| 1. |
- Herzan, A., et al.
(author)
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Detailed spectroscopy of Bi-195
- 2017
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In: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 96:1
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Journal article (peer-reviewed)abstract
- An experiment focused on the study of shape coexistence and new high-spin structures in Bi-195 has been performed. The nucleus is in a transitional region of the bismuth isotope chain. A large number of new states have been found, resulting in a significant extension of the previously known level scheme. Several new collective structures have been identified. A strongly coupled rotational band built upon the 13/2(+) isomeric state was extended up to I-pi = (49/2(+)) and an energy of 5706 keV. The I-pi = 31/2(+) member of the pi i(13/2) band was also found to feed a new long-lived isomeric state with an excitation energy of 2616 keV and a spin and parity of I-pi = 29/2(+). The half-life of the 29/2+ isomeric state was determined to be 1.49(1) mu s. It decays via the emission of 457-keV E2 and 236-keV E1 transitions, respectively. A low-energy 46-keV E2 transition has been identified to depopulate the (29/(2-)) isomeric state, with a measured half-life of T-1/2 = 614(5) ns. This transition allows the excitation energy of the isomeric state to be determined as 2381 keV. The feeding patterns of both 29/2(+) and (29/2(-)) isomeric states have also been described. This is the first time collective structures have also been observed up to high spins and excitation energies in the neutron-deficient Bi-195 nucleus. Evidence for the manifestation of shape coexistence in Bi-195 is also discussed.
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| 2. |
- Berdan, Emma L, 1983, et al.
(author)
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Mutation accumulation opposes polymorphism: supergenes and the curious case of balanced lethals
- 2022
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In: Philosophical Transactions of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8436 .- 1471-2970. ; 377:1856
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Journal article (peer-reviewed)abstract
- Supergenes offer spectacular examples of long-term balancing selection in nature, but their origin and maintenance remain a mystery. Reduced recombination between arrangements, a critical aspect of many supergenes, protects adaptive multi-trait phenotypes but can lead to mutation accumulation. Mutation accumulation can stabilize the system through the emergence of associative overdominance (AOD), destabilize the system, or lead to new evolutionary outcomes. One outcome is the formation of maladaptive balanced lethal systems, where only heterozygotes remain viable and reproduce. We investigated the conditions under which these different outcomes occur, assuming a scenario of introgression after divergence. We found that AOD aided the invasion of a new supergene arrangement and the establishment of a polymorphism. However, this polymorphism was easily destabilized by further mutation accumulation, which was often asymmetric, disrupting the quasi-equilibrium state. Mechanisms that accelerated degeneration tended to amplify asymmetric mutation accumulation between the supergene arrangements and vice-versa. As the evolution of balanced lethal systems requires symmetric degeneration of both arrangements, this leaves only restricted conditions for their evolution, namely small population sizes and low rates of gene conversion. The dichotomy between the persistence of polymorphism and degeneration of supergene arrangements likely underlies the rarity of balanced lethal systems in nature.This article is part of the theme issue 'Genomic architecture of supergenes: causes and evolutionary consequences'.
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| 3. |
- Hugoson, Anders, et al.
(author)
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Caries prevalence and distribution in 20-80-year-olds in Jönköping, Sweden, in 1973, 1983, and 1993
- 2000
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In: Community Dentistry and Oral Epidemiology. - 0301-5661 .- 1600-0528. ; 28:2, s. 90-96
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Journal article (peer-reviewed)abstract
- In 1973, a cross-sectional study on oral health status was performed on 1000 individuals in the age groups 3-70 years in Jönköping, Sweden. In 1983 and 1993, new cross-sectional studies were carried out in the age groups 3-80 years. The aim of the present study was to analyze caries prevalence and distribution in the three investigations 1973, 1983, and 1993 in the age groups 20-80 years. In the younger age groups (20-40 years), a larger proportion of individuals with good oral health was found in 1993 than in 1973 or 1983. A steady increase in the number of teeth in the age groups 40-80 years could be found, which was also reflected in the increasing number of decayed and filled tooth surfaces (DFS) in the same age groups. A marked decrease in proximal DFS in 20-50-year-olds in 1993 compared to 1973 and 1983 was found. However, a rather large and unchanging group of individuals suffering from severe caries was also observed. This situation demands an individualized caries treatment strategy based on risk assessment.
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| 4. |
- Hugoson, Anders, et al.
