. ; 47:16, s. 8807-8820
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Tidskriftsartikel (refereegranskat)abstract
- Translation is controlled by numerous accessory proteins and translation factors. In the yeast Saccharomyces cerevisiae, translation elongation requires an essential elongation factor, the ABCF ATPase eEF3. A closely related protein, New1, is encoded by a non-essential gene with cold sensitivity and ribosome assembly defect knock-out phenotypes. Since the exact molecular function of New1 is unknown, it is unclear if the ribosome assembly defect is direct, i.e. New1 is a bona fide assembly factor, or indirect, for instance due to a defect in protein synthesis. To investigate this, we employed yeast genetics, cryo-electron microscopy (cryo-EM) and ribosome profiling (Ribo-Seq) to interrogate the molecular function of New1. Overexpression of New1 rescues the inviability of a yeast strain lacking the otherwise strictly essential translation factor eEF3. The structure of the ATPase-deficient (EQ2) New1 mutant locked on the 80S ribosome reveals that New1 binds analogously to the ribosome as eEF3. Finally, Ribo-Seq analysis revealed that loss of New1 leads to ribosome queuing upstream of 3′-terminal lysine and arginine codons, including those genes encoding proteins of the cytoplasmic translational machinery. Our results suggest that New1 is a translation factor that fine-tunes the efficiency of translation termination or ribosome recycling.
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| 27. |
- Liu, Chang, et al.
(författare)
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SN 2022joj : A Peculiar Type Ia Supernova Possibly Driven by an Asymmetric Helium-shell Double Detonation
- 2023
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Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 958:2
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Tidskriftsartikel (refereegranskat)abstract
- We present observations of SN 2022joj, a peculiar Type Ia supernova discovered by the Zwicky Transient Facility. SN 2022joj exhibits an unusually red g ZTF - r ZTF color at early times and a rapid blueward evolution afterward. Around maximum brightness, SN 2022joj shows a high luminosity ( MgZTF,max similar or equal to-19.7 mag), a blue broadband color (g ZTF - r ZTF similar or equal to -0.2 mag), and shallow Si ii absorption lines, consistent with those of overluminous, SN 1991T-like events. The maximum-light spectrum also shows prominent absorption around 4200 angstrom, which resembles the Ti ii features in subluminous, SN 1991bg-like events. Despite the blue optical-band colors, SN 2022joj exhibits extremely red ultraviolet minus optical colors at maximum luminosity (u - v similar or equal to 0.6 mag and uvw1 - v similar or equal to 2.5 mag), suggesting a suppression of flux at similar to 2500-4000 angstrom. Strong C ii lines are also detected at peak. We show that these unusual spectroscopic properties are broadly consistent with the helium-shell double detonation of a sub-Chandrasekhar mass (M similar or equal to 1 M circle dot) carbon/oxygen white dwarf from a relatively massive helium shell (M s similar or equal to 0.04-0.1 M circle dot), if observed along a line of sight roughly opposite to where the shell initially detonates. None of the existing models could quantitatively explain all the peculiarities observed in SN 2022joj. The low flux ratio of [Ni ii] lambda 7378 to [Fe ii] lambda 7155 emission in the late-time nebular spectra indicates a low yield of stable Ni isotopes, favoring a sub-Chandrasekhar mass progenitor. The significant blueshift measured in the [Fe ii] lambda 7155 line is also consistent with an asymmetric chemical distribution in the ejecta, as is predicted in double-detonation models.
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| 28. |
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| 29. |
- Ljungberg, Daniel, 1980, et al.
(författare)
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Polarization of the Swedish University Sector: Structural Characteristics and Positioning
- 2009
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Ingår i: McKelvey, M. and M. Holmén (2009). Learning to Compete European Universities: From Social Institutions to Knowledge Business. - Cheltenham UK : Edward Elgar Publishers. - 9781848440012 - 978 1 84844 001 2
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter relates the structural characteristics of Swedish universities, to the propensity of different categories of university to attract external research funding, including industry financing. Existing literature about the ability of universities to obtain research grants in general, and to obtain industrial funding for research in particular, have focused on questions such as the quality of the research performed, the impact of informal networks in creating constructed communities, and the ‘Matthew effect’ for indiv¬idual researchers. While these streams of literature raise interesting relevant issues about the quality and orientation of research, this paper takes a different angle. By addressing structural characteristics, the chapter is related to debates about the need for critical mass and excellence, not only within research groups but also within universities. These notions leads firstly to a categorization of the Swedish university sector, and secondly to the ability of the different universities to obtain external research funding. The chapter draws upon a national database of statistical material reported to the government and additional sources to test these ideas. This chapter thus addresses the university sector in Sweden, based on time-scale data at the micro-level of specific universities.
