Fakultet for naturvitenskap og teknologi: Recent submissions
Now showing items 1461-1480 of 5304
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Wood Jams Or Beaver Dams? Pliocene Life, Sediment And Landscape Interactions In The Canadian High Arctic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-28)During the mid-Pliocene (Zanclean, ca. ~ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–228C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative ... -
Effects of feedbacks for an energy balance model on a circle
(Mastergradsoppgave; Master thesis, 2022-05-31)A simple, North like, energy balance model on a circle is studied using boundary formulations derived with Green's functions for the stationary case, and a pseudo-spectral and finite difference solution for the time dependent case. The bifurcation software Auto-07p is also applied. The boundary formulation solution can be solved analytically in most cases, and is solved for bifurcation diagrams. ... -
Towards population counting of marine mammals based on drone images
(Mastergradsoppgave; Master thesis, 2022-07-11)In marine science, there is a need for tools for population counting of species. Through this thesis we aim to achieve the follow three objectives: first, briefly discuss the state-of-the-art object detectors that can be used for the detection of porpoises in drone images/videos. Second, test and compare a few stateof-the-art object detectors in both quantitative and qualitative manner. Third, based ... -
Multifocus microscopy with optical sectioning and high axial resolution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022)Multifocus microscopy enables recording of entire volumes in a single camera 11 exposure. In dense samples, multifocus microscopy is severely hampered by background haze. 12 Here, we introduce a scalable multifocus method that incorporates optical sectioning and offers 13 improved axial resolution capabilities. In our method, a dithered oblique light-sheet scans the 14 sample volume during a ... -
A standard protocol for describing the evaluation of ecological models
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-21)Numerical models of ecological systems are increasingly used to address complex environmental and resource management questions. One challenge for scientists, managers, and stakeholders is to appraise how well suited these models are to answer questions of scientific or societal relevance, that is, to perform, communicate, or access transparent evaluations of ecological models. While there have been ... -
Standards for reporting randomized controlled trials in medical informatics: a systematic review of CONSORT adherence in RCTs on clinical decision support
(Journal article; Tidsskriftartikkel; Peer reviewed, 2011-07-29)Introduction The Consolidated Standards for Reporting Trials (CONSORT) were published to standardize reporting and improve the quality of clinical trials. The objective of this study is to assess CONSORT adherence in randomized clinical trials (RCT) of disease specific clinical decision support (CDS).<p> <p>Methods A systematic search was conducted of the Medline, EMBASE, and Cochrane databases. ... -
Reconstruction of the Virtual Geomagnetic Pole (VGP) path at high latitude for the last 22 kyr: The role of radial field flux patches as VGP attractor
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-24)Reconstruction of geomagnetic field changes has a strong potential to complement geodynamo modeling and improve the understanding of Earth's core dynamics. Recent works based on geomagnetic measurements pointed out that over the last two decades the position of the north magnetic pole has been largely determined by the influence of two competing flux lobes under Canada and Siberia. In order to ... -
Structural and biophysical analysis of interactions between cod and human uracil-DNA N-glycosylase (UNG) and UNG inhibitor (Ugi)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-07-25)Uracil-DNA N-glycosylase from Atlantic cod (cUNG) shows cold-adapted features such as high catalytic efficiency, a low temperature optimum for activity and reduced thermal stability compared with its mesophilic homologue human UNG (hUNG). In order to understand the role of the enzyme–substrate interaction related to the cold-adapted properties, the structure of cUNG in complex with a bacteriophage ... -
Evolution of β-lactamase-mediated cefiderocol resistance
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-11)Background: Cefiderocol is a novel siderophore β-lactam with improved hydrolytic stability toward β-lactamases, including carbapenemases, achieved by combining structural moieties of two clinically efficient cephalosporins, ceftazidime and cefepime. Consequently, cefiderocol represents a treatment alternative for infections caused by MDR Gram-negatives.<p> <p>Objectives: To study the role of ... -
Springtime nitrogen oxides and tropospheric ozone in Svalbard: results from the measurement station network
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-09)Svalbard is a remote and scarcely populated Arctic archipelago and is considered to be mostly influenced by long-range-transported air pollution. However, there are also local emission sources such as coal and diesel power plants, snowmobiles and ships, but their influence on the background concentrations of trace gases has not been thoroughly assessed. This study is based on data of tropospheric ... -
