Viser treff 654-673 av 1515

    • Homing behaviour of Atlantic salmon (Salmo salar) during final phase of marine migration and river entry 

      Davidsen, Jan Grimsrud; Rikardsen, Audun H.; Thorstad, Eva Bonsak; Halttunen, Elina; Mitamura, Hiromichi; Præbel, Kim; Skardhamar, Jofrid; Næsje, Tor (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Little is known about Atlantic salmon behaviour during the last phase of the marine homing migration and subsequent river entry. In this study, 56 adult Atlantic salmon in the Alta Fjord in northern Norway were equipped with acoustic transmitters. Salmon generally followed the coastline, but their horizontal distribution was also affected by wind-induced spreading of river water across the fjord. ...
    • 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 ...
    • Hooded seal Cystophora cristata foraging areas in the Northeast Atlantic Ocean—Investigated using three complementary methods 

      Vacquie-Garcia, Jade; Lydersen, Christian; Biuw, Martin; Haug, Tore; Fedak, Michael A.; Kovacs, Kit M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-06)
      Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs) to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles). Three ...
    • Horizon scanning of potential threats to high-Arctic biodiversity, human health and the economy from marine invasive alien species: A Svalbard case study 

      Cottier-Cook, Elizabeth Joanne; Bentley-Abbot, Jude; Cottier, Finlo Robert; Minchin, Dan; Olenin, Sergej; Renaud, Paul Eric (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-09)
      The high Arctic is considered a pristine environment compared with many other regions in the northern hemisphere. It is becoming increasingly vulnerable to invasion by invasive alien species (IAS), however, as climate change leads to rapid loss of sea ice, changes in ocean temperature and salinity, and enhanced human activities. These changes are likely to increase the incidence of arrival and ...
    • Horizontal and Vertical Migration of Anglerfish Lophius piscatorius in Relation to Hydrography in Faroese Waters 

      Ofstad, Lise Helen; Hátún, Hjálmar; Pedersen, Torstein; Steingrund, Petur; Mikkelsen, Bjarni (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-04)
      Adult anglerfish conduct annual migrations between spawning areas and feeding areas; for Faroese waters this migration has so far not been described. Therefore, anglerfish migration and distribution in Faroese waters was investigated by mark-recapture studies, including data storage tags, as well as data from scientific trawl surveys, commercial trawlers and gillnetters. The fish distribution was ...
    • Host range, symbiotic effectiveness and nodulation competitiveness of some indigenous cowpea bradyrhizobia isolates from the transitional savanna zone of Ghana 

      Ampomah, Osei Yaw; Ofori-Ayeh, E; Solheim, Bjørn; Svenning, Mette M (Journal article; Tidsskriftartikkel; Peer reviewed, 2008)
    • A host-free transcriptome for haustoriogenesis in Cuscuta campestris: signature gene expression identifies markers of successive development stages 

      Bawin, Thomas Georges A; Bruckmüller, Julien-Alexander; Olsen, Stian; Krause, Kirsten (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-01-20)
      The development of the infection organ of the parasitic angiosperm genus Cuscuta is a dynamic process that is normally obscured from view as it happens endophytically in its host. We artificially induced haustoriogenesis in C. campestris by far-red light to define specific morphologically different stages and analyze their transcriptional patterns. This information enabled us to extract sets of ...
    • How can a binary switch within the pars tuberalis control seasonal timing of reproduction? 

      Wood, Shona Hiedi (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10)
      Life in seasonally changing environments is challenging. Biological systems have to not only respond directly to the environment, but also schedule life history events in anticipation of seasonal changes. The cellular and molecular basis of how these events are scheduled is unknown. Cellular decision-making processes in response to signals above certain thresholds regularly occur i.e. cellular fate ...
    • How Many Reindeer? UAV Surveys as an Alternative to Helicopter or Ground Surveys for Estimating Population Abundance in Open Landscapes 

      Paulsen, Ingrid M.; Pedersen, Åshild Ø; Hann, Richard; Blanchet, Marie-Anne; Eischeid, Isabell; van Hazendonk, Charlotte Maartje; Ravolainen, Virve; Stien, Audun; Le Moullec, Mathilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-20)
      Conservation of wildlife depends on precise and unbiased knowledge on the abundance and distribution of species. It is challenging to choose appropriate methods to obtain a sufficiently high detectability and spatial coverage matching the species characteristics and spatiotemporal use of the landscape. In remote regions, such as in the Arctic, monitoring efforts are often resource-intensive and there ...
    • How microbial food web interactions shape the arctic ocean bacterial community revealed by size fractionation experiments 

      Müller, Oliver; Seuthe, Lena; Pree, Bernadette; Bratbak, Gunnar; Larsen, Aud; Paulsen, Maria Lund (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-17)
      In the Arctic, seasonal changes are substantial, and as a result, the marine bacterial community composition and functions differ greatly between the dark winter and light-intensive summer. While light availability is, overall, the external driver of the seasonal changes, several internal biological interactions structure the bacterial community during shorter timescales. These include specific ...
    • How rapidly do invasive birch forest geometrids recruit larval parasitoids? Insights from comparison with a sympatric native geometrid 

