| 1. |
- Charman, D. J., et al.
(författare)
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Climate-related changes in peatland carbon accumulation during the last millennium
- 2013
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4189. ; 10:2, s. 929-944
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Tidskriftsartikel (refereegranskat)abstract
- Peatlands are a major terrestrial carbon store and a persistent natural carbon sink during the Holocene, but there is considerable uncertainty over the fate of peatland carbon in a changing climate. It is generally assumed that higher temperatures will increase peat decay, causing a positive feedback to climate warming and contributing to the global positive carbon cycle feedback. Here we use a new extensive database of peat profiles across northern high latitudes to examine spatial and temporal patterns of carbon accumulation over the past millennium. Opposite to expectations, our results indicate a small negative carbon cycle feedback from past changes in the long-term accumulation rates of northern peatlands. Total carbon accumulated over the last 1000 yr is linearly related to contemporary growing season length and photosynthetically active radiation, suggesting that variability in net primary productivity is more important than decomposition in determining long-term carbon accumulation. Furthermore, northern peatland carbon sequestration rate declined over the climate transition from the Medieval Climate Anomaly (MCA) to the Little Ice Age (LIA), probably because of lower LIA temperatures combined with increased cloudiness suppressing net primary productivity. Other factors including changing moisture status, peatland distribution, fire, nitrogen deposition, permafrost thaw and methane emissions will also influence future peatland carbon cycle feedbacks, but our data suggest that the carbon sequestration rate could increase over many areas of northern peatlands in a warmer future.
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| 2. |
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| 3. |
- Nordmark, Gunnel, et al.
(författare)
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Association of EBF1, FAM167A(C8orf13)-BLK and TNFSF4 gene variants with primary Sjögren's syndrome
- 2011
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Ingår i: Genes and Immunity. - : Springer Science and Business Media LLC. - 1466-4879 .- 1476-5470. ; 12:2, s. 100-109
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Tidskriftsartikel (refereegranskat)abstract
- We performed a candidate gene association study in 540 patients with primary Sjögren's Syndrome (SS) from Sweden (n=344) and Norway (n=196) and 532 controls (n=319 Swedish, n=213 Norwegian). A total of 1139 single-nucleotide polymorphisms (SNPs) in 84 genes were analyzed. In the meta-analysis of the Swedish and Norwegian cohorts, we found high signals for association between primary SS and SNPs in three gene loci, not previously associated with primary SS. These are the early B-cell factor 1 (EBF1) gene, P=9.9 × 10−5, OR 1.68, the family with sequence similarity 167 member A–B-lymphoid tyrosine kinase (FAM167A–BLK) locus, P=4.7 × 10−4, OR 1.37 and the tumor necrosis factor superfamily (TNFSF4=Ox40L) gene, P=7.4 × 10−4, OR 1.34. We also confirmed the association between primary SS and the IRF5/TNPO3 locus and the STAT4 gene. We found no association between the SNPs in these five genes and the presence of anti-SSA/anti-SSB antibodies. EBF1, BLK and TNFSF4 are all involved in B-cell differentiation and activation, and we conclude that polymorphisms in several susceptibility genes in the immune system contribute to the pathogenesis of primary SS.
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| 4. |
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| 5. |
- Wang, C. L., et al.
(författare)
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DNA phosphorothioation is widespread and quantized in bacterial genomes
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108, s. 2963-2968
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorothioate (PT) modification of DNA, with sulfur replacing a nonbridging phosphate oxygen, was recently discovered as a product of the dnd genes found in bacteria and archaea. Given our limited understanding of the biological function of PT modifications, including sequence context, genomic frequencies, and relationships to the diversity of dnd gene clusters, we under-took a quantitative study of PT modifications in prokaryotic genomes using a liquid chromatography-coupled tandem quadrupole mass spectrometry approach. The results revealed a diversity of unique PT sequence contexts and three discrete genomic frequencies in a wide range of bacteria. Metagenomic analyses of PT modifications revealed unique ecological distributions, and a phylogenetic comparison of dnd genes and PT sequence contexts strongly supports the horizontal transfer of dnd genes. These results are consistent with the involvement of PT modifications in a type of restriction-modification system with wide distribution in prokaryotes.
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| 6. |
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| 7. |
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| 8. |
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| 9. |
- Alm, A., et al.
