Viser treff 461-480 av 1600

    • Why Rudolph's nose is red: observational study 

      Ince, Can; van Kuijen, Anne-Marie; Milstein, Dan M J; Yürük, Koray; Folkow, Lars; Fokkens, Wytske J; Blix, Arnoldus S (Journal article; Tidsskriftartikkel, 2012-12-17)
      Objective To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus’s sleigh, is due to the presence of a highly dense and rich nasal microcirculation.<p> <p>Design Observational study.<p> <p>Setting Tromsø, ...
    • Resemblance Reporting on Children: Sisters Are More Proactive than Brothers 

      Fisktjønmo, Guro Hole; Bårdsen, Bård-Jørgen; Folstad, Ivar (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-02)
      The asymmetric grandparental investment in humans may ultimately be explained by the paternity uncertainty hypothesis. The proximate mechanisms leading to grandparental bias in investment in grandchildren are, however, unclear. In a study of 233 males and females with an opposite sexed sibling, we examined whether comments on resemblance regarding one’s own child, or one’s sibling’s child, ...
    • Immobilization of muskoxen (Ovibos moschatus) with etorphine and xylazine 

      Blix, Arnoldus S; Lian, Hans; Ness, john (Journal article; Tidsskriftartikkel; Peer reviewed, 2011-06-27)
      One hundred and thirty three “wild” muskoxen, 81 of which of known body mass, were successfully immobilized using etorphine (M99), and xylazine (Rompun®), delivered by use of a dart gun. A dose of 0.05 mg/kg M99, supplemented by 0.15 mg/kg Rompun was found to be very effective. This dose is much higher than currently recommended e.g. by Handbook of Wildlife Chemical Immobilization.
    • Upregulation of tryptophanyl-tRNA synthethase adapts human cancer cells to nutritional stress caused by tryptophan degradation 

      Adam, Isabell; Dewi, Dyah L.; Mooiweer, Joram; Sadik, Ahmed; Mohapatra, Soumya R.; Berdel, Bianca; Keil, Melanie; Sonner, Jana K.; Thedieck, Kathrin; Rose, Adam J.; Platten, Michael; Heiland, Ines; Trump, Saskia; Opitz, Christiane A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-05)
      Tryptophan (Trp) metabolism is an important target in immuno-oncology as it represents a powerful immunosuppressive mechanism hijacked by tumors for protection against immune destruction. However, it remains unclear how tumor cells can proliferate while degrading the essential amino acid Trp. Trp is incorporated into proteins after it is attached to its tRNA by tryptophanyl-tRNA synthestases. As ...
    • Herbivore Effects on Ecosystem Process Rates in a Low-Productive System 

      Tuomi, Maria Wilhelmina; Stark, Sari; Hoset, Katrine Skamfer; Väisänen, Maria; Oksanen, Lauri; Murguzur, Francisco Javier Ancin; Tuomisto, Hanna; Dahlgren, Jonas; Bråthen, Kari Anne (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-17)
      Mammalian herbivores shape the structure and function of many nutrient-limited or low-productive terrestrial ecosystems through modification of plant communities and plant–soil feedbacks. In the tundra biome, mammalian herbivores may both accelerate and decelerate plant biomass growth, microbial activity and nutrient cycling, that is, ecosystem process rates. Selective foraging and associated ...
    • Hooded seal (Cystophora cristata) pups ingest snow and seawater during their post-weaning fast 

      Schots, Pauke Carlijn; Bue, Marie Emilie Sørdal; Nordøy, Erling Sverre (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-11-09)
      The purpose of this study was to evaluate the importance of exogenous water intake (snow/seawater) in hooded seal (Cystophora cristata) pups during their postweaning fast. In this study, five hooded seal pups had ad lib access to snow and seawater for the first 12 and last 21 days of their post-weaning fast, respectively. Total body water and water flux were determined during both exposure periods ...
    • Machine learning for classification of an eroding scarp surface using terrestrial photogrammetry with nir and rgb imagery 

      Bernsteiner, H.; Brozova, N.; Eischeid, Isabell; Hamer, A.; Haselberger, S.; Huber, M.; Kollert, A.; Vandyk, T. M.; Pirotti, F. (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-03)
      Increasingly advanced and affordable close-range sensing techniques are employed by an ever-broadening range of users, with varying competence and experience. In this context a method was tested that uses photogrammetry and classification by machine learning to divide a point cloud into different surface type classes. The study site is a peat scarp 20 metres long in the actively eroding river bank ...
    • Effect of glacial drainage water on the CO2 system and ocean acidification state in an Arctic tidewater-glacier fjord during two contrasting years 

