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Sökning: WAKA:kon > Naturhistoriska riksmuseet

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3.
  • Bisang, Irene, et al. (författare)
  • Infraspecific sex ratio variation and its predictors in mosses – the case of the wetland moss Drepanocladus lycopodioides
  • 2015
  • Ingår i: Botany 2015. Science and Plants for People. Abstracts..
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • Sex ratio variation is a common but unexplained phenomenon of many species with chromosomal sex determination, including many bryophytes. Expressed sex ratio variation could be related to environmental conditions in a few mosses investigated to date. However, many bryophyte populations are non-fertile during their entire life cycle and intraspecific genetic sex ratio variation remains highly unexplored in natural populations. Drepanocladus lycopodioides, a pleurocarpous wetland moss with a distribution largely confined to Western Eurasia, rarely to occasionally forms sexual organs. It belongs to the majority of bryophytes that exhibits a female bias in expressed sex ratio. We applied a novel approach to sex individual shoots irrespective of their reproductive state using a specifically designed female-targeting molecular marker. We demonstrated that the bias in sex expression corresponds to a genetic female bias in the European adult population. Here, we investigated three regional populations of D. lycopodioides in its core distribution area. We asked whether haplotype diversity (H), sex expression (SE), genetic sex ratios, and sporophyte frequency varied within and among regions, whether these characteristics were related with each other, and / or to environmental parameters. Levels of H differed among regions and were positively related to habitat patch size. H was unequally partitioned between the sexes and was associated with estimated regional sporophyte frequency. Recorded plot-wise sporophyte frequency was generally very low in all regions. Overall genetic sex ratio was female-biased in all regions. Sex expression and genetic sex ratio varied strongly within regions (SE 0 –75%), with 27% of the plots lacking sex organs and 78% of the plots one-sexed, but differences among regions were non-significant. While no sex expression occurred in habitats deeper than 25cm, genetic sex ratio was not related to the measured environmental parameters.
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4.
  • Bisang, Irene, et al. (författare)
  • Mass occurrence of springtails on a moss cushion – what are they doing?
  • 2015
  • Ingår i: Melting Pot, Swedish Museum of Natural History, Abstracts: https://vega.nrm.se/vanstermenyn/forskningochsamlingar/meltingpot/2015.9654.html.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The motile spermatozoids of bryophytes can swim up to a few centimetres. They require free water to fertilize the egg of the female organs, which sit on plants separate from the males in more than 50% of the species. When the sex organs are produced on different plants, this presents a serious obstacle to successful fertilization. The problems are overcome by a variety of mechanisms. Some of the more spectacular include spermatozoid transport up to at least several decimetres by water movement, by water drops spread from splash-cups surrounding the male organs up to two meters, by ejection up to15 centimetres into the air, or by having dwarf males that grow directly on the female plants. Here we report on another special kind of spermatozoid transfer that we came across during fieldwork in 2014, namely by micro-arthropods. Bryophyte fertilization mediated by animals was suggested more than a century ago, and was recently shown to occur in experimental settings. However, our observation is likely one of the first made directly in nature.  
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5.
  • Bisang, Irene (författare)
  • SYNTHESYS offers access to European Natural History museums
  • 2014
  • Ingår i: Gothenburg Systematikdagarna. Abstracts.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • SYNTHESYS offers access to European Natural History museums.Twenty partner institutions from 12 European countries form SYNTHESYS, and offer coordinated access to their vast natural history collections and state-of-the art analytical facilities and qualified support from in-house researchers and curators. The institutions also co-operate in Network activities to improve the collections’ management, long-term preservation and accessibility. A Joint research activity develops tools to enhance the quality of and increase access to digitalized collections and data within Natural History institutions. SYNTHESYS was initiated by CETAF and receives funding by the European Union’s Research Framework Programs. It recently  secured EC funding for a third period (SYNTHESYS3 in FP7; Grant no. 312253), which started on 1st September 2013 and lasts for four years. Scientists in based in European member or associate states apply for grants covering research costs and subsistence at one or several partner institutions with a proposal that is assessed by a committee based on scientific quality.
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6.