(författare)
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Caries in adolescence - influence from early childhood
- 2012
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Ingår i: Community Dentistry and Oral Epidemiology. - : Wiley. - 0301-5661 .- 1600-0528. ; 40:2, s. 125-133
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To analyse the relationship between caries determinants in early childhood and caries prevalence in proximal surfaces in adolescents at the age of 15 years. Methods: The present longitudinal study is part of a series of surveys of oral health in 671 children followed from 1 to 15 years of age. Data were selected from examinations, interviews and questionnaires at 1, 3 and 6 years and bitewing radiographs at 15 years of age. Uni- and multivariable logistic regression analyses were performed to identify caries-related determinants. The outcome variable was carious lesions and fillings (DFa) in approximal tooth surfaces at 15 years of age. Statistical comparisons were made between caries-free teenagers, DFa = 0 and teenagers with DFa > 0, DFa 4 and DFa 8, respectively. Results: In the final logistic regression analyses, caries experience at 6 years and mother's self-estimation of her oral health care as being less good to poor remained statistically significant and were related to caries in all three caries groups (i.e. DF > 0, 4 and 8) at 15 years of age. The consumption of sweets at 1 year remained statistically significant, with a caries experience of DF 4 and 8. The variables 'parents born abroad' and female gender were statistically significantly associated with DFa 4 and DFa 8, respectively. Furthermore, infrequent toothbrushing habits at 3 years of age and failure to attend the examination at 1 year were statistically significantly associated with caries at 15 years in the univariable analyses. Conclusion: Early caries experience, consumption of sweets at an early age and mother's self-estimation of her oral health care as being less good to poor are associated with approximal caries in adolescents. The study indicates that caries determinants identified during early childhood have a strong impact on approximal caries in adolescence.
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| 10. |
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| 11. |
- Alm, Henrik, et al.
(författare)
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In Vitro Neurotoxicity of PBDE-99 : Immediate and Concentration-Dependent Effects on Protein Expression in Cerebral Cortex Cells
- 2010
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 9:3, s. 1226-1235
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Tidskriftsartikel (refereegranskat)abstract
- Polybrominated diphenyl ethers (PBDEs) are commonly used flame retardants in various consumer products. Pre- and postnatal exposure to congeners of PBDEs disrupts normal brain development in rodents. Two-dimensional difference gel electrophoresis (2D-DIGE) was used to analyze concentration-dependent differences in protein expression in cultured cortical cells isolated from rat fetuses (GD 21) after 24 h exposure to PBDE-99 (3, 10, or 30 muM). Changes on a post-translational level were studied using a 1 h exposure to 30 muM PBDE-99. The effects of 24 h exposure to 3 and 30 muM PBDE-99 on mRNA levels were measured using oligonucleotide microarrays. A total of 62, 46, and 443 proteins were differentially expressed compared to controls after 24 h of exposure to 3, 10, and 30 muM PDBE-99, respectively. Of these, 48, 43, and 238 proteins were successfully identified, respectively. We propose that the biological effects of low-concentration PBDE-99 exposure are fundamentally different than effects of high-concentration exposure. Low-dose PBDE-99 exposure induced marked effects on cytoskeletal proteins, which was not correlated to cytotoxicity or major morphological effects, suggesting that other more regulatory aspects of cytoskeletal functions may be affected. Interestingly, 0.3 and 3 muM, but not 10 or 30 muM increased the expression of phosphorylated (active) Gap43, perhaps reflecting effects on neurite extension processes.
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| 12. |
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| 13. |
- Durbeej, N., et al.
(författare)
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P02-54 - Is outpatient-based substance abuse treatment a predictor of re-offending and other outcomes among Swedish offenders subjected to psychiatric assessment?
