| 1. |
- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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| 2. |
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Chauvin, Maxime, et al.
(författare)
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Shedding new light on the Crab with polarized X-rays
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7:7816, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Strong magnetic fields, synchrotron emission, and Compton scattering are omnipresent in compactcelestial X-ray sources. Emissions in the X-ray energy band are consequently expected to be linearlypolarized. X-ray polarimetry provides a unique diagnostic to study the location and fundamentalmechanisms behind emission processes. The polarization of emissions from a bright celestial X-raysource, the Crab, is reported here for the first time in the hard X-ray band (~20–160 keV). The Crab isa complex system consisting of a central pulsar, a diffuse pulsar wind nebula, as well as structures inthe inner nebula including a jet and torus. Measurements are made by a purpose-built and calibratedpolarimeter, PoGO+. The polarization vector is found to be aligned with the spin axis of the pulsar for apolarization fraction, PF = (20.9 ± 5.0)%. This is higher than that of the optical diffuse nebula, implyinga more compact emission site, though not as compact as, e.g., the synchrotron knot. Contrary tomeasurements at higher energies, no significant temporal evolution of phase-integrated polarisationparameters is observed. The polarization parameters for the pulsar itself are measured for the first timein the X-ray energy band and are consistent with observations at optical wavelengths.
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| 8. |
- Chauvin, Maxime, et al.
(författare)
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The PoGO plus view on Crab off-pulse hard X-ray polarization
- 2018
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Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966 .- 1745-3925 .- 1745-3933. ; 477:1, s. L45-L49
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Tidskriftsartikel (refereegranskat)abstract
- The linear polarization fraction (PF) and angle of the hard X-ray emission from the Crab provide unique insight into high-energy radiation mechanisms, complementing the usual imaging, timing, and spectroscopic approaches. Results have recently been presented by two missions operating in partially overlapping energy bands, PoGO+ (18-160 keV) and AstroSat CZTI (100-380 keV). We previously reported PoGO+ results on the polarization parameters integrated across the light curve and for the entire nebula-dominated off-pulse region. We now introduce finer phase binning, in light of the AstroSat CZTI claim that the PF varies across the off-pulse region. Since both missions are operating in a regime where errors on the reconstructed polarization parameters are non-Gaussian, we adopt a Bayesian approach to compare results from each mission. We find no statistically significant variation in off-pulse polarization parameters, neither when considering the mission data separately nor when they are combined. This supports expectations from standard high-energy emission models.
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| 9. |
- Dinasquet, Julie, et al.
(författare)
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Cascading effects of the ctenophore Mnemiopsis leidyi on the planktonic food web in a nutrient-limited estuarine system
- 2012
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Ingår i: Marine Ecology Progress Serie. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 460, s. 49-61
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Tidskriftsartikel (refereegranskat)abstract
- Increasing biomasses of gelatinous zooplankton presumably have major implications for the structure and function of marine food webs at large; however, current data on lower trophic levels are scarce, as most studies have focused on the immediate effects on zooplankton and fish larvae only. We examined the short-term impact of larvae and adults of the invasive ctenophore Mnemiopsis leidyi on a summer planktonic food web in the estuarine southern Baltic Sea, with special emphasis on the microbial loop. Grazing by M. leidyi reduced the mesozooplankton biomass, followed by increased dinoflagellate biomass in treatments with M. leidyi. While chlorophyll a increased most in the treatments with M. leidyi, small phytoplankton and ciliates decreased in all treatments. M. leidyi had a slight effect on bacterial abundance, but not on bacterial production, ectoenzymatic activities, or community composition. Undetectable levels of phosphate and a gradual accumulation of dissolved organic carbon during the experiment suggested a malfunctioning microbial loop scenario. The experiment shows that direct and indirect short-term effects of M. leidyi on the estuarine food web are limited to higher trophic levels and indicates that top-down and bottom-up consequences of M. leidyi expansions on the microbial loop will likely depend on local nutrient conditions.
