English
norskFakultet for naturvitenskap og teknologi: Nye registreringer
Viser treff 1721-1740 av 5336
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The impact of interplay between electronic and steric effects on the synthesis and the linear and non-linear optical properties of diketopyrrolopyrrole bearing benzofuran moieties
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-07)An in-depth investigation of the reaction of substituted salicylaldehydes with chloroacetonitrile led to the development of new conditions for the synthesis of 2-cyanobenzofurans. The crucial improvement lies in the use of phase-transfer catalysis in the second step, i.e., intramolecular aldol type condensation. In a two-step process, the reactants were transformed into a library of 3,6-bis(ben ... -
Maritime safety and the ISM code: a study of investigated casualties and incidents
(Journal article; Tidsskriftartikkel; Peer reviewed, 2013-08-27)Abstract In 1993, the International Maritime Organization adopted the International Safety Management (ISM) Code which requires all shipping companies operating certain types of vessels to establish safety management systems. Nevertheless, two decades later, maritime safety remains a concern. This article studies 94 maritime cases investigated by the Maritime Accident Investigation Branch in the ... -
Limitations of Ice Accretion on Offshore Aquaculture Facilities
(Master thesis; Mastergradsoppgave, 2021-12-15)Sea spray icing is a constant risk for fish farms operating in cold climates, such as on the Northern Norwegian coast, and there must therefore exist methods to reduce this risk. This thesis discusses the consequences of ice accretion to the traditional plastic circular fish cage design, and how the cage reacts under the pressure of added mass from sea spray icing. The prediction of sea spray icing ... -
Resilience, Reliability, and Recoverability (3Rs)
(Master thesis; Mastergradsoppgave, 2022-01-06)Recent natural and human-made disasters, mortgage derivatives crises, and the need for stable systems in different areas have renewed interest in the concept of resilience, especially as it relates to complex industrial systems with mechanical failures. This concept in the engineering systems (infrastructure) domain could be interpreted as the probability that system conditions exceed an irrevocable ... -
Training of seafarers working on ships operating in polar waters
(Master thesis; Mastergradsoppgave, 2022-01-11)The aim of this thesis is to identify the competence gaps for seafarers who sail in polar waters have after completing the existing training courses based on the Polar Code. The best way to protect the environment and people in the Polar regions is by increasing the knowledge and competence of the people working in the vulnerable regions to ensure they make the best possible decisions and avoid ... -
The Use of Foraminiferal Geochemistry to Investigate Methane Seepage at the Svyatogor Ridge, Arctic Ocean
(Master thesis; Mastergradsoppgave, 2022-05-12)Methane is a greenhouse gas contributing to contemporaneous global warming, and seepage is one of the ways through which it migrates from the deep sedimentary basins, all the way up to the hydro- and atmosphere. The study of methane seepage is still young as scientists are yet to discover most seep sites as well as seep associated biological species. A record of past methane seepage can be derived ... -
Climatic variations and sediment provenance during the last 16 000 years in the North Hinlopen Trough, Svalbard
(Master thesis; Mastergradsoppgave, 2019-06-02)Gravity core HH18-1500GC retrieved from the Hinlopen Trough, Arctic Ocean, has been investigated in order to reconstruct the climatic evolution and ocean circulation over the last 16 000 years. The core was taken at the edge of the trough on the northern Svalbard shelf in order to be certain to reach into till, with the intent of dating the retreat of the ice sheet. The Fram Strait is located between ... -
Computational and experimental insights into asymmetric Rh‐catalyzed hydrocarboxylation with CO2
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-18)The asymmetric Rh‐catalyzed hydrocarboxylation of α,β‐unsaturated carbonyl compounds was originally developed by Mikami and co‐workers but gives only moderate enantiomeric excesses. In order to understand the factors controlling the enantioselectivity and to propose novel ligands for this reaction, we have used computational and experimental methods to study the Rh‐catalyzed hydrocarboxylation with ... -
Investigating the latency cost of statistical learning of a Gaussian mixture simulating on a convolutional density network with adaptive batch size technique for background modeling
(Master thesis; Mastergradsoppgave, 2021-05-31)Background modeling is a promising field of study in video analysis, with a wide range of applications in video surveillance. Deep neural networks have proliferated in recent years as a result of effective learning-based approaches to motion analysis. However, these strategies only provide a partial description of the observed scenes' insufficient properties since they use a single-valued mapping ... -