(author)
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Oral health of individuals aged 3-80 years in Jönköping, Sweden in 1973, 1983, and 1993 : II. Review of clinical and radiographic findings
- 1995
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In: Swedish Dental Journal. - 0347-9994. ; 19:6, s. 243-260
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Journal article (peer-reviewed)abstract
- The aim of this epidemiological study was to analyse various clinical and radiographic data on oral health and compare the results to those of two cross-sectional studies carried out in 1973 and 1983. In 1973, 1983, and 1993 a random sample of 1000, 1104, and 1078 individuals, respectively were studied. The individuals were evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60, and 70 years. In 1983 and 1993 80-year-olds were also included. All subjects were inhabitants of the community of Jönköping, Sweden. The clinical and radiographic examination assessed edentulousness, removable dentures, implants, number of teeth, caries, restorations and overhangs, oral hygiene, calculus, periodontal status, endodontic treatment, and periapical status. The number of edentulous individuals was reduced by half from 1973 to 1993 and is now 8% in the age groups 40-70 years. The mean number of teeth has increased and up to the age of 50 years the individuals had more or less complete dentitions. During the 20-year period there was generally decreasing number of carious lesions and restorations. In the 15- and 20-year-olds, however, there was an increasing number of decayed/filled tooth surfaces in 1993 compared to 1983. Furthermore, after the age of 50 there was an increase in number of restored tooth surfaces. As regards secondary caries there was an increase for the 10- and 15-year-olds between 1983 and 1993. For all other age groups there were only minor differences. Generally restorations exhibited a high quality and 85-90% had no proximal overhangs. In 1973 this figure was about 60%. Concerning the frequency of tooth surfaces exhibiting plaque and gingival inflammation there was a considerable decrease from 1973 to 1983, but during the period from 1983 to 1993 there seems to be no improvement. In some age groups there was even a significant increase in plaque (15-year-olds) and gingivitis (3-, 5-, 15-, 20-, and 60-year-olds). The frequency of individuals with one or more periodontal pockets (> 4 mm) increased with age. In 1993 the bone level at the age of 40 years corresponded to the bone level at the age of 20 years in 1973. The percentage of endodontically treated teeth was lower in 1993 in all age groups than in 1973 and 1983. The percentage of endodontically treated teeth with periapical or juxtaradicular destructions was unchanged in all three studies. The comparison of the three studies from 1973, 1983, and 1993 shows that there has been a great improvement in oral health over this 20-year period. In 1993, however, the increasing number of decayed/filled tooth surfaces in the 15- and 20-year-olds and an increase in plaque and gingivitis in some younger age groups calls for special attention.
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| 5. |
- Hugoson, Anders, et al.
(author)
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Oral health of individuals aged 3-80 years in Jönköping, Sweden in 1973, 1983, and 1993 : I. Review of findings on dental care habits and knowledge of oral health
- 1995
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In: Swedish Dental Journal. - 0347-9994. ; 19:6, s. 225-241
-
Journal article (peer-reviewed)abstract
- The aim of the present study was to compare data on dental care habits and knowledge of oral health in three cross-sectional studies carried out in 1973, 1983, and 1993. The 1973 study constituted a random sample of 1000 individuals evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60, and 70 years. The same age groups with addition of a group of 80-year-olds were included in the 1983 and 1993 studies which comprised 1104 and 1078 individuals, respectively. A questionnaire (23-101 questions) about dental care habits and knowledge of oral health was used in connection with a clinical and radiographic examination. The same questions were used in all the three studies. An addition to the 1993 investigation was questions concerning ethnographic background. In 1993 approximately 95% of all individuals were visiting the dentist on a regular basis every or every second year. The 30-year-olds, however, did not visit a dentist as regularly in 1993 as in 1983. The 70- and 80-year-olds visited a dentist more regularly in 1993 than in 1983. An increased number of adults in all age groups, except for the 70-year-olds, received their dental care in the Public Dental Service in 1993 compared to 1983 and 1973. Most 40-year-olds and older, however, received their dental care by private practitioners. About 80% of all adults in 1993 were enrolled in a recall system on the dentist's initiative while in 1973 most appointments were based on the patient's own initiative. The number of individuals who felt discomfort at the prospect of an appointment with the dentist was more or less the same in 1973, 1983, and 1993. The knowledge of the etiology of dental diseases has not changed much between 1973 and 1993. The frequency of toothbrushing has increased since 1973 and in 1993 more than 95% of all individuals brushed their teeth daily. The use of dental floss and toothpicks as well as disclosing tablets decreased in 1993 compared to 1983. Almost all individuals in 1993 used fluoride toothpaste. The use of topical fluorides and fluoride tablets in children had decreased considerably in 1993 compared to 1983.
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| 6. |
- Pesková, R. E., et al.