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| 10. |
- Feng, Shaohong, et al.
(författare)
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Dense sampling of bird diversity increases power of comparative genomics
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 587:7833
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Tidskriftsartikel (refereegranskat)abstract
- Whole-genome sequencing projects are increasingly populating the tree of life and characterizing biodiversity(1-4). Sparse taxon sampling has previously been proposed to confound phylogenetic inference(5), and captures only a fraction of the genomic diversity. Here we report a substantial step towards the dense representation of avian phylogenetic and molecular diversity, by analysing 363 genomes from 92.4% of bird families-including 267 newly sequenced genomes produced for phase II of the Bird 10,000 Genomes (B10K) Project. We use this comparative genome dataset in combination with a pipeline that leverages a reference-free whole-genome alignment to identify orthologous regions in greater numbers than has previously been possible and to recognize genomic novelties in particular bird lineages. The densely sampled alignment provides a single-base-pair map of selection, has more than doubled the fraction of bases that are confidently predicted to be under conservation and reveals extensive patterns of weak selection in predominantly non-coding DNA. Our results demonstrate that increasing the diversity of genomes used in comparative studies can reveal more shared and lineage-specific variation, and improve the investigation of genomic characteristics. We anticipate that this genomic resource will offer new perspectives on evolutionary processes in cross-species comparative analyses and assist in efforts to conserve species. A dataset of the genomes of 363 species from the Bird 10,000 Genomes Project shows increased power to detect shared and lineage-specific variation, demonstrating the importance of phylogenetically diverse taxon sampling in whole-genome sequencing.
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| 11. |
- Selsing, J., et al.
(författare)
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The X-shooter GRB afterglow legacy sample (XS-GRB)
- 2019
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Ingår i: Astronomy and Astrophysics. - : EDP SCIENCES S A. - 0004-6361 .- 1432-0746. ; 623
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present spectra of all gamma-ray burst (GRB) afterglows that have been promptly observed with the X-shooter spectrograph until 31/03/2017. In total, we have obtained spectroscopic observations of 103 individual GRBs observed within 48 hours of the GRB trigger. Redshifts have been measured for 97 per cent of these, covering a redshift range from 0.059 to 7.84. Based on a set of observational selection criteria that minimise biases with regards to intrinsic properties of the GRBs, the follow-up effort has been focused on producing a homogeneously selected sample of 93 afterglow spectra for GRBs discovered by the Swift satellite. We here provide a public release of all the reduced spectra, including continuum estimates and telluric absorption corrections. For completeness, we also provide reductions for the 18 late-time observations of the underlying host galaxies. We provide an assessment of the degree of completeness with respect to the parent GRB population, in terms of the X-ray properties of the bursts in the sample and find that the sample presented here is representative of the full Swift sample. We have constrained the fraction of dark bursts to be <28 per cent and confirm previous results that higher optical darkness is correlated with increased X-ray absorption. For the 42 bursts for which it is possible, we have provided a measurement of the neutral hydrogen column density, increasing the total number of published HI column density measurements by similar to 33 per cent. This dataset provides a unique resource to study the ISM across cosmic time, from the local progenitor surroundings to the intervening Universe.
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| 12. |
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| 13. |
- Midgley, S, et al.
(författare)
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Human group A rotavirus infections in children in Denmark; detection of reassortant G9 strains and zoonotic P[14] strains.
