Now showing items 2841-2860 of 5336

    • Relationship between the source size at the diffuser plane and the longitudinal spatial coherence function of the optical coherence microscopy system 

      Usmani, Kashif; Ahmad, Azeem; Joshi, Rakesh; Dubey, Vishesh Kumar; Butola, Ankit; Mehta, Dalip Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-25)
      Coherence properties of light sources are indispensable for optical coherence microscopy/tomography as they greatly influence the signal-to-noise ratio, axial resolution, and penetration depth of the system. In the present paper, we report the investigation of longitudinal spatial coherence properties of a pseudothermal light source (PTS) as a function of the laser spot size at the rotating diffuser ...
    • Progradation rates measured at modern river outlets: A first-order constraint on the pace of deltaic deposition 

      Aadland, Tore; Helland-Hansen, William (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-29)
      We present a compilation of modern shoreline progradation rates measured close to river outlets entering deltaic coastlines, and we discuss how these observations relate to the overall evolution of both modern and ancient deltaic coastlines. We analyzed Landsat‐derived satellite images to identify plan view changes in the subaerial morphology of 331 modern deltaic coastlines. Our rate compilation ...
    • Characterization and engineering of a DNA polymerase reveals a single amino-acid substitution in the fingers subdomain to increase strand-displacement activity of A-family prokaryotic DNA polymerases 

      Piotrowski, Yvonne; Gurung, Man Kumari; Larsen, Atle Noralf (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-09)
      <i>Background</i> - The discovery of thermostable DNA polymerases such as Taq DNA polymerase revolutionized amplification of DNA by polymerase chain reaction methods that rely on thermal cycling for strand separation. These methods are widely used in the laboratory for medical research, clinical diagnostics, criminal forensics and general molecular biology research. Today there is a growing demand ...
    • Thickness-Dependent Resonant Raman and E' Photoluminescence Spectra of Indium Selenide and Indium Selenide/Graphene Heterostructures 

      Tamalampudi, Srinivasa Reddy; Sankar, Raman; Apostoleris, Harry; Almahri, Mariam Ali; Alfakes, Boulos; Al-Hagri, Abdulrahman; Li, Ru; Gougam, Adel; Almansouri, Ibraheem; Chiesa, Matteo; Lu, Jin-You (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-28)
      Atomically thin, two-dimensional (2D) indium selenide (InSe) has attracted considerable attention because of the dependence of its bandgap on sample thickness, making it suitable for small-scale optoelectronic device applications. In this work, by the use of Raman spectroscopy with three different laser wavelengths, including 488, 532, and 633 nm, representing resonant, near-resonant, and conventional ...
    • Hybrid graphene metasurface for near-infrared absorbers 

      Mahfuzur Rahman, MD; Raza, Aikifa; Younes, Hammad; Alghaferi, Amal; Chiesa, Matteo; Lu, Jin-You (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-19)
      We experimentally demonstrated an amorphous graphene-based metasurface yielding near-infrared super absorber characteristic. The structure is obtained by alternatively combining magnetron-sputtering deposition and graphene transfer coating fabrication techniques. The thickness constraint of the physical vapor–deposited amorphous metallic layer is unlocked and as a result, the as-fabricated graphene-based ...
    • Comparative net energy analysis of renewable electricity and carbon capture and storage 

      Sgouridis, Sgouris; Carbajales-Dale, Michael; Csala, Denes; Chiesa, Matteo; Bardi, Ugo (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-08)
      Carbon capture and storage (CCS) for fossil-fuel power plants is perceived as a critical technology for climate mitigation. Nevertheless, limited installed capacity to date raises concerns about the ability of CCS to scale sufficiently. Conversely, scalable renewable electricity installations—solar and wind—are already deployed at scale and have demonstrated a rapid expansion potential. Here we show ...
    • Evaluation of Six Atmospheric Reanalyses over Arctic Sea Ice from Winter to Early Summer 

      Graham, Robert; Cohen, Lana; Ritzhaupt, Nicole; Segger, Benjamin; Graversen, Rune; Rinke, Anette; Walden, Von P.; Granskog, Mats; Hudson, Stephen (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-19)
      This study evaluates the performance of six atmospheric reanalyses (ERA-Interim, ERA5, JRA-55, CFSv2, MERRA-2, and ASRv2) over Arctic sea ice from winter to early summer. The reanalyses are evaluated using observations from the Norwegian Young Sea Ice campaign (N-ICE2015), a 5-month ice drift in pack ice north of Svalbard. N-ICE2015 observations include surface meteorology, vertical profiles from ...
    • High-Throughput Total Internal Reflection Fluorescence and Direct Stochastic Optical Reconstruction Microscopy Using a Photonic Chip 

