Viser treff 161-180 av 294

    • Origins and impacts of spatial and temporal long-range dependence in the climate system 

      Fredriksen, Hege-Beate (Doctoral thesis; Doktorgradsavhandling, 2017-11-27)
      The internal variability of most Earth surface temperatures has a power spectral density well described by a power law, S(f) ~ f<sup>-β</sup>, and we typically observe 0 < β < 1. This characterizes variability exhibiting long-range dependence (LRD), which has no characteristic time scale. However, there is no consensus about the physical mechanisms behind this property, and the topic of this thesis ...
    • Prediction of ship icing in Arctic waters - Observations and modelling for application in operational weather forecasting 

      Samuelsen, Eirik Mikal (Doctoral thesis; Doktorgradsavhandling, 2017-11-20)
      A ship travelling in sub-freezing conditions may encounter sea spray, rain, fog or snow freezing onto various parts of it. Such ship icing is a well-known threat for those individuals who have served on ships operating in a cold marine climate. As de-icing techniques may be energy consuming, accurate prediction of icing is also desirable from a financial point of view. Throughout the last 60 years ...
    • Combining Satellite and Terrestrial Interferometric Radar Data to Investigate Surface Displacement in the Storfjord and Kåfjord Area, Northern Norway. 

      Eriksen, Harald Øverli (Doctoral thesis; Doktorgradsavhandling, 2017-10-10)
      Due to their all-weather all-day capabilities and increased availability, synthetic aperture radar (SAR) interferometric displacement datasets have gained popularity in a variety of scientific disciplines. Both satellite and ground-based platforms are used. Satellite-based radar instruments cover large areas on a regular basis without the need for in-situ instrumentation. As with all measuring ...
    • Diagnostics of Ion Beam and Current Free Double Layer in Helicon Plasma Devices with Expanding Magnetic Field 

      Gulbrandsen, Njål (Doctoral thesis; Doktorgradsavhandling, 2017-09-18)
      The main focus of this thesis is the diagnostics of ion beams in helicon plasma devices with expanding magnetic field, and running in an inductive mode. These ion beams are closely connected to the concept of current-free double layers (CFDL). We started by investigating how to best interpret the measurements from a Retarding Field Energy Analyzer (RFEA) through 3-dimensional particle-in-cell ...
    • Fluid flow at the Snøhvit field, SW Barents Sea: processes, driving mechanisms and multi-phase modelling 

      Tasianas, Alexandros (Doctoral thesis; Doktorgradsavhandling, 2017-07-03)
      The research undertaken in this PhD project was part of a large EU interdisciplinary project named ECO2: Sub-seabed CO2 Storage: Impact on Marine Ecosystems. The overall goal of the ECO2 project was to understand the short-term and long-term impacts of CO2 storage on marine ecosystems. I concentrated my work on the Snøhvit site, which is located in the SW Barents Sea, on the Norwegian continental ...
    • The OXA-class of β-lactamases. A structural view on antibiotic resistance 

      Lund, Bjarte Aarmo (Doctoral thesis; Doktorgradsavhandling, 2017-09-01)
      Antibiotic resistance is a topic that concerns everyone, and by 2050 deaths due to antibiotic resistant bacteria may surpass number of deaths due to cancer. The OXA-class of antibiotic resistance enzymes is a formidable threat, but has not received the same attention as other resistance enzymes. The goal of the project was to understand antibiotic resistance enzymes at an atomic scale and to develop ...
    • Studies on selectivity determinants of protein kinase inhibitor binding 

      Alam, Kazi Asraful (Doctoral thesis; Doktorgradsavhandling, 2017-06-09)
      Protein kinases are involved in many essential cellular processes, and are regulated in a dynamic manner by the movement of domains or motifs via interaction with various proteins and substrates. Protein kinase deregulation can lead to a variety of diseases, including cancer and diabetes. Protein kinase A (PKA) has been a prototype to study the entire family, including for studies in drug discovery ...
    • META-pipe – Distributed Pipeline Analysis of Marine Metagenomic Sequence Data 

      Robertsen, Espen Mikal (Doctoral thesis; Doktorgradsavhandling, 2017-05-19)
      With the accelerated advances in sequencing technology the last decade, the field of metagenomics has progressed immensely. Sampling and sequencing of metagenomic data is now prevalent, and publicly available data sets from mundane soil and water environments to exotic niche habitats such as geothermal hot springs are readily available through sequence data repositories such as the European Nucleotide ...
    • Biomonitoring and risk assessment tools to manage impact of diesel oil in tropical coastal habitats 

      Sardi, Adriana Eva (Doctoral thesis; Doktorgradsavhandling, 2017-05-05)
      The focus of this work is in developing biology–based tools for environmental monitoring and risk assessment associated with diesel oil contamination in tropical coastal habitats. Prediction of impacts is generally conducted via environmental monitoring, in which environmental quality over time and space is assessed by repeated observations. Prediction of risk is included within the risk ...
    • A Biofocussed Chemoprospecting Approach to Drug Discovery: Design, Synthesis and Bioactivity Screening of Diverse Biofocussed Chemical Libraries 

      Thakkar, Balmukund (Doctoral thesis; Doktorgradsavhandling, 2017-04-28)
      With pharma R & D witnessing rising cost, high attrition rates and an overall decline in productivity in recent times, newer approaches are needed for more efficient early phase drug discovery. This thesis describes a new approach, “biofocussed chemoprospecting”. The essence of the approach is to use diverse, yet “bio-like” compounds for efficient hit-finding, along with property filtering and ...
    • Surface properties tune thermal adaptation of enzymes - Computational studies of endonuclease A 

