Recent additions

  • Scalable-resolution structured illumination microscopy 

    Butola, Ankit; Acuña, Sebastian; Hansen, Daniel Henry; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-15)
    Structured illumination microscopy suffers from the need of sophisticated instrumentation and precise calibration. This makes structured illumination microscopes costly and skill-dependent. We present a novel approach to realize super-resolution structured illumination microscopy using an alignment non-critical illumination system and a reconstruction algorithm that does not need illumination ...
  • Mitochondrial dynamics and quantification ofmitochondria-derived vesicles in cardiomyoblastsusing structured illumination microscopy 

    Opstad, Ida Sundvor; Godtliebsen, Gustav; Ahluwalia, Balpreet Singh; Myrmel, Truls; Agarwal, Krishna; Birgisdottir, Åsa birna (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-11-12)
    Mitochondria are essential energy-providingorganelles of particular importance inenergy-demanding tissue such as theheart. The production of mitochondria-derived vesicles (MDVs) is a cellularmechanism by which cells ensure ahealthy pool of mitochondria. These vesi-cles are small and fast-moving objects noteasily captured by imaging. In this work,we have tested the ability of the ...
  • Using radar beam-parks to characterize the Kosmos-1408 fragmentation event 

    Kastinen, Daniel; Vierinen, Juha; Grydeland, Tom; Kero, Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-10-22)
    We describe the use of radar beam-park experiments to characterize the space debris resulting from a recent fragmentation event, the deliberate demolition of the defunct Kosmos-1408 satellite. We identify the Kosmos-1408 fragments and present distribution of measurement parameters as well as proxy orbit parameters. We present and apply a novel technique to estimate the size of objects by matching ...
  • Manx Arrays: Perfect Non-Redundant Interferometric Geometries 

    McKay, Derek; Grydeland, Tom; Gustavsson, Bjorn Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-09)
    Interferometry applications (e.g., radio astronomy) often wish to optimize the placement of the interferometric elements. One such optimal criterion is a uniform distribution of non-redundant element spacings (in both distance and position angle). While large systems, with many elements, can rely on saturating the sample space, and disregard “wasted” sampling, small arrays with only a few elements ...
  • Finite element simulation of transmission and reflection of acoustic waves in the ultrasonic transducer 

    Shukla, Kaushik; Ahmad, Azeem; Habib, Anowarul; Singh Ahluwalia, Balpreet; Melandsø, Frank (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-03-30)
    In scanning acoustic microscopy (SAM), the image quality depends on several factors such as noise level, resolution, and interaction of the waves with sample boundaries. The theoretical equations for the reflection coefficient and transmission coefficient are suitable for plane boundaries but fail for curved/rough boundaries. We presented a finite element method-based modeling for the loss ...
  • The future of auroral E-region plasma turbulence research 

    Huyghebaert, Devin Ray; Billett, Daniel; Chartier, Alex; Chau, Jorge L.; Hussey, Glenn C.; Hysell, David L.; Ivarsen, Magnus Fagernes; Mesquita, Rafael L. A.; Rojas, Enrique; Vierinen, Juha; Young, Matthew (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-15)
    The heating caused by ionospheric E-region plasma turbulence has documented global implications for the energy transfer from space into the terrestrial atmosphere. Traveling atmospheric disturbances, neutral wind motion, energy deposition rates, and ionospheric conductance have all been shown to be potentially affected by turbulent plasma heating. Therefore it is proposed to enhance and expand ...
  • Time-Dependent Electron Transport I: Modelling of Supra-Thermal Electron Bursts Modulated at 5–10 Hz With Implications for Flickering Aurora 

    Gustavsson, Björn Johan (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-04)
    A time-dependent multi-stream electron transport model, AURORA, has been developed for studies of auroral emission-rates during precipitation with large variations on sub-second time-scales. The transport-code accurately takes time-of-flight, energy degradation, scattering and production of secondary electrons into account. AURORA produces ionospheric electron-flux as a function of energy, altitude, ...
  • On the origin of bonding in metals: lithium as a case study 

    Røeggen, Inge Arvid; Gao, Bin (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-05)
    The bonding in metals is analysed within the framework of the PATMOS (Perturbed AToms in MOlecules and Solids) model. The electronic binding energy per atom is written as a sum of a distortion energy of the atoms and the partitioned interaction energy comprising Coulombic, exchange and correlation terms. The adopted physical model of the infinite system, is spherical embedding of the atoms of the ...
  • Functional Connectome of the Human Brain with Total Correlation 

    Li, Qiang; Steeg, Greg Ver; Yu, Shujian; Malo, Jesus (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-25)
    Recent studies proposed the use of Total Correlation to describe functional connectivity among brain regions as a multivariate alternative to conventional pairwise measures such as correlation or mutual information. In this work, we build on this idea to infer a large-scale (whole-brain) connectivity network based on Total Correlation and show the possibility of using this kind of network as ...
  • Automatic detection of the mental foramen for estimating mandibular cortical width in dental panoramic radiographs: the seventh survey of the Tromsø Study (Tromsø7) in 2015-2016 

    Edvardsen, Isak Paasche; Teterina, Anna; Johansen, Thomas Haugland; Myhre, Jonas Nordhaug; Godtliebsen, Fred; Bolstad, Napat Limchaichana (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-22)
    Objective To apply deep learning to a data set of dental panoramic radiographs to detect the mental foramen for automatic assessment of the mandibular cortical width.<p> <p>Methods Data from the seventh survey of the Tromsø Study (Tromsø7) were used. The data set contained 5197 randomly chosen dental panoramic radiographs. Four pretrained object detectors were tested. We randomly chose 80% of the ...
  • Multiple Damage Detection in PZT Sensor Using Dual Point Contact Method 

