| 11. |
- Dwibedi, Chinmay Kumar, 1987-
(författare)
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Francisella tularensis: persistence, dissemination and source attribution : a theoretical and computational approach
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The bacterium Francisella tularensis causing tularemia in humans and other mammals displays little genetic diversity among genomes across temporal and spatial scales. F. tularensis infects humans with an extremely low infectious dose and causes natural seasonal tularemia outbreaks. During the Cold War, this bacterium was developed as a biological weapon.In paper I, we aimed at investigating the genetic diversity of F. tularensis over space and time and were especially interested in the influence of spatial dispersal on the genetic diversity. By analyses of single-nucleotide polymorphisms (SNPs) among 205 F. tularensis genomes, we found that tularemia had moved from East to West over the European continent by dispersal patterns characterized by multiple long-range dispersal events. Evolutionary rate estimates based on the year of bacterial isolation from 1947 to 2012 indicated non-measurable rates. In outbreak areas with multiple recent outbreaks, however, there was a measurable rate of 0.4 SNPs/genome/year indicating that in areas with more intense disease activity, there is a detectable evolutionary rate. The findings suggest that long-range geographical dispersal events and mostly very low evolutionary rates are important factors contributing to a very low genetic diversity of F. tularensis populations.In paper II, we focused on a geographically restricted area with a history of frequent tularemia outbreaks to study F. tularensis persistence. By analyzing F. tularensis genomes from 138 individuals infected from 1994 to 2010 in Örebro County in Sweden and performing a long-term laboratory storage experiment, we explored the microbial population concept of a pathogen seed-bank. We found that eight indistinguishable genomes – each of them defined by no SNPs across 1.65 million whole-genome nucleotides – locally persisted over 2-9 years. We found unmeasurable SNP accumulation rates and overlapping bacterial generations among the outbreak genomes and that F. tularensis survived in saline for four years without nutrients. By these findings, and analyses of nucleotide substitution patterns, we suggest that a pathogen seed-bank effect is an important feature of F. tularensis ecology influencing genetic diversity.In paper III, we developed a new concept for source attribution of a F. tularensis sample. We aimed to identify genetic variation that is characteristic to laboratory culturing and we used culture amplification to identify genetic variation present at exceedingly low frequencies in a sample. Based on a biological enrichment scheme followed by high-throughput sequencing, we could track genetic variation back to a source sample. These results suggest that the concept has potential for linking a F. tularensis sample to its laboratory source sample.Taken together, the results presented in this thesis provide new understanding of the dissemination patterns and local persistence of tularemia. This is important for the interpretation of molecular epidemiology investigations of the disease. In a wider context, the results demonstrate how spatial dispersal and a microbial seed-bank effect may contribute to the diversity of a disease-causing agent. Finally, we have described a promising concept for source attribution of F. tularensis samples
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| 12. |
- Einarsson, Emma
(författare)
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Imaging of tissue degeneration in knee osteoarthritis using magnetic resonance and synchrotron radiation
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Osteoarthritis (OA) is a very common disease, especially in the knee. It is characterized by the breakdown of articular cartilage but involves all parts of the joint. OA is usually diagnosed at a late stage when the articular cartilage has begun to disappear. What happens before these macroscopic alterations is to alarge extent unknown. In this thesis the focus is on articular cartilage and meniscus and methods to study these tissues.Magnetic resonance imaging (MRI) is suitable for imaging of cartilage and meniscus, and quantitative imaging methods have the potential to probe the molecular composition and microstructure. Using such methods, we can gain new insight in the development of OA and the role of different structures of theknee.The results of this thesis show that MR relaxation times T2*, T2 and T1 are longer in the posterior horn of medial menisci from patients with severe medial compartment knee OA, compared both to the contralateral meniscus and menisci from deceased donors without known knee OA (Paper I). Relaxationtimes also seem to reflect more subtle changes in the meniscus as they are associated with gold standard histopathological scoring of degeneration characteristics (Paper II).gagCEST is a promising MRI method that has the potential to directly reflect the glycosaminoglycan (GAG) depletion within early degeneration of articular cartilage. However, in a phantom study in this thesis, gagCEST demonstrated a low sensitivity to the type of GAG most abundant in mature human articular cartilage (Paper III).An intrinsic limitation to MRI is the low spatial resolution. Even though MRI-based techniques may have the ability to probe the microscopic composition, other methods are needed to directly visualize the microstructure of the tissue. Here we show that synchrotron radiation (SR)-based microcomputed tomography (μCT) with phase contrast enhancement can resolve the collagen fibre structure of meniscus tissue, including fibre crimping and structural changes related to degeneration (Paper IV). Imaging of tissue samples without fixation or embedding is of interest in studies of meniscus biomechanics.The methods evaluated in this thesis have the potential to detect and follow tissue degeneration in articular cartilage and meniscus and could become valuable tools in future studies to increase our knowledge of disease progression in OA.