      Michetti, Davide (Doctoral thesis; Doktorgradsavhandling, 2017-04-26)
      The endonucleases A from Aliivibrio salmonicida (VsEndA, cold-adapted) and Vibrio cholerae (VcEndA, warm-adapted) have been studied in this work. The goal was to compare these two systems, in order to find structural differences that could explain the mechanism of cold adaptation in the psychrophilic EndA. These two enzymes have previously been studied experimentally and the crystal structures have ...
    • Structural determinants of ligand binding to ATP dependent enzymes: Studies of Protein Kinase and Heat Shock Protein 70. 

      Narayanan, Dilip (Doctoral thesis; Doktorgradsavhandling, 2017-04-07)
      Enzymes are protein molecules that accelerate, or “catalyze”, specific chemical reactions. The reacting molecules, or substrates, bind to the enzyme which then enables their effective conversion into different product molecules. Virtually all metabolic processes in the cell need enzymes to occur at speeds fast enough to maintain life. The kinases are a large group of phosphotransferases, i.e. enzymes ...
    • Vertical nitrate fluxes in the Arctic Ocean 

      Randelhoff, Achim (Doctoral thesis; Doktorgradsavhandling, 2017-03-16)
      Upward mixing of remineralized nutrients is essential for photosynthesis in the upper ocean. Weak vertical mixing, which restricts nutrient supply, and sea ice, which leads to low light levels, conspire to severely inhibit marine primary productivity in the Arctic Ocean. However, little has been known about their relative contributions. No large-scale quantitative estimates of the vertical nutrient ...
    • A Data Management Model For Large-Scale Bioinformatics Analysis 

      Pedersen, Edvard (Doctoral thesis; Doktorgradsavhandling, 2017-01-18)
      Bioinformatics has seen an extreme data growth in later years due to the reduction in cost per megabase of sequencing, which today is around 1/400,000th of the cost in 2001. This reduction in cost enables new types of studies, such as searching for novel enzymes in marine environments using metagenomic approaches. However, it also leads to an increase in volume of data, which shifts overall cost ...
    • Lie-Algebraic Approaches to Highly Symmetric Geometries 

      Winther, Henrik (Doctoral thesis; Doktorgradsavhandling, 2017-02-24)
      We facilitate the exploration and development of geometry by symmetry-based methods. To this end, we answer several natural questions that appear when considering symmetries, for particular examples of geometries
    • The Polarizable Continuum Model Goes Viral! Extensible, Modular and Sustainable Development of Quantum Mechanical Continuum Solvation Models 

      Di Remigio, Roberto (Doctoral thesis; Doktorgradsavhandling, 2017-01-16)
      Synergistic theoretical and experimental approaches to challenging chemical problems have become more and more widespread, due to the availability of efficient and accurate ab initio quantum chemical models. Limitations to such an approach do, however, still exist. The vast majority of chemical phenomena happens in complex environments, where the molecule of interest can interact with a large number ...
    • Trends and variability of polar mesopause region temperatures attributed to atmospheric dynamics and solar activity 

      Holmen, Silje Eriksen (Doctoral thesis; Doktorgradsavhandling, 2016-12-19)
      The mesopause region can be considered a "boundary region" between the neutral atmosphere, where atmospheric constituents and momentum are transported mainly by winds and turbulent eddies, and the ionosphere, where the main transport mechanism is molecular diffusion. In the mesopause, complex interactions between dynamics and photochemistry occur, and we are far from a complete understanding of these ...
    • Mutational, structural and inhibitory investigations of metallo-β-lactamases involved in antibiotic resistance 

      Skagseth, Susann (Doctoral thesis; Doktorgradsavhandling, 2017-02-16)
      This thesis focuses on metallo-β-lactamases (MBLs) enzymes that break down a wide variety of antibiotics. Bacteria harboring genes expressing MBLs are antibiotic resistant. If the MBL genes are found on mobile genetic elements, the spread of the genes between bacteria becomes easier. To date, there are no MBL inhibitors available for blocking the enzyme activity, and thus there is an urgent need to ...
    • Investigations of summer sea ice with X and C-band multi-polarimetric synthetic aperture radar (SAR) 

      Fors, Ane Schwenke (Doctoral thesis; Doktorgradsavhandling, 2017-03-17)
      In this thesis, we explore the possibilities and limitations of using space-borne multi-polarimetric SAR in summer sea ice investigations. Both X and C-band data are examined. The study utilizes two data sets collected in the Arctic in 2011 (Fram Strait) and 2012 (north of Spitsbergen). Both sets combine satellite SAR scenes with co-located ground and air-borne measurements. Firstly, the study ...
    • Wind Energy at Nygårdsfjellet – Norway. Wind field characterization and modelling 

      Bilal, Muhammad (Doctoral thesis; Doktorgradsavhandling, 2016-11-25)
      The research focuses on the characterization of wind flow over complex terrain of Nygårdsfjell and numerical wind flow modelling. In the context to research focus, the main contributions of this research thesis are within the following areas: Characterization of wind flow at the Nygårdsfjell wind farm, situated in the arctic circle in Norway. Wind data is collected from the anemometers installed on ...