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- Ahlinder, Jon, et al.
(författare)
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Increased knowledge of Francisella genus diversity highlights the benefits of optimised DNA-based assays
- 2012
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 12, s. 220-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recent advances in sequencing technologies offer promising tools for generating large numbers of genomes, larger typing databases and improved mapping of environmental bacterial diversity. However, DNA-based methods for the detection of Francisella were developed with limited knowledge about genetic diversity. This, together with the high sequence identity between several Francisella species, means there is a high risk of false identification and detection of the highly virulent pathogen Francisella tularensis. Moreover, phylogenetic reconstructions using single or limited numbers of marker sequences often result in incorrect tree topologies and inferred evolutionary distances. The recent growth in publicly accessible whole-genome sequences now allows evaluation of published genetic markers to determine optimal combinations of markers that minimise both time and laboratory costs. Results: In the present study, we evaluated 38 previously published DNA markers and the corresponding PCR primers against 42 genomes representing the currently known diversity of the genus Francisella. The results highlight that PCR assays for Francisella tularensis are often complicated by low specificity, resulting in a high probability of false positives. A method to select a set of one to seven markers for obtaining optimal phylogenetic resolution or diagnostic accuracy is presented. Conclusions: Current multiple-locus sequence-typing systems and detection assays of Francisella, could be improved by redesigning some of the primers and reselecting typing markers. The use of only a few optimally selected sequence-typing markers allows construction of phylogenetic topologies with almost the same accuracy as topologies based on whole-genome sequences.
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| 2. |
- Karlsson, Edvin, et al.
(författare)
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The phylogeographic pattern of Francisella tularensis in Sweden indicates a Scandinavian origin of Eurosiberian tularaemia
- 2013
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Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 15:2, s. 634-645
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Tidskriftsartikel (refereegranskat)abstract
- Previous studies of the causative agent of tularaemia, Francisella tularensis have identified phylogeographic patterns suggestive of environmental maintenance reservoirs. To investigate the phylogeography of tularaemia in Sweden, we selected 163 clinical isolates obtained during 1995-2009 in 10 counties and sequenced one isolate's genome to identify new genetic markers. An improved typing scheme based on two indels and nine SNPs was developed using hydrolysis or TaqMan MGB probe assays. The results showed that much of the known global genetic diversity of F. tularensis subsp. holarctica is present in Sweden. Thirteen of the 163 isolates belonged to a new genetic group that is basal to all other known members of the major genetic clade B.I, which is spread across the Eurosiberian region. One hundred and twenty-five of the 163 Swedish isolates belonged to B.I, but individual clades' frequencies differed from county to county (P < 0.001). Subsequent analyses revealed a correlation between genotype variation over time and recurrent outbreaks at specific places, supporting the 'maintenance reservoir' environmental maintenance hypothesis. Most importantly, the findings reveal the presence of diverse source populations of F. tularensis subsp. holarctica in Sweden and suggest a historical spread of the disease from Scandinavia to other parts of Eurosiberia.
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| 5. |
- Lundborg, Petter, et al.
(författare)
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GETTING READY FOR THE MARRIAGE MARKET? A RESPONSE
- 2012
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Ingår i: Journal of Biosocial Science. - : Cambridge University Press. - 0021-9320 .- 1469-7599. ; 44:2, s. 235-242
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Overweight and obesity constitute a major and increasing health and welfare problem throughout the world. Assessing the multifaceted mechanisms - biological, environmental and behavioural - behind this development is a crucial task in medical, social and economic sciences. We are, therefore, grateful to have been given the opportunity to, once again, discuss whether the risk of divorce may be one of the factors influencing the incentives of becoming overweight or obese and, hence, ultimately the physical appearance among the married. In this Debate, colleagues Schneider and Grimps present the results of a multilevel analysis, in which they could not identify any statistically significant association between body mass index (BMI) and divorce risk among married people. Thus, they question the findings, previously published in this Journal (Lundborg et al., 2007). The Schneider and Grimps arguments are not convincing, however. So, we still claim that the statistical material at hand does, indeed, imply that divorce risk at the national level may well influence the weight of the married.
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| 9. |
- Nakeva von Mentzer, Cecilia, et al.
(författare)
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Computer-assisted intervention for children with hearing impairment : Cognitive factors and phonological change
- 2013
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Ingår i: CHSCOM2013. - : Linköping University Electronic Press.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Thirty-two children with hearing impairment (HI) using cochlear implants (CI) and/or hearing aids (HA), and sixteen with normal hearing (NH) participated in a computer-assisted intervention study that focused on perceiving and memorizing phonemic sounds. The first purpose was to study cognitive abilities in NH and HI children, how they related to phonological processing skills (PhPS) pre intervention and to phonological growth post intervention. The second purpose was to analyze children’s performance at different fine-grained levels of phonological processing, i.e. how they manipulated, stored and produced phonological entities of different size with or without semantic content. This was put in relation to children’s type of auditory stimulation (electrical; bilateral CI, bimodal: CI + HA and acoustical; bilateral HA). Results showed significant correlations between complex working memory and PhPS in children with HI but not in children with NH. This suggests different cognitive strategies in the children when dealing with phonological processing tasks. Poor phoneme discrimination was the strongest predictor of phonological growth in the children with HI as a function of training. Thus, the computer-assisted program was beneficial for HI children with weak initial phoneme discrimination skills. Children with CI showed reduced performance at fine-grained levels of receptive phonological processing but not on expressive phonological lexical tasks.
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| 10. |
- Nakeva von Mentzer, Cecilia, et al.
(författare)
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Computer-assisted intervention for Deaf and Hard of hearing (D/HH) children with cochlear implants or hearing aids : Cognitive factors and phonological change
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aim: Study cognitive abilities; specifically working memory and lexical access in NH and DHH children, and their correlations to phonological processing skills (PhPS) pre intervention. Analyze how cognitive abilities related to phonological change post intervention. Material and Method: Tasks for lexical access, complex and visual working memory and Phpr were assessed pre and post intervention.Conclusion: DHH children performed at a lower level than NH children on lexical access but equally on complex and visual working memory. Significant correlations between complex working memory and PhPS were evident in DHH children but not in NH. This suggests that DHH children recruit more cognitive resources when performing PhPr tasks. Weak initial performance on a task for phonological representations (Phrep) was the only significant predictor of phonological change in DHH children. Weak PhRep was associated with a higher age at diagnosis, higher age at implant, and shorter usage-time with CI.
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