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Snow Mass Recharge of the Greenland Ice Sheet Fueled by Intense Atmospheric River
Get PDFAtmospheric rivers (ARs) have been linked with extreme rainfall and melt events across the Greenland ice sheet (GrIS), accelerating its mass loss. However, the impact of AR-fueled snowfall has received less attention, partly due to limited empirical evidence. Here, we relate new firn core stratigraphy and isotopic analyses with glacio-meteorological data sets from SE Greenland to examine an intense AR in mid-March 2022. We demonstrate that the associated snowfall—up to 11.6 gigatons d−1—delayed summer melt onset by11-days and offset Greenland's 2022 net mass loss by 8%. Since 2010, our synoptic analysis reveals that snow accumulation across SE Greenland increased by 20 mm water equivalent a−1, driven by enhanced Atlantic cyclonicity. We find that the impact of ARs on the GrIS is not exclusively negative and their capacity to contribute mass recharge may become increasingly significant under ongoing Arctic amplification and predicted poleward intrusion of mid-latitude moisture
Regulated Power Supply with High Power Factor for Hyperspectral Imaging Applications
Get PDFIllumination is a crucial factor in hyperspectral imaging systems. In this respect, this work is focused on analyzing the influence of the light power source in acquiring hyperspectral images. To this end, a custom regulated power supply was designed and developed. This power supply was then integrated into a hyperspectral acquisition system, and several light stability measurements were conducted. Finally, several parameters related to the stability of the light produced by those systems were extracted using image analysis techniques, and a statistical comparison among the different power supplies was performed. Two commercial power supplies were also analyzed under the same experimental conditions and compared with the proposed power supply. The hyperspectral measurements were conducted using light transmission and reflectance. The results indicate that the proposed power supply performs better than or at least as well as commercial power supplies in terms of light stability. Additionally, this study shows the impact of power supply design on the stability and quality of hyperspectral illumination, especially concerning the signal-to-noise ratio (SNR) across different spectral bands. It is shown that optimizing the design of the power supply could improve light stability in hyperspectral imaging applications
Mothers` experience with transitions in the process towards neonatal digital homecare
Get PDFObjective - This study aimed to explore mothers` experiences with transitions from the neonatal intensive care unit (NICU) to digital homecare.
Methods - Semi-structured, in-depth interviews were conducted with five mothers whose preterm infants had received digital homecare from a NICU in Norway. All interviews were conducted through video call due to COVID-19 safety restrictions. Interview transcripts were analysed using Tjora's stepwise deductive inductive method. Meleis' Transition Theory provides the theoretical framework for this analysis.
Results - The study identifies two critical transitions. The informants experienced specific conditions that affected the transitions, resulting in varying perceptions of whether the transitions towards digital homecare were good and, subsequently, whether the transitions were health-promoting, such as coping with the parental role. Three themes emerged: (1) the need for ongoing information, (2) relational continuity, and (3) defined roles.
Conclusions - Mothers in the NICU undergo a complex and multifaceted transition as they assume the responsibilities of independent caregivers while simultaneously managing the various situational shifts within the unit and the progression toward early discharge. Given the challenges inherent in this process, healthcare professionals must prioritize comprehensive support throughout each phase, ensuring an optimal and well-coordinated transition
Ultrasound & Photoacoustic Microscopy for Biomedical Applications
Get PDFUltrasound and photoacoustic microscopy hold great promise for deep tissue imaging with high resolution, offering different applications in biological research. The primary aim of this thesis is to perform correlative photoacoustic and ultrasound microscopy experiments on various biological samples.