- 2014
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Ingår i: Infection, Genetics and Evolution. - : Elsevier BV. - 1567-7257 .- 1567-1348. ; 27, s. 114-120
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Tidskriftsartikel (refereegranskat)abstract
- One of the leading causes of severe childhood gastroenteritis are group A rotaviruses, and they have been found to be associated with ∼40% of the annual gastroenteritis-associated hospitalizations in young Danish children <5years of age (Fischer et al., 2011). In this study, we investigated the diversity of rotavirus strains circulating among young children <5years of age, presenting with gastroenteritis disease either at the general practitioner or in the hospital, during the period 2009-2013. A total of 831 rotavirus positive stool samples were genotyped in the study period, and the majority of samples (74%) were from hospitalized children. G and P genotypes were successfully determined for 826 of samples, with G1P[8] being the most commonly detected genotype. Detection of G1 showed a decreasing trend over time, and an inverse trend was seen for the emerging G9P. The common human genotypes (G1/G3/G4/G9P[8] and G2P[4]) were detected in the majority of samples (n=733, 88.2%). Rare genotype combinations such as G6P[14] were detected in <1% of samples. Rare genotype strains and strains which failed to amplify in genotyping RT-PCR were subjected to genetic characterization by sequencing one or all of the following genes; VP7, VP4, VP6 and NSP4. Sequences of sufficient length and quality were available for all 4 genes for 28 strains. Phylogenetic analysis revealed that reassortant G9P[4] strains circulated with 3 different genotype combinations. As rotavirus vaccines are not widely used in Denmark or its neighboring countries, the diversity of rotavirus strains identified in this study most likely reflects naturally occurring selection pressures and viral evolution.
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| 14. |
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| 15. |
- Wedervang-Resell, K, et al.
(författare)
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Reduced levels of circulating adhesion molecules in adolescents with early-onset psychosis
- 2020
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Ingår i: NPJ schizophrenia. - : Springer Science and Business Media LLC. - 2334-265X. ; 6:1, s. 20-
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Tidskriftsartikel (refereegranskat)abstract
- It is suggested that neurodevelopmental abnormalities are involved in the disease mechanisms of psychotic disorders. Although cellular adhesion molecules (CAMs) participate in neurodevelopment, modulate blood–brain barrier permeability, and facilitate leukocyte migration, findings concerning their systemic levels in adults with psychosis are inconsistent. We examined plasma levels and mRNA expression in peripheral blood mononuclear cells (PBMCs) of selected CAMs in adolescents with early-onset psychosis (EOP) aged 12–18 years (n = 37) and age-matched healthy controls (HC) (n = 68). EOP patients exhibited significantly lower circulating levels of soluble platelet selectin (~−22%) and soluble vascular cell adhesion molecule-1 (~−14%) than HC. We found no significant associations with symptom severity. PSEL mRNA expression was increased in PBMCs of patients and significantly negatively correlated to duration of illness. These findings suggest a role for CAMs in the pathophysiology of psychotic disorders.
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| 16. |
- Bergman, Lina, 1982, et al.
(författare)
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Preeclampsia and increased permeability over the blood brain barrier - a role of vascular endothelial growth receptor 2.
- 2021
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Ingår i: American journal of hypertension. - : Oxford University Press (OUP). - 1941-7225 .- 0895-7061. ; 34:1, s. 73-81
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Tidskriftsartikel (refereegranskat)abstract
- Cerebral complications in preeclampsia are leading causes of maternal mortality worldwide but the underlying pathophysiology is largely unknown and a challenge to study. Using an in vitro model of the human blood brain barrier (BBB), we explored the role of vascular endothelial growth factor receptor 2 (VEGFR2) in preeclampsia.The human brain endothelial cell line (hCMEC/D3) cultured on Tranwells insert were exposed (12h) to plasma from women with preeclampsia (n=28), normal pregnancy (n=28) and non-pregnant (n=16) controls. Transendothelial electrical resistance (TEER) and permeability to 70kDa FITC-dextran were measured for assessment of BBB integrity. We explored possible underlying mechanisms, with focus on expression of tight junction proteins and phosphorylation of two tyrosine residues of VEGFR2, associated with vascular permeability and migration (pY951) and cell proliferation (pY1175). Plasma concentrations of soluble FMS like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF) were measured in order to establish correlations with in vitro results.hCMEC/D3 exposed to plasma from women with preeclampsia exhibited reduced TEER and increased permeability to 70kDa FITC-dextran. Further, these cells up-regulated the mRNA levels of VEGFR2, as well as pY951-VEGFR2; but reduced pY1175-VEGFR2 (p&0.05 in all cases). No difference in mRNA expression of tight junction protein was observed between gruops. There was no correlation between angiogenic biomarkers and BBB permeability.We present a promising in vitro model of the BBB in preeclampsia. Selective tyrosine phosphorylation of VEGFR2 may participate in the increased BBB permeability in preeclampsia irrespective of plasma concentrations of angiogenic biomarkers.
