Viser treff 22861-22880 av 37048

    • Survey of conditions for artificial aurora experiments at EISCAT Tromsø using dynasonde data 

      Tsuda, T. T.; Rietveld, Michael T; Kosch, Michael J.; Oyama, S; Hosokawa, K.; Nozawa, Satonori; Kawabata, T; Mizuno, A; Ogawa, Y (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-14)
      We report a brief survey on conditions for artificial aurora optical experiments in F region heating with O-mode at the EISCAT Tromsø site using dynasonde data from 2000 to 2017. The results obtained in our survey indicate the following: The possible conditions for conducting artificial aurora experiments are concentrated in twilight hours in both evening and morning, compared with late-night hours; ...
    • K2 Campaign 5 observations of pulsating subdwarf B stars: Binaries and super-Nyquist frequencies 

      Reed, Michael D; Armbrecht, EL; Telting, John H; Baran, Andrzej S; Østensen, Roy; Blay, Pere; Kvammen, Andreas; Kuutma, Teet; Pursimo, Tapio; Ketzer, Laura; Jeffery, C. Simon (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-05)
      We report the discovery of three pulsating subdwarf B stars in binary systems observed with the <i>Kepler</i> space telescope during Campaign 5 of K2. EPIC 211696659 (SDSS J083603.98+155216.4) is a g-mode pulsator with a white dwarf companion and a binary period of 3.16 d. EPICs 211823779 (SDSS J082003.35+173914.2) and 211938328 (LB 378) are both p-mode pulsators with main-sequence F companions. The ...
    • Tundra Trait Team: A database of plant traits spanning the tundra biome 

      Bjorkman, Anne D.; Myers-Smith, Isla H.; Elmendorf, Sarah C.; Normand, Signe; Thomas, Haydn J.D.; Alatalo, Juha M.; Alexander, Heather; Anadon-Rosell, Alba; Angers-Blondin, Sandra; Bai, Yang; Baruah, Gaurav; te Beest, Mariska; Berner, Logan; Björk, Robert G.; Blok, Daan; Bruelheide, Helge; Buchwal, Agata; Buras, Allan; Carbognani, Michele; Christie, Katherine; Collier, Laura Siegwart; Cooper, Elisabeth J.; Cornelissen, J. Hans C.; Dickinson, Katharine J.M.; Dullinger, Stefan; Elberling, Bo; Eskelinen, Anu; Forbes, Bruce C.; Frei, Esther R.; Iturrate-Garcia, Maitane; Good, Megan K.; Grau, Oriol; Green, Peter; Greve, Michelle; Grogan, Paul; Haider, Sylvia; Hájek, Tomáš; Hallinger, Martin; Happonen, Konsta; Harper, Karen A.; Heijmans, Monicque M.P.D.; Henry, Gregory H.R.; Hermanutz, Luise; Hewitt, Rebecca E.; Hollister, Robert D.; Hudson, James; Hülber, Karl; Iversen, Colleen M.; Jaroszynska, Francesca; Jiménez-Alfaro, Borja; Johnstone, Jill; Jørgensen, Rasmus Halfdan; Kaarlejärvi, Elina; Klady, Rebecca; Klimešová, Jitka; Korsten, Annika; Kuleza, Sara; Kulonen, Aino; Lamarque, Laurent J.; Lantz, Trevor; Lavalle, Amanda; Lembrechts, Jonas J.; Lévesque, Esther; Little, Chelsea J.; Luoto, Miska; Macek, Petr; Mack, Michelle C.; Mathakutha, Rabia; Michelsen, Anders; Milbau, Ann; Molau, Ulf; Morgan, John W.; Mörsdorf, Martin Alfons; Nabe-Nielsen, Jacob; Nielsen, Sigrid Schøler; Ninot, Josep M.; Oberbauer, Steven F.; Olofsson, Johan; Onipchenko, Vladimir G.; Petraglia, Alessandro; Pickering, Catherine; Prevéy, Janet S.; Rixen, Christian; Rumpf, Sabine Bettina; Schaepman-Strub, Gabriela; Semenchuk, Philipp; Shetti, Rohan; Soudzilovskaia, Nadejda A.; Spasojevic, Marko J.; Speed, James David Mervyn; Street, Lorna E.; Suding, Katharine; Tape, Ken D.; Tomaselli, Marcello; Trant, Andrew; Treier, Urs A.; Tremblay, Jean-Pierre; Tremblay, Maxime; Venn, Susanna; Virkkala, Anna-Maria; Vowles, Tage; Weijers, Stef; Wilmking, Martin; Wipf, Sonja; Zamin, Tara (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-22)
      <p><i>Motivation</i>: The Tundra Trait Team (TTT) database includes field‐based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade‐offs, trait–environment relationships and environmental filtering, and trait variation across spatial scales, to validate satellite ...
    • Updates on old and weary haematopoiesis 