    Bhattacharya, Sayantani; Yadav, Nitin; Ahmad, Azeem; Melandsø, Frank; Habib, Anowarul (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-25)
    Lead Zirconate Titanate (PZT) is used to make ultrasound transducers, sensors, and actuators due to its large piezoelectric coefficient. Several micro-defects develop in the PZT sensor due to delamination, corrosion, huge temperature fluctuation, etc., causing a decline in its performance. It is thus necessary to identify, locate, and quantify the defects. Non-Destructive Structural Health Monitoring ...
  • A Comparative Study of PMETAC-Modified Mesoporous Silica and Titania Thin Films for Molecular Transport Manipulation 

    Alberti, Sebastian; Giussi, Juan; Azzaroni, Omar; Soler-Illia, Galo J. A. A. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-09)
    The manipulation and understanding of molecular transport across functionalized nanopores will take us closer to mimicking biological membranes and thus to design high-performance permselective separation systems. In this work, Surface-initiated atom transfer radical polymerization (SI-ATRP) of (2-methacryloyloxy)-ethyltrimethylammonium chloride (METAC) was performed on both mesoporous silica and ...
  • Supervised Classifications of Optical Water Types in Spanish Inland Waters 

    Pereira-Sandoval, Marcela; Ruescas, Ana Belen; García-Jimenez, Jorge; Blix, Katalin; Delegido, Jesús; Moreno, José (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-04)
    Remote sensing of lake water quality assumes there is no universal method or algorithm that can be applied in a general way on all inland waters, which usually have different in-water components affecting their optical properties. Depending on the place and time of year, the lake dynamics, and the particular components of the water, non-tailor-designed algorithms can lead to large errors or lags in ...
  • Spatial variability of nocturnal stability regimes in an operational weather prediction model 

    Kähnert, Marvin; Sodemann, Harald; Remes, Teresa Maaria; Fortelius, Carl; Bazile, Eric; Esau, Igor (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-15)
    Forecast errors in near-surface temperatures are a persistent issue for numerical weather prediction models. A prominent example is warm biases during cloud-free, snow-covered nights. Many studies attribute these biases to parametrized processes such as turbulence or radiation. Here, we focus on the contribution of physical processes to the nocturnal temperature development. We compare model timestep ...
  • Traveling Ionospheric Disturbances in the Vicinity of Storm-Enhanced Density at Midlatitudes 

    Zhang, Shunrong; Nishimura, Yukitoshi; Erickson, Philip J.; Aa, Ercha; Kil, Hyosub; Deng, Yue; Thomas, Evan; Rideout, William; Coster, Anthea J.; Kerr, Robert; Vierinen, Juha (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-08)
    This study provides first storm time observations of the westward-propagating medium-scale traveling ionospheric disturbances (MSTIDs), particularly, associated with characteristic subauroral storm time features, storm-enhanced density (SED), subauroral polarization stream (SAPS), and enhanced thermospheric westward winds over the continental US. In the four recent (2017–2019) geomagnetic storm ...
  • Impulse-driven oscillations of the near-Earth's magnetosphere 

    Sato, Hiroatsu; Pecseli, Hans Laszlo; Trulsen, Jan Karsten; Sandholt, Per Even; Farrugia, Charles J. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-09)
    It is argued that a simple model based on magnetic image arguments suffices to give a convincing insight into both the basic static as well as some transient dynamic properties of the near-Earth's magnetosphere, particularly accounting for damped oscillations being excited in response to impulsive perturbations. The parameter variations of the frequency are given. Qualitative results can also be ...
  • Scalable-resolution structured illumination microscopy 

    Butola, Ankit; Acuna Maldonado, Sebastian Andres; Hansen, Daniel Henry; Agarwal, Krishna (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-15)
    Structured illumination microscopy suffers from the need of sophisticated instrumentation and precise calibration. This makes structured illumination microscopes costly and skill-dependent. We present a novel approach to realize super-resolution structured illumination microscopy using an alignment non-critical illumination system and a reconstruction algorithm that does not need illumination ...
  • Errors in Simple Climate Model Emulations of Past and Future Global Temperature Change 

    Jackson, Lawrence S.; Maycock, Amanda C.; Andrews, Timothy; Fredriksen, Hege-Beate; Smith, Christopher J.; M. Forster, Piers (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-08-04)
    Climate model emulators are widely used to generate temperature projections for climate scenarios, including in the recent Intergovernmental Panel on Climate Change Sixth Assessment Report. Here we evaluate the performance of a two-layer energy balance model in emulating historical and future temperature projections from Coupled Model Intercomparison Project Phase 6 models. We find that emulation ...
  • On the Exploitation of Multimodal Remote Sensing Data Combination for Mesoscale/Submesoscale Eddy Detection in the Marginal Ice Zone 

    Khachatrian, Eduard; Sandalyuk, Nikita V. (Journal article; Tidsskriftartikkel, 2022-10-17)
    The detection and analysis of ocean eddies via remote sensing have become a hot topic in physical oceanography during the last few decades. However, eddy identification and tracking via remote sensing can be a challenging task, since each sensor has some limitations. In order to overcome potential challenges, it is crucial to exploit the complementary information provided by different sensing systems. ...
  • A self-guided anomaly detection-inspired few-shot segmentation network 

    Hansen, Stine; Gautam, Srishti; Kampffmeyer, Michael; Jenssen, Robert (Journal article; Tidsskriftartikkel; Peer reviewed, 2022)
    Standard strategies for fully supervised semantic segmentation of medical images require large pixel-level annotated datasets. This makes such methods challenging due to the manual labor required and limits the usability when segmentation is needed for new classes for which data is scarce. Few-shot segmentation (FSS) is a recent and promising direction within the deep learning literature designed ...

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