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| 17. |
- Chauvin, Maxime, et al.
(författare)
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Calibration and performance studies of the balloon-borne hard X-ray polarimeter PoGO
- 2017
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : ELSEVIER SCIENCE BV. - 0168-9002 .- 1872-9576. ; 859, s. 125-133
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Tidskriftsartikel (refereegranskat)abstract
- Polarimetric observations of celestial sources in the hard X-ray band stand to provide new information on emission mechanisms and source geometries. PoGO+ is a Compton scattering polarimeter (20-150 keV) optimised for the observation of the Crab (pulsar and wind nebula) and Cygnus X-1 (black hole binary), from a stratospheric balloon-borne platform launched from the Esrange Space Centre in summer 2016. Prior to flight, the response of the polarimeter has been studied with polarised and unpolarised X-rays allowing a Geant4-based simulation model to be validated. The expected modulation factor for Crab observations is found to be M-Crab = (41.75 +/- 0.85)%, resulting in an expected Minimum Detectable Polarisation (MDP) of 7.3% for a 7 day flight. This will allow a measurement of the Crab polarisation parameters with at least 5 sigma statistical significance assuming a polarisation fraction similar to 20% - a significant improvement over the PoGOLite Pathfinder mission which flew in 2013 and from which the PoGO+ design is developed.
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| 18. |
- Chioza, B., et al.
(författare)
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Evaluation of CACNA1H in European patients with childhood absence epilepsy
- 2006
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Ingår i: Epilepsy Res. - : Elsevier BV. - 0920-1211. ; 69:2, s. 177-81
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Tidskriftsartikel (refereegranskat)abstract
- CACNA1H was evaluated in a resource of Caucasian European patients with childhood absence epilepsy by linkage analysis and typing of sequence variants previously identified in Chinese patients. Linkage analysis of 44 pedigrees provided no evidence for a locus in the CACNA1H region and none of the Chinese variants were found in 220 unrelated patients.
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| 19. |
- Egfjord, Anne Friis Holm, et al.
(författare)
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Genomic Steppe ancestry in skeletons from the Neolithic Single Grave Culture in Denmark
- 2021
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- The Gjerrild burial provides the largest and best-preserved assemblage of human skeletal material presently known from the Single Grave Culture (SGC) in Denmark. For generations it has been debated among archaeologists if the appearance of this archaeological complex represents a continuation of the previous Neolithic communities, or was facilitated by incoming migrants. We sampled and analysed five skeletons from the Gjerrild cist, buried over a period of c. 300 years, 2600/2500–2200 cal BCE. Despite poor DNA preservation, we managed to sequence the genome (>1X) of one individual and the partial genomes (0.007X and 0.02X) of another two individuals. Our genetic data document a female (Gjerrild 1) and two males (Gjerrild 5 + 8), harbouring typical Neolithic K2a and HV0 mtDNA haplogroups, but also a rare basal variant of the R1b1 Y-chromosomal haplogroup. Genome-wide analyses demonstrate that these people had a significant Yamnaya-derived (i.e. steppe) ancestry component and a close genetic resemblance to the Corded Ware (and related) groups that were present in large parts of Northern and Central Europe at the time. Assuming that the Gjerrild skeletons are genetically representative of the population of the SGC in broader terms, the transition from the local Neolithic Funnel Beaker Culture (TRB) to SGC is not characterized by demographic continuity. Rather, the emergence of SGC in Denmark was part of the Late Neolithic and Early Bronze Age population expansion that swept across the European continent in the 3rd millennium BCE, resulting in various degrees of genetic replacement and admixture processes with previous Neolithic populations.
