Artikler, rapporter og annet (fysikk og teknologi): Recent submissions
Now showing items 241-260 of 1057
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The Departure from Mixed-Layer Similarity During the Afternoon Decay of Turbulence in the Free-Convective Boundary Layer: Results from Large-Eddy Simulations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-21)This study analyses the departure of the velocity-variances profiles from their quasi-steady state described by the mixed-layer similarity, using large-eddy simulations with different prescribed shapes and time scales of the surface kinematic heat flux decay. Within the descriptive frames where the time is tracked solely by the forcing time scale (either constant or time-dependent) describing the ... -
Extreme Horizontal Wind Perturbations in the Mesosphere and Lower Thermosphere Over South America Associated With the 2022 Hunga Eruption
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-13)On 15 January 2022, the Hunga volcano produced a massive explosion that generated perturbations in the entire atmosphere. Nonetheless, signatures in the mesosphere and lower thermosphere (MLT) have been challenging to identify. We report MLT horizontal wind perturbations using three multistatic specular meteor radars on the west side of South America (spanning more than 3,000 km). The most ... -
Sea Ice Remote Sensing—Recent Developments in Methods and Climate Data Sets
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-03)Sea ice monitoring by polar orbiting satellites has been developed over more than four decades and is today one of the most well-established applications of space observations. This article gives an overview of data product development from the first sensors to the state-of-the-art regarding retrieval methods, new products and operational data sets serving climate monitoring as well as daily operational ... -
Single-Molecule Sizing through Nanocavity Confinement
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-24): An approach relying on nanocavity confinement is developed in this paper for the sizing of nanoscale particles and single biomolecules in solution. The approach, termed nanocavity diffusional sizing (NDS), measures particle residence times within nanofluidic cavities to determine their hydrodynamic radii. Using theoretical modeling and simulations, we show that the residence time of particles ... -
Solved and unsolved riddles about low-latitude daytime valley region plasma waves and 150-km echoes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-27)The Earth’s atmosphere near both the geographic and magnetic equators and at altitudes between 120 and 200 km is called the low-latitude valley region (LLVR) and is among the least understood regions of the ionosphere/thermosphere due to its complex interplay of neutral dynamics, electrodynamics, and photochemistry. Radar studies of the region have revealed puzzling daytime echoes scattered from ... -
RELAX: Representation Learning Explainability
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-11)Despite the significant improvements that self-supervised representation learning has led to when learning from unlabeled data, no methods have been developed that explain what influences the learned representation. We address this need through our proposed approach, RELAX, which is the first approach for attribution-based explanations of representations. Our approach can also model the uncertainty ... -
Preconditioning of Summer Melt Ponds From Winter Sea Ice Surface Temperature
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-22)Comparing helicopter-borne surface temperature maps in winter and optical orthomosaics in summer from the year-long Multidisciplinary drifting Observatory for the Study of Arctic Climate expedition, we find a strong geometric correlation between warm anomalies in winter and melt pond location the following summer. Warm anomalies are associated with thinner snow and ice, that is, surface depression ... -
Comparing quality of breast cancer care in the Netherlands and Norway by federated propensity score analytics
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-06-05)Purpose - The aim of the study was to benchmark and compare breast cancer care quality indicators (QIs) between Norway and the Netherlands using federated analytics preventing transfer of patient-level data.<p> <p>Methods - Breast cancer patients (2017–2018) were retrieved from the Netherlands Cancer Registry and the Cancer Registry of Norway. Five European Society of Breast Cancer Specialists ... -
Predicting Regions of Local Recurrence in Glioblastomas Using Voxel-Based Radiomic Features of Multiparametric Postoperative MRI
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-22)The globally accepted surgical strategy in glioblastomas is removing the enhancing tumor. However, the peritumoral region harbors infiltration areas responsible for future tumor recurrence. This study aimed to evaluate a predictive model that identifies areas of future recurrence using a voxel-based radiomics analysis of magnetic resonance imaging (MRI) data. This multi-institutional study included ... -
Energy budget diagnosis of changing climate feedback
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-21)The climate feedback determines how Earth’s climate responds to anthropogenic forcing. It is thought to have been more negative in recent decades due to a sea surface temperature “pattern effect,” whereby warming is concentrated in the western tropical Pacific, where nonlocal radiative feedbacks are very negative. This phenomenon has however primarily been studied within climate models. We diagnose ... -
