Fakultet for naturvitenskap og teknologi: Nye registreringer
Viser treff 361-380 av 5364
-
Computational Study of the Ir-Catalyzed Formation of Allyl Carbamates from CO2
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-05)We have employed computational methods to investigate the iridium-catalyzed allylic substitution leading to the formation of enantioenriched allyl carbamates from carbon dioxide (CO<sub>2</sub>). The reaction occurs in several steps, with initial formation of an iridium-allyl, followed by nucleophilic attack by the carbamate formed in situ from CO<sub>2</sub> and an amine. A detailed isomeric analysis ... -
Convergence rates for sums-of-squares hierarchies with correlative sparsity
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-25)This work derives upper bounds on the convergence rate of the moment-sum-of-squares hierarchy with correlative sparsity for global minimization of polynomials on compact basic semialgebraic sets. The main conclusion is that both sparse hierarchies based on the Schmüdgen and Putinar Positivstellensätze enjoy a polynomial rate of convergence that depends on the size of the largest clique in the sparsity ... -
Block-matching and 3D filtering-based denoising of acoustic images obtained through point contact excitation and detection method
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-01-13)A novel experimental method based on the Coulomb coupling technique is used for visualizing the interaction of ultrasonic waves in PZT (Lead Zirconate Titanate - (Pb[ZrxTi1-x]O3 (0 ≤ x ≤ 1)) ceramic materials. The method of excitation and detection through a point contact produces representations of propagating wave vectors in the time domain as a series of images. In the acoustic image, several ... -
Revisiting the mechanism of asymmetric Ni-catalyzed reductive carbo-carboxylation with CO2: The additives affect the product selectivity
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-25)The mechanistic details of the asymmetric Ni-catalyzed reductive cyclization/carboxylation of alkenes with CO2 have been revisited using DFT methods. Emphasis was put on the enantioselectivity and the mechanistic role of Lewis acid additives and in situ formed salts. Our results show that oxidative addition of the substrate is rate-limiting, with the formed Ni(II)-aryl intermediate preferring a ... -
Major tunnel valleys and sedimentation changes document extensive Early Pleistocene glaciations of the Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-02)Sedimentary records of Early Pleistocene (~2.6–0.8 Ma) glaciations are sparse on shelves, yet trough mouth fans on adjacent continental slopes provide a continuous record of ice-sheet and climate development throughout the Quaternary. Here, we interpret high-quality 3D seismic reflection data combined with borehole and chronostratigraphic information from a shelf-slope setting in the southwestern ... -
Edward W. Said: Not so lost reflections On Lost Causes such as the one-state solution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-22)The article examines the enduring relevance of Edward Said's perspectives on the Israeli-Palestinian conflict, juxtaposing contemporary challenges with Said's visionary advocacy for a one-state solution. The analysis delves into the complexities of the evolving Middle East dynamics, emphasising the need to reconsider alternative frameworks. Central to our analysis is Said's intellectual ethos, which ... -
Pliocene-Pleistocene warm-water incursions and water mass changes on the Ross Sea continental shelf (Antarctica) based on foraminifera from IODP Expedition 374
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-11)International Ocean Discovery Program (IODP) Expedition 374 sailed to the Ross Sea in 2018 to reconstruct paleoenvironments, track the history of key water masses, and assess model simulations that show warm-water incursions from the Southern Ocean led to the loss of marine-based Antarctic ice sheets during past interglacials. IODP Site U1523 (water depth 828 m) is located at the continental shelf ... -
Converting for terrorist purposes: challenging the conceptual unidirectionality of the threat
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-02-08)Terrorism is typically included among the grave societal challenges resulting from radicalisation of certain groups. The phrase ‘radical converts’ typically evokes an image of a convert to Islam, whereas an individual converting from Islam to other religions is not associated with a terrorist threat. When it comes to threat assessment, the conversion of Christianity to Islam is typically deemed a ... -
Preparation of a high-coordinated-silicon-centered spiro-cyclic compound
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-06-10)Silicon compounds containing silicon–silicon bond with a variety of unusual oxidation states are quite important, because their high reactivity leads to the formation of a variety of silicon compounds. The isolation of such compounds with unusual oxidation states requires a resilient synthetic strategy. Herein, we report the synthesis of a silicon based spirocyclic compound containing a hyper-valent ... -
2-D Total Electron Content and 3-D Ionospheric Electron Density Variations During the 14 October 2023 Annular Solar Eclipse
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-18)This study investigates the ionospheric total electron content (TEC) responses in the 2‐D spatial domain and electron density variations in the 3‐D spatial domain during the annular solar eclipse on 14 October 2023, using ground‐based Global Navigation Satellite System (GNSS) observations, a novel TEC‐based ionospheric data assimilation system (TIDAS), ionosonde measurements, and satellite in ... -