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| 13. |
- Fredlund, Cecilia, 1984-, et al.
(författare)
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Self-reported frequency of sex as self-injury (SASI) in a national study of Swedish adolescents and association to sociodemographic factors, sexual behaviors, abuse and mental health
- 2017
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Ingår i: Child and Adolescent Psychiatry and Mental Health. - : BioMed Central. - 1753-2000. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sex as self-injury has become a concept in Swedish society; however it is a largely unexplored area of research, not yet conceptualized and far from accepted in the research field. The use of sex as a way of affect regulation is known in the literature and has, in interviews with young women who sell sex, been compared to direct selfinjury, such as cutting or burning the skin. The aim of this study was to investigate the self-reported frequency of sex as self-injury and the association to sociodemographic factors, sexual orientation, voluntary sexual experiences, sexual risk-taking behaviors, sexual, physical and mental abuse, trauma symptoms, healthcare for psychiatric disorders and non-suicidal self-injury. Methods: A representative national sample of 5750 students in the 3rd year of Swedish high school, with a mean age of 18 years was included in the study. The study was questionnaire-based and the response rate was 59.7%. Mostly descriptive statistics were used and a final logistic regression model was made. Results: Sex as self-injury was reported by 100 (3.2%) of the girls and 20 (. 8%) of the boys. Few correlations to sociodemographic factors were noted, but the group was burdened with more experiences of sexual, physical and emotional abuse. Non-heterosexual orientation, trauma symptoms, non-suicidal self-injury and healthcare for suicide attempts, depression and eating disorders were common. Conclusions: Sex used as self-injury seems to be highly associated with earlier traumas such as sexual abuse and poor mental health. It is a behavior that needs to be conceptualized in order to provide proper help and support to a highly vulnerable group of adolescents.
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| 14. |
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| 15. |
- Hanna, Paul, et al.
(författare)
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Role model advocacy for sustainable transport
- 2018
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Ingår i: Transportation Research Part D. - : Elsevier. - 1361-9209 .- 1879-2340. ; 61:Part: B, s. 373-382
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Tidskriftsartikel (refereegranskat)abstract
- Individual aspirations of associating with role models are routinely harnessed by marketers, who for instance, use celebrity endorsement in selling brands and products. It appears there has been no research to date, however, on the potential for celebrity activism, or role model advocacy beyond celebrities, such as from politicians, to form effective interventions for encouraging sustainable transport behavior. This is despite studies suggesting that celebrity endorsement is a potential gateway for transforming public opinion on carbon intensive transport modes. The present paper consequently offers a critical review of the literature on role model advocacy and celebrity activism, and how these concepts have been harnessed to address environmental issues, in order to conceptually assess the potential for extending these intervention techniques to the context of sustainable transport. The scope of the paper includes the potential that high profile politicians/celebrities might play as role models in exercising referent power to influence social norms surrounding sustainable transport, given that the success of social marketing interventions are closely tied to the need for changes in the policy landscape. Key dimensions of role model endorsement in transport are identified and applied to a series of examples of how celebrity and political role models have influenced transport cultures. In addition to offering an original application of a theoretical framework to a new context, in order to help address the increasingly important societal issue of transport's growing contribution to climate change, the paper discusses the challenges associated with the neoliberal framing of this approach.
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| 16. |
- Holm, Olof, 1973-
(författare)
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The Use of Silver as a Medium of Exchange in Jämtland, c. 875–1050
- 2017
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Ingår i: Viking-age transformations. - London : Routledge. - 9781472470775 ; , s. 42-58
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Bokkapitel (refereegranskat)abstract
- At Viking-period emporia such as Kaupang and Birka there is an abundance of archaeological evidence of silver being used as money. But what about rural areas in Scandinavia? This paper discusses a regional case: an area located inland, right in the middle of the Scandinavian Peninsula, namely the province of Jämtland. One could perhaps presume that in a remote rural region like this (as seen from Viking period trading centres) silver was not used in trading activities to any large extent among the populace. But the archaeological evidence from the middle and late Viking period suggests the opposite.
