Viser treff 41-60 av 291

    • Holocene precipitation seasonality on Svalbard and in Northern Fennoscandia reconstructed using organic geochemical and stable isotope proxies 

      Kjellman, Sofia Elisabeth (Doctoral thesis; Doktorgradsavhandling, 2022-09-23)
      The Arctic experiences faster climate change than the global average. Feedback mechanisms between the atmosphere, cryosphere and the oceans amplify the warming, and intensify the water cycle. Arctic precipitation is projected to increase because of enhanced winter evaporation due to diminishing sea ice, increased poleward moisture transport in summer, and increased atmospheric moisture content in ...
    • Ice in Norwegian subarctic fjords and coastal regions: An examination of ice formation, properties, and trends based on remote sensing and in situ data 

      O'Sadnick, Megan (Doctoral thesis; Doktorgradsavhandling, 2022-09-16)
      Larger fjords along the Norwegian coast are ice free all year due to the influence of warm Atlantic water, however, sea ice can form in the inner parts of fjords and in smaller fjord branches. While a wide breadth of work exists examining mainland Norwegian fjords often focused on water mass dynamics and their link to biological processes, little research has been conducted on specifically sea ice ...
    • Marine natural product inspired synthesis towards new antimicrobial and antifouling agents 

      Langer, Manuel Karl (Doctoral thesis; Doktorgradsavhandling, 2022-08-30)
      Natural products (NPs) have been the major source for the development of new small molecule drugs in modern medicine. Despite NPs being so prominent, marine natural products (MNPs) and derivatives thereof are hardly found in clinically approved agents. Therefore, using bioactive MNPs as structural guidance for drug development is a largely untapped source. The focus of the presented thesis is on ...
    • Hydrological Modelling and Climate Change Impact Assessment on Future Floods in the Norwegian Arctic Catchments 

      Bui, Minh Tuan (Doctoral thesis; Doktorgradsavhandling, 2022-08-26)
      Climate change is expected to alter the hydrological cycle in the Arctic, which would result in the increase in intensity and frequency of hydrological extreme events such as flooding. Noticeably, the changes in flooding due to climate change would severely affect human life, infrastructures, the environment, ecosystem, and socio-economic development in the impacted areas. Hydrological models are ...
    • Statistical Curve Analysis: Developing Methods and Expanding Knowledge in Health 

      Uteng, Stig (Doctoral thesis; Doktorgradsavhandling, 2022-08-19)
      <p>The analysis of curves can be claimed to be the core of most scientific ventures. In this dissertation, we focus on the statistical aspect of this type of analysis. Here, the curves originate from health and food-related areas and include improvements in blood glucose measurements, classification of moles, measurements of parameters during liver transplants in pigs, and data from the monitoring ...
    • Autonomous Navigation in (the Animal and) the Machine 

      Leikanger, Per Roald (Doctoral thesis; Doktorgradsavhandling, 2022-07-05)
      Understanding the principles underlying autonomous navigation might be the most enticing quest the computational neuroscientist can undertake. Autonomous operation, also known as voluntary behavior, is the result of higher cognitive mechanisms and what is known as executive function in psychology. A rudimentary knowledge of the brain can explain where and to a certain degree how parts of a computation ...
    • On the linkage between atmospheric circulation changes and Arctic climate change 

      Heiskanen, Tuomas Ilkka Henrikki (Doctoral thesis; Doktorgradsavhandling, 2022-06-10)
      Polar amplification is a prominent feature of recent and projected climate change. The Arctic region shows some of the strongest signs of climate change, including sea-ice retreat and temperatures increasing at twice the rate averaged over the northern hemisphere. A major concern for humanity is the sea-level rise associated with the melting of the ice-sheets and glaciers due to climate change. The ...
    • Boreal rodents fluctuating in space and time: Tying the observation process to the modeling of seasonal population dynamics 

      Nicolau, Pedro Guilherme (Doctoral thesis; Doktorgradsavhandling, 2022-06-03)
      Small rodents are some of the most important elements of boreal/arctic food webs, where they play essential functional roles. Their population dynamics are characterized by large amplitude multi-annual cycles regulated by direct and delayed density-dependence. These drastic variations in abundance have deep cascading effects into the whole ecosystem. Hence, the study boreal rodent population processes ...
    • Expanding the toolbox for the study of antimicrobial peptides 

      Rainsford, Philip (Doctoral thesis; Doktorgradsavhandling, 2022-06-02)
      There is an urgent lack of new antibiotics in the face of an ever-expanding antimicrobial resistance crisis. The fact that fewer new classes of antibiotics are being developed, and resistance soon follows newly available antibiotics, only serves to underline the urgency of the matter. There is a clear need of a paradigm shift with regards to antibiotics, and one such hope is antimicrobial peptides ...
    • Advanced signal processing techniques with EISCAT3D 

      Stamm, Johann (Doctoral thesis; Doktorgradsavhandling, 2022-05-24)
      A new, modern ionospheric radar, called EISCAT3D, is under construction in northern Fennoscandia. In the first stage, the radar will have three sites, one combined transmit/receiver site shouth of Skibotn, and receiver sites in Kaaresuvanto and Kaiseniemi. The radar will consist of large groups of dipole antennas that are steered by shifting the phase of the transmitted or received signal. The beam ...
    • Modelling the subglacial hydrology of the former Barents Sea Ice Sheet 

