| 1. |
- Agredo Chavez, Angelica Maria, et al.
(författare)
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Cracking and Fatigue of Heavy Loaded Prestressed Concrete Bridge in Sweden
- 2022
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Ingår i: IABSE Symposium Prague 2022: Challenges for Existing and Oncoming Structures - Report, International Association for Bridge and Structural Engineering. - Zürich : International Association for Bridge and Structural Engineering. ; , s. 792-799
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Konferensbidrag (refereegranskat)abstract
- A prestressed concrete bridge was built in 1963 with BBRV cables. It has three spans and a total length of 134.8 m. Due to mining activities the bridge was loaded with trucks with a total weight of 90 ton during 2012-2014 and from 2019. Crack development has been monitored manually and from 2020 with strain gauges and LVDTs.Cracks normally vary between 0.1 to 0.3 mm in width and grow in length with time. In November 2020 some of the strain gauges on the concrete showed alarming growth and the bridge was closed for traffic. Additional strain gauges were installed on vertical reinforcement bars and an assessment was carried out of the fatigue capacity of the bridge. It was found that the new strain gauges did not indicate any growth in strain and that the fatigue capacity was sufficient. The bridge could be opened again for traffic after being closed for five weeks. Monitoring drift in the strain gauges and fatigue are discussed.
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| 2. |
- Ahlborg, Mikael G., et al.
(författare)
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SoCap YMH - youth mental health, social capital and help-seeking : a study protocol
- 2024
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Ingår i: Frontiers in Public Health. - : Frontiers Media S.A.. - 2296-2565. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: The increase in adolescents reporting mental health problems presents a major public health challenge. The complex association between mental health and social capital motivates further investigation of social capital as a crucial aspect in shaping adolescents' help-seeking knowledge, attitudes, and behaviours.Aim: This protocol presents a project that aims to investigate social capital in relation to help-seeking and mental health in close collaboration with adolescents and key stakeholders in the school setting, in the southern part of Sweden.Methods: A mixed-method design with three interconnected work packages (WP) will be undertaken with an emphasis on co-production where adolescents are involved throughout the process. WP1 is a development and validation of two questionnaire instruments for assessing social capital and help-seeking in adolescence. WP2 is a longitudinal quantitative study involving 1,500 adolescents from two regions representing rural and suburban/urban settings. Adolescents aged 15 will be asked to complete questionnaires concerning social capital, mental health, and help-seeking in a baseline and one-year follow-up, allowing for investigation of the role of social capital for help-seeking. WP3 is designed to elucidate experiences and knowledge of adolescents and key stakeholders via collaborative World Café workshops. These will be held along the project to evolve the generated knowledge and maximize it's applicability during and after the project is finalized.Conclusion: The results are expected to further the understanding of the relationship between adolescents' social capital, mental health, and help-seeking, to contribute to a deeper understanding of the mechanisms behind the paradoxical help-seeking patterns among adolescents today and to narrow the gap between research and practice to produce sustainable and efficient strategies, which may facilitate help-seeking and improve the mental health of adolescents within existing organizational structures.
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| 3. |
- Ahlborg, Mikael, 1985-, et al.
(författare)
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SoCap YMH - youth mental health, social capital and help-seeking : a study protocol
- 2024
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Ingår i: Frontiers in Public Health. - Lausanne : Frontiers Media S.A.. - 2296-2565. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Background: The increase in adolescents reporting mental health problems presents a major public health challenge. The complex association between mental health and social capital motivates further investigation of social capital as a crucial aspect in shaping adolescents' help-seeking knowledge, attitudes, and behaviours. Aim: This protocol presents a project that aims to investigate social capital in relation to help-seeking and mental health in close collaboration with adolescents and key stakeholders in the school setting, in the southern part of Sweden. Methods: A mixed-method design with three interconnected work packages (WP) will be undertaken with an emphasis on co-production where adolescents are involved throughout the process. WP1 is a development and validation of two questionnaire instruments for assessing social capital and help-seeking in adolescence. WP2 is a longitudinal quantitative study involving 1,500 adolescents from two regions representing rural and suburban/urban settings. Adolescents aged 15 will be asked to complete questionnaires concerning social capital, mental health, and help-seeking in a baseline and one-year follow-up, allowing for investigation of the role of social capital for help-seeking. WP3 is designed to elucidate experiences and knowledge of adolescents and key stakeholders via collaborative World Café workshops. These will be held along the project to evolve the generated knowledge and maximize it's applicability during and after the project is finalized. Conclusion: The results are expected to further the understanding of the relationship between adolescents' social capital, mental health, and help-seeking, to contribute to a deeper understanding of the mechanisms behind the paradoxical help-seeking patterns among adolescents today and to narrow the gap between research and practice to produce sustainable and efficient strategies, which may facilitate help-seeking and improve the mental health of adolescents within existing organizational structures. Copyright © 2024 Ahlborg, Morgan, Svedberg, Nygren, Eriksson and Westberg.