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| 30. |
- Maljutenko, Ilja, et al.
(författare)
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Modelling spatial dispersion of contaminants from shipping lanes in the Baltic Sea
- 2021
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 173
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Tidskriftsartikel (refereegranskat)abstract
- Major sources of pollution from shipping to marine environments are antifouling paint residues and discharges of bilge, black, grey and ballast water and scrubber discharge water. The dispersion of copper, zinc, naphthalene, pyrene, and dibromochloromethane have been studied using the Ship Traffic Emission Assessment Model, the General Estuarine Transport Model, and the Eulerian tracer transport model in the Baltic Sea in 2012. Annual loads of the contaminants ranged from 10-2 tons for pyrene to 100 s of tons for copper. The dispersion of the contaminants is determined by the surface kinetic energy and vertical stratification at the location of the discharge. The elevated concentration of the contaminants at the surface persists for about two-days and the contaminants are dispersed over the spatial scale of 10-60 km. The Danish Sounds, the southwestern Baltic Sea and the Gulf of Finland are under the heaviest pressure of shipborne contaminants in the Baltic Sea.
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| 31. |
- Morfeldt, Johannes, 1983, et al.
(författare)
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Emission pathways and mitigation options for achieving consumption-based climate targets in Sweden
- 2023
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Ingår i: Communications Earth & Environment. - Göteborg : IVL Svenska Miljöinstitutet AB. - 2662-4435. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- National emission reduction targets under the Paris Agreement have a territorial focus, incentivizing mitigation actions domestically. Here we examine the theoretical basis for adopting complementary consumption-based net-zero emission targets and assess the consequences of adopting such proposed targets for Sweden. We apply scenario analyses based on a prospective lifecycle assessment framework. The framework is a hybrid of bottom-up simulations for passenger travel, construction and housing, and food, and top-down analyses for remaining consumption. In this work, we show how consumption-based climate targets may accentuate the need for new demand-side climate policies that contribute to reducing emissions along supply chains of products and services.Our scenario analysis suggests that combining advanced mitigation technologies with behavioral changes could reduce emissions from 9.8 tons of carbon dioxide equivalents per capita in 2019 to between 2.7 and 4.8 tons by 2045 for Swedish residents, depending on global decarbonization pathways. Combining advanced mitigation technologies with behavioural changes could achieve the lowest carbon emissions per capita in Sweden, suggest scenario analyses combining bottom-up simulations for passenger travel, construction and housing, and food, and top-down analyses for remaining consumption.
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| 32. |
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| 33. |
- Pérez-González, P.G.P., et al.
(författare)
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Improving the identification of high-z Herschel sources with position priors and optical/NIR and FIR/mm photometric redshifts
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L15
-
Tidskriftsartikel (refereegranskat)abstract
- We present preliminary results about the detection of high redshift (U)LIRGs in the Bullet cluster field by the PACS and SPIRE instruments within the Herschel Lensing Survey (HLS) Program. We describe in detail a photometric procedure designed to recover robust fluxes and deblend faint Herschel sources near the confusion noise. The method is based on the use of the positions of Spitzer/MIPS 24 mu m sources as priors. Our catalogs are able to reliably (5 sigma) recover galaxies with fluxes above 6 and 10 mJy in the PACS 100 and 160 mu m channels, respectively, and 12 to 18 mJy in the SPIRE bands. We also obtain spectral energy distributions covering the optical through the far-infrared/millimeter spectral ranges of all the Herschel detected sources, and analyze them to obtain independent estimations of the photometric redshift based on either stellar population or dust emission models. We exemplify the potential of the combined use of Spitzer position priors plus independent optical and IR photometric redshifts to robustly assign optical/NIR counterparts to the sources detected by Herschel and other (sub-)mm instruments.
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| 34. |
- Rebalski, Ella, 1989, et al.