      Coucheron, David Andre; Helle, Øystein Ivar; Øie, Cristina Ionica; Tinguely, Jean-Claude; Ahluwalia, Balpreet Singh (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-16)
      Total internal reflection fluorescence (TIRF) is commonly used in single molecule localization based super-resolution microscopy as it gives enhanced contrast due to optical sectioning. The conventional approach is to use high numerical aperture microscope TIRF objectives for both excitation and collection, severely limiting the field of view and throughput. We present a novel approach to generating ...
    • On the Role of the Atmospheric Energy Transport in 2xCO2-Induced Polar Amplification in CESM1 

      Graversen, Rune; Langen, Peter L. (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-06-12)
      A doubling of the atmospheric CO<sub>2</sub> content leads to global warming that is amplified in the polar regions. The CO<sub>2</sub> forcing also leads to a change of the atmospheric energy transport. This transport change affects the local warming induced by the CO<sub>2</sub> forcing. Using the Community Earth System Model (CESM), the direct response to the transport change is investigated. ...
    • Patch Size Evolution During Pulsating Aurora 

      Partamies, Noora; Bolmgren, Karl; Heino, Erkka; Ivchenko, Nickolay; Borovsky, Joseph E.; Sundberg, Hanna (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-05-30)
      We report both decreasing and increasing trends in the patch sizes during pulsating aurora events. About 150 pulsating auroral events over the Fennoscandian Lapland have been successfully analyzed for their average patch size, total patch area, and number of patches as a function of event time, typically 1–2 hr. An automatic routine has been developed to detect patches in the all‐sky camera images. ...
    • Observation of mesospheric dust and ionospheric conditions during the G-chaser rocket campaign 

      Trollvik, Henriette Marie Tveitnes; Gunnarsdottir, Tinna; Mann, Ingrid; Olsen, Sveinung viggo; Restad, Erlend; Antonsen, Tarjei; Fredriksen, Åshild; Eilertsen, Yngve; Havnes, Ole; Hansen, Rikke; Floer, Markus; Bjørk, Arne; Bootby, Christopher; Latteck, Ralph (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10)
      SPID, Smoke Particle Impact Detector, is a Faraday cup detector designed to measure nanometer-sized meteoric smoke particles during rocket flights. We report measurements made with SPID during the G-Chaser student rocket campaign 13 January 2019 and describe the design of the SPID instruments. Model calculations of dust trajectories within the detector result in an effective crosssection of 0.97 for ...
    • Late Paleoproterozoic and Mesoproterozoic magmatism of the Nico Pérez Terrane (Uruguay): Tightening up correlations in southwestern Gondwana 

      Oriolo, Sebastián; Oyhantcabal, Pedro; Konopásek, Jiří; Basei, Miguel A.S.; Frei, Robert; Sláma, Jiří; Wemmer, Klaus; Siegesmund, Siegfried (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-04)
      New geochronological, isotopic and geochemical data were obtained from the late Paleoproterozoic and Mesoproterozoic magmatic units of the Nico Pérez Terrane (Uruguay). A U-Pb LA-ICP-MS zircon age of 1768 ± 11 Ma confirms the Statherian age for the Illescas rapakivi intrusion, being thus comparable with the age of the Campanero Unit felsic orthogneisses. Though both the Illescas and Campanero ...
    • På vei mot en kollegial tilnærming til undervisning – seminarundervisning og pedagogisk opplæring av stipendiater 

      Johansen, Greta Kristine; Beerepoot, Maarten (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-19)
      Seminarundervisning har en viktig rolle i realfagsundervisning i høyere utdanning. Læringsaktivitetene i seminarene samsvarer ofte godt med eksamensformen og dermed bidrar seminarundervisning betydelig til <i>constructive alignment</i> (Biggs, 1999) i et emne. Den viktige rollen seminarundervisning har står i sterk kontrast med den begrensede eller fraværende opplæring ...
    • Leaders’ Influence Tactics for Safety: An Exploratory Study in the Maritime Context 