Variability in transport of terrigenous material on the shelves and the deep Arctic Ocean during the Holocene
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-12-09)Arctic coastal zones serve as a sensitive filter for terrigenous matter input onto the shelves via river discharge and coastal erosion. This material is further distributed across the Arctic by ocean currents and sea ice. The coastal regions are particularly vulnerable to changes related to recent climate change. We compiled a pan-Arctic review that looks into the changing Holocene sources, transport ... -
Locally Resolved Stress-State in Samples During Experimental Deformation: Insights Into the Effect of Stress on Mineral Reactions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-17)Understanding conditions in the Earth's interior requires data derived from laboratory experiments. Such experiments provide important insights into the conditions under which mineral reactions take place as well as processes that control the localization of deformation in the deep Earth. We performed Griggs-type general shear experiments in combination with numerical models, based on continuum ... -
Iron isotopes constrain sub-seafloor hydrothermal processes at the Trans-Atlantic Geotraverse (TAG) active sulfide mound
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-29)Sub-seafloor hydrothermal processes along volcanically active plate boundaries are integral to the formation of seafloor massive sulfide deposits and to oceanic iron cycling, yet the nature of their relationship is poorly understood. Here we apply iron isotope analysis to sulfide minerals from the Trans-Atlantic Geotraverse (TAG) mound and underlying stockwork, 26°N Mid-Atlantic Ridge, to trace ... -
Rapid Colorimetric pH-Responsive Gold Nanocomposite Hydrogels for Sensing Applications
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-04-27)Surface functionalization of metallic nanoparticles (NPs) with external groups can be engineered to fabricate sensors that are responsive to various stimuli like temperature, pH, and numerous ions. Herein, we report the synthesis of gold nanoparticles (GNPs) functionalized with 3-mercaptopropionic acid (GNPs-MPA) and the doping of these nanoparticles into hydrogel materials using the ... -
Configuring electrochemical 3D printer for PCB production
(Master thesis; Mastergradsoppgave, 2022-08-02)In this document I look at an electrochemical 3D printer and compare it to a more established machine for the making of printing printed circuit board. -
A new Method for Estimating 3-Dimensional Ionospheric Currents from Ground-Based Magnetometers
(Mastergradsoppgave; Master thesis, 2022-07-17)The ionosphere is a region of the upper atmosphere where a significant rate of photo-ionisation from solar ultraviolet radiation cause an increased plasma density. In this region a system of electrical currents flow, driven by electric fields generated by fluctuating dynamics within the Earths magnetosphere. These fluctuating dynamics are caused by interactions between the magnetosphere and the solar ... -
Deep Representation-aligned Graph Multi-view Clustering for Limited Labeled Multi-modal Health Data
(Mastergradsoppgave; Master thesis, 2022-06-01)Today, many fields are characterised by having extensive quantities of data from a wide range of dissimilar sources and domains. One such field is medicine, in which data contain exhaustive combinations of spatial, temporal, linear, and relational data. Often lacking expert-assessed labels, much of this data would require analysis within the fields of unsupervised or semi-supervised learning. Thus, ... -
Significant ionospheric hole and equatorial plasma bubbles after the 2022 Tonga volcano eruption
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-06-28)This paper investigates the local and global ionospheric responses to the 2022 Tonga volcano eruption, using ground-based Global Navigation Satellite System total electron content (TEC), Swarm in situ plasma density measurements, the Ionospheric Connection Explorer (ICON) Ion Velocity Meter (IVM) data, and ionosonde measurements. The main results are as follows: (a) A significant local ionospheric ... -
Imaging the Effects of Whole-Body Vibration on the Progression of Hepatic Steatosis by Quantitative Ultrasound Based on Backscatter Envelope Statistics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-29)Hepatic steatosis causes nonalcoholic fatty liver disease. Whole-body vibration (WBV) has been recommended to allow patients who have difficulty engaging in exercise to improve the grade of hepatic steatosis. This study proposed using ultrasound parametric imaging of the homodyned K (HK) distribution to evaluate the effectiveness of WBV treatments in alleviating hepatic steatosis. Sixty mice were ... -
Multiple E-Region Radar Propagation Modes Measured by the VHF SIMONe Norway System During Active Ionospheric Conditions
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-10)Multiple propagation modes between different bistatic radar links were measured during the operations of a very high frequency (VHF) 32.55 MHz radar system in northern Norway. The Spread Spectrum Interferometric Multistatic meteor radar Observing Network (SIMONe) Norway system detected meteor trails, direct transmitter to receiver signal propagation, over-the-horizon signal propagation from the ...