- 2010
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Ingår i: European psychiatry. - : Elsevier. - 0924-9338 .- 1778-3585. ; 25:Supplement 1, s. 674-674
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Substance abuse is associated with criminal recidivism. Substance abuse treatment has been found to correlate negatively with re-offending among treatment utilizers. However, for offenders with mental health problems and substance abuse, research on how substance abuse treatment affects re-offending is sparse. Objectives: The study aimed to examine the relationship between self-reported outpatient-based substance abuse treatment and self-reported a) re-offending, b) substance use and c) psychiatric problems among offenders with mental health and substance use problems. Methods: Data were gathered from a naturalistic follow-up study with 208 participants, subjected to a court-ordered psychiatric assessment. This analysis covers 91 individuals who were followed-up after an average study period of 17 months. Among these, 68% had been sentenced to institutional imprisonment or forensic psychiatric care. Results: Offences, substance use and psychiatric problems declined between baseline and follow-up. However, the reduction was not associated with self-reported treatment utilization. Among participants who were sentenced to non-institutional corrections, more individuals had utilized outpatient-based treatment compared to individuals who were sentenced to imprisonment or forensic psychiatric care. Conclusions: A definitive conclusion about the effect of treatment is difficult to draw. For instance, self-reported data may not reflect actual treatment consumption. However, one interpretation is that participants naturally recovered over time. Institutional correction might also have resulted in positive outcomes equivalent to outpatient-based treatment.
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| 14. |
- Durbeej, N., et al.
(författare)
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Substance abuse treatment as a predictor of criminal recidivism among psychiatrically examined Swedish offenders
- 2010
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Ingår i: European psychiatry. - : Elsevier. - 0924-9338 .- 1778-3585. ; 25:Supplement 1, s. 32-32
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Konferensbidrag (refereegranskat)abstract
- Background. Substance abuse is clearly associated with criminal recidivism among offenders with and without mental disorder. Treatment for substance abuse correlates with lower rates of re-offending among participants in outpatient-based as well as institution-based substance abuse treatment programs. However, for offenders with mental disorder, research on the possible preventive effect of substance abuse treatment on criminal recidivism is sparse. This paper reports from on an ongoing naturalistic and prospective interview study on the relationship between post-release outpatient substance abuse treatment and re-offending. Methods. The Stockholm county sample comprises 246 offenders of both genders subjected to a forensic psychiatric assessment, who screened positive for substance abuse problems. Eighty-five percent (n=210) agreed to participate in the study. Baseline data and follow-up interview data, collected immediately on release from incarceration (prison/forensic hospital) and 6 and 12 months later, include self-reported substance abuse, treatment involvement and criminality. By February 2010, data will be available from the first follow-up for 150 participants, from the second follow-up for 80 individuals and from the third follow-up for 10 subjects. Results and conclusions. The focus of the presentation will be recidivism comparisons between substance abuse treatment utilizers and those who decline treatment. Data on ongoing levels of substance abuse, mental health problems and offending will serve as dependent variables. Additional analyses will present perceived benefit from and reasons for accepting or rejecting treatment.
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| 15. |
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| 16. |
- Ebert, Karin, et al.
(författare)
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DEM identification of macroscale stepped relief in arctic northern Sweden
- 2011
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Ingår i: Geomorphology. - : Elsevier BV. - 0169-555X .- 1872-695X. ; 132:3-4, s. 339-350
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Tidskriftsartikel (refereegranskat)abstract
- Stepped relief is a characteristic feature of many upland areas on Earth. In this study, we examine if stepped relief can be identified objectively by GIS-analysis of digital elevation models (DEMs). We specifically study the stepped relief landscapes of northern Sweden, comprising areas of contrasting topography in the mountainous northern Scandes and on the inselberg plains of the Precambrian basement east of the Caledonides.We mainly use hypsographic curves to examine the elevation distribution of the study areas and to identify palaeosurfaces. Peaks in the hypsographic curves are interpreted as palaeosurfaces, while hypsographic minima are interpreted as breaks in slope, separating these surfaces. In the northern Scandes, where only patchy remnants of palaeosurfaces remain, we use empirical cutoff values of slope angles to restrict palaeosurface areas to those identified in thefield and in air photos. In addition, air photo andfield mapping of glacially eroded areas is necessary to exclude glacially formed low relief surfaces, such as valley floors. These latter procedures introduce an unavoidable degree of subjectivity to the study. Our results indicate that in the northern Scandes, surfaces with an inclination of 11°, after glacially formed features are abstracted, correspond well with palaeosurface remnants. Breaks in slope separating the surface generations in themountains are centred around 860, 1320, and 1520 masl (above sea level), respectively. On the plains east of the northern Scandes, hypsographic data were filtered to remove inselbergs in order to analyse only the plains. Hypsographic curves of both the filtered and the unfiltered data of the inselberg plains show minima at elevations that correspond to steps separating multiple palaeosurfaces at elevations of 190, 250, and 400 masl. The steps separating the different palaeosurfaces are, in places, aligned with known geological discontinuities, but extensive remnants also transect structure. The presence of stepped relief is consistent with existing models of phased Cenozoic uplift and incision in northern Fennoscandia.