      Konieczny, Joanna; Arranz, Lorena (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-29)
      Blood formation, or haematopoiesis, originates from haematopoietic stem cells (HSCs), whose functions and maintenance are regulated in both cell- and cell non-autonomous ways. The surroundings of HSCs in the bone marrow create a specific niche or microenvironment where HSCs nest that allows them to retain their unique characteristics and respond rapidly to external stimuli. Ageing is accompanied ...
    • DNA barcoding a taxonomically complex hemiparasitic genus reveals deep divergence between ploidy levels but lack of species-level resolution 

      Wang, Xumei; Gusarova, Galina; Ruhsam, Markus; de Vere, Natasha; Metherell, Chris; Hollingsworth, Peter M.; Twyford, Alex D. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-04-24)
      DNA barcoding is emerging as a useful tool not only for species identification but also for studying evolutionary and ecological processes. Although plant DNA barcodes do not always provide species-level resolution, the generation of large DNA barcode data sets can provide insights into the mechanisms underlying the generation of species diversity. Here, we study evolutionary processes in taxonomically ...
    • Developing an observational design for epibenthos and fish assemblages in the Chukchi Sea 

      Iken, Katrin; Mueter, Franz J.; Grebmeier, Jacqueline M.; Cooper, Lee W.; Danielson, Seth L.; Bluhm, Bodil (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-14)
      In light of ongoing, and accelerating, environmental changes in the Pacific sector of the Arctic Ocean, the ability to track subsequent changes over time in various marine ecosystem components has become a major research goal. The high logistical efforts and costs associated with arctic work demand the prudent use of existing resources for the most comprehensive information gain. Here, we compare ...
    • Age and Sex-Associated Changes of Complement Activity and Complement Levels in a Healthy Caucasian Population 

      Gaya de Costa, Mariana; Poppelaars, Felix; van Kooten, Cees; Mollnes, Tom Eirik; Tedesco, Francesco; Würzner, Reinhard; Trouw, Leendert A.; Truedsson, Lennart; Daha, Mohamed R.; Roos, Anja; Seelen, Marc A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-20)
      <p><i>Introduction</i>: The complement system is essential for an adequate immune response. Much attention has been given to the role of complement in disease. However, to better understand complement in pathology, it is crucial to first analyze this system under different physiological conditions. The aim of the present study was therefore to investigate the inter-individual variation in complement ...
    • High goose abundance reduces nest predation risk in a simple rodent-free high-Arctic ecosystem 

      Pedersen, Åshild Ønvik; Stien, Jennifer; Eidesen, Pernille Bronken; Ims, Rolf Anker; Jepsen, Jane Uhd; Stien, Audun; Tombre, Ingunn; Fuglei, Eva (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-12-13)
      Breeding geese are the preferred prey of the Arctic fox Vulpes lagopus in the high-Arctic Svalbard archipelago. According to the <i>apparent competition hypothesis (ACH)</i>, less-abundant prey species (e.g. ptarmigan, waders and small passerines) will experience higher predation rates when breeding in association with the more common prey (geese), due to spill-over predation by the shared predator. ...
    • Nonlocal damage mechanics for quantification of health for piezoelectric sensor 

      Habib, Anowarul; Shelke, Amit; Amjad, U; Pietsch, Ullrich; Banerjee, S (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-18)
      In this paper, a novel method to quantify the incubation of damage on piezoelectric crystal is presented. An intrinsic length scale parameter obtained from nonlocal field theory is used as a novel measure for quantification of damage precursor. Features such as amplitude decay, attenuation, frequency shifts and higher harmonics of guided waves are commonly-used damage features. Quantification of the ...
    • How Is Adolescent Bone Mass and Density Influenced by Early Life Body Size and Growth? The Tromsø Study: Fit Futures—A Longitudinal Cohort Study From Norway 

      Evensen, Elin; Skeie, Guri; Wilsgaard, Tom; Christoffersen, Tore; Dennison, Elaine; Furberg, Anne-Sofie; Grimnes, Guri; Winther, Anne; Emaus, Nina (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-03-30)
      The effect of birth weight and childhood body mass index (BMI) on adolescents’ bone parameters is not established. The aim of this longitudinal, population‐based study was to investigate the association of birth weight, childhood BMI, and growth, with adolescent bone mass and bone density in a sample of 633 adolescents (48% girls) from The Tromsø Study: Fit Futures. This population‐based cohort study ...
    • When Life Happens: Investigating Short and Long-Term Effects of Life Stressors on Life Satisfaction in a Large Sample of Norwegian Mothers 

      Dyrdal, Gunvor Marie; Røysamb, Espen; Nes, Ragnhild Bang; Vittersø, Joar (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-08-25)
      The purpose of this study was to examine the impact of major life stressors on the short and long-term life satisfaction (LS) of Norwegian mothers using data from the Norwegian Mother and Child Cohort study (MoBa, N = 46,342). Data on LS were collected at T1 (6 months postpartum) and T3 (36 months postpartum), and data on life stressors at T2 (18 months postpartum) and T3. Altogether, 24,216 ...
    • Do Norwegian Sami and non-indigenous individuals understand questions about mental health similarly? A SAMINOR 2 study 

