Publikationer från Uppsala Universitet
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Stress och psykisk ohälsa bland unga universitetsstudenter i Sverige och Europa : En systematisk litteraturstudie
No full textTelecom Light-Emitting Diodes Based on Nanoconfined Self-Assembled Silicon-Based Color Centers
No full textSilicon color centers (SiCCs) have recently emerged as potential building blocks for light emitters in Si photonics, quantum emitters with spin storage capabilities, and Si-based quantum repeaters. We have recently developed a noninvasive method to engineer carbon-related SiCCs confined to ultrathin nanolayers within a pristine crystalline environment, which is of utmost importance for the photostability of SiCCs. Here, we demonstrate embedding these C-doping-based SiCCs into the only 9 nm wide intrinsic region of a p-i-n diode using the epitaxial self-assembly of color centers. We report electrically pumped light emission with an exponential increase in the intensity as a function of the driving current until saturation. We associate this property with the shift of quasi-Fermi-level position upon electrical driving, which simultaneously improves the spectral homogeneity of the engineered SiCCs. Despite the low employed growth temperatures, our study demonstrates the electrical control and driving of near-infrared emitters in high-quality silicon diodes, an essential milestone for advancing classical and quantum optoelectronics
Biostratigraphy and correlation of the Cambrian Series 2 (Stage 4) to Miaolingian (Wuliuan) Thorntonia Limestone, south-eastern Georgina Basin (Queensland, Australia)
No full textThe Australian Cambrian stratigraphic record is one of the most complete for any continent. However, there is a general division, with older Cambrian rocks in South Australia (predominantly Terreneuvian, Stage 2 to Miaolingian, Wuliuan) and younger rocks in northern Australia (mostly latest Series 2, Stage 4 and younger), with minimal stratigraphic overlap. The recently ratified boundary between Cambrian Series 2 and Miaolingian occurs in the interval of overlap between these successions, hence investigation of these levels is a priority. The successions in the southern and eastern parts of the Georgina Basin (Queensland and Northern Territory) underpin the Cambrian biostratigraphy of northern Australia. Therefore, targeted, multi-proxy work on these successions is important for developing a fully resolved Australian Cambrian chronostratigraphy. Here we present new insights into this critical interval via biostratigraphic analysis of the Thorntonia Limestone (shown to span the Cambrian Series 2 - Miaolingian boundary) in three recently drilled core holes near Boulia, Queensland, in the south-eastern Georgina Basin. A diverse fossil fauna (>50 species) is described from these cores, including biostratigraphically important trilobites, agnostids, brachiopods, bradoriids, echinoderms, hyoliths, molluscs, sponges and other small shelly fossils (SSFs). These show affinities with Australian Ordian (late Stage 4) to Templetonian (Wuliuan) faunas, with a potential Floran (early Drumian) interval in the uppermost Thorntonia Limestone. Many SSF taxa recovered from the Thorntonia Limestone show close affinities with other East Gondwanan assemblages from North China and Antarctica in particular, as well as with assemblages from Laurentia, Siberia, South China, Kazakhstan, the Himalaya and West Gondwana
Power for progress : The impact of electricity on individual labor market outcomes
No full textHow does new technology impact labor market outcomes? We address this question by examining the adoption of electricity in Sweden during the early 20th century. Leveraging detailed individual-level data that covers the entire labor market and exogenous variation in electricity access driven by proximity to hydro-power plants, we estimate the impact of electrification on individual labor market outcomes. Our findings show significantly higher earnings in electricity-adopting parishes compared to control areas. The income gains were particularly pronounced among lower-income workers and those with primary education only, resulting in reduced income inequality. These effects held across labor markets with both strong and weak union presence, suggesting that electricity functioned as a labor-supporting technology. Our results highlight how specific technologies can shape individual outcomes and income distributions
