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- Abdalla, E., et al.
(författare)
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Cosmology intertwined : A review of the particle physics, astrophysics, and cosmology associated with the cosmological tensions and anomalies
- 2022
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Ingår i: Journal of High Energy Astrophysics. - : Elsevier BV. - 2214-4048 .- 2214-4056. ; 34, s. 49-211
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Tidskriftsartikel (refereegranskat)abstract
- The standard Λ Cold Dark Matter (ΛCDM) cosmological model provides a good description of a wide range of astrophysical and cosmological data. However, there are a few big open questions that make the standard model look like an approximation to a more realistic scenario yet to be found. In this paper, we list a few important goals that need to be addressed in the next decade, taking into account the current discordances between the different cosmological probes, such as the disagreement in the value of the Hubble constant H0, the σ8–S8 tension, and other less statistically significant anomalies. While these discordances can still be in part the result of systematic errors, their persistence after several years of accurate analysis strongly hints at cracks in the standard cosmological scenario and the necessity for new physics or generalisations beyond the standard model. In this paper, we focus on the 5.0σ tension between the Planck CMB estimate of the Hubble constant H0 and the SH0ES collaboration measurements. After showing the H0 evaluations made from different teams using different methods and geometric calibrations, we list a few interesting new physics models that could alleviate this tension and discuss how the next decade's experiments will be crucial. Moreover, we focus on the tension of the Planck CMB data with weak lensing measurements and redshift surveys, about the value of the matter energy density Ωm, and the amplitude or rate of the growth of structure (σ8,fσ8). We list a few interesting models proposed for alleviating this tension, and we discuss the importance of trying to fit a full array of data with a single model and not just one parameter at a time. Additionally, we present a wide range of other less discussed anomalies at a statistical significance level lower than the H0–S8 tensions which may also constitute hints towards new physics, and we discuss possible generic theoretical approaches that can collectively explain the non-standard nature of these signals. Finally, we give an overview of upgraded experiments and next-generation space missions and facilities on Earth that will be of crucial importance to address all these open questions.
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- Pöntinen, M., et al.
(författare)
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Euclid: Identification of asteroid streaks in simulated images using deep learning
- 2023
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 679
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Tidskriftsartikel (refereegranskat)abstract
- The material composition of asteroids is an essential piece of knowledge in the quest to understand the formation and evolution of the Solar System. Visual to near-infrared spectra or multiband photometry is required to constrain the material composition of asteroids, but we currently have such data, especially in the near-infrared wavelengths, for only a limited number of asteroids. This is a significant limitation considering the complex orbital structures of the asteroid populations. Up to 150 000 asteroids will be visible in the images of the upcoming ESA Euclid space telescope, and the instruments of Euclid will offer multiband visual to near-infrared photometry and slitless near-infrared spectra of these objects. Most of the asteroids will appear as streaks in the images. Due to the large number of images and asteroids, automated detection methods are needed. A non-machine-learning approach based on the Streak Det software was previously tested, but the results were not optimal for short and/or faint streaks. We set out to improve the capability to detect asteroid streaks in Euclid images by using deep learning. We built, trained, and tested a three-step machine-learning pipeline with simulated Euclid images. First, a convolutional neural network (CNN) detected streaks and their coordinates in full images, aiming to maximize the completeness (recall) of detections. Then, a recurrent neural network (RNN) merged snippets of long streaks detected in several parts by the CNN. Lastly, gradient-boosted trees (XGBoost) linked detected streaks between different Euclid exposures to reduce the number of false positives and improve the purity (precision) of the sample. The deep-learning pipeline surpasses the completeness and reaches a similar level of purity of a non-machine-learning pipeline based on the StreakDet software. Additionally, the deep-learning pipeline can detect asteroids 0.25–0.5 magnitudes fainter than StreakDet. The deep-learning pipeline could result in a 50% increase in the number of detected asteroids compared to the StreakDet software. There is still scope for further refinement, particularly in improving the accuracy of streak coordinates and enhancing the completeness of the final stage of the pipeline, which involves linking detections across multiple exposures.
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- Amendola, L., et al.
(författare)
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Cosmology and fundamental physics with the Euclid satellite
- 2018
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Ingår i: Living Reviews in Relativity. - : Springer. - 1433-8351 .- 2367-3613. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- Euclid is a European Space Agency medium-class mission selected for launch in 2020 within the cosmic vision 2015–2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid’s Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.
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- Grassi, A., et al.
(författare)
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Minimally Invasive Versus Open Repair for Acute Achilles Tendon Rupture: Meta-Analysis Showing Reduced Complications, with Similar Outcomes, After Minimally Invasive Surgery
- 2018
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Ingår i: The Journal of bone and joint surgery. American volume. - 1535-1386. ; 100:22, s. 1969-1981
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There is no consensus on the optimal technique for repairing an acute Achilles tendon rupture. The purpose of this meta-analysis was to compare the complications, subjective outcomes, and functional results between minimally invasive surgery and open repair of an Achilles tendon rupture. METHODS: A systematic literature search of MEDLINE/PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), EBSCOhost, and ClinicalTrials.gov was performed. Eligible studies were randomized controlled trials (RCTs) comparing minimally invasive surgery and open repair of acute Achilles tendon ruptures. A meta-analysis was performed, while bias and the quality of the evidence were rated according to the Cochrane Database questionnaire and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines. The meta-analysis was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. RESULTS: Eight studies, with 182 patients treated with minimally invasive surgery and 176 treated with open repair, were included. The meta-analysis showed a significantly decreased risk ratio (RR) of 0.21 (95% confidence interval [CI] = 0.10 to 0.40, p = 0.00001) for overall complications and 0.15 (95% CI = 0.05 to 0.46, p = 0.0009) for wound infection after minimally invasive surgery. Patients treated with minimally invasive surgery were more likely to report good or excellent subjective results (RR = 1.18, 95% CI = 1.04 to 1.33, p = 0.009). No differences between groups were found with respect to reruptures, sural nerve injury, return to preinjury activity level, time to return to work, or ankle range of motion. The overall quality of evidence was generally low because of a substantial risk of bias, heterogeneity, indirectness of outcome reporting, and evaluation of a limited number of patients. CONCLUSIONS: There was a significantly decreased risk of postoperative complications, especially wound infection, when acute Achilles tendon rupture was treated with minimally invasive surgery compared with open surgery. Patients treated with minimally invasive surgery were significantly more likely to report a good or excellent subjective outcome. Current evidence is associated with high heterogeneity and a considerable risk of bias. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
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