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| 17. |
- Isaksson, Helén, et al.
(författare)
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Prevalence of dental erosion and association with lifestyle factors in Swedish 20-year olds
- 2014
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Ingår i: Acta Odontologica Scandinavica. - : Informa UK Limited. - 0001-6357 .- 1502-3850. ; 72:6, s. 448-457
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To investigate the prevalence, distribution and severity of dental erosion and its association with lifestyle, oral and general health in young adults. Materials and methods. Four hundred and ninety-four individuals, 20-years of age, participated. Dental erosion in molars and maxillary incisors was evaluated. Caries, plaque and gingivitis were registered. Saliva samples were taken and the subjects were interviewed about behavioural and dietary habits and oral and general health. Body mass index (BMI) was calculated. The individuals were sub-divided into two groups according to the presence and absence of dental erosion: within the group with erosion was a sub-group of individuals with extensive erosion. Results. Of the individuals 25% had no erosion, 75% had erosion and 18% had extensive erosion. Erosion was found in molars in 74% of the individuals and on buccal and palatal surfaces in maxillary incisors in 4% and 7%, respectively. Cupping was seen in 65% of individuals and severe erosion in molars in 1.6%. Compared to subjects with no erosion, those with extensive erosion had a higher consumption of soft drinks (p = 0.05), caries prevalence (p < 0.01), prevalence of mutans Streptococci (p < 0.01) and BMI (p < 0.05). Furthermore, subjects with erosion had higher caries prevalence (p < 0.01) and BMI (p < 0.01) than those with no erosion. Conclusions. Swedish young adults have a high prevalence of dental erosion, but the level of severe erosion is low. The study disclosed a relationship between dental erosion and behavioural factors, oral health and BMI.
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| 18. |
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| 19. |
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| 20. |
- Lind, Ulrika, et al.
(författare)
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Octopamine receptors from the barnacle balanus improvisus are activated by the alpha2-adrenoceptor agonist medetomidine.
- 2010
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Ingår i: Molecular pharmacology. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 1521-0111 .- 0026-895X. ; 78:2, s. 237-48
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Tidskriftsartikel (refereegranskat)abstract
- G protein-coupled octopamine receptors of insects and other invertebrates represent counterparts of adrenoceptors in vertebrate animals. The alpha(2)-adrenoceptor agonist medetomidine, which is in clinical use as a veterinary sedative agent, was discovered to inhibit the settling process of barnacles, an important step in the ontogeny of this crustacean species. Settling of barnacles onto ship hulls leads to biofouling that has many harmful practical consequences, and medetomidine is currently under development as a novel type of antifouling agent. We now report that medetomidine induces hyperactivity in the barnacle larvae to disrupt the settling process. To identify the molecular targets of medetomidine, we cloned five octopamine receptors from the barnacle Balanus improvisus. We show by phylogenetic analyses that one receptor (BiOctalpha) belongs to the alpha-adrenoceptor-like subfamily, and the other four (BiOctbeta-R1, BiOctbeta-R2, BiOctbeta-R3, and BiOctbeta-R4) belong to the beta-adrenoceptor-like octopamine receptor subfamily. Phylogenetic analyses also indicated that B. improvisus has a different repertoire of beta-adrenoceptor-like octopamine receptors than insects. When expressed in CHO cells, the cloned receptors were activated by both octopamine and medetomidine, resulting in increased intracellular cAMP or calcium levels. Tyramine activated the receptors but with much lesser potency than octopamine. A hypothesis for receptor discrimination between tyramine and octopamine was generated from a homology three-dimensional model. The characterization of B. improvisus octopamine receptors is important for a better functional understanding of these receptors in crustaceans as well as for practical applications in development of environmentally sustainable antifouling agents.
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| 21. |
- Loisel, Julie, et al.