  • Bouchal, Johannes M., 1979-, et al. (författare)
  • An overview of the palynoflora of the Miocene Yatağan basin, Turkey
  • 2014
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The palynoflora of the lignite strip mines of the Yatağan basin, located in the Muğla province of western Turkey, is the focus of this study. Samples were taken from the Eskihisar, Salihpasalar and Tinaz mines. In the Yatağan basin two Miocene formations, formed from river and lake deposits, Eskihisar Formation (middle Miocene) and Yatağan Formation (late Miocene) have been designated. Both show a general lithology consisting of conglomerate, sandstone, claystone, limestone and tuffite, the mined/excavated lignite bearing strata are restricted to the Eskihisar Formation.Until now, pollen from the Yatağan basin has mostly been described according to conventional morphological nomenclature, using light microscopy (LM) only. In this study, the same individual pollen grains are investigated by using both, LM and scanning electron microscopy (SEM). The  high resolution pictographs allow a higher taxonomic resolution.The rich palynoflora (Table 1) is comprised of diverse spores (at least nine morphotypes), gymnosperm pollen from Cupressaceae, Gnetales, Pinaceae, and angiosperm pollen from Poaceae, Typhaceae, Altingiaceae,  Amaranthaceae (Chenopodieae), Anacardiaceae, Apiaceae, Betulaceae, Buxaceae, Caprifoliaceae (Dipsacoideae, Lonicera) Caryophyllaceae, Compositae (Asteroideae, Cichoriodeae), Cornaceae, Eucommiaceae, Fabaceae, Fagaceae (Fagus, Quercus, Trigonobalanopsis) Geraniaceae, Juglandaceae, Malvaceae, Myricaceae, Nymphaeaceae, Oleaceae, Palmae, Plumbaginaceae (Armeria, Plumbago), Polygonaceae (Rumex), Salicaceae, Sapindaceae (Acer), Smilacaceae, and Ulmaceae (Cedrelospermum, Ulmus, Zelkova).
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7.
  • Bouchal, Johannes M., 1979-, et al. (författare)
  • Palynological and palaeobotanical investigations in the Miocene Yatağan basin, Turkey : High-resoluton taxonomy and biostratigraphy
  • 2015
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The subject of this study is the palynology (biostratigraphic and taxonomic) and the plant remains of the lignite strip mines of Eskihisar, Salihpasalar, and Tinaz (Muğla province, western Turkey). In the Yatağan basin two Miocene to Pliocene formations are present, the Eskihisar Formation (early to middle Miocene) and the Yatağan Formation (late Miocene to early Pliocene). Both formations represent river and lake deposits consisting mainly of conglomerate, sandstone, claystone, limestone, tuffite, and intercalated lignite; the thickest, actively mined lignite seams occur in the Sekköy member of the Eskihisar Formation.Previous palynological studies of the palynoflora of the Yatağan basin mainly focussed on its biostratigraphic and palaeoclimatic significance, using conventional morphological nomenclature and light microscopy (LM).In this study the „single grain method“ is applied. Using this method, the same individual pollen grains are investigated by using both LM and scanning electron microscopy (SEM). The resulting high-resolution pictographs enable a much higher taxonomic resolution. The studied palynoflora is very rich and taxonomically diverse. Cryptogams are represented by more than ten spore morphotypes of at least three families (Osmundaceae, Pteridaceae, Polypodiaceae). Gymnosperm pollen is dominated by Cupressaceae, Gnetales (Ephedra), and Pinaceae (Cathaya, Keteleeria, Pinus). Angiosperm pollen can be assigned to 57 different genera belonging to Poaceae, Typhaceae, Altingiaceae, Amaranthaceae (Chenopodieae), Anacardiaceae, Apiaceae (three types), Asteraceae (Asteroideae, Cichoriodeae), Betulaceae (Alnus, Betula, Carpinus, Ostrya) Buxaceae, Campanulaceae, Caprifoliaceae (Lonicera), Caryophyllaceae, Dipsacaceae, Eucommiaceae, Euphorbiaceae, Fabaceae, Fagaceae (Fagus, Quercus, Trigonobalanopsis) Geraniaceae, Juglandaceae, Linnaceae (Linnum), Malvaceae, Myricaceae, Nymphaeaceae, Oleaceae (four different types), Plumbaginaceae (Armeria,), Polygonaceae (Rumex), Rosaceae, Sapindaceae (Acer), Ulmaceae (Cedrelospermum, Ulmus, Zelkova), and Zingiberales (Spirematospermum). In addition, more than two thousand plant macrofossils were collected in the course of repeated field trips, including remains of Pinaceae, Berberidiaceae (Mahonia), Betulaceae (Alnus, Carpinus), Buxaceae (Buxus), Fagaceae (Fagus, Quercus), Lauraceae, Malvaceae (Tilia), Myricaceae (Myrica), Rosaceae, Salicaceae (Populus, Salix), Sapindaceae (Acer), Smilacaceae (Smilax), Typhaceae (Typha), Ulmaceae (Zelkova). A combined analysis integrating these rich and diverse plant macro- and microfossil records will lead to a better understanding and refined reconstruction of the vegetation in the Yatağan basin during the middle to late Miocene.
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8.