This thesis discusses multiple imaging modes, including A-scan, B-scan, and C-scan, each offering an unique perspectives on the sample data visualization. This includes the development of a novel approach to combine and visualize SAM (Scanning Acoustic Microscopy) and PAM (Photoacoustic Microscopy) data simultaneously, using tailored color and transparency mappings. Advanced visualization tools like MATLAB and 3D Slicer were also employed for biomedical image processing, enabling the integration of multiple datasets for comprehensive 3-D rendering. This approach reveals the concentration and distribution of pigment map has been revealed as 3-D PAM image. The integration of SAM and PAM images on top of each other gives a comprehensive visualization method and it can be explored for further studies such as effects of seasons, effect of any external stimuli on the pigments or studying several diseases, which affects the pigments. The pigment can also be quantified using photoacoustic microscopy and this can provide insights about stress levels and overall health of marine species.
Different applications in plant biology harnessing the endogenous pigment anthocyanin have been explored such as blueberry, rhubarb, Drosera capensis using PAM and SAM. We experimented with multilayered agarose embedding for microparticles, which aims to create a boundaryless medium and reduce signal artifacts. For samples like salmon skin and shrimp shells, a 'lifted samples' technique using polyamide thin film was employed. We also present a multi-layered method of sample preparation where the majority of microparticles are lifted, floating, and almost lying in the same plane. Overall, the emphasis is on consistency in preparation methods to ensure reproducibility across experiments. Although, this imaging modalities has been applied for applications related to human beings for example blood oxygenation but has not been applied to marine biology and botanical applications. Different pigments such as anthocyanin and astaxanthin have not been explored using this microscopy technique.
The research results are presented in four original scientific papers. Paper I focuses on the acoustic imaging where coded waveforms such as Ricker and chirp waves are used, and a performance comparison is made on different parameters for a commercial polyvinylidene fluoride (PVDF) and in-house fabricated poly (vinylidene fluoride-trifluoro ethylene) also known as P(VDF-TrFe) transducer. B- and C-scan images were obtained from the recorded time series and several parameters such as resolution, signal-to-noise-ratio, point spread function and depth imaging capabilities of both the transducer were compared. In Paper II, laser generated ultrasound for polystyrene microspheres of different sizes was performed in our lab. The COMSOL simulation for the experimental setup where all the components involved in light delivery to acoustic detection was simulated. The experimental and simulation results were in close agreement with each other. The presence of Scholte wave was detected both experimentally and in simulation. The Eigenvalues in the frequency spectrum aligned in a close agreement in both the frequency spectrums. In Paper III, the estimation of hardness using thin films calibration where a reflection coefficient is found out and utilized it for finding the hardness of the shrimp shells is shown. as to the best of our knowledge, we have used ultrasound to estimate the acoustic impedance of shrimp’s shell for the first time. Astaxanthin pigment has been used for an endogenous contrast agent in shells and antennae in PAM image generation. This work is, to our understanding, the first experimental application of PAM for shrimps. This thesis is a step forward in PAM’s potential in imaging of marine organisms. Paper IV discusses the application of SAM and PAM for salmon skin. Ultrasound and photoacoustic images are overlayed on top of each other with a tailored colormap and alpha map in MATLAB. The 3-D mapping reveals the concentration and density of the pigments from three different datasets. A comparison of PAM and optical image is shown showing high resolution imaging with deep penetration depth. A histogram for calculation of voxels contributing to the PAM and SAM signal is shown.