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| 20. |
- Ehnhage, A, et al.
(författare)
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Corrigendum
- 2016
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Ingår i: Acta oto-laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 136:9, s. 982-982
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Tidskriftsartikel (refereegranskat)
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| 21. |
- Everett, K. V., et al.
(författare)
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Linkage and association analysis of CACNG3 in childhood absence epilepsy
- 2007
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Ingår i: Eur J Hum Genet. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 15:4, s. 463-72
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Tidskriftsartikel (refereegranskat)abstract
- Childhood absence epilepsy (CAE) is an idiopathic generalised epilepsy characterised by absence seizures manifested by transitory loss of awareness with 2.5-4 Hz spike-wave complexes on ictal EEG. A genetic component to aetiology is established but the mechanism of inheritance and the genes involved are not fully defined. Available evidence suggests that genes encoding brain expressed voltage-gated calcium channels, including CACNG3 on chromosome 16p12-p13.1, may represent susceptibility loci for CAE. The aim of this work was to further evaluate CACNG3 as a susceptibility locus by linkage and association analysis. Assuming locus heterogeneity, a significant HLOD score (HLOD = 3.54, alpha = 0.62) was obtained for markers encompassing CACNG3 in 65 nuclear families with a proband with CAE. The maximum non-parametric linkage score was 2.87 (P < 0.002). Re-sequencing of the coding exons in 59 patients did not identify any putative causal variants. A linkage disequilibrium (LD) map of CACNG3 was constructed using 23 single nucleotide polymorphisms (SNPs). Transmission disequilibrium was sought using individual SNPs and SNP-based haplotypes with the pedigree disequilibrium test in 217 CAE trios and the 65 nuclear pedigrees. Evidence for transmission disequilibrium (P < or = 0.01) was found for SNPs within a approximately 35 kb region of high LD encompassing the 5'UTR, exon 1 and part of intron 1 of CACNG3. Re-sequencing of this interval was undertaken in 24 affected individuals. Seventy-two variants were identified: 45 upstream; two 5'UTR; and 25 intronic SNPs. No coding sequence variants were identified, although four variants are predicted to affect exonic splicing. This evidence supports CACNG3 as a susceptibility locus in a subset of CAE patients.
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| 22. |
- Hermann, Florian M., et al.
(författare)
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An insulin hypersecretion phenotype precedes pancreatic beta cell failure in MODY3 patient-specific cells
- 2023
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Ingår i: Cell Stem Cell. - : Elsevier. - 1934-5909 .- 1875-9777. ; 30:1, s. 38-51
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Tidskriftsartikel (refereegranskat)abstract
- MODY3 is a monogenic hereditary form of diabetes caused by mutations in the transcription factor HNF1A. The patients progressively develop hyperglycemia due to perturbed insulin secretion, but the pathogenesis is unknown. Using patient-specific hiPSCs, we recapitulate the insulin secretion sensitivity to the membrane depolarizing agent sulfonylurea commonly observed in MODY3 patients. Unexpectedly, MODY3 patient -specific HNF1A+/R272C R cells hypersecrete insulin both in vitro and in vivo after transplantation into mice. Consistently, we identified a trend of increased birth weight in human HNF1A mutation carriers compared with healthy siblings. Reduced expression of potassium channels, specifically the KATP channel, in MODY3 0 cells, increased calcium signaling, and rescue of the insulin hypersecretion phenotype by pharmacological targeting ATP-sensitive potassium channels or low-voltage-activated calcium channels suggest that more efficient membrane depolarization underlies the hypersecretion of insulin in MODY3 0 cells. Our findings identify a pathogenic mechanism leading to 0 cell failure in MODY3.
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| 23. |
- Hermann, Florian M., et al.