      Fransson, Agneta Ingrid; Chierici, Melissa; Nomura, Daiki; Granskog, Mats A.; Kristiansen, Svein; Martma, Tõnu; Nehrke, Gernot (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-02-03)
      In order to investigate the effect of glacial water on the CO<sub>2</sub> system in the fjord, we studied the variability of the total alkalinity (A<sub>T</sub>), total dissolved inorganic carbon (C<sub>T</sub>), dissolved inorganic nutrients, oxygen isotopic ratio (δ<sup>18</sup>O), and freshwater fractions from the glacier front to the outer Tempelfjorden on Spitsbergen in winter 2012 (January, ...
    • Distribution, density and abundance of Antarctic ice seals off Queen Maud Land and the eastern Weddell Sea 

      Gurarie, Eliezer; Bengtson, John L; Bester, MN; Blix, Arnoldus S; Cameron, Michael; Bornemann, Horst; Nordøy, Erling Sverre; Plötz, Joachim; Steinhage, Daniel; Boveng, Peter (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-09-09)
      The Antarctic Pack Ice Seal (APIS) Program was initiated in 1994 to estimate the abundance of four species of Antarctic phocids: the crabeater seal Lobodon carcinophaga, Weddell seal Leptonychotes weddellii, Ross seal Ommatophoca rossii and leopard seal Hydrurga leptonyx and to identify ecological relationships and habitat use patterns. The Atlantic sector of the Southern Ocean (the eastern ...
    • Determinants of parasite distribution in Arctic charr populations: catchment structure versus dispersal potential 

      Paterson, Rachel Anne; Knudsen, Rune; Blasco-Costa, Isabel; Dunn, Alison M; Hytterød, Sigurd; Hansen, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-18)
      Parasite distribution patterns in lotic catchments are driven by the combined influences of unidirectional water flow and the mobility of the most mobile host. However, the importance of such drivers in catchments dominated by lentic habitats are poorly understood. We examined parasite populations of Arctic charr Salvelinus alpinus from a series of linear-connected lakes in northern Norway to ...
    • High Arctic Mytilus spp.: occurrence, distribution and history of dispersal 

      Leopold, Peter; Renaud, Paul Eric; Ambrose, William G; Berge, Jørgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-16)
      Many marine species are known to change their distribution in response to changing climatic conditions. One such example is the blue mussel Mytilus spp., spreading northward coincident with an increase in ocean temperatures. On Svalbard, the frst living specimens of Mytilus spp. were discovered in 2004. Here we present an analysis of the current distribution of Mytilus spp. on Svalbard, with a ...
    • Freshwater and its role in the Arctic Marine System: Sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans 

      Carmack, Eddy C.; Yamamoto-Kawai, Michiyo; Haine, Thomas W.N.; Bacon, Sheldon; Bluhm, Bodil; Lique, Camille; Melling, Humfrey; Polyakov, Igor V.; Straneo, Fiamma; Timmermans, Mary Louise E.; Williams, William J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-11)
      The Arctic Ocean is a fundamental node in the global hydrological cycle and the ocean’s thermohaline circulation. We here assess the system’s key functions and processes: (1) the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle, and Pacific Ocean inflows; (2) the disposition (e.g., sources, pathways, and ...
    • Freeze–thaw cycles have minimal effect on the mineralisation of low molecular weight, dissolved organic carbon in Arctic soils 

      Foster, A.; Jones, Davey L.; Cooper, Elisabeth J.; Roberts, Paula (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-03-11)
      Warmer winters in Arctic regions may melt insulating snow cover and subject soils to more freeze– thaw cycles. The effect of freeze–thaw cycles on the microbial use of low molecular weight, dissolved organic carbon (LMW-DOC) is poorly understood. In this study, soils from the Arctic heath tundra, Arctic meadow tundra and a temperate grassland were frozen to -7.5 C and thawed once and three ...
    • Why do the boreal forest ecosystems of Northwestern Europe differ from those of Western North America? 

      Boonstra, Rudy; Andreassen, Harry Peter; Boutin, Stan; Husek, Jan; Ims, Rolf Anker; Krebs, Charles J.; Skarpe, Christina; Wabakken, Petter (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-07-20)
      The boreal forest is one of the largest terrestrial biomes on Earth. Conifers normally dominate the tree layer across the biome, but other aspects of ecosystem structure and dynamics vary geographically. The cause of the conspicuous differences in the understory vegetation and the herbivore–predator cycles between northwestern Europe and western North America presents an enigma. Ericaceous dwarf ...
    • Genomic Changes Associated with the Evolutionary Transitions of Nostoc to a Plant Symbiont 