(författare)
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A database and synthesis of northern peatland soil properties and Holocene carbon and nitrogen accumulation
- 2014
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 24:9, s. 1028-1042
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Tidskriftsartikel (refereegranskat)abstract
- Here, we present results from the most comprehensive compilation of Holocene peat soil properties with associated carbon and nitrogen accumulation rates for northern peatlands. Our database consists of 268 peat cores from 215 sites located north of 45 degrees N. It encompasses regions within which peat carbon data have only recently become available, such as the West Siberia Lowlands, the Hudson Bay Lowlands, Kamchatka in Far East Russia, and the Tibetan Plateau. For all northern peatlands, carbon content in organic matter was estimated at 42 +/- 3% (standard deviation) for Sphagnum peat, 51 +/- 2% for non-Sphagnum peat, and at 49 +/- 2% overall. Dry bulk density averaged 0.12 +/- 0.07 g/cm(3), organic matter bulk density averaged 0.11 +/- 0.05 g/cm(3), and total carbon content in peat averaged 47 +/- 6%. In general, large differences were found between Sphagnum and non-Sphagnum peat types in terms of peat properties. Time-weighted peat carbon accumulation rates averaged 23 +/- 2 (standard error of mean) g C/m(2)/yr during the Holocene on the basis of 151 peat cores from 127 sites, with the highest rates of carbon accumulation (25-28 g C/m(2)/yr) recorded during the early Holocene when the climate was warmer than the present. Furthermore, we estimate the northern peatland carbon and nitrogen pools at 436 and 10 gigatons, respectively. The database is publicly available at https://peatlands.lehigh.edu.
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| 22. |
- Parducci, Laura, et al.
(författare)
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Glacial Survival of Boreal Trees in Northern Scandinavia
- 2012
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 335:6072, s. 1083-1086
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Tidskriftsartikel (refereegranskat)abstract
- It is commonly believed that trees were absent in Scandinavia during the last glaciation and first recolonized the Scandinavian Peninsula with the retreat of its ice sheet some 9000 years ago. Here, we show the presence of a rare mitochondrial DNA haplotype of spruce that appears unique to Scandinavia and with its highest frequency to the west-an area believed to sustain ice-free refugia during most of the last ice age. We further show the survival of DNA from this haplotype in lake sediments and pollen of Trondelag in central Norway dating back similar to 10,300 years and chloroplast DNA of pine and spruce in lake sediments adjacent to the ice-free Andoya refugium in northwestern Norway as early as similar to 22,000 and 17,700 years ago, respectively. Our findings imply that conifer trees survived in ice-free refugia of Scandinavia during the last glaciation, challenging current views on survival and spread of trees as a response to climate changes.
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| 23. |
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| 24. |
- Stenius, F., et al.
(författare)
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Lifestyle factors and sensitization in children : the ALADDIN birth cohort
- 2011
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Ingår i: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 66:10, s. 1330-1338
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Tidskriftsartikel (refereegranskat)abstract
- Background: Several cross-sectional studies indicate that an anthroposophic lifestyle reduces the risk of allergy in children. We initiated the Assessment of Lifestyle and Allergic Disease During Infancy (ALADDIN) birth cohort to elucidate the role of specific factors supposed to mediate this effect. The aims of this study are to describe the ALADDIN cohort and to report patterns of exposure and allergic sensitization during the first years of life. Methods: The ALADDIN study is a prospective birth cohort study of 330 children from families with an anthroposophic, partly anthroposophic, or nonanthroposophic lifestyle. The children and their parents were following an extensive data collection scheme, including repeated questionnaires and biological samples. Blood samples were collected from the parents and from the child at birth as well as at 6, 12, and 24 months of age. Results: Several lifestyle factors differed between the groups, such as diet, medication, and place of delivery. Children of families with an anthroposophic lifestyle had a markedly decreased risk of sensitization during the first 2 years of life compared with children of nonanthroposophic families with adjusted OR 0.25 (95% CI 0.10-0.64) and P-value 0.004. A similar situation held true for children from families with a partly anthroposophic lifestyle, adjusted OR 0.31 (95% CI 0.15-0.54), and P-value 0.002. Conclusions: The anthroposophic lifestyle comprises several factors of interest for allergy development and is here shown to be associated with reduced risk of IgE sensitization already in infancy. Identifying the factors responsible for this association would be of significant clinical importance.
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| 25. |
- Uusijärvi, A., et al.