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| 4. |
- Ahlström, Christer, et al.
(författare)
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Assessing Aortic Stenosis using Sample Entropy of the Phonocardiographic Signal in Dogs
- 2008
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Ingår i: IEEE Transactions on Biomedical Engineering. - 0018-9294 .- 1558-2531. ; 55:8, s. 2107-2109
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Tidskriftsartikel (refereegranskat)abstract
- In aortic valve stenosis (AS), heart murmurs arise as an effect of turbulent blood flow distal to the obstructed valves. With increasing AS severity, the flow becomes more unstable, and the ensuing murmur becomes more complex. We hypothesize that these hemodynamic flow changes can be quantified based on the complexity of the phonocardiographic (PCG) signal. In this study, sample entropy (SampEn) was investigated as a measure of complexity using a dog model. Twenty-seven boxer dogs with various degrees of AS were examined with Doppler echocardiography, and the peak aortic flow velocity (Vmax) was used as a reference of AS severity. SampEn correlated to Vmax with R = 0.70 using logarithmic regression. In a separate analysis, significant differences were found between physiologic murmurs and murmurs caused by AS (p < 0.05), and the area under a receiver operating characteristic curve was calculated to 0.96. Comparison with previously presented PCG measures for AS assessment showed improved performance when using SampEn, especially for differentiation between physiological murmurs and murmurs caused by mild AS. Studies in patients will be needed to properly assess the technique in humans.
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| 5. |
- Ahlström, Christer, 1977-, et al.
(författare)
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Distinguishing Innocent Murmurs from Murmurs caused by Aortic Stenosis by Recurrence Quantification Analysis
- 2006
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Ingår i: ROCEEDINGS OF WORLD ACADEMY OF SCIENCE, ENGINEERING AND TECHNOLOGY, VOL 18. - Canakkale, Turkey : World Academy of Science, Engineering and Technology (W A S E T). ; , s. 40-45
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Konferensbidrag (refereegranskat)abstract
- It is sometimes difficult to differentiate between innocent murmurs and pathological murmurs during auscultation. In these difficult cases, an intelligent stethoscope with decision support abilities would be of great value. In this study, using a dog model, phonocardiographic recordings were obtained from 27 boxer dogs with various degrees of aortic stenosis (AS) severity. As a reference for severity assessment, continuous wave Doppler was used. The data were analyzed with recurrence quantification analysis (RQA) with the aim to find features able to distinguish innocent murmurs from murmurs caused by AS. Four out of eight investigated RQA features showed significant differences between innocent murmurs and pathological murmurs. Using a plain linear discriminant analysis classifier, the best pair of features (recurrence rate and entropy) resulted in a sensitivity of 90% and a specificity of 88%. In conclusion, RQA provide valid features which can be used for differentiation between innocent murmurs and murmurs caused by AS.
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| 6. |
- Axelsson, Erik, et al.
(författare)
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The genetic consequences of dog breed formation-Accumulation of deleterious genetic variation and fixation of mutations associated with myxomatous mitral valve disease in cavalier King Charles spaniels
- 2021
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 17:9
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Tidskriftsartikel (refereegranskat)abstract
- Selective breeding for desirable traits in strictly controlled populations has generated an extraordinary diversity in canine morphology and behaviour, but has also led to loss of genetic variation and random entrapment of disease alleles. As a consequence, specific diseases are now prevalent in certain breeds, but whether the recent breeding practice led to an overall increase in genetic load remains unclear. Here we generate whole genome sequencing (WGS) data from 20 dogs per breed from eight breeds and document a similar to 10% rise in the number of derived alleles per genome at evolutionarily conserved sites in the heavily bottlenecked cavalier King Charles spaniel breed (cKCs) relative to in most breeds studied here. Our finding represents the first clear indication of a relative increase in levels of deleterious genetic variation in a specific breed, arguing that recent breeding practices probably were associated with an accumulation of genetic load in dogs. We then use the WGS data to identify candidate risk alleles for the most common cause for veterinary care in cKCs-the heart disease myxomatous mitral valve disease (MMVD). We verify a potential link to MMVD for candidate variants near the heart specific NEBL gene in a dachshund population and show that two of the NEBL candidate variants have regulatory potential in heartderived cell lines and are associated with reduced NEBL isoform nebulette expression in papillary muscle (but not in mitral valve, nor in left ventricular wall). Alleles linked to reduced nebulette expression may hence predispose cKCs and other breeds to MMVD via loss of papillary muscle integrity.