  • Bouchal, Johannes M., 1979-, et al. (författare)
  • Palynostratigraphical correlation of the excavated Miocene lignite seams of the Yatağan basin (Muğla Province, south-western Turkey)
  • 2016
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The excavated main lignite seams and overlying lacustrine sediments of the opencast mines Eskihisar, Salihpaşalar, and Tınaz, Muğla Province, south-western Turkey were investigated using a high taxonomic resolution palynological approach.The Eskihisar section comprises 47m and 56 samples of which 30 were usable for palynological analysis. The Tınaz section comprises 75 m and 29 samples of which 15 were usable for palynological analysis. Finally, the Salihpaşalar section comprises 25 m and 26 samples of which 16 were usable for palynological analysis. The age of the palynological sections is middle to late Miocene based on radiometric dating and vertebrate fossils. In order to investigate dispersed pollen and spores and their botanical affinities a combined light microscopy and scanning electron microscopy approach was used. The rich palynoflora comprises seven types of algal cysts (Botryococcus, Zygnemataceae), seventeen spore types (Lycopsida, Marsileaceae, Osmundaceae, Pteridaceae, Polypodiaceae), 14 types of gymnosperm pollen (Ephedraceae, Cupressaceae, Pinaceae), five types of monocotyledone pollen (Poaceae, Typhaceae) and ca 90 dicotyledone pollen types (Altingiaceae, Amaranthaceae, Anacardiaceae, Apiaceae, Aquifoliaceae, Asteraceae, Betulaceae, Campanulaceae, Cannabaceae, Caprifoliaceae, Caryophyllaceae, Ericaceae, Eucommiaceae, Euphorbiaceae, Fabaceae, Fagaceae, Geraniaceae, Juglandaceae, Lamiaceae, Linaceae, Lythraceae, Malvaceae, Myricaceae, Oleaceae, Onagraceae, Plumbaginaceae, Polygonaceae, Ranunculaceae, Rosaceae, Salicaceae, Sapindaceae, Sapotaceae, Ulmaceae). The objectives of this investigation were (1) to evaluate whether the three palynological sections were deposited at the same time, and (2) to show regional vegetation differences within a single sedimentary basin. We found three general pollen zones corresponding to different sedimentary settings and palaeoenvironments. The first pollen zone was linked to lignite formation (swamp forest, fern spores, Alnus, Decodon). The second pollen zone reflects lacustrine conditions (Typhaceae) and surrounding hinterland vegetation dominated by Fagaceae. The third pollen zone is dominated by herbaceous taxa, whereas woody taxa are less diverse and less abundant. In general, the three palynological sections are congruent in reflecting distinct pollen zones. However main vegetation types may be represented by different dominating taxa (e. g. Alnus dominace in Eskihisar and Tınaz localities while absent in Salihpaşalar) and rare taxa may differ between localities. Our results demonstrate that in order to achieve a comprehensive understanding of environmental and vegetation conditions in a sedimentary basin, a single palynological section (locality) may not capture the entirety of environmental conditions and changes.
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9.
  • Bouchal, Johannes M., 1979-, et al. (författare)
  • Some new pollen taxa from the middle Miocene of south western Anatolia
  • 2016
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • In an ongoing study, focussing on the plant fossils and palynofloras of the lignite strip mines of the Yatağan basin(Muğla province), a number of pollen taxa, previously not reported from middle Miocene terrestrial sediments of Anatolia were encountered.
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10.
  • Cámara, Fernando, 1967-, et al. (författare)
  • Old samples - new amphiboles
  • 2022
  • Ingår i: Abstracts, International Mineralogical Association 23<sup>rd</sup> General meeting. - Lyon. ; , s. 42-42
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The scientific value of old and well-preserved collections is priceless. Samples that already have been studied and described can still give very useful information. For instance, minerals with complex solid solutions like amphiboles sometimes show new compositions that are feasible because of crystal-chemistry and charge arrangements, based on the current classification scheme by Hawthorne et al. (2012) for the amphibole supergroup. In the last four years, a fruitful collaboration between the Swedish Museum of Natural History and the Department of Earth Sciences of the University of Milan has allowed the identification of new amphibole species, recognized by CNMNC-IMA. First of all, we identified hjalmarite, [ANaB(NaMn)CMg5TSi8O22W(OH)2], which is related to richterite via the homovalent substitution [B]Ca2+ → [B]Mn2+, and is the second recognized member of the sodium–(magnesium–iron–manganese) subgroup, after ferri-ghoseite. Sjögren (1891) had described a physically similar, MnO-rich sample from Långban, named “astochit”. A related amphibole, although belonging to a different subgroup, that we have formally described is potassic-richterite, [AKB(NaCa)CMg5TSi8O22W(OH)2]. It was found in a sample from the Pajsberg iron and manganese ore mines, which was originally collected by the mineralogist Lars Johan Igelström, probably in the 1850s. The most recent amphibole we have described is ferri-taramite [ANaB(NaCa)C(Mg3Fe3+2)T(Si6Al2)O22W(OH)2], found in a skarn sample from the Jakobsberg manganese mine: it was once examined by Flink (1914), who noted the unusual character of the amphibole and described it as a “strange hornblende”.
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