(författare)
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An insulin hypersecretion phenotype precedes pancreatic β cell failure in MODY3 patient-specific cells
- 2023
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 30:1, s. 8-51
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Tidskriftsartikel (refereegranskat)abstract
- MODY3 is a monogenic hereditary form of diabetes caused by mutations in the transcription factor HNF1A. The patients progressively develop hyperglycemia due to perturbed insulin secretion, but the pathogenesis is unknown. Using patient-specific hiPSCs, we recapitulate the insulin secretion sensitivity to the membrane depolarizing agent sulfonylurea commonly observed in MODY3 patients. Unexpectedly, MODY3 patient-specific HNF1A+/R272C β cells hypersecrete insulin both in vitro and in vivo after transplantation into mice. Consistently, we identified a trend of increased birth weight in human HNF1A mutation carriers compared with healthy siblings. Reduced expression of potassium channels, specifically the KATP channel, in MODY3 β cells, increased calcium signaling, and rescue of the insulin hypersecretion phenotype by pharmacological targeting ATP-sensitive potassium channels or low-voltage-activated calcium channels suggest that more efficient membrane depolarization underlies the hypersecretion of insulin in MODY3 β cells. Our findings identify a pathogenic mechanism leading to β cell failure in MODY3.
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| 24. |
- Holm, Paul Martin, et al.
(författare)
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An 40Ar-39Ar study of the Cape Verde hotspot: Temporal evolution in a semi-staionary plate environment.
- 2008
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Ingår i: Journal of Geophysical Research: Solid Earth. - 1934-8843. ; 113:B8
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Tidskriftsartikel (refereegranskat)abstract
- The 40Ar-39Ar analyses of 28 groundmass separates from volcanic rocks from the islands of Santiago, Sal, and São Vicente, Cape Verde archipelago, are presented. The new age data record the volcanic evolution for Santiago from 4.6 to 0.7 Ma, for Sal from around 15 to 1.1 Ma, and for São Vicente from 6.6 to 0.3 Ma. The major submarine constructional phase of Santiago was erupted within a few hundred thousand years interval around 4.6 Ma. Most of the subaerial Santiago volcanic rocks were erupted in a second episode from 3.3 to 2.2 Ma and late volcanism occurred at 1.1-0.7 Ma. Volcanism on Sal evolved in five stages: (1) poorly constrained early Miocene activity, (2) 16-14 Ma, (3) 12-8 Ma, (4) around 5.4 Ma, and (5) 1.1-0.6 Ma. São Vicente was constructed during three active periods: (1) >6.6-5.9 Ma, (2) 4.7-4.5 Ma, and (3) ~0.3 Ma. Sr isotope analyses of carbonates from Maio confirm an Early Cretaceous age for limestones deposited on the seafloor and later uplifted. The Cape Verde Rise is indicated to have fully formed in the early Miocene around 22 Ma, accompanied by the initial alkaline volcanism. Considerable volcanism on Sal, Boa Vista, and Maio took place in the Miocene and Pliocene and extended over much larger areas than the present islands, whereas volcanism of the southwestern and northwestern island groups developed mainly during the Pliocene and Pleistocene and was mostly confined to the present island areas. The periods of volcanic activity may be broadly correlated between the northwestern and southwestern groups of islands. Young volcanism (0.3-0.1 Ma) throughout the northwestern group extends along a 150 km long NW-SE trending lineament. A relatively moderate average melting rate for the hot spot over the 22 Ma period is estimated at ~0.026 km3/a, corresponding to a total volume of 570 × 103 km3 of magma emplaced in the crust and a mantle volume flux of 28 m3/s, much lower than Iceland or Hawaii. The archipelago is situated to the south and SW of the center of the mantle plume anomaly and ahead of its relative movement. The timing and location of volcanism suggest that mantle melting takes place in three channels, an eastern one that has been active for 22 Ma and in southwestern and northwestern channels since late Miocene
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| 25. |
- Jaspers, C., et al.