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| 7. |
- Bagge, Niklas, 1987-, et al.
(författare)
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Full Scale Test of a PC Bridge to Calibrate Assessment Methods
- 2021
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Ingår i: IABSE Congress Ghent 2021. - Zurich, Switzerland : International Association for Bridge and Structural Engineering (IABSE). ; , s. 965-973
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Konferensbidrag (refereegranskat)abstract
- In this paper, experiences on the development of an assessment method for existing bridges are presented. The method is calibrated using the results of full-scale testing to failure of a prestressed bridge in Sweden. To evaluate the key parameters for the structural response, measured by deflections, strains in tendons and stirrups and crack openings, a sensitivity study based on the concept of fractional factorial design is incorporated to the assessment. Results showed that the most significant parameters are related to the tensile properties of the concrete (tensile strength and fracture energy) and the boundary conditions. A finite element (FE) model in which the results of the sensitivity analysis were applied, was able to predict accurately the load-carrying capacity of the bridge and its failure mode. Two additional existing prestressed concrete bridges, that will be used to improve further the method, are also described, and discussed.
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| 8. |
- Bayane, Imane, et al.
(författare)
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Real-Time Crack Detection in Bridges Using Monitoring and Machine Learning-Verified with an Actual Damage Case
- 2023
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Ingår i: Structural Health Monitoring 2023: Designing SHM for Sustainability, Maintainability, and Reliability - Proceedings of the 14th International Workshop on Structural Health Monitoring. - : DEStech Publications. ; , s. 1636-1644
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Konferensbidrag (refereegranskat)abstract
- Detecting damage in bridges that present signs of deterioration or have exceeded the expected lifespan is critical for ensuring safety in service. This paper suggests an approach for real-time damage detection for such bridges through monitoring and machine learning algorithms, which serve as timely alarms for decision-making and subsequent damage identification. The approach involves five steps: monitoring, data collection, data separation, feature extraction, and anomaly detection in real-time. Monitoring is ensured by strain gauges, accelerometers, and a temperature sensor. Data collection is ensured at high frequency continuously to capture the dynamic effects of loading. Data separation is provided to classify monitoring data according to loading events, which is in the case of the study characterized by the bridge opening, the bridge closing, and train passages. Feature extraction is provided to characterize monitoring data for each loading event. Anomaly detection is performed by the Isolation Forest and the One-Class Support Vector Machine algorithms. The algorithms are implemented in real-time for each new event. The approach is illustrated in a full-scale post-damage case study of a steel-bascule-railway bridge, in service since 1916, with signs of corrosion and fatigue. The results demonstrate the ability of the approach to capture a cracking event in real-time. The Isolation Forest algorithm is found to be more robust for damage detection compared to the One-Class Support Vector Machine. It assigned high scores to the events occurring during and after the cracking, highlighting its ability to capture such incidents promptly. These findings have significant implications for bridge owners as they can identify damage in components in real time, enabling them to take timely measures such as traffic interruption and subsequent repairs.
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| 9. |
- Bergström, Tomas F., et al.
(författare)
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First genome-wide CNV mapping in FELIS CATUS using next generation sequencing data
- 2018
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Ingår i: BMC Genomics. - : Springer Science and Business Media LLC. - 1471-2164. ; 19
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCopy Number Variations (CNVs) have becoming very significant variants, representing a major source of genomic variation. CNVs involvement in phenotypic expression and different diseases has been widely demonstrated in humans as well as in many domestic animals. However, genome wide investigation on these structural variations is still missing in Felis catus. The present work is the first CNV mapping from a large data set of Next Generation Sequencing (NGS) data in the domestic cat, performed within the 99 Lives Consortium.ResultsReads have been mapped on the reference assembly_6.2 by Maverix Biomics. CNV detection with cn.MOPS and CNVnator detected 592 CNVs. These CNVs were used to obtain 154 CNV Regions (CNVRs) with BedTools, including 62 singletons. CNVRs covered 0.26% of the total cat genome with 129 losses, 19 gains and 6 complexes. Cluster Analysis and Principal Component Analysis of the detected CNVRs showed that breeds tend to cluster together as well as cats sharing the same geographical origins. The 46 genes identified within the CNVRs were annotated.ConclusionThis study has improved the genomic characterization of 14 cat breeds and has provided CNVs information that can be used for studies of traits in cats. It can be considered a sound starting point for genomic CNVs identification in this species.
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| 10. |
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