Reduction of negative charge in mercaptoacetyl-based chelators influences the biodistribution of prostate-specific membrane antigen-targeting pseudopeptides labeled with technetium-99m
No full textProstate cancer (PCa) is the most common cancer and the second leading cause of death among men worldwide. Significant progress has been made in managing PCa by targeting the prostate-specific membrane antigen (PSMA), which holds great promise for improving the accuracy and effectiveness of diagnosis. Previously, we reported a high-affinity glutamate-urea-lysine (EuK)-based PSMA-targeting tracer, BQ0413, containing the maE3 chelator for labeling with technetium-99m for single-photon emission tomography diagnostic imaging. BQ0413 demonstrated efficient tumor targeting in PCa patients with concomitant elevated activity retention in the kidneys, which is typical for EuK-based PSMA-targeting tracers. We hypothesized that a decrease in the tracer's total negative charge, by substituting negatively charged glutamate residues in the maE3 chelator with polar neutral serine, could decrease activity retention in the kidneys. The present study aimed to evaluate the tumor targeting and biodistribution profile of two new PSMA-targeting tracers, BQ0500 (maESE) and BQ0501 (maS3), in comparison to BQ0413 (maE3). Conjugates were successfully radiolabeled with technetium-99m and characterized in vitro and in vivo. [99mTc]Tc-BQ0500 and [99mTc]Tc-BQ0501 demonstrated PSMA-specific binding to PC3-pip cells with picomolar affinity; however, the affinity was 3-5-fold compromised in comparison with the reference [99mTc]Tc-BQ0413. Full replacement of glutamate residues by serines in [99mTc]Tc-BQ0501 resulted in an improved overall clearance from normal organs with a moderately increased accumulation of activity in the gastrointestinal tract. [99mTc]Tc-BQ0501 demonstrated efficient tumor targeting and improved tumor-to-background ratios. These results suggest that chelator modifications, such as charge alteration, play a critical role in improving tumor targeting and pharmacokinetics for EuK-based PSMA-targeting tracers
Disruption of Planetary System Architectures by Stellar Flybys
No full textWe investigate the survivability of solar system-like planetary systems during close encounters in stellar associations using a suite of 1980 N-body simulations. Each system is based on one of the possible five-planet resonant configurations proposed to represent the initial solar system architecture and is systematically scaled in both planetary mass and orbital compactness to explore the parameter space of observed exoplanetary architectures. Simulations explore a range of stellar encounter scenarios drawn from four distinct cluster environments. Our results show that system survival depends critically on the interplay between planetary mass and orbital scale: compact configurations are more resistant to external perturbations, while increased planetary mass improves resilience only up to a threshold, beyond which internal instabilities dominate. No system whose planets are twice as massive as the ones in the solar system survives stellar encounters. Systems that are at least an order of magnitude more compact than the solar system remain stable under typical encounter conditions. These findings place strong constraints on the initial architectures of planetary systems that can endure stellar-dense birth environments
A de novo metalloenzyme for hydrogen evolution : Enzyme design in human hands
No full textThe climate is changing and we need new, sustainable energy systems to stymie the release of CO2-equivalents in the atmosphere which cause global warming which is the root of it all. Sustainable energy sources are abundant, including wind and solar, and we are adept at using them. They are however transient, and storage for times when there is no wind or sun is required. Batteries are commonly used, but it is not always a practical solution, especially not for upscaled energy storage. Producing fuels from sustainable electricity is a crucial puzzle piece in the energy systems of the future, and one such fuel is hydrogen gas (H2). The current production of H2 is unsustainable, leading to massive release of CO2. This thesis aims to provide insight into a sustainable method for H2 production using biomimetic compounds to create a de novo