The unique ability of PAM for providing morphological and functional information paves the way for understanding the complex marine organism interactions. This thesis studies different approaches of sample preparation, building an experimental setup, simulating the experiments, analyzing the data and visualization for different SAM and PAM applications
Symbolic-AI-fusion deep learning (SAIF-DL): Encoding knowledge into training with answer set programming loss penalties by a novel loss function approach
Get PDFThis paper presents a hybrid methodology that enhances the training process of deep learning (DL) models by embedding domain expert knowledge using ontologies and answer set programming (ASP). By integrating these symbolic AI methods, we encode domain-specific constraints, rules, and logical reasoning directly into the model’s learning process, thereby improving both performance and trustworthiness. The proposed approach is flexible and applicable to both regression and classification tasks, demonstrating generalizability across various fields such as healthcare, autonomous systems, engineering, and battery manufacturing applications. Unlike other state-of-the-art methods, the strength of our approach lies in its scalability across different domains. The design allows for the automation of the loss function by simply updating the ASP rules, making the system highly scalable and user-friendly. This facilitates seamless adaptation to new domains without significant redesign, offering a practical solution for integrating expert knowledge into DL models in industrial settings such as battery manufacturing
Emplacing watery encounters: listening, care, and embodied knowledge for sustainable climate futures
No full textThe climate crisis is full of marginalized human and more-than-human voices who are systematically silenced by solution-oriented, universalizing discourses. Listening as method is the opposite of silencing; it is an experiential form of knowledge production that conveys intention and care when done cautiously. We posit climate studies can learn from feminist listening practices how to listen rather than silence. Reviewing relevant theory and case studies, we situate listening among diverse actors as becoming-in-common in-place through sound, with a focus on Arctic waters. Heightened awareness of acoustic ecologies internalizes sound to place, affecting our understanding of possible actions to enable sustainable climate futures
On the Future of Arctic Sea Ice - Projections, Dynamics, and Human Impacts
Get PDFArctic sea ice (ASI) is a critical component of the Earth’s climate system, serving as both a regulator of energy exchange and a sensitive indicator of climate change. Over recent decades, ASI has experienced a dramatic decline in both extent and thickness, driven by rising global temperatures and amplified by Arctic feedback mechanisms. This decline is a key driver of Arctic amplification, a phenomenon where the Arctic region warms nearly four times faster than the global average. The consequences of this rapid warming extend beyond the Arctic, affecting local ecosystems, global climate systems, and human activities. Despite significant advances in observational tools and climate modeling, projecting the future of ASI remains challenging due to the complex interplay of feedback mechanisms and increasing variability in the ice cover. Even the most advanced models in the latest phase of the Coupled Model Intercomparison Project (CMIP6) show significant discrepancies in predicting the timing and temperature threshold of complete ASI loss, highlighting the challenges of accurately representing ASI dynamics. The scope of this thesis is to investigate the future of ASI through three interconnected studies. The first study develops an observation-based projection of the September ASI area — the time of year when ASI extent reaches its annual minimum — revealing an accelerated decline in response to rising global mean temperatures. Our results narrow the spread found in CMIP6 model predictions, placing the complete loss of September ASI cover (area below 1 million km2) between 1.5°C and 2.2°C above pre-industrial levels. The second study investigates the variability in year-to-year fluctuations of the September ASI area across models participating in CMIP6, under varying levels of greenhouse gas emissions. It identifies a consistent pattern of increasing variability as ASI nears complete loss, with the most pronounced effects observed in the Central Arctic. These findings suggest a loss of stability in this historically stable region as ASI decline progresses, highlighting a shift in Arctic dynamics. Lastly, the third study explores the effects of black carbon emissions from Arctic shipping, an activity that is growing rapidly in response to the decline in ASI cover. It compares the impacts of two major maritime routes — the Northern Sea Route and the Transpolar Sea Route — on ASI, revealing regionally distinct changes in ASI reflectivity between the two pathways and underscoring the importance of careful planning for anthropogenic activities in the region
Indigenous Cultural Rights, the Green Transition, and the Right to a Healthy Environment
Get PDFPhasing out fossil fuels in favour of renewable energy is essential to mitigating human-induced climate change. However, this transition also poses challenges. One of them is that infrastructure for renewable energy production, such as wind and hydropower, can significantly impact Indigenous peoples’ cultural rights.
In the Fosen case, the Supreme Court of Norway recognized that fundamental rights, such as the right to a healthy environment, in specific situations may be weighed against Indigenous cultural rights. This article examines the scope for such balancing and possible interventions, analysing relevant case law and human rights principles.
