Viser treff 2341-2360 av 5336

    • Lake Sedimentary DNA Research on Past Terrestrial and Aquatic Biodiversity: Overview and Recommendations 

      Capo, Eric; Giguet-Covex, Charline; Rouillard, Alexandra; Nota, Kevin; Heintzman, Peter D.; Vuillemin, Aurèle; Ariztegui, Daniel; Arnaud, Fabien; Belle, Simon; Bertilsson, Stefan; Bigler, Christian; Bindler, Richard; Brown, Antony G.; Clarke, Charlotte L.; Crump, Sarah E.; Debroas, Didier; Englund, Göran; Ficetola, Gentile Francesco; Garner, Rebecca E.; Gauthier, Joanna; Gregory-Eaves, Irene; Heinecke, Liv; Herzschuh, Ulrike; Ibrahim, Anan; Kisand, Veljo; Kjær, Kurt H.; Lammers, Youri; Littlefair, Joanne; Messager, Erwan; Monchamp, Marie-Eve; Olajos, Fredrik; Orsi, William; Pedersen, Mikkel W.; Rijal, Dilli P.; Rydberg, Johan; Spanbauer, Trisha; Stoof-Leichsenring, Kathleen R.; Taberlet, Pierre; Talas, Liisi; Thomas, Camille; Walsh, David A.; Wang, Yucheng; Willerslev, Eske; van Woerkom, Anne; Zimmermann, Heike H.; Coolen, Marco J. L.; Epp, Laura S.; Domaizon, Isabelle; Alsos, Inger G.; Parducci, Laura (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-02-13)
      The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original ...
    • Small calcium isotope fractionation at slow precipitation rates in methane seep authigenic carbonates 

      Blättler, Clara L.; Hong, Wei-Li; Kirsimae, Kalle; Higgins, John A.; Lepland, Aivo (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-01)
      Natural calcium carbonate minerals express a range of calcium isotope fractionations, with the precipitated mineral typically enriched in the lighter isotopes of calcium relative to source fluids. Experimental and theoretical evidence shows a strong dependence on precipitation rate, although this relationship has not been well quantified over the range of precipitation rates observed in natural ...
    • Arctic sea-ice loss fuels extreme European snowfall 

      Bailey, Hannah L.; Hubbard, Alun Lloyd; Klein, Eric S.; Mustonen, Kaisa-Riikka; Akers, Pete D.; Marttila, Hannu; Welker, Jeffrey M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-01)
      The loss of Arctic sea-ice has been implicated with severe cold and snowy mid-latitude winters. However, the mechanisms and a direct link remain elusive due to limited observational evidence. Here we present atmospheric water vapour isotope measurements from Arctic Finland during ‘the Beast from the East’—a severe anticyclonic outbreak that brought heavy snowfall and freezing across Europe in February ...
    • Dense dilated convolutions merging network for land cover classification 

      Liu, Qinghui; Kampffmeyer, Michael; Jenssen, Robert; Salberg, Arnt Børre (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-06)
      Land cover classification of remote sensing images is a challenging task due to limited amounts of annotated data, highly imbalanced classes, frequent incorrect pixel-level annotations, and an inherent complexity in the semantic segmentation task. In this article, we propose a novel architecture called the dense dilated convolutions' merging network (DDCM-Net) to address this task. The proposed ...
    • Machine Learning for Arctic Sea Ice Physical Properties Estimation Using Dual-Polarimetric SAR Data 

      Blix, Katalin; Espeseth, Martine; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-22)
      This work introduces a novel method that combines machine learning (ML) techniques with dual-polarimetric (dual-pol) synthetic aperture radar (SAR) observations for estimating quad-polarimetric (quad-pol) parameters, which are presumed to contain geophysical sea ice information. In the training phase, the output parameters are generated from quad-pol observations obtained by Radarsat-2 (RS2), and ...
    • Retrieval of Marine Surface Slick Dielectic Properties From Radarsat-2 Data via a Polarimetric Two-Scale Model 

