Fakultet for naturvitenskap og teknologi: Recent submissions
Now showing items 2861-2880 of 5336
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A thermally stable {FeNO}(8) complex: properties and biological reactivity of reduced MNO systems
(Journal article; Tidsskriftartikkel; Peer reviewed, 2012-10-06)Reduced nitrogen oxide ligands such as NO<sup>−</sup>/HNO or nitroxyl participate in chemistry distinct from nitric oxide (NO). Nitroxyl has been proposed to form at heme centers to generate the Enemark–Feltham designated {FeNO}<sup>8</sup> system. The synthesis of a thermally stable {FeNO}<sup>8</sup> species namely, [Co(Cp<sup>*</sup>)<sub>2</sub>][Fe(LN<sub>4</sub>)(NO)] (3), housed in a heme-like ... -
The pyrite multiple sulfur isotope record of the 1.98 Ga Zaonega Formation: Evidence for biogeochemical sulfur cycling in a semi-restricted basin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-21)The pyrite sulfur isotope record of the 1.98 Ga Zaonega Formation in the Onega Basin, NW Russia, has played a central role in understanding ocean-atmosphere composition and inferring worldwide fluctuations of the seawater sulfate reservoir during the pivotal times of the Paleoproterozoic Era. That, in turn, has led to a concept that Earth's atmospheric oxygen levels underwent global-scale changes. ... -
A functional and structural study of three bacterial nucleic acid-interacting proteins. The story of a Ferric Uptake Regulator, an Oligoribonuclease and an ATP-dependent DNA ligase
(Doctoral thesis; Doktorgradsavhandling, 2020-02-07)Nucleic acid-interacting proteins are essential players in cellular processes of all living organisms. In the present study, we explore three psychrophilic-derived proteins involved in gene regulation, RNA degradation and DNA ligation in bacterial cells, with one common feature; they perform their activity by interacting with nucleic acids. The Ferric uptake regulator (Fur) is a global transcription ... -
Geomorfologiske undersøkelser av skråningsavsetninger og -prosesser i Kåfjorddalen i Troms
(Master thesis; Mastergradsoppgave, 2019-12-13)Hovedformålet med denne oppgaven er å beskrive og tolke skredavsetninger og -prosesser i den sørvestre dalsiden i Kåfjorddalen i Troms. I tillegg blir det gjort en overordnet vurdering av hvordan sedimenttransporten kan ha vært gjennom holocen og hvordan skredaktiviteten forventes å bli som følge av klimaendringene. Fjorten skredvifter er beskrevet og tolket. Beskrivelsene og tolkningene av ... -
The benthic foraminiferal δ34S records fux and timing of paleo methane emissions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-28)In modern environments, pore water geochemistry and modelling simulations allow the study of methane (CH<sub>4</sub>) sources and sinks at any geographic location. However, reconstructing CH<sub>4</sub> dynamics in geological records is challenging. Here, we show that the benthic foraminiferal δ<sup>34</sup>S can be used to reconstruct the fux (i.e., difusive vs. advective) and timing of CH<sub>4</sub> ... -
Risk Assessment of Operation and Maintenance of Wind Turbines in the Arctic [poster]
(Conference object; Konferansebidrag, 2019) -
Analyse av energibruk og teknisk drift ved Bryne videregående skole
(Master thesis; Mastergradsoppgave, 2019-12-15)Tidligere Bryne videregående skole (vgs.) og Time vgs. ble i 2015 slått sammen til nye Bryne vgs. I den anledning ble det bygget tre nye skolebygg med et moderne og komplekst energisystem. Skolen er et pilotprosjekt i tråd med Rogaland fylkeskommune sin miljøpolitikk og er bygget med fokus på bærekraftige prinsipper, lavt energiforbruk og bruk av energikilder med begrenset CO2 utslipp. Skolens varme ... -
Comparison of the Ice Watch Database and Sea Ice Classification from Sentinel-1 Imagery
(Master thesis; Mastergradsoppgave, 2019-12-13)In this thesis,we investigate the potential use of in-situ sea ice observations from the Ice Watch database as ground truth data for an automated classification algorithm of sea ice types from Sentinel-1 SAR data. The Ice Watch database and the Sentinel-1 data archive are searched for in-situ observations and satellite data acquisitions in Extra Wide swath mode overlapping in both space and time. ... -
Wind resource assessment using weather research and forecasting model. A case study of the wind resources at Havøygavlen wind farm
(Master thesis; Mastergradsoppgave, 2019-12-13)The need for energy increases globally due to rapid expansion of population and prosperity. To meet this demand while decreasing carbon emission and eventually transition out fossil fuel, efficient utilization of wind power is prominent. This study evaluates the performance of the Weather Research and Forecast model (WRF) with respect to wind speed and wind direction. The area of the study is ... -
Short-term wind power prediction models in complex terrain based on statistical time series analysis