(författare)
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Use of antibiotics in infancy and childhood and risk of recurrent abdominal pain-a Swedish birth cohort study
- 2014
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Ingår i: Neurogastroenterology and Motility. - : Wiley-Blackwell. - 1350-1925 .- 1365-2982. ; 26:6, s. 841-850
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Tidskriftsartikel (refereegranskat)abstract
- Background: The etiology of recurrent abdominal pain of functional origin (AP) is largely unknown. Antibiotic treatment influences the intestinal microbiota, and a few studies have indicated an increased risk of AP in adults after antibiotic treatment. Corresponding data in children are lacking. The aim of this study was to explore the association between antibiotic treatment during childhood and AP at 12years.Methods: Two thousand seven hundred and thirty-two children from a Swedish, population-based birth cohort. Parents reported antibiotic use for the children between birth and 2years. Antibiotic use between 9 and 12years was collected from the Swedish Prescribed Drug Register. The children answered questionnaires regarding AP at age 12. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for AP at 12years as a function of antibiotic use.Key Results: Antibiotic treatment between 9 and 12years was not associated with AP at 12. Children who had received 3 courses, or broad-spectrum antibiotics between 9 and 12years had an increased risk of AP at 12, but these associations failed to reach statistical significance. Antibiotic treatment during both the first and the second year of life increased the risk of AP in girls at 12 (OR 1.65; 95% CI: 1.09-2.49), but not in boys or the whole cohort.Conclusions & Inferences: Antibiotic treatment does not seem to be a major risk factor for AP at 12years. However, we cannot exclude that repeated courses, especially to infant girls, or use of broad-spectrum antibiotics between 9 and 12years may be associated with an increased risk of AP.
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| 26. |
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| 27. |
- Westram, A. M., et al.
(författare)
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Do the same genes underlie parallel phenotypic divergence in different Littorina saxatilis populations?
- 2014
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083. ; 23:18, s. 4603-4616
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Tidskriftsartikel (refereegranskat)abstract
- Parallel patterns of adaptive divergence and speciation are cited as powerful evidence for the role of selection driving these processes. However, it is often not clear whether parallel phenotypic divergence is underlain by parallel genetic changes. Here, we asked about the genetic basis of parallel divergence in the marine snail Littorina saxatilis, which has repeatedly evolved coexisting ecotypes adapted to either crab predation or wave action. We sequenced the transcriptome of snails of both ecotypes from three distant geographical locations (Spain, Sweden and United Kingdom) and mapped the reads to the L. saxatilis reference genome. We identified genomic regions potentially under divergent selection between ecotypes within each country, using an outlier approach based on FST values calculated per locus. In line with previous studies indicating that gene reuse is generally common, we expected to find extensive sharing of outlier loci due to recent shared ancestry and gene flow between at least two of the locations in our study system. Contrary to our expectations, we found that most outliers were country specific, suggesting that much of the genetic basis of divergence is not shared among locations. However, we did find that more outliers were shared than expected by chance and that differentiation of shared outliers is often generated by the same SNPs. We discuss two mechanisms potentially explaining the limited amount of sharing we observed. First, a polygenic basis of divergent traits might allow for multiple distinct molecular mechanisms generating the same phenotypic patterns. Second, additional, location-specific axes of selection that we did not focus on in this study may produce distinct patterns of genetic divergence within each site.
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| 28. |
- Ågren, Jonas, et al.
(författare)
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Improving the Swedish quasigeoid by gravity observations on the ice of Lake Vänern
- 2014
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Ingår i: International Association of Geodesy Symposia. - Cham : Springer International Publishing. - 9783319108360 ; , s. 171-177
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Konferensbidrag (refereegranskat)abstract
- One of the key activities in Geodesy 2010, the Swedish strategic plan for geodetic activities during the period 2011–2020, is the restoration of the gravity network and data in order to improve the accuracy of the national quasigeoid model. One weak point has been that very few gravity observations have been available over Lake Vänern, Sweden’s largest lake. During the extremely cold winters 2010 and 2011, the ice became sufficiently thick to make ice observation of gravity. The main purpose of this paper is to present the 2011 ice gravity campaign, summarise the experiences made and investigate how much the new ice observations improve the computed quasigeoid model in the area. This is investigated under the assumption that a modern Earth Gravitational Model based on GRACE and GOCE is used. It is found that new ice measurements improve the quasigeoid with a RMS of about 2–3 cm in and around the lake with a maximum improvement of 7 cm.
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