(author)
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Second language and mother tongue education for immigrant children in Nordic educational policies : Search for a common nordic dimension
- 2024
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In: Scrutinising the Nordic Dimension in Education. - : Taylor & Francis Group. - 9781040108161 - 9781032674537 ; , s. 190-207
-
Book chapter (other academic/artistic)abstract
- The purpose of this chapter is to investigate whether and how a common Nordic dimension underlies existing policies on second language (L2) and immigrant mother tongue (L1) education. Our research question was: What do policy documents in the five Nordic countries say about L2 and L1 instruction? The theoretical foundation lies in the research fields of language policies and social justice. Document analysis was used to analyze policy documents. Our results show that there is a common Nordic dimension regarding L2 and L1 instruction, demonstrated through an explicit ambition to provide opportunities for the education of immigrant students in L2 and L1. However, there are differences between the Nordic countries in their commitment to principles of social justice, and how the policies are implemented.
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| 7. |
- Slotte, Tanja, et al.
(author)
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Genomic Determinants of Protein Evolution and Polymorphism in Arabidopsis
- 2011
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In: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 3, s. 1210-1219
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Journal article (peer-reviewed)abstract
- Recent results from Drosophila suggest that positive selection has a substantial impact on genomic patterns of polymorphism and divergence. However, species with smaller population sizes and/or stronger population structure may not be expected to exhibit Drosophila-like patterns of sequence variation. We test this prediction and identify determinants of levels of polymorphism and rates of protein evolution using genomic data from Arabidopsis thaliana and the recently sequenced Arabidopsis lyrata genome. We find that, in contrast to Drosophila, there is no negative relationship between nonsynonymous divergence and silent polymorphism at any spatial scale examined. Instead, synonymous divergence is a major predictor of silent polymorphism, which suggests variation in mutation rate as the main determinant of silent variation. Variation in rates of protein divergence is mainly correlated with gene expression level and breadth, consistent with results for a broad range of taxa, and map-based estimates of recombination rate are only weakly correlated with nonsynonymous divergence. Variation in mutation rates and the strength of purifying selection seem to be major drivers of patterns of polymorphism and divergence in Arabidopsis. Nevertheless, a model allowing for varying negative and positive selection by functional gene category explains the data better than a homogeneous model, implying the action of positive selection on a subset of genes. Genes involved in disease resistance and abiotic stress display high proportions of adaptive substitution. Our results are important for a general understanding of the determinants of rates of protein evolution and the impact of selection on patterns of polymorphism and divergence.
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| 8. |
- Slotte, T., et al.
(author)
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Intrageneric phylogeny of Capsella (Brassicaceae) and the origin of the tetraploid C-bursa-pastoris based on chloroplast and nuclear DNA sequences
- 2006
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In: American Journal of Botany. - : Wiley. - 0002-9122 .- 1537-2197. ; 93:11, s. 1714-1724
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Journal article (peer-reviewed)abstract
- Polyploidization, often accompanied by hybridization, has been of major importance in flowering plant evolution. Here we investigate the importance of these processes for the evolution of the tetraploid crucifer Capsella bursa-pastoris using DNA sequences from two chloroplast loci as well as from three nuclear low-copy genes. The near-absence of variation at the C. bursa-pastoris chloroplast markers suggests a single and recent origin of the tetraploid. However, despite supporting a single phylogeny, chloroplast data indicate that neither of the extant Capsella diploids is the maternal parent of the tetraploid. Combined with data from the three nuclear loci, our results do not lend support to previous hypotheses on the origin of C. bursa-pastoris as an allopolyploid between the diploids C. grandiflora and C. rubella or an autopolyploid of C. grandiflora. Nevertheless, for each locus, some of the C. bursa-pastoris accessions harbored C. rubella alleles, indicating that C. rubella contributed to the gene pool of C. bursa-pastoris, either through allopolyploid speciation or, more likely, through hybridization and introgression. To our knowledge, this study is the first of a wild, nonmodel plant genus that uses a combination of chloroplast and multiple low-copy nuclear loci for phylogenetic inference of polyploid evolution.
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| 9. |
- Slotte, Tanja, et al.
(author)
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The Capsella rubella genome and the genomic consequences of rapid mating system evolution
- 2013
-
In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:7, s. 831-U165
-
Journal article (peer-reviewed)abstract
- The shift from outcrossing to selfing is common in flowering plants(1,2), but the genomic consequences and the speed at which they emerge remain poorly understood. An excellent model for understanding the evolution of self fertilization is provided by Capsella rubella, which became self compatible <200,000 years ago. We report a C. rubella reference genome sequence and compare RNA expression and polymorphism patterns between C. rubella and its outcrossing progenitor Capsella grandiflora. We found a clear shift in the expression of genes associated with flowering phenotypes, similar to that seen in Arabidopsis, in which self fertilization evolved about 1 million years ago. Comparisons of the two Capsella species showed evidence of rapid genome-wide relaxation of purifying selection in C. rubella without a concomitant change in transposable element abundance. Overall we document that the transition to selfing may be typified by parallel shifts in gene expression, along with a measurable reduction of purifying selection.
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