      Sørlie, Tore; Hansen, Ketil Lenert; Friborg, Oddgeir (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-06-05)
      The Western culturally developed Hopkins Symptom Checklist (HSCL-10) is a self-report measure of mental distress widely used for both clinical and epidemiological purposes – also in the multiethnic epidemiological SAMINOR studies in Northern Norway, but without any proper cross-cultural validation. Our objective was to test invariance of the HSCL-10 measurements among Sami and the non-indigenous ...
    • Mild cognitive impairment impacts health outcomes of patients with atrial fibrillation undergoing a disease management intervention 

      Ball, Jocasta; Løchen, Maja-Lisa; Carrington, Melinda; Wiley, Joshua F; Stewart, Simon (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-02-07)
      <p><i>Objective</i>: Mild cognitive impairment (MCI) is prevalent in atrial fibrillation (AF) and has the potential to contribute to poor outcomes. We investigated the influence of MCI on survival and rehospitalisation in patients with chronic forms of AF undergoing a home-based, AF-specific disease management intervention (home-based intervention (HBI)) or standard management (SM).</p> <p><i>M ...
    • The molecular origin of cold adaptation: A comparative study of cold- and warm-active uracil DNA glycosylase 

      Olufsen, Magne (Doctoral thesis; Doktorgradsavhandling, 2007-05-25)
      During the last decade or so, scientists at the Norwegian Structural Biology Centre (NorStruct) have used the enzyme uracil DNA glycosylase (UDG) as a model system in the study of cold-adaptation, protein-DNA recognition and enzyme specificity. The cod UDG (cUDG) and human UDG (hUDG) are thoroughly biologically characterized and there are established well-functioning recombinant expression systems ...
    • A Comparative Study of Different Control Structures for Flight Control with New Results 

      Oland, Espen; Kristiansen, Raymond; Gravdahl, Jan Tommy (Peer reviewed; Book; Chapter, 2018-10-24)
      This paper presents several different control structures that facilitate flight control and does a comparison between them. Specifically, this paper considers command-filtered backstepping, nonlinear dynamic inversion (NDI), and a new decoupled approach that decouples the rotational and translational dynamics by estimating the higher order derivatives of the angle of attack and sideslip angle. The ...
    • Risk Assessment of Hazards Due to the Installation and Maintenance of Onshore Wind Turbines 

      Mustafa, Albara Mohamad Yazid Faisal; Mahadin, Aziz (Peer reviewed; Book; Chapter, 2018-06-11)
      In this work, an assessment of four types of risks is carried out for wind turbines during four phases, namely: transportation, installation, operation and maintenance. This work mainly focuses on onshore type of wind turbines and briefly mentioning the offshore wind turbines. The introduction gives an overview of the main parts and components of wind turbine, in addition to discussing the process ...
    • A Comparison of Two Location Models in Optimizing the Decision-making on the Relocation Problem of Post Offices at Narvik, Norway 

      Yu, Hao; Solvang, Wei Deng (Peer reviewed; Book; Chapter, 2018)
      Since 2013, the postal service provider in Norway: Posten has implemented a new strategic plan to close their large post offices across the country for improving the cost and operational efficiency. Instead, with the cooperation with large retailers, the local postal service is provided at the Posten sub-branches at some supermarkets. In this paper, an optimization problem for relocating the post ...
    • Failure intensity of offshore power plants under varying maintenance policies 

      Perera, Lokukaluge Prasad; Machado, Mario M.; Valland, Anders; Manguinho, Diego A.P. (Journal article; Peer reviewed; Tidsskriftartikkel, 2019-01-06)
      System reliability of an offshore power plant with several gas turbine engines is analyzed in this study to understand the failure intensity of a selected gas turbine engines under varying maintenance activities. A set of event data of a selected gas turbine engine is considered to identify system failure intensity levels, where unknown maintenance actions were implemented (i.e. various repairs ...
    • A comparison of the energy consumption for CO2 compression process alternatives 

      Jackson, Steven; Brodal, Eivind (Journal article; Peer reviewed; Tidsskriftartikkel, 2018)
      The efficient transportation of large volumes of CO2 generally requires pipelines that will operate above the critical pressure of CO2. Since most capture processes release CO2 at low pressure, compression of CO2 from the point of capture to pipeline will generally be required. The compression duty can be achieved using conventional multi-stage compressors or using newer shockwave type compressors. ...
    • Auroral molecular-emission effects on the atomic oxygen line at 777.4 nm 

      Oyama, Shin-Ichiro; Tsuda, Takuo T.; Hosokawa, Keisuke; Ogawa, Yasunobu; Miyoshi, Yoshizumi; Kurita, Satoshi; Kero, Antti; Fujii, Ryochi; Tanaka, Yoshimasa; Mizuno, Akira; Kawabata, Tetsuya; Gustavsson, Björn Johan; Leyser, Thomas (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-16)
      One of the representative auroral emission lines that radiates from F-region heights and is measurable on the ground is the 777.4 nm line from excited atomic oxygen. This line has been adopted, along with another E-region emission line, for example 427.8 nm, to estimate the mean energy and total energy flux of precipitating auroral electrons. The influence of emissions from part of the molecular ...