(författare)
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Reproduction rates under variable food conditions and starvation in Mnemiopsis leidyi: significance for the invasion success of a ctenophore
- 2015
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Ingår i: Journal of Plankton Research. - : Oxford University Press (OUP). - 0142-7873 .- 1464-3774. ; 37:5, s. 1011-1018
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Tidskriftsartikel (refereegranskat)abstract
- The ctenophore Mnemiopsis leidyi is characterized by high growth rates and a large reproductive capacity. However, reproductive dynamics are not yet well understood. Here, we present laboratory data on food-dependent egg production in M. leidyi and egg hatching time and success. Further, we report on the reproduction of laboratory-reared and field-caught animals during starvation. Our results show that the half-saturation zooplankton prey concentration for egg production is reached at food levels of 12-23 mu gC L-1, which is below the average summer food concentration encountered in invaded areas of northern Europe. Furthermore, starved animals continue to produce eggs for up to 12 days after cessation of feeding with high overall hatching success of 65-90%. These life history traits allow M. leidyi to thrive and reproduce in environments with varying food conditions and give it a competitive advantage under unfavourable conditions. This may explain why recurrent population blooms are observed and sustained in localized areas in invaded northern Europe, where water exchange is limited and zooplankton food resources are quickly depleted by M. leidyi. We suggest that these reproductive life history traits are key to its invasion success.
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| 26. |
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| 30. |
- Knipp, D.J., et al.
(författare)
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Ionospheric Convection Response to Slow, Strong Variations in a Northward Interplanetary Magnetic Field: A Case Study for January 14, 1988
- 1993
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 98, s. 19273-19292
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Tidskriftsartikel (refereegranskat)abstract
- We analyze ionospheric convection patterns over the polar regions during the passage of an interplanetary magnetic cloud on January 14, 1988, when the interplanetary magnetic field (IMF) rotated slowly in direction and had a large amplitude. Using the assimilative mapping of ionospheric electrodynamics (AMIE) procedure, we combine simultaneous observations of ionospheric drifts and magnetic perturbations from many different instruments into consistent patterns of high-latitude electrodynamics, focusing on the period of northward IMF. By combining satellite data with ground-based observations, we have generated one of the most comprehensive data sets yet assembled and used it to produce convection maps for both hemispheres. We present evidence that a lobe convection cell was embedded within normal merging convection during a period when the IMF B(y) and B(z) components were large and positive. As the IMF became predominantly northward, a strong reversed convection pattern (afternoon-to-morning potential drop of around 100 kV) appeared in the southern (summer) polar cap, while convection in the northern (winter) hemisphere became weak and disordered with a dawn-to-dusk potential drop of the order of 30 kV. These patterns persisted for about 3 hours, until the IMF rotated significantly toward the west. We interpret this behavior in terms of a recently proposed merging model for northward IMF under solstice conditions, for which lobe field lines from the hemisphere tilted toward the Sun (summer hemisphere) drape over the dayside magnetosphere, producing reverse convection in the summer hemisphere and impeding direct contact between the solar wind and field lines connected to the winter polar cap. The positive IMF B(x) component present at this time could have contributed to the observed hemispheric asymmetry. Reverse convection in the summer hemisphere broke down rapidly after the ratio \textbackslashB(y)/B(z)\textbackslash exceeded unity, while convection in the winter hemisphere strengthened. A dominant dawn-to-dusk potential drop was established in both hemispheres when the magnitude of B(y) exceeded that of B(z), with potential drops of the order of 100 kV, even while B(z) remained northward. The later transition to southward B(z) produced a gradual intensification of the convection, but a greater qualitative change occurred at the transition through \textbackslashB(y)/B(z)\textbackslash = 1 than at the transition through B(z) = 0. The various convection patterns we derive under northward IMF conditions illustrate all possibilities previously discussed in the literature: nearly single-cell and multicell, distorted and symmetric, ordered and unordered, and sunward and antisunward.