(författare)
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Brace for impacts: Perceived impacts and responses relating to the state of connected and autonomous vehicles in Gothenburg
- 2024
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Ingår i: Case Studies on Transport Policy. - 2213-6258 .- 2213-624X. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- It is anticipated that Connected and Autonomous Vehicles (CAVs) will be introduced for public use in the coming decade. Thus, it is important to consider how ready cities are to integrate them into the urban environment. To address this question, this article frames the introduction of CAVs within the context of a socio-technical transition. We use the Drivers, Pressures, State, Impact and Response (DPSIR) framework to identify the impacts and responses of the introduction of CAVs in cities, with a specific emphasis on Gothenburg, Sweden. The results of the DPSIR analysis are then analyzed through the lens of transition management, in which the responses are related to strategical, tactical, operational and reflexive governance strategies. It was found that the reflexive component is likely to be critical for a successful introduction of CAVs in cities, so that policies can be adjusted as the uptake of the technology changes. Many issues that could arise from CAVs, such as increased car traffic and physical barriers to mobility, are already addressed in the City of Gothenburg's official transportation strategy, but there is room for clearer policy with regard to CAV technology.
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| 35. |
- Rebalski, Ella, 1989, et al.
(författare)
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Too much pressure? Driving and restraining forces and pressures relating to the state of connected and autonomous vehicles in cities
- 2022
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Ingår i: Transportation Research Interdisciplinary Perspectives. - : Elsevier BV. - 2590-1982. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Connected and Autonomous Vehicles (CAVs) are predicted by many analysts to transform the transport system over the coming decades. Which direction and path this transformation will take remains highly uncertain, as do the related environmental effects. In the present study we examine the introduction of CAVs in cities in terms of the indirect or underlying processes (drivers) and the direct expressions of interest that are related to specific actions, events or processes (pressures). The drivers and pressures are identified in interviews with stakeholders from across the quadruple helix (academia, industry, government and civil society). We then use an analytical framework that combines the drivers and pressures of the DPSIR (Driving forces, Pressures, States, Impacts, Responses) model and force field analysis. This framework is used to map survey data on the strength of the driving and restraining forces and pressures behind the introduction of CAVs in cities, and to identify which stakeholders are involved in this socio-technical transition. Results showed that there was a strong belief across stakeholder groups that CAVs should be connected with mobility planning strategies. This need for planning has been discussed at length in other contexts, and now our results show that respondents find this need is also present in the Swedish context. An unexpected finding was that those who are sceptical to CAVs may form unique groups with a broad range of stakeholder types, for example elderly people, cyclists, people who are concerned because of conspiracies related to new technology, and those who are concerned about environmental effects.
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| 36. |
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| 37. |
- Rex, M., et al.
(författare)
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The far-infrared/submillimeter properties of galaxies located behind the Bullet cluster
- 2010
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 518:Article Number: L13
-
Tidskriftsartikel (refereegranskat)abstract
- The Herschel Lensing Survey (HLS) takes advantage of gravitational lensing by massive galaxy clusters to sample a population of high-redshift galaxies which are too faint to be detected above the confusion limit of current far-infrared/submillimeter telescopes. Measurements from 100-500 mu m bracket the peaks of the far-infrared spectral energy distributions of these galaxies, characterizing their infrared luminosities and star formation rates. We introduce initial results from our science demonstration phase observations, directed toward the Bullet cluster (1E0657-56). By combining our observations with LABOCA 870 mu m and AzTEC 1.1 mm data we fully constrain the spectral energy distributions of 19 MIPS 24 mu m-selected galaxies which are located behind the cluster. We find that their colors are best fit using templates based on local galaxies with systematically lower infrared luminosities. This suggests that our sources are not like local ultra-luminous infrared galaxies in which vigorous star formation is contained in a compact highly dust-obscured region. Instead, they appear to be scaled up versions of lower luminosity local galaxies with star formation occurring on larger physical scales.
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| 38. |
- Schultheiss, Fredrik, et al.
(författare)
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Machinability of CuZn21Si3P brass
- 2016
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Ingår i: Materials Science and Technology. - : Informa UK Limited. - 1743-2847 .- 0267-0836. ; 32:17, s. 1744-1750
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Tidskriftsartikel (refereegranskat)abstract
- New brass alloys containing less or even no lead are being developed, decreasing the environmental impact of the material. One example of an alternative brass is CuZn21Si3P, which contains less than 0.09 wt-% Pb. The research presented in this article evaluates the machinability of CuZn21Si3P as compared to more common, lead-containing free-machining brasses. The results show a marked decrease in the machinability of CuZn21Si3P. When longitudinally turning CuZn21Si3P the cutting tool failed after 142 min of machining. This tool wear was to a large extent remedied through the use of a coating on the cutting tool. CuZn21Si3P appears as a viable substitute for lead-containing brasses, thus implying the possibility for improving the sustainability of modern production.