Assessing ocean ensemble drift predictions by comparison with observed oil slicks
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-16)Geophysical models are cornerstone pieces in marine forecasting of floating objects and pollution, such as marine surface oil slicks. Trajectory forecasts of oil spills inherit the uncertainties from the underlying geophysical forcing. In this work we compare the forecast capabilities of an ocean ensemble prediction system (EPS) to those from a higher resolution deterministic model on ... -
Improving satellite-based monitoring of the polar regions: Identification of research and capacity gaps
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-17)We present a comprehensive review of the current status of remotely sensed and in situ sea ice, ocean, and land parameters acquired over the Arctic and Antarctic and identify current data gaps through comparison with the portfolio of products provided by Copernicus services. While we include several land parameters, the focus of our review is on the marine sector. The analysis is facilitated by the ... -
A dataset of direct observations of sea ice drift and waves in ice
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-03)Variability in sea ice conditions, combined with strong couplings to the atmosphere and the ocean, lead to a broad range of complex sea ice dynamics. More in-situ measurements are needed to better identify the phenomena and mechanisms that govern sea ice growth, drift, and breakup. To this end, we have gathered a dataset of in-situ observations of sea ice drift and waves in ice. A total of 15 ... -
Gender inequality and self-publication are common among academic editors
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-01-16)Scientific editors shape the content of academic journals and set standards for their fields. Yet, the degree to which the gender makeup of editors reflects that of scientists, and the rate at which editors publish in their own journals, are not entirely understood. Here, we use algorithmic tools to infer the gender of 81,000 editors serving more than 1,000 journals and 15 disciplines over five ... -
Probing power laws in multifrequency AFM
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-17)Quantification of conservative forces in multifrequency atomic force microscopy requires solving the general equations of the theory expressed in terms of the virials of interaction. Power law expressions are commonly utilized when dealing with electrostatic, ferroelectric, magnetic, or long range (van der Waals) forces. Here, we discuss long range forces modeled in terms of power laws (n), where ... -
α-Synuclein fibril and synaptic vesicle interactions lead to vesicle destruction and increased lipid-associated fibril uptake into iPSC-derived neurons
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-15)Monomeric alpha-synuclein (aSyn) is a well characterised protein that importantly binds to lipids. aSyn monomers assemble into amyloid fibrils which are localised to lipids and organelles in insoluble structures found in Parkinson’s disease patient’s brains. Previous work to address pathological aSyn-lipid interactions has focused on using synthetic lipid membranes, which lack the complexity of ... -
Knowledge Gaps and Impact of Future Satellite Missions to Facilitate Monitoring of Changes in the Arctic Ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-30)Polar-orbiting satellite observations are of fundamental importance to explore the main scientific challenges in the Arctic Ocean, as they provide information on bio-geo-physical variables with a denser spatial and temporal coverage than in-situ instruments in such a harsh and inaccessible environment. However, they are limited by the lack of coverage near the North Pole (Polar gap), the polar night, ... -
Viewing life without labels under optical microscopes
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-05-25)Optical microscopes today have pushed the limits of speed, quality, and observable space in biological specimens revolutionizing how we view life today. Further, specific labeling of samples for imaging has provided insight into how life functions. This enabled label-based microscopy to percolate and integrate into mainstream life science research. However, the use of labelfree microscopy has been ... -
A probabilistic framework for source localization in anisotropic composite using transfer learning based multi-fidelity physics informed neural network (mfPINN)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-17)The practical application of data-driven frameworks like deep neural network in acoustic emission (AE) source localization is impeded due to the collection of significant clean data from the field. The utility of the such framework is governed by data collected from the site and/or laboratory experiment. The noise, experimental cost and time consuming in the collection of data further worsen the ... -
Stochastic modeling of blob-like plasma filaments in the scrape-off layer: Theoretical foundation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-25)A stochastic model for a superposition of uncorrelated pulses with a random distribution of amplitudes, sizes, and velocities is presented. The pulses are assumed to move radially with fixed shape and amplitudes decaying exponentially in time due to linear damping. The pulse velocities are taken to be time-independent but randomly distributed. The implications of a distribution of pulse amplitudes, ...