SARS-CoV2 Nsp1 is a metal-dependent DNA and RNA endonuclease
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-28)Over recent years, we have been living under a pandemic, caused by the rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). One of the major virulence factors of Coronaviruses is the Non-structural protein 1 (Nsp1), known to suppress the host cells protein translation machinery, allowing the virus to produce its own proteins, propagate and invade new cells. To ... -
The Value of Sentinel-1 Ocean Wind Fields Component for the Study of Polar Lows
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-10-10)Polar lows can pose serious threats to maritime operations and coastal communities in polar regions, especially due to their extreme wind speeds. The accurate and reliable representation of their wind field thus plays a crucial role in forecasting and mitigating the risks associated with this phenomenon. This study aims to evaluate the value of the SAR-based Sentinel-1 Ocean Wind Field product ... -
Morphological analysis of mass-transport deposits in Cenozoic sediments at the Southern Vøring Margin
(Mastergradsoppgave; Master thesis, 2024-08-30)This thesis builds an evolutionary history of recent times for a region of the Southern Vøring margin west of the Vigrid Syncline, focusing mainly on the morphological traits of mass-transport complexes and selected internal structures. The scenario covers the last 0.8 million years, the three later periods of Naust time. Preliminary research was done on pertinent geological processes and features ... -
Linking ship-associated emissions and resource development in the Arctic: Trends and predictions along the Northern Sea Route
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-08-09)Arctic ship traffic has increased significantly due to continuous sea ice loss and resource extraction. The shipping sector is an important contributor to atmospheric emissions of nitrogen oxides (NO<sub>x</sub>) and sulphur dioxide (SO<sub>2</sub>), and an increase in ship activity will lead to significant increases in these emissions. However, there is a lack of studies linking ship activities and ... -
Some issues related to the Svalbardian tectonic event (Ellesmerian Orogeny) in Svalbard
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-07-23)Svalbard has long been thought to represent the easternmost realm of the Ellesmerian Orogeny in the late Devonian or early Mississippian (Svalbardian tectonic event). Several authors do not agree and present alternative interpretations of the observed structures in older and more recent articles. This article discusses a number of issues that, in our opinion, are not sufficiently considered in ... -
Strukturforståelse av abc-formelen
(Mastergradsoppgave; Master thesis, 2024-08-15)Denne kvalitative studien handler om å undersøke hvorvidt et undervisningsopplegg som vektlegger sammenhengen mellom geometri og algebra i løsning av andregradslikninger, bidrar til at elevene sitter igjen med strukturforståelse av løsningsmetoden, abc-formelen. Hensikten med oppgaven var å planlegge og gjennomføre et annerledes undervisningsdesign innenfor temaet andregradslikninger i en ... -
Vurdering av åpne oppgaver i matematikk: En kvalitativ studie av hvordan tre lærere vurderer åpne oppgaver i matematikk på 10.trinn
(Mastergradsoppgave; Master thesis, 2024-08-14)Etter innføringen av Læreplanverket for Kunnskapsløftet i 2020 (LK20) har åpne oppgaver fått en større plass i matematikkfaget, noe som kommer til syne både på halvårsvurderinger utviklet av ulike forlag og på eksamensoppgaver i matematikk for 10. trinn. Mine erfaringer fra praksisperioder i studietiden har gjort meg oppmerksom og nysgjerrig på hvordan åpne oppgaver vurderes. Denne masterstudien ... -
LSNetv2: Improving weakly supervised power line detection with bipartite matching
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-03-24)This paper addresses the crucial task of power line detection and localization in electrical infrastructure inspection using Unmanned Aerial Vehicles (UAVs) from weak supervision, polyline annotations. We first identify several limitations in the state-of-the-art approach LSNet. In particular, the inability of LSNet to detect line-crossings and lines in close proximity. To overcome these limitations, ... -
A review of information sources and analysis methods for data driven decision aids in child and adolescent mental health services
(Journal article; Tidsskriftartikkel; Peer reviewed, 2024-05-13)Objective: Clinical data analysis relies on effective methods and appropriate data. Recognizing distinctive clinical services and service functions may lead to improved decision-making. Our first objective is to categorize analytical methods, data sources, and algorithms used in current research on information analysis and decision support in child and adolescent mental health services (CAMHS). ... -
Generating and grading 34 optimised norm-conserving Vanderbilt pseudopotentials for actinides and super-heavy elements in the PseudoDojo
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-11-07)In the last decades, material discovery has been a very active research field driven by the need to find new materials for many different applications. This has also included materials with heavy elements, beyond the stable isotopes of lead, as most actinides exhibit unique properties that make them useful in various applications. Furthermore, new heavy elements beyond actinides, collectively referred ...