metalloenzyme for hydrogen evolution. The cobalamin-mimicking catalyst cobaloxime has been combined with the de novo protein α3C, forming the de novo metalloenzyme Co-MePy-α3C. Cobaloxime is a thoroughly studied catalyst, and it has previously been applied to make artificial metalloenzymes for hydrogen evo-lution by combining it with natural protein scaffolds. The protein α3C is a fully de novo protein and was designed to be structurally robust and redox-inert at biologically relevant conditions. By circular dichroism (CD) spectroscopy it was found that the protein portion of Co-MePy-α3C is structurally distinct from α3C. By electron paramagnetic resonance (EPR) spectroscopy the cobaloxime in Co-MePy-α3C was confirmed to coordinate to the protein scaffold. The hydrogen evolution reaction (HER) by cobaloxime and Co-MePy-α3C were characterised using two reduction strategies: by chemical reduction using [Eu(EGTA)]2− and by photosensitisation using [Ru(bpy)3]2+, ascorbate and light. The initial rate of hydrogen evolution and the turnover number (TON) of the hydrogen evolution reaction (HER) by the two complexes were calculated, and it was found that the TONs of Co-MePy-α3C are mildly perturbed compared to that of cobaloxime (80-90% of the cobaloxime TON). The initial rates when using photosensitisation remain unchanged, but with chemical reduction it is reduced to less than half of that of cobaloxime (ca 40%). This lowering of rate is likely due to the insulating effect of the protein scaffold on the catalyst, slowing the rate of transfer of protons and electrons to it. The effect is not visible when using photosensitisation as the reducing equivalents are produced slowly over several hours, which slow the reaction down significantly for both cobaloxime and Co-MePy-α3C, resulting in matched rates. By cyclic voltammetry (CV) the mechanism of electrocatalytic HER by cobaloxime and Co-MePy-α3C was investi-gated. A pH-dependence study was conducted to characterise the process taking place in a reducing peak that appear at ca −0.9 V vs normal hydrogen electrode (NHE) for both Co-MePy-α3C and cobaloxime. The calculated pH-de-pendencies suggest that a 1 H+/1 e− process is taking place at this potential. Comparing with previously suggested mechanisms it is likely the reduction of the cobaloxime Co(II) to Co(I), coupled with the protonation to Co(III)–H, but further studies are necessary to ascertain precisely the process giving rise to the reducing peak at −0.9 V vs NHE. Future studies on Co-MePy-α3C include a foot of the wave analysis (FOWA) of the cyclic voltammograms to deter-mine initial rates of electrocatalytic HER by Co-MePy-α3C and cobaloxime. To conclude, Co-MePy-α3C has been shown to act as a de novo enzyme for hydrogen evolution, and the effect on the incorporation of a catalyst into a de novo protein scaffold has been characterised. Further studies to characterise the electrocatalytic HER by Co-MePy-α3C are planned, but initial data suggests that it behaves similarly to cobaloxime, as evidenced by comparison with previously published data
Euclid preparation : LXVII. Deep learning true galaxy morphologies for weak lensing shear bias calibration
No full textTo date, galaxy image simulations for weak lensing surveys usually approximate the light profiles of all galaxies as a single or double S & eacute;rsic profile, neglecting the influence of galaxy substructures and morphologies deviating from such a simplified parametric characterisation. While this approximation may be sufficient for previous data sets, the stringent cosmic shear calibration requirements and the high quality of the data in the upcoming Euclid survey demand a consideration of the effects that realistic galaxy substructures and irregular shapes have on shear measurement biases. Here we present a novel deep learning-based method to create such simulated galaxies directly from Hubble Space Telescope (HST) data. We first build and validate a convolutional neural network based on the wavelet scattering transform to learn noise-free representations independent of the point-spread function (PSF) of HST galaxy images. These can be injected into simulations of images from Euclid's optical instrument VIS without introducing noise correlations during PSF convolution or shearing. Then, we demonstrate the generation of new galaxy images by sampling from the model randomly as well as conditionally. In