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| 39. |
- Schwan, D., et al.
(författare)
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APEX-SZ: The Atacama Pathfinder EXperiment Sunyaev-Zel'dovich Instrument
- 2012
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Ingår i: The Messenger. ; 147, s. 7-12
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The APEX–SZ instrument was a millimetre-wave (150 GHz) cryogenic receiverfor the APEX telescope designedto observe galaxy clusters via theSunyaev–Zel’dovich Effect (SZE). Thereceiver contained a focal plane of280 superconducting transition-edgesensor bolometers equipped with afrequency-domain-multiplexed readoutsystem, and it played a key role in theintroduction of these new, robust, andscalable technologies. With 1-arcminuteresolution, the instrument had a higherinstantaneous sensitivity and covered alarger field of view (22 arcminutes) thanearlier generations of SZE instruments.During its period of operation from 2007to 2010, APEX–SZ was used to imageover 40 clusters and map fields overlappingwith external datasets. This paperbriefly describes the instrument anddata reduction procedure and presentsa cluster image gallery, as well as resultsfor the Bullet cluster, Abell 2204, Abell2163, and a power spectrum analysis inthe XMM-LSS field.
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| 40. |
- Schwan, D., et al.
(författare)
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Invited Article: Millimeter-wave bolometer array receiver for the Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument
- 2011
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 82:9
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Tidskriftsartikel (refereegranskat)abstract
- The Atacama pathfinder experiment Sunyaev-Zel'dovich (APEX-SZ) instrument is a millimeter-wave cryogenic receiver designed to observe galaxy clusters via the Sunyaev-Zel'dovich effect from the 12 m APEX telescope on the Atacama plateau in Chile. The receiver contains a focal plane of 280 superconducting transition-edge sensor (TES) bolometers instrumented with a frequency-domain multiplexed readout system. The bolometers are cooled to 280 mK via a three-stage helium sorption refrigerator and a mechanical pulse-tube cooler. Three warm mirrors, two 4 K lenses, and a horn array couple the TES bolometers to the telescope. APEX-SZ observes in a single frequency band at 150 GHz with 1' angular resolution and a 22' field-of-view, all well suited for cluster mapping. The APEX-SZ receiver has played a key role in the introduction of several new technologies including TES bolometers, the frequency-domain multiplexed readout, and the use of a pulse-tube cooler with bolometers. As a result of these new technologies, the instrument has a higher instantaneous sensitivity and covers a larger field-of-view than earlier generations of Sunyaev-Zel'dovich instruments. The TES bolometers have a median sensitivity of 890 mu K(CMB)root s (NEy of 3.5 x 10(-4) root s). We have also demonstrated upgraded detectors with improved sensitivity of 530 mu K(CMB) root s (NEy of 2.2 x 10(-4) root s). Since its commissioning in April 2007, APEX-SZ has been used to map 48 clusters. We describe the design of the receiver and its performance when installed on the APEX telescope.
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| 41. |
- Verendel, Vilhelm, 1980, et al.
(författare)
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Strategic reasoning and bargaining in catastrophic climate change games
- 2016
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Ingår i: Nature Climate Change. - : Springer Science and Business Media LLC. - 1758-6798 .- 1758-678X. ; 6:3, s. 265-268
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Tidskriftsartikel (refereegranskat)abstract
- Two decades of international negotiations show that agreeing on emission levels for climate change mitigation is a hard challenge. However, if early warning signals were to show an upcoming tipping point with catastrophic damage, theory and experiments suggest this could simplify collective action to reduce greenhouse gas emissions. At the actual threshold, no country would have a free-ride incentive to increase emissions over the tipping point, but it remains for countries to negotiate their emission levels to reach these agreements. We model agents bargaining for emission levels using strategic reasoning to predict emission bids by others and ask how this affects the possibility of reaching agreements that avoid catastrophic damage. It is known that policy elites often use a higher degree of strategic reasoning, and in our model this increases the risk for climate catastrophe. Moreover, some forms of higher strategic reasoning make agreements to reduce greenhouse gases unstable. We use empirically informed levels of strategic reasoning when simulating the model.
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| 42. |
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