Polar Vantage and Oura Physical Activity and Sleep Trackers: Validation and Comparison Study
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-27)Background: Consumer-based activity trackers are increasingly used in research, as they have the potential to promote increased physical activity and can be used for estimating physical activity among participants. However, the accuracy of newer consumer-based devices is mostly unknown, and validation studies are needed.<p> <p>Objective: The objective of this study was to compare the Polar Vantage ... -
On the linkage between atmospheric circulation changes and Arctic climate change
(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
(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 ... -
Origin-independent two-photon circular dichroism calculations in coupled cluster theory
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016-05-03)We present the first origin-independent approach for the treatment of two-photon circular dichroism (TPCD) using coupled cluster methods. The approach is assessed concerning its behavior on the choice of the basis set and different coupled cluster methods. We also provide a comparison of results from CC2 with those from density functional theory using the CAM-B3LYP functional. Concerning the basis ... -
A Quantitative Analysis of Seasonal and Regional Forcing on the Terminus of Store Glacier, Greenland, from High Resolution Photogrammetry
(Master thesis; Mastergradsoppgave, 2022-01-15)A quantitative analysis of seasonal and regional forcing on the terminus of Store Glacier, Greenland, from high resolution photogrammetry for the period between 10 May 2014 and 13 June 2014. Imagery is analyzed through ImGRAFT processing to create a detailed velocity and strain rate for the proglacial mélange and glacial terminus in order to investigate changes to glacial calving dynamics during ... -
Platinum corroles
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-09)Platinum has been inserted into corroles for the first time and three oxidized Pt<sup>IV</sup>(corrole<sup>2-</sup>)ArAr0 complexes have been structurally characterized. The Soret maxima of these complexes exhibit an unusually strong dependence on the meso-aryl substituents on the corrole, indicating aryl - corrole<sup>2-</sup> charge transfer character in these transitions. -
The role of ocean and atmospheric dynamics in the marine-based collapse of the last Eurasian Ice Sheet
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-19)Information from former ice sheets may provide important context for understanding the response of today’s ice sheets to forcing mechanisms. Here we present a reconstruction of the last deglaciation of marine sectors of the Eurasian Ice Sheet, emphasising how the retreat of the Norwegian Channel and the Barents Sea ice streams led to separation of the British-Irish and Fennoscandian ice sheets at ... -
Permafrost in monitored unstable rock slopes in Norway-New insights from temperature and surface velocity measurements, geophysical surveying, and ground temperature modelling
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-01)The warming and subsequent degradation of mountain permafrost within alpine areas represent an important process influencing the stability of steep slopes and rock faces. The unstable and monitored slopes of Mannen (Møre and Romsdal county, southern Norway) and Gámanjunni-3 (Troms and Finnmark county, northern Norway) were classified as high-risk sites by the Norwegian Geological Survey (NGU). ... -
Impacts of a sudden stratospheric warming on the mesospheric metal layers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-11)We report measurements of atomic sodium, iron and temperature in the mesosphere and lower thermosphere (MLT) made by ground-based lidars at the ALOMAR observatory (69°N, 16°E) during a major sudden stratospheric warming (SSW) event that occurred in January 2009. The high resolution temporal observations allow the responses of the Na and Fe layers to the SSW at high northern latitudes to be ... -
Expanding the toolbox for the study of antimicrobial peptides
(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 ... -
The three Endonuclease III variants of Deinococcus radiodurans possess distinct and complementary DNA repair activities
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-28)Endonuclease III (EndoIII) is a bifunctional DNA glycosylase that removes oxidized pyrimidines from DNA. The genome of Deinococcus radiodurans encodes for an unusually high number of DNA glycosylases, including three EndoIII enzymes (drEndoIII1-3). Here, we compare the properties of these enzymes to those of their well-studied homologues from E. coli and human. Our biochemical and mutational data, ...