the latter case, we fine-tune the interpolation between latent space vectors of sample galaxies to directly obtain new realistic objects following a specific S & eacute;rsic index and half-light radius distribution. Furthermore, we show that the distribution of galaxy structural and morphological parameters of our generative model matches the distribution of the input HST training data, proving the capability of the model to produce realistic shapes. Next, we quantify the cosmic shear bias from complex galaxy shapes in Euclid-like simulations by comparing the shear measurement biases between a sample of model objects and their best-fit double-S & eacute;rsic counterparts, thereby creating two separate branches that only differ in the complexity of their shapes. Using the Kaiser, Squires, and Broadhurst shape measurement algorithm, we find a multiplicative bias difference between these branches with realistic morphologies and parametric profiles on the order of (6.9 +/- 0.6)x10(-3) for a realistic magnitude-S & eacute;rsic index distribution. Moreover, we find clear detection bias differences between full image scenes simulated with parametric and realistic galaxies, leading to a bias difference of (4.0 +/- 0.9)x10(-3) independent of the shape measurement method. This makes complex morphology relevant for stage IV weak lensing surveys, exceeding the full error budget of the Euclid Wide Survey (Delta mu(1, 2) < 2 x 10(3))
“De är coola, de är smarta, de är mäktiga – de är mammor” : En retorisk analys av dygder i “Årets Mama” 2004–2025
No full textSyftet med denna uppsats är att synliggöra att ett idealt moderskap framställs genom tidningen Mamas pris “Årets mama”. För att uppnå detta syfte analyseras de dygder som framkommer i texterna. I uppsatsen granskas även om framställningen av det ideala moderskapet förändras över tid och i sådana fall hur
Att bo i höghus : Familjer och barns vardagsliv i den täta staden
No full textAtt skapa täta städer har varit en central strategi för att arbeta med urban hållbarhet, vilket resulterat i att allt fler familjer bor i flerbostadshus. Forskning visar samtidigt på samband mellan täta stadsmiljöer och barns minskade mobilitet och utomhuslek. Rapporten presenterar resultaten från forskningsprojektet Hållbara vertikala barndomar? Familjers lägenhetsboende och barns vardagsmobilitet och lek som har analyserat familjers vardagsmobilitet och lek i tre olika bostadsområden i Uppsala i Sverige. En central utgångspunkt har varit att utforska urban hållbarhet utifrån ett vardagslivsperspektiv. Det övergripande syftet har varit att undersöka hur familjer med barn upplever boende i flerbostadshus i områden med olika arkitektoniska ideal och struktur, hur de organiserar sin vardag med tanke på barns lek, och hur de rör sig i sin bostad, på bostadsgården och i bostadsområdet. Var och hur leker barnen? Var, hur och med vem rör sig barnen i bostaden eller bostadsområdet? Projektet baseras på kvalitativa metoder och utgår ifrån teorier om urban hållbarhet, mobilitet samt familjers tidsrumsliga organisation. En central ambition är att visa hur samhällsplanering genomsyras av sociala och kulturella föreställningar om vardagslivet och vilka behov människor har. Vi tar avstamp i att det finns en relation mellan planeringsideologi och hur den materialiseras i den byggda miljön. Vi menar att det finns en tydlig koppling mellan områdenas fysiska struktur och vilka möjligheter och hinder som miljön innebär för familjernas vardagsmoblitet och barnens möjlighet att röra sig och leka i sina bostadsområden. Ett tydligt resultat är att det täta stadsidealet medför betydande inskränkningar för barn när det gäller deras lek, vardagsmobilitet och utevistelser. En tydlig slutsats är också att de långtgående byggprocesser som förtätningen och byggande av nya stadsdelar medför har en tydlig påverkan på både familjers och barns upplevelser av bostadsområdet både ur trivsel- och trygghets- och säkerhetsaspekter. I rapporten lyfter vi fram ett alternativ till förtätning som planeringsideal, nämligen omhändertagande boendemiljöer. Vi menar att idén om omhändertagande boendemiljöer flyttar fokus från den byggda miljön till relationen mellan den byggda miljön och invånarna. Omhändertagande boendemiljöer stöttar invånarnas vardagsliv samtidigt som invånarna har möjlighet att justera, anpassa och omforma den byggda miljön i takt med att vardagslivet förändras