      Laksforsmo Vindstad, Ole Petter; Schott, Tino; Hagen, Snorre; Jepsen, Jane Uhd; Kapari, Lauri Teemu; Ims, Rolf Anker (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Two related issues in studies of biological invasions are how quickly the enemy complexes of invasive species become as species-rich and efficient as those of native species and how important enemy release is for the establishment and spread of invaders. We addressed these issues for the geometrid moths Operophtera brumata and Agriopis aurantiaria, who invaded the coastal mountain birch forest ...
    • How spatial variation in areal extent and configuration of labile vegetation states affect the riparian bird community in Arctic Tundra 

      Henden, John-André; Yoccoz, Nigel; Ims, Rolf Anker; Langeland, Knut (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond ...
    • Human long intrinsically disordered protein regions are frequent targets of positive selection 

      Afanasyeva, Arina; Bockwoldt, Mathias; Cooney, Christopher; Heiland, Ines; Gossmann, Toni Ingolf (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-01)
      Intrinsically disordered regions occur frequently in proteins and are characterized by a lack of a well-defined three-dimensional structure. Although these regions do not show a higher order of structural organization, they are known to be functionally important. Disordered regions are rapidly evolving, largely attributed to relaxed purifying selection and an increased role of genetic drift. It has ...
    • Human myiasis caused by the reindeer warble fly, Hypoderma tarandi, case series from Norway, 2011 to 2016 

      Landehag, Jörgen; Skogen, Andreas; Åsbakk, Kjetil; Kan, Boris (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07)
      Hypoderma tarandi causes myiasis in reindeer and caribou ( Rangifer tarandus spp.) in most northern hemisphere regions where these animals live. We report a series of 39 human myiasis cases caused by H. tarandi in Norway from 2011 to 2016. Thirty-two were residents of Finnmark, the northernmost county of Norway, one a visitor to Finnmark, and six lived in other counties of Norway where reindeer live. ...
    • Human-animal agency in reindeer management: Sami herders perspectives on vegetation dynamics under climate change 

      Horstkotte, Tim; Utsi, Tove Aagnes; Larsson-Blind, Åsa; Burgess, Peter; Johansen, Bernt; Kayhko, Jukka; Oksanen, Lauri Kalervo; Forbes, B.C. (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-13)
      Many primary livelihoods in Arctic and sub-Arctic regions experience accelerating effects of environmental change. The often close connection between indigenous peoples and their respective territories allows them to make detailed observations of how these changes transform the landscapes where they practice their daily activities. Here, we report Sámi reindeer herders’ observations based on their ...
    • Hva forskerne egentlig gjør 

      Wiedmann, Ingrid (Chronicle; Kronikk, 2018-10-19)
      <p><i>Introduction</i>: Forskningsdagene ved UiT Norges arktiske universitet, åpen dag ved Framsenteret, ulike arrangement rundt UiTs 50 års jubileum og en UiT spesialforestilling på Hålogaland teater: Forskningen i Tromsø har vist seg seg fram denne høsten. Uansett hvor du går i Tromsø, så formidler forskere til deg at forskning er spennende og at det er kjempegøy å være forsker. Som forsker står ...
    • Hydrography, inorganic nutrients and chlorophyll a linked to sea ice cover in the Atlantic Water inflow region north of Svalbard 

      Renner, Angelika; Bailey, Allison Michelle; Reigstad, Marit; Sundfjord, Arild; Chierici, Melissa; Jones, Elizabeth Marie (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-04)
      Changes in the inflow of Atlantic Water (AW) and its properties to the Arctic Ocean bring more warm water, contribute to sea ice decline, promote borealisation of marine ecosystems, and affect biological and particularly primary productivity in the Eurasian Arctic Ocean. One of the two branches of AW inflow follows the shelf break north of Svalbard, where it dominates oceanographic conditions, ...
    • Hydrozoan diversity on hard bottom in Kongsfjorden, Svalbard 

      Voronkov, Andrey; Stepanjants, S.D.; Hop, Haakon (Journal article; Tidsskriftartikkel; Peer reviewed, 2010)
      Hydroids in Kongsfjorden, Svalbard, were studied on five hard-bottom transects along gradients of environmental conditions from the glacier at the fjord’s head to the fjord’s mouth at depth-range 0–30 m. Hydrozoa colonies are widely distributed on rock and gravel substrata in Kongsfjorden. In general, however, hydroids are not dominant or subdominant in zoobenthic communities. The exception is ...
    • Hyperbenthic food-web structure in an Arctic fjord 

      McGovern, Maeve; Berge, Jørgen; Szymczycha, Beata; Węsławski, Jan Marcin; Renaud, Paul Eric (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-17)
      Current knowledge of the Arctic marine ecosystem is based primarily on studies performed during the polar day on the pelagic and benthic realms. Both the polar night and the hyperbenthic layer remain as substantial knowledge gaps in our understanding of the marine system at high latitudes. This study investigated the hyperbenthic food web in Kongsfjord, a high-latitude, ice-free fjord, in September ...
    • Hypoxia Inducible Factor 1α Inhibits the Expression of Immunosuppressive Tryptophan-2,3-Dioxygenase in Glioblastoma 

      Mohapatra, Soumya R.; Sadik, Ahmed; Tykocinski, Lars-Oliver; Dietze, Jørn; Poschet, Gernot; Heiland, Ines; Opitz, Christiane A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-04)
      Abnormal circulation in solid tumors results in hypoxia, which modulates both tumor intrinsic malignant properties as well as anti-tumor immune responses. Given the importance of hypoxia in glioblastoma (GBM) biology and particularly in shaping anti-tumor immunity, we analyzed which immunomodulatory genes are differentially regulated in response to hypoxia in GBM cells. Gene expression analyses ...