      Quigley, Cornelius; Brekke, Camilla; Eltoft, Torbjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-27)
      We propose the use of a polarimetric two-scale surface scattering model to retrieve the dielectric parameters of oil slick from the polarimetric synthetic aperture radar. The ocean surface is modeled as an ensemble of randomly orientated, slightly roughened, tilted facets, for which the small perturbation model is assumed to be valid under the condition of no tilt. The orientation of the random ...
    • The crystal structure of the tetrameric DABA-aminotransferase EctB, a rate-limiting enzyme in the ectoine biosynthesis pathway 

      Hillier, Heidi Therese; Altermark, Bjørn; Leiros, Ingar (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-29)
      L‐2,4‐diaminobutyric acid (DABA) aminotransferases can catalyze the formation of amines at the distal ω‐position of substrates, and is the intial and rate‐limiting enzyme in the biosynthesis pathway of the cytoprotecting molecule (S)‐2‐methyl‐1,4,5,6‐tetrahydro‐4‐pyrimidine carboxylic acid (ectoine). Although there is an industrial interest in the biosynthesis of ectoine, the DABA aminotransferases ...
    • A Lagrangian Snow Evolution System for Sea Ice Applications (SnowModel‐LG): Part II - Analyses 

      Stroeve, Julienne C.; Liston, Glen E.; Buzzard, Samantha; Zhou, Lu; Mallett, Robbie; Barrett, Andrew; Tschudi, Mark; Tsamados, Michel; Itkin, Polona; Stewart, Scott (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-09-02)
      Sea ice thickness is a critical variable, both as a climate indicator and for forecasting sea ice conditions on seasonal and longer time scales. The lack of snow depth and density information is a major source of uncertainty in current thickness retrievals from laser and radar altimetry. In response to this data gap, a new Lagrangian snow evolution model (SnowModel‐LG) was developed to simulate snow ...
    • Magnetopause Compressibility at Saturn with Internal Drivers 

      Hardy, Flavien; Achilleos, Nicholas; Guio, Patrick (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-07)
      We use magnetopause crossings of the Cassini spacecraft to study the response of Saturn's magnetosphere to changes in external and internal drivers. We explain how solar wind pressure can be corrected to account for the local variability in internal plasma particle pressure. The physics‐based method is applied to perform the most robust estimation of magnetopause compressibility at Saturn to date, ...
    • Ship behavior prediction via trajectory extraction-based clustering for maritime situation awareness 

      Murray, Brian; Perera, Lokukaluge Prasad (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-20)
      This study presents a method in which historical AIS data are used to predict the future trajectory of a selected vessel. This is facilitated via a system intelligence-based approach that can be subsequently utilized to provide enhanced situation awareness to navigators and future autonomous ships, aiding proactive collision avoidance. By evaluating the historical ship behavior in a given geographical ...
    • Simulation of Meteorological and Oceanographic Parameters: An Application in Spray Icing Prediction 

      Shojaei Barjouei, Abolfazl (Master thesis; Mastergradsoppgave, 2020-07-13)
      Sea spray icing is considered as a major environmental challenge in the Arctic Ocean, which poses a critical risk not only to the vessels and industrial operations but also to human safety. Although some studies have been carried out to estimate spray icing rate (e.g., RIGICE04 and ICEMOD models), such models suffer from some unrealistic modeling assumptions and limited verification. Moreover, limited ...
    • Feasibility study of Preventing Snow Accumulations on Roofs using Airflows 

      Sjøveian, Andreas Eide (Master thesis; Mastergradsoppgave, 2020-07-09)
      This thesis is intended to contribute to research in cold climate engineering. Further it intends to provide a principle solution for structural and avalanche safety due to snowfall on roofs. We have conducted a feasibility study of preventing snow from accumulating on roofs using airflows. This includes empirical, numerical and experimental methods. Snow loads on roofs makes great impact on ...
    • A Feasibility Study of Using Waste Thermal Energy from a District Heating System for Absorption Cooling 