It concludes that the necessity requirement within the principle of proportionality,
along with protections established by UN monitoring bodies for Indigenous cultures,
leaves limited room for restricting Indigenous cultural rights in favour of competing
interests
Investigating laser-induced bond breaking in high density polyethylene pyrolysis
No full textA particular laser harmonic with an effective combination of process parameters can break plastic bonds by surpassing the dissociation threshold. Exploring this direction is imperative to uncover new physics and chemistry related to laser-high-density polyethylene (HDPE) interactions and to understand the phenomena occurring during laser induced degradation. An experiment was conducted in an open-air environment using the first (1064 nm), second (532 nm), and fourth (266 nm) harmonics at a 20 Hz repetition rate, with pulse energies of 5–40 mJ for the first and second harmonics, and 3–10 mJ for the fourth harmonic. The findings revealed that all laser harmonics broke HDPE bonds, with the fourth harmonic being the most effective in directly breaking bonds, particularly C–H bonds, which was evident from a prominent Ha peak at 656.3 nm. The results demonstrate initial, partial, and post-bond breaking, which can address deficiencies in laser-HDPE recycling and enable laser-induced HDPE pyrolysis, which has not been investigated. Optical microscopic analysis showed that craters formed by the fourth harmonic were wider and exhibited more efficient photon absorption with minimal ablation. Additionally, a high confidence interval (R2) value of 0.9758 with increased electron density and plasma temperatures, further supports the efficiency of bond breaking
Innenforskapet i Utenforskapet: en kvalitativ studie om utenforskap, og forebyggingsarbeidets potensielle forbedring
Get PDFDet er gjort mye forskning på utenforskap de siste årene. Men lite på spesifikt utenforskaps begrepet, og hva utenforskap betyr for samfunnet, og spesielt i forhold til de unge individene. Når det tidligere er gjort forskning på utenforskap, har denne tatt for seg enkeltstående av de flere problemene under samlingsbegrepet utenforskap. Jeg ønsket derfor i denne oppgaven å se på utenforskap som et samlingsbegrep, som tar opp forskjellige samfunnsproblem som ungdom kan møte gjennom livet. Slik som kriminalitet, rus, ensomhet, psykisk uhelse, stigmatisering, sosial stempling, skolevegring, atferdsproblematikk, press, og lignende problemer. Det jeg da ønsket å se på er hvordan man effektivt kan forebygge for redusere disse problemene. Og finne bakgrunnen for at unge mennesker velger de negative miljøene i stedet for de positive.
I dette studiet ble benyttet en kvalitativ tilnærming for å undersøke dette fagfeltet. Metoden som ble brukt var semistrukturerte intervju. Prosessen tok for seg å intervjue sju informanter som jobber med ungdom på forskjellige arenaer, med mye og forskjellig erfaring. Ved hjelp av utsagn fra deres erfaringer og kunnskap, sammen med det teoretiske rammeverket fra Bourdieu som har et konfliktteoretisk perspektiv, Becker og Goffman som bruker sosial internasjonalisme, og Putnams sosiale kapital som er et funksjonalistisk ståsted, er det prøvd å finne forslag til en bedre og mer effektiv måte å forebygge disse samfunnsproblemene. Ved å koble sammen disse teoretiske tilnærmingene vil man få et sosialkonstruktivistisk perspektiv på utenforskap som samfunnsproblem. Det vil gi svar på hvordan utenforskap oppstår, samt hvordan man kan effektivisere og optimalisere forebyggendearbeid på både et lokalt og nasjonalt nivå.
Funnene i denne oppgaven ser på flere faktorer som kan forårsake utenforskap. Der informantene har snakket om eksempler fra deres opplevelser, og erfaringer i deres arbeid med ungdom. Samt også gitt deres meninger om forbedringer og utfordringer innenfor arbeidet med å forebygge og redusere utenforskap i seg selv, samt de samfunnsproblemene som er en del av utenforskapsfølelsen. Til slutt er utsagnene til informantene diskutert opp mot det teoretiske rammeverket, og forskning på nasjonalt og internasjonalt nivå