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| 17. |
- Huang, Rujing, et al.
(författare)
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Beyond Diverse Datasets : Responsible MIR, Interdisciplinarity, and the Fractured Worlds of Music
- 2023
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Ingår i: Transactions of the International Society for Music Information Retrieval. - : Ubiquity Press, Ltd.. - 2514-3298. ; 6:1, s. 43-59
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Tidskriftsartikel (refereegranskat)abstract
- Musical worlds, not unlike our lived realities, are fundamentally fragmented and diverse, a fact often seen as a challenge or even a threat to the validity of research in Music Information Research (MIR). In this article, we propose to treat this characteristic of our musical universe(s) as an opportunity to fundamentally enrich and re-orient MIR. We propose that the time has arrived for MIR to reflect on its ethical and cultural turns (if they have been initiated at all) and take them a step further, with the goal of profoundly diversifying the discipline beyond the diversification of datasets. Such diversification, we argue, is likely to remain superficial if it is not accompanied by a simultaneous auto-critique of the discipline’s raison d’être. Indeed, this move to diversify touches on the philosophical underpinnings of what MIR is and should become as a field of research: What is music (ontology)? What are the nature and limits of knowledge concerning music (epistemology)? How do we obtain such knowledge (methodology)? And what about music and our own research endeavor do we consider “good” and “valuable” (axiology)? This path involves sincere inter- and intra-disciplinary struggles that underlie MIR, and we point to “agonistic interdisciplinarity” — that we have practiced ourselves via the writing of this article — as a future worth reaching for. The two featured case studies, about possible philosophical re-orientations in approaching ethics of music AI and about responsible engineering when AI meets traditional music, indicate a glimpse of what is possible.
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| 18. |
- Huang, Sheng, et al.
(författare)
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On achievability of linear source coding over finite rings
- 2013
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Ingår i: IEEE International Symposium on Information Theory. - : IEEE conference proceedings. - 9781479904464 ; , s. 1984-1988
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Konferensbidrag (refereegranskat)abstract
- We propose using linear mappings over finite rings as encoders in the Slepian-Wolf and the source coding for computing problems. It is known that the arithmetic of many finite rings is substantially easier to implement than the one of finite fields. Hence, one of the advantages of using linear mappings over rings, instead of its field counterparts, is reducing implementation complexity. More importantly, the ring version dominates the field version in terms of achieving strictly better coding rates with strictly smaller alphabet size in the source coding for computing problem [1]. This paper is dedicated to proving an achievability theorem of linear source coding over finite rings in the Slepian-Wolf problem. This result includes those given by Elias [2] and Csiszár [3] saying that linear coding over finite fields is optimal, i.e. achieves the Slepian-Wolf region. Although the optimality issue remains open, it has been verified in various scenarios including particularly many cases use non-field rings [1], [4].
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| 19. |
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| 20. |
- Larsson Ringqvist, Eva
(författare)
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Le développement des connaissances métalinguistiques des apprenants de francais langue étrangère
- 2006
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Ingår i: Synergies Pays Scandinaves. - : Systime A/S och Gerflint, Århus. - 1901-3809. ; :1, s. 100-113
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Tidskriftsartikel (refereegranskat)abstract
- Dans cet article seront présentés les résultats préliminaires d’un projet de recherche qui vise à capter les représentations mentales des étudiants suédophones du français langue étrangère dans un domaine de la grammaire française qui continue à poser des problèmes même à un niveau avancé, à savoir la distinction entre les temps du passé. Les connaissances métalinguistiques des apprenants évoluent vraisemblablement sous l’influence de divers facteurs présents dans l’enseignement : les textes des manuels, les explications fournies en classe et l’exposition des apprenants à la langue elle-même. Même s’il s’agit, en premier lieu, d’une acquisition du savoir sur le mode explicite, il existe des indices que l’acquisition se fait simultanément aussi sur le mode implicite. L’établissement des représentations chez les apprenants suppose, dans les deux cas, une phase d’interprétation et de reconstruction du savoir, ce qui rend plausible l’existence d’écarts entre les représentations individuelles de différents apprenants, et entre les représentations des apprenants et celles des enseignants et des grammairiens. Ces écarts risquent d’être cachés par l’utilisation commune d’une terminologie non scientifique relativement vague, ce qui indique la nécessité d’une négociation continue et approfondie du sens des notions fondamentales.
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