      Obi, Gerald Nsenkeng (Master thesis; Mastergradsoppgave, 2020-07-13)
      Waste incineration-based district heating plants in Norway struggle from energy efficiency drawbacks during the warmer months of the year from May - September due to the reduced demand in heating. As a result, thermal energy gets discarded to ambient air, which affects the energy efficiency of the plants. This study aims at presenting an overview of the waste incineration industry in Norway and ...
    • Study of failure profiles in the bridge structures 

      Amiri, Razieh (Master thesis; Mastergradsoppgave, 2019-10-15)
      Bridge safety is an indispensable part of transportation safety. However, each bridge is unique with respect to its material, design and the environment which it is located in, and other relevant factors. This makes defining a unified framework for studying and categorizing failures in the bridges a difficult task. The current report aims at taking the first step to reach such a goal. This report ...
    • Resilience assessment of the transport corridor from Stokmarknes to Stockholm 

      Ashrafi, Behrooz (Master thesis; Mastergradsoppgave, 2019-08-01)
      Timely delivery of the required goods plays an important role in meeting the availability and reducing the downtime of Markets. Salmon transport logistics is affected in complex ways while operating in the Arctic, since the area is sparsely populated and has insufficient infrastructure. It is also greatly affected by the distinctive operational environment of the region, such as cold temperature, ...
    • Cyclostratigraphic age constraining for Quaternary sediments in the Makarov Basin of the western Arctic Ocean using manganese variability 

      Park, Kwangkyu; Kim, Jung-Hyun; Asahi, Hirofumi; Polyak, Leonid; Khim, Boo-Keun; Schreck, Michael; Niessen, Frank; Kong, Gee Soo; Nam, Seung-Il (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-26)
      The Quaternary paleoenvironmental history of the Arctic Ocean remains uncertain, mainly due to the limited chronological constraints, especially beyond the 14C dating limits of accelerator mass spectrometry (AMS). The difficulty in establishing reliable chronostratigraphies is mainly attributed to low sedimentation rates and diagenetic sediment changes, resulting in very poor preservation of ...
    • Late Quaternary depositional and glacial history of the Arliss Plateau off the East Siberian margin in the western Arctic Ocean 

      Joe, Young Jin; Polyak, Leonid; Schreck, Michael; Niessen, Frank; Yoon, Seok Hoon; Kong, Gee Soo; Nam, Seung-II (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-19)
      Sedimentary stratigraphy and facies analysis along with seismostratigraphic and multibeam bathymetrydata are used to reconstruct the last glacial impact on the Arliss Plateau (AP) and attendant sedimen-tation in the adjacent Chukchi Basin (CB) in the western Arctic Ocean off the East Siberian margin.Sediment core ARA02B/16B-GC from the AP lower slope captures glacier-related depositional historyduring ...
    • Comment to “Neoproterozoic magmatic arc systems of the central Ribeira belt, SE-Brazil, in the context of the West-Gondwana pre-collisional history: A review” 

      Fossen, Haakon; Meira, Vinicius T.; Cavalcante, Carolina; Konopásek, Jiří; Janoušek, Vojtěch (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-25)
    • Glucose Regulation for In-Silico Type 1 Diabetes Patients Using Reinforcement Learning 

      Tejedor Hernández, Miguel Ángel (Doctoral thesis; Doktorgradsavhandling, 2021-05-07)
      Type 1 diabetes is a metabolic disorder characterized by high blood glucose levels as a consequence of deficiency of the hormone insulin, requiring the patient to follow a strict personalized protocol of food intake, subcutaneous insulin administration as a lifelong treatment for the high blood glucose levels, and exercise. This condition leads to acute complications, damaging several organs and ...