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| 37. |
- Pulkkinen, TI, et al.
(författare)
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Two substorm intensifications compared: Onset, expansion, and global consequences
- 1998
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - : AMER GEOPHYSICAL UNION. ; 103:A1, s. 15-27
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- We present observations of two sequential substorm onsets on May 15, 1996. The first event occurred during persistently negative IMF B-Z, whereas the second expansion followed a northward turning of the interplanetary magnetic field (IMF). While the first
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| 42. |
- Taghavi, K., et al.
(författare)
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Colposcopy telemedicine: live versus static swede score and accuracy in detecting CIN2+, a cross-sectional pilot study
- 2018
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Ingår i: Bmc Womens Health. - : Springer Science and Business Media LLC. - 1472-6874. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: This cross-sectional pilot study evaluates diagnostic accuracy of live colposcopy versus static image Swede-score evaluation for detecting significant precancerous cervical lesions greater than, or equal to grade 2 severity (CIN2+). Methods: VIA or HrHPV positive women were examined using a mobile colposcope, in a rural clinic in Kolkata, India. Live versus static Swede-score colposcopy assessments were made independently. All assessments were by gynecologists, junior or expert. Static image assessors were blinded to live scoring, patient information and final histopathology result. Primary outcome was the ability to detect CIN2+ lesions verified by directed biopsies. Diagnostic accuracy was calculated for live versus static Swede-score in detecting CIN2+ lesions, as well as for interclass correlation. Results: 495 images from 94 VIA positive women were evaluated in this study. Thirteen women (13.9%) had CIN2+ on biopsy. No significant difference was found in the detection of CIN2+ lesions between live and static assessors (area under curve = 0.69 versus 0.71, p = 0.63). A Swede-score of 4+, had a sensitivity of 76.9% (95% CI 46.2-95.0%) and 84.6% (95% CI 54.6-98.1%), for live-and static-image assessment respectively. The corresponding positive predictive values were found to be 90.9% (95% CI 75.7-98.1%) and 92.6% (95% CI 75.7-99.1%). The interclass correlation was good (kappa statistic = 0.60) for the senior static assessors. Conclusions: Swede-score evaluation of static colposcopy images was found to reliably detect CIN2+ lesions in this study. Larger studies are needed to further develop the colposcopy telemedicine concept which may offer reliable guidance in management where direct specialist input is not available. Trial registration: Ethical approval of the study was obtained by the Chittaranjan National Cancer Institute (CNCI) Human Research Ethics Committee (4.311/27/2014).
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- Zhang, C., et al.
(författare)
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Near Earth Vortices Driving of Field Aligned Currents Based on Magnetosphere Multiscale and Swarm Observations
- 2019
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Ingår i: Chinese Journal of Space Science. - : National Space Science Center, Chinese Academy of Sciences. - 0254-6124. ; 39:1, s. 9-17
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Tidskriftsartikel (refereegranskat)abstract
- A long-standing mystery in the study of Field-Aligned Currents (FACs) has been that: how the currents are generated and why they appear to be much stronger at high altitudes than in the ionosphere. Here we present two events of magnetotail FACs observed by the Magnetospheric Multiscale Spacecraft (MMS) on 1st July and 14th July 2016, to show how the Substorm Current Wedges (SCW) were formed. The results show that particles were transferred heading towards the Earth during the expansion phase of substorms. The azimuthal flow formed clockwise (counter-clockwise) vortex-like motion, and then generated downward (upward) FACs on the tailward/poleward side of the distorted field with opposite vorticity on their Earthward/equatorward side. We also analyzed the Region 1 FACs observed by the Earth Explorer Swarm spacecraft on 1st July 2016 and found that they were associated with FACs observed by MMS, although differing by a factor of 10. This difference suggests that either there was the closure of the currents at altitudes above 500 km or the currents were not strictly parallel to B and closed at longitudes away from where they were generated.
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