| 1. |
- Acciari, V. A., et al.
(författare)
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Radio Imaging of the Very-High-Energy gamma-Ray Emission Region in the Central Engine of a Radio Galaxy
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 325:5939, s. 444-448
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Tidskriftsartikel (refereegranskat)abstract
- The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we report on radio and VHE observations of the radio galaxy Messier 87, revealing a period of extremely strong VHE gamma-ray flares accompanied by a strong increase of the radio flux from its nucleus. These results imply that charged particles are accelerated to very high energies in the immediate vicinity of the black hole.
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| 2. |
- Alstrup, Vagn, et al.
(författare)
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Lichenicolous fungi from the Skibotn area, Troms, Norway
- 2008
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Ingår i: Graphis Scripta. - Stockholm : NLF. - 0901-7593. ; 20:1, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Altogether 93 species of lichenicolous fungi are reported, the majority collected during the Nordic Lichen Society excursion in 2003 to the Skibotn area, Troms, Norway. Cornutispora ciliata, Intralichen cf. lichenum, Opegrapha stereocaulicola and Sphaerulina cf. dubiella are new to Scandinavia, 11 species are new to Norway, and further 42 are new to Troms. Stigmidium aggregata is also reported as new to Greenland. Host lichens, localities, collectors and collection numbers are given.
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| 3. |
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| 4. |
- Arup, Ulf, et al.
(författare)
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The sister group relation of Parmeliaceae (Lecanorales, Ascomycota)
- 2007
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Ingår i: Mycologia. - : Informa UK Limited. - 0027-5514 .- 1557-2536. ; 99:1, s. 42-49
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Tidskriftsartikel (refereegranskat)abstract
- The family Parmeliaceae (Lecanorales, Ascomycota) is possibly the largest, best known and most thoroughly studied lichen family within its order. Despite this fact the relationship between Parmeliaceae and other groups in Lecanorales is still poorly known. The aim of the present study is to contribute to finding the sister group of Parmeliaceae as an aid in future studies on the phylogeny and character evolution of the group. We do this by sampling all potential relatives to the Parmeliaceae that we have identified, i.e. Cypsoplaca, Japewia, Mycoblastus, Protoparmelia, and Tephromela, a good representation of the major groups within the Parmeliaceae s. lat. and a good representation of other taxa in the core Lecanorales. We use molecular data from two genes, the large subunit of the nuclear ribosomal RNA gene (nrLSU) and the small subunit of the mitochondrial ribosomal RNA gene (mrSSU), and a Bayesian analysis of the combined data. The results show that the closest relatives to Parmeliaceae are the two genera Protoparmelia and Gypsoplaca, which are crustose lichens. Parmeliaceae in our sense is a well supported group, including also the family segregates Alectoriaceae, Hypogymniaceae, Usneaceae and Anziaceae.
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| 5. |
- Gueidan, Cecile, et al.
(författare)
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Generic classification of the Verrucariaceae (Ascomycota) based on molecular and morphological evidence : recent progress and remaining challenges
- 2009
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Ingår i: Taxon. - 0040-0262 .- 1996-8175. ; 58:1, s. 184-208
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Forskningsöversikt (refereegranskat)abstract
- Recent molecular phylogenetic analyses and morphological Studies have shown that it is necessary to revise the present morphology-based generic delineation of the lichen family Verrucariaceae in order to account for evolutionary relatedness between species. Consequently, several genera were recently described or resurrected, and others were re-circumscribed. As an additional step toward this generic revision, three new genera (Hydropunctaria, Parabagliettoa, Wahlenbergiella) and eleven new combinations are proposed here. A summary of the Current taxonomic and morphological circumscription of all genera investigated so far is also presented. Several monophyletic groups are identified for which further taxonomical changes will be required, but for which taxon and gene sampling is presently viewed as insufficient. Clear morphological synapomorphies were found to be rare for newly delimited genera. In some cases (reduced morphology or plesiomorphism), even the combinations of slightly homoplasious phenotypic characters do not allow a clear morphological generic circumscription. Molecular features are envisioned as characters for delimiting these taxa.
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| 6. |
- Savić, Sanja, 1963-
(författare)
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Phylogeny and Taxonomy of Polyblastia and allied taxa (Verrucariaceae)
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Polyblastia A. Massal. is a genus of lichenized fungi belonging to Verrucariaceae (Ascomycota). Traditional classification heavily rested on a few cardinal characters, primarily ascoma structure and spore morphology, but the delimitation of Polyblastia was problematic. Using DNA sequences from nucLSU, and RPB1 the position of the ‘Polyblastia group’, as a strongly supported clade within Verrucariaceae, was confirmed. A three marker phylogeny (including nucITS) based on a wide taxon sampling reveals strongly supported clades within the ‘Polyblastia group’. Thus Polyblastia s.str. is recognized. The phylogeny of the strongly supported Thelidium clade is not completely resolved. In a different clade, Verrucaria rupestris, the type of Verrucaria, is a sister to the Henrica melaspora/H. theleodes clade. Trimmatothele perquisita, the type of Trimmatothele, forms a strongly supported group with a Verrucaria species. The genus Sporodictyon, until recently included in Polyblastia, is resurrected. Species delimitation in Sporodictyon is investigated, and the morphological variation within and between the monophyletic groups is evaluated in an effort to reconcile morphological and molecular data. A taxonomic revision of Sporodictyon, occurring in Northern Europe and the adjacent Arctic is provided, and two new species are described. A comprehensive material is investigated, a key to the species is provided. A generic revision of the family Verrucariaceae, based on recent molecular phylogenetic analyses and previous morphological studies, is offered. Three new genera (Hydropunctaria, Parabagliettoa and Wahlenbergiella) are proposed. Several other monophyletic groups are identified for which the taxon sampling is insufficient for proposing taxonomic changes. The nomenclature of the genera in the family is revised, including the study of type materials and several lectotypifications are suggested. The new genus Atla (Verrucariaceae) is described, and three new species to science, A. alpina, A. palicei and A. praetermissa, are included. An identification key to the species and a revision of the genus is supplied.
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