      Kim, Tae-Eun; Gausdal, Anne Haugen (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-05)
      A growing body of research has pointed out effective leadership as an important influencing factor for safety performance in various high-risk industrial contexts. However, limited systematic knowledge is available about how leaders can effectively persuade rule compliance, and stimulate actions and participation. Recognizing effective means of influence is of value for safety leadership development ...
    • Detection of gas hydrates in faults using azimuthal seismic velocity analysis,Vestnesa Ridge, W-Svalbard Margin 

      Singhroha, Sunny; Bünz, Stefan; Plaza Faverola, Andreia Aletia; Chand, Shyam (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-24)
      Joint analysis of electrical resistivity and seismic velocity data is primarily used todetect the presence of gas hydrate-filled faultsand fractures. In this study, we present a novel approach to inferthe occurrence of structurally-controlled gas hydrateaccumulations using azimuthal seismic velocity analysis. We perform thisanalysis using ocean-bottom seismic (OBS) data at two sites on Vestnesa ...
    • PKI and high-level security programming abstractions for SNOOP 

      Stenhaug, Håkon (Master thesis; Mastergradsoppgave, 2019-12-15)
      When working with sensitive data in a distributed setting, secure multi-partycomputations(SMC) protocols aims to preserve the privacy of participants. Acore aspect of any SMC protocol is secure communication between participants.Based on the NOOP and SNOOP middleware with a combination of secret keyand public-key cryptography we design and implement a public key infrastruc-ture(PKI) to share signed ...
    • 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 

      Johansson, Malin; Malnes, Eirik; Gerland, Sebastian; Cristea, Anca; Doulgeris, Anthony Paul; Divine, Dmitry V; Pavlova, Olga; Lauknes, Tom Rune (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-17)
      Synthetic Aperture Radar (SAR) satellite images are used to monitor Arctic sea ice, with systematic data records dating back to 1991. We propose a semi-supervised classification method that separates open water from sea ice and can utilise ERS-1/2, Envisat ASAR, RADARSAT-2 and Sentinel-1 SAR images. The classification combines automatic segmentation with a manual segment selection stage. The ...
    • The First International Conference on 'Processes and Palaeo-Environmental Changes in the Arctic: From Past to Present' (PalaeoArc) 

      Lyså, Astrid; Benediktsson, Ívar Örn; Emery, Andy; Gregoire, Lauren; Jennings, Anne; Morigi, Caterina; Müller, Juliane; O'Regan, Matt; Sarala, Pertti; Stokes, Chris; Szczuciński, Witold; Winsborrow, Monica (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-09-13)
      The new international network PalaeoArc (Processes and Palaeo Environmental Changes in the Arctic: From Past to Present) held its first meeting in Poznan, 20-24 May 2019. The meeting was hosted by the Faculty of Geographical and Geological Sciences, Adam Mickiewicz University, Poznan, and organized by a local committee chaired by Witold Szczuciński.
    • Performance of data enhancements and training optimization for neural network: A polyp detection case study 

      Henriksen, Fredrik Lund; Jensen, Rune; Stensland, Håkon Kvale; Johansen, Dag; Riegler, Michael; Halvorsen, Pål (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-08-05)
      Deep learning using neural networks is becoming more and more popular. It is frequently used in areas like video analysis, image retrieval, traffic forecast and speech recognition. In this respect, the learning and training process usually requires a lot of data. However, in many areas, data is scarce which is definitely the case in our medical application scenario, i.e., polyp detection in the ...
    • Glacier algae accelerate melt rates on the south-western Greenland Ice Sheet 

      Cook, Joseph M.; Tedstone, Andrew J.; Williamson, Christopher; McCutcheon, Jenine; Hodson, Andrew J.; Dayal, Archana; Skiles, McKenzie; Hofer, Stefan; Bryant, Robert; McAree, Owen; McGonigle, Andrew; Ryan, Jonathan; Anesio, Alexandre M.; Irvine-Fynn, Tristram D.L.; Hubbard, Alun Lloyd; Hanna, Edward; Flanner, Mark; Mayanna, Sathish; Benning, Liane G.; van As, Dirk; Yallop, Marian; McQuaid, James B.; Gribbin, Thomas; Tranter, Martyn (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-29)
      Melting of the Greenland Ice Sheet (GrIS) is the largest single contributor to eustatic sea level and is amplified by the growth of pigmented algae on the ice surface, which increases solar radiation absorption. This biological albedo-reducing effect and its impact upon sea level rise has not previously been quantified. Here, we combine field spectroscopy with a radiative-transfer model, supervised ...