      Warshan, Denis; Liaimer, Anton; Pederson, Eric; Kim, Sea-Yong; Shapiro, Nicole; Woyke, Tanja; Altermark, Bjørn; Pawlowski, Katharina; Weyman, Philip D.; Dupont, Christopher L.; Rasmussen, Ulla (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-15)
      Cyanobacteria belonging to the genus Nostoc comprise free-living strains and also facultative plant symbionts. Symbiotic strains can enter into symbiosis with taxonomically diverse range of host plants. Little is known about genomic changes associated with evolutionary transition of Nostoc from free-living to plant symbiont. Here, we compared the genomes derived from 11 symbiotic Nostoc strains ...
    • Getting ready for host invasion: Elevated expression and action of xyloglucan endotransglucosylases/hydrolases in developing haustoria of the holoparasitic angiosperm Cuscuta 

      Olsen, Stian; Ketelsen Striberny, Bernd; Hollmann, Julien; Schwacke, Rainer; Popper, Zoe A.; Krause, Kirsten (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-11-11)
      Changes in cell walls have been previously observed in the mature infection organ, or haustorium, of the parasitic angiosperm Cuscuta, but are not equally well charted in young haustoria. In this study, we focused on the molecular processes in the early stages of developing haustoria; that is, before the parasite engages in a physiological contact with its host. We describe first the identification ...
    • The salmon louse genome may be much larger than sequencing suggests. 

      Wyngaard, Grace; Skern-Mauritzen, Rasmus; Malde, Ketil; Prendergast, Rachel; Peruzzi, Stefano (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-22)
      The genome size of organisms impacts their evolution and biology and is often assumed to be characteristic of a species. Here we present the frst published estimates of genome size of the ecologically and economically important ectoparasite, Lepeophtheirus salmonis (Copepoda, Caligidae). Four independent L. salmonis genome assemblies of the North Atlantic subspecies Lepeophtheirus salmonis ...
    • Five decades of terrestrial and freshwater research at Ny-Ålesund, Svalbard 

      Pedersen, Åshild Ønvik; Convey, P.; Newsham, Kevin K.; Mosbacher, Jesper Bruun; Fuglei, Eva; Ravolainen, Virve; Hansen, Brage Bremset; Jensen, Thomas Correll; Augusti, A.; Biersma, Elisabeth Mackteld; Cooper, Elisabeth J.; Coulson, S.J.; Gabrielsen, Geir W.; Gallet, Jean-Charles; Karsten, U.; Kristiansen, Silje Marie; Svenning, Mette Marianne; Tveit, Alexander; Uchida, M.; Baneschi, I.; Calizza, E.; Cannone, N.; de Goede, E.M.; Doveri, M.; Elster, J.; Giamberini, M.S.; Hayashi, K.; Lang, Simone; Lee, Y.K.; Nakatsubo, T.; Pasquali, V.; Paulsen, I.M.G.; Pedersen, Christina Alsvik; Peng, F.; Provenzale, A.; Pushkareva, E.; Sandström, C.A.M.; Sklet, Vera; Stach, A.; Tojo, M.; Tytgat, B.; Tømmervik, Hans; Velazquez, D.; Verleyen, E.; Welker, J.M.; Yao, Y.-F.; Loonen, M.J.J.E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-19)
      For more than five decades, research has been conducted at Ny-Ålesund, in Svalbard, Norway, to understand the structure and functioning of High-Arctic ecosystems and the profound impacts on them of environmental change. Terrestrial, freshwater, glacial and marine ecosystems are accessible year-round from Ny-Ålesund, providing unique opportunities for interdisciplinary observational and experimental ...
    • High-throughput DNA sequencing of the moose rumen from different geographical locations reveals a core ruminal methanogenic archaeal diversity and a differential ciliate protozoal diversity 

      Ishaq, Suzanne L.; Sundset, Monica Alterskjær; Crouse, John; Wright, Andre-Denis G. (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-10-13)
      Moose rumen samples from Vermont, Alaska and Norway were investigated for methanogenic archaeal and protozoal density using real-time PCR, and diversity using high-throughput sequencing of the 16S and 18S rRNA genes. Vermont moose showed the highest protozoal and methanogen densities. Alaskan samples had the highest percentages of Methanobrevibacter smithii, followed by the Norwegian samples. One ...
    • Management decisions and knowledge gaps: Learning by doing in a case of a declining population of slavonian grebe Podiceps auritus 

      Stien, Jenny; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-01)
      Species of national conservation concern require management action to reduce the threat of extinction. As part of its obligations to reduce national loss of biodiversity, the Norwegian authority for nature management (Th e Norwegian Environment Agency) published an action plan in 2010 for one of these species, the Slavonian grebe Podiceps auritus . Th e American mink Neovison vison , a non-native, ...