      Gudlaugsson, Eythor (Doctoral thesis; Doktorgradsavhandling, 2015-12-01)
      Ice dynamics are strongly controlled by processes taking place at the interface between the ice and the underlying bed. In modern day ice sheets, up to 90% of mass is lost through fast-flowing corridors of ice, called ice streams. These are typically underlain by a thin layer of water and wet sediment, both of which promote fast flow. In recent years it has emerged that subglacial hydrology played ...
    • Late glacial and deglacial paleoceanographic and environmental changes at Vestnesa Ridge, Fram Strait: challenges in reading methane-influenced sedimentary records 

      Sztybor, Kamila (Doctoral thesis; Doktorgradsavhandling, 2017-01-18)
      Denne avhandlingen er basert på fire sedimentkjerner fra et område ved Vest Svalbard hvor metan siver opp fra havbunnen. Studien fokuserer på å rekonstruere graden av metanutsiving i fortiden, samt klimavariasjoner i Arktiske strøk med bruk av bentiske foraminiferer. Foraminiferer er encellede organismer som produserer en kalkholdig skall som bevares i sedimentene på havbunnen. Ved å se på geokjemiske ...
    • North Atlantic–Norwegian Sea exchanges during the past 135,000 years: Evidence from foraminiferal ∆14C, d11B, d18O, d13C, Mg/Ca, and Cd/Ca 

      Ezat, Mohamed M. (Doctoral thesis; Doktorgradsavhandling, 2015-07-03)
      The ocean is an essential regulator of climate through its effect on redistribution of heat and air-sea exchange of greenhouse gases.The modern circulation pattern of surface and deep water between the Arctic Mediterranean seas and North Atlantic is an important part of the global meridional ocean circulation. In this study we investigate the North Atlantic-Norwegian Sea exchanges of heat and carbon ...
    • Lithostratigraphy and chemostratigraphy of Triassic black shales on Edgeøya, eastern Svalbard: Implications for understanding Triassic source rock formation on the Norwegian Barents Shelf 

      Wesenlund, Fredrik (Doctoral thesis; Doktorgradsavhandling, 2022-03-25)
      The Norwegian Barents Shelf (NBS) is an Arctic petroleum province with a complex geological history. Current geochemical work on oil discoveries in the region has identified Triassic mudstones as important petroleum source rocks. A review of the published literature found that several source rock-forming processes have been suggested as contributors to their formation. The aim of this thesis is thus ...
    • Measuring Methane in the Arctic Ocean - From legal framework to time series analysis via technology innovation 

      Dølven, Knut Ola (Doctoral thesis; Doktorgradsavhandling, 2022-03-24)
      <p>Understanding how the earth system interacts with ongoing climate change is important to find a realistic route towards a sustainable future. The impact of Arctic seabed methane seepage on contemporary and future climate is still poorly constrained, described, and quantified. An important limiting factor in our understanding of seabed seepage in the Arctic is a lack of in situ measurements; ...
    • Cracking into Cryoseismology 

      Romeyn, Rowan (Doctoral thesis; Doktorgradsavhandling, 2022-03-22)
      The cryosphere encompasses the seasonally and perennially frozen parts of the earth and its extent is both sensitive to and impacts upon the global climate through surface energy and moisture fluxes and feedbacks. The dynamics of ice and frozen ground also impact directly on, e.g., construction and maintenance of roads in cold regions or transportation across floating ice sheets. The aim of this ...
    • Applications of Multiwavelets to Energies and Properties 

      Brakestad, Anders (Doctoral thesis; Doktorgradsavhandling, 2022-02-18)
      The goal of quantum chemistry is to provide fast and accurate algorithms for the computation of molecular energies and properties. Over the years, a large number of methods have become available, and today computational chemists have a very rich toolbox of protocols that can be used to gain insight to chemistry. Gaussian type orbital (GTO) basis sets are at the core of most modern algorithms, and ...
    • Neoproterozoic orogenesis in south-eastern South America - An examination of pre-orogenic rifting, sedimentation, and mountain building processes recorded in the Dom Feliciano Belt 

      Percival, Jack James (Doctoral thesis; Doktorgradsavhandling, 2022-01-25)
      The Dom Feliciano Belt records the convergence between multiple South American and African cratonic bodies during the Neoproterozoic, and forms part of the larger South Atlantic Neoproterozoic Orogenic System (SANOS). Studying the evolution of the Dom Feliciano Belt allows the development of tectonic models spanning the time from pre-orogenic rifting to orogenesis, and the information recorded in ...
    • Machine Learning-based Classification, Detection, and Segmentation of Medical Images 

      Jha, Debesh (Doctoral thesis; Doktorgradsavhandling, 2022-01-21)
      Gastrointestinal tract (GI) cancers are among the most common types of cancers worldwide. In particular, colorectal cancer (CRC) is the most lethal in terms of number of incidences and mortality (third most common cause of cancer and the second common cause of cancer-related deaths). Colonoscopy is the gold standard for screening patients for CRC. During the colonoscopy, gastroenterologists examine ...
    • Arctic planktonic calcifiers in a changing ocean - A study on recent planktonic foraminifera and shelled pteropods in the Fram Strait-Barents Sea region 

      Ofstad, Siri (Doctoral thesis; Doktorgradsavhandling, 2021-12-16)
      The Arctic marine realm is being transformed due to the anthropogenically-induced climate change. In the Arctic, the effects of climate change are intensified due to polar amplification and have led to processes in the ocean such as sea-ice retreat, ocean acidification and the increased presence of boreal species referred to as ‘Atlantification’. This thesis presents rare investigations of marine ...