(Master thesis; Mastergradsoppgave, 2019-12-13)One of the largest challenges with the utilization of wind as a renewable resource, is its natural variability and intermittent nature. To achieve a sustainable integration of wind power into the power grid, a precise and reliable prediction method is therefore required. In this study, several short-term wind power prediction models based on statistical time series analysis were developed and tested, ... -
Affinity-Guided Image-to-Image Translation for Unsupervised Heterogeneous Change Detection
(Master thesis; Mastergradsoppgave, 2019-12-16)Change detection in earth observation remote sensing images can be used to describe the extent of natural disasters, e.g., forest fires and floods. When time is of the essence, the ability to utilize heterogeneous images is fundamental, i.e., images that are not directly comparable due to the sensors used or the capturing conditions. The recent advances in machine learning have dispersed into the ... -
Gold dipyrrin-bisphenolates: A combined experimental and DFT study of metal-ligand interactions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-02)Given that noninnocent and metalloradical-type electronic structures are ubiquitous among dipyrrin-bisphenolate (DPP) complexes, we synthesized the gold(III) derivatives as potentially innocent paradigms against which the properties of other metallo-DPP derivatives can be evaluated. Electronic absorption spectra, electrochemical studies, a single-crystal X-ray structure, and DFT calculations all ... -
On-Site Ribosome Remodeling by Locally Synthesized Ribosomal Proteins in Axons
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-10)Ribosome assembly occurs mainly in the nucleolus, yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a sequence motif, ... -
Detectionof gas hydrates infaults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-24)Joint analysis of electrical resistivity and seismic velocity data is primarily used to detect the presence of gas hydrate‐filled faults and fractures. In this study, we present a novel approach to infer the occurrence of structurally‐controlled gas hydrate accumulations using azimuthal seismic velocity analysis. We perform this analysis using ocean‐bottom seismic (OBS) data at two sites on Vestnesa ... -
Partially spatially coherent digital holographic microscopy and machine learning for quantitative analysis of human spermatozoa under oxidative stress condition
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-05)Semen quality assessed by sperm count and sperm cell characteristics such as morphology and motility, is considered to be the main determinant of men’s reproductive health. Therefore, sperm cell selection is vital in assisted reproductive technology (ART) used for the treatment of infertility. Conventional bright field optical microscopy is widely utilized for the imaging and selection of sperm cells ... -
Auditing Industrial Safety Management: A Case Study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019)As industries are becoming increasingly self-regulatory, external auditing has become increasingly important to ensure that industrial practices are in line with regulations and the public good. This study asks if there is a fit between the industrial practices of safety management and external auditing. It concludes that while companies largely manage safety through operational-level experience and ... -
Noisy multi-label semi-supervised dimensionality reduction
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)Noisy labeled data represent a rich source of information that often are easily accessible and cheap to obtain, but label noise might also have many negative consequences if not accounted for. How to fully utilize noisy labels has been studied extensively within the framework of standard supervised machine learning over a period of several decades. However, very little research has been conducted ... -
On the Ewald Oseen scattering formulation for light scattering: stability, singularity and parallelization.
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-15)In this paper we discuss some of the mathematical and numerical issues that have to be addressed when calculating wave scattering using the Ewald Oseen scattering (EOS) formulation which is newly developed for solving linear and nonlinear scattering problems. The discussion is framed in context of light scattering by objects whose optical response can be of a nonlinear and/or inhomogeneous nature. ... -
Consistent ice and open water classification combining historical synthetic aperture radar satellite images from ERS-1/2, Envisat ASAR, RADARSAT-2, and Sentinel-1A/B
(Journal article; Tidsskriftartikkel, 2020) -
Uncertainty and interpretability in convolutional neural networks for semantic segmentation of colorectal polyps
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-20)Colorectal polyps are known to be potential precursors to colorectal cancer, which is one of the leading causes of cancer-related deaths on a global scale. Early detection and prevention of colorectal cancer is primarily enabled through manual screenings, where the intestines of a patient is visually examined. Such a procedure can be challenging and exhausting for the person performing the screening. ...