Search for Cosmic-Ray Events Using Radio Signals and CNNs in Data from the IceTop Enhancement Prototype Station

Cosmic-ray air showers emit radio waves that can be used to measure the properties of cosmic-ray primary particles. The radio detection technique presents several advantages, such as low cost and year-round duty cycle as well as the ability to provide high sensitivity to Xmax and energy estimation with minimal theoretical uncertainties, making it a promising tool for studying cosmic rays at the highest energies. However, the primary limitation of radio detection is the irreducible background from various sources that obscure the impulsive signals generated by air showers. To address this issue, we investigated the use of Convolutional Neural Networks (CNNs), trained on CoREAS simulations and radio backgrounds measured by a prototype station at the South Pole. We developed two different CNNs: a Classifier that distinguishes between cosmic ray event radio signals and pure background waveforms, and a Denoiser that mitigates background noise to recover the underlying cosmic-ray signal. After training the networks we apply them to the air-shower data to search for radio events. With two months data, we were able to identify 51 candidate events. The event’s arrival direction reconstructed using CNN denoised radio waveforms is found to bein good agreement with the IceTop reconstruction. Finally, our approach demonstrated improved directional reconstruction compared to traditional methods

Undersökande arbetssätt om aktuella frågor - en medicin som ger motiverade elever?

A problem which I have encountered is that many students are not interested or motivated by the school’s science. To stimulate motivation for science is one of my greatest challenges as a science teacher. The aim of this study was to investigate if inquiry- and context-based teaching can increase students’ motivation for science. In inquiry-based teaching, students are engaged in research inquiries by asking questions, planning and doing experiments, interpreting data and communicate their findings. By doing this, students will become more motivated and attain a deeper understanding of the nature of science (Driver et al., 1996). With context-based teaching, the topics which are addressed will have relevance for the students and/or the society. These topics may be socio-scientific issues, where the students use science while discussing and debating controversial subjects (Ekborg et al., 2013). Such questions are more likely to be meaningful, relevant and motivating for students. The study was conducted using questionnaires, in which the students answered to what extend they agreed or disagreed to a set of statements. The statements addressed students’ experiences of their science lessons. A total of 10 secondary school students (4 girls and 6 boys in year 8) participated in the study. Three different topics were addressed and evaluated; antibiotics, chemicals in the environment and microplasics. All these issues have been frequently appearing in Swedish media recently and have huge importance for people, environment and society. Further, the responses from these experimental lessons were compared to an ordinary science lesson. The results showed that inquiry-based teaching was perceived as positive by the students and suggests an increased interest in science. These findings are corroborated by previous studies (e.g. Chen & Cowie, 2013; Seraphin et al., 2013). The small sample size makes it hard to conclude more with certainty, but there are several tendencies, e.g. indicating positive influences on curiosity and critical thinking. Thus, there are still several questions which merit further research in this area. Especially the long term effects on motivation and interest, as well as the students’ ability to use their knowledge in other contexts or questions

When children have a say in comprehensive planning : Key learnings from three Swedish municipalities

Under flera decennier har barn fått stå tillbaka när städer har utvecklats utefter andra intressen. Barnkonventionen blev lag i Sverige år 2020 och efterföljdes av allmänna val år 2022. Därmed har det funnits anledning för många kommuner att revidera sina översiktsplaner och vid den revideringen arbeta med barns perspektiv och delaktighet. Frågan om barns perspektiv kan däremot urskiljas vara en utmaning för planerare på kommunerna. Denna studie har därför haft som syfte att undersöka hur kommuner kan arbeta med barns perspektiv i översiktlig planering för att skapa legitimitet för processen. Detta har gjorts genom att undersöka hur tre olika stora kommuner har gått till väga efter sina förutsättningar.  I studien har kommunernas dialograpporter och översiktsplaner studerats samt kompletteras med intervjuer av tjänstepersoner med inblick i processerna. Kommunernas arbete har därefter analyserats utifrån delaktighetsmodeller, olika synsätt på barn, planeringsteorier och en legitimitetsmodell.  Studien har visat att det råder stor skillnad i förutsättningarna för att hantera frågan i de tre undersökta kommunerna. Möjligheterna har varit störst i Göteborg, som märkbart också har haft en längre erfarenhet av att arbeta med frågan. I Lund har förutsättningarna varit något sämre och i Lysekil, som är den minsta av de tre kommunerna, har det funnits andra utmaningar som inte återfunnits i Göteborg och Lund. I Lysekil genomfördes ett arbete med barnkartor i GIS medan i Lund och Göteborg arbetades det främst med workshopar och dialoger för att få tillgång till barnens synpunkter. Slutsatser som kan dras från studien är att de planerande förvaltningarna på de studerade kommunerna har saknat rätt kompetenser för att arbeta med barn vilket har gjort stöttning utifrån vital. Rätt kompetens har antingen kunnat hittas inom andra förvaltningar eller inom andra pedagogiska institutioner inom kommunen. Samtidigt har det visat sig att det varit av stor vikt för att barns synpunkter skulle få genomslag i översiktsplanen, att personer på planavdelningarna varit direkt delaktiga i dialogerna med barn. När arbetet varit transparent, effektivt med återkoppling och översiktsplanen färgats av barns synpunkter har det inneburit en ökad nivå av delaktighet och legitimitet för de delaktiga barnen. Studien visar även att det finns ett syfte att åtminstone försöka driva processer med barns perspektiv då det kan bidra till högre ambitioner och mer kunskap oavsett utfall.For several decades, children have had to stand back when cities have developed according to the interests of other stakeholders. The Convention on the Rights of the Child became law in Sweden in 2020 and was followed by a general election in 2022, which means that municipalities have had reason to revise their comprehensive plans and include children's perspectives when doing so. Children's participation has however been shown to be something that urban planners find challenging. The objective of this study is to examine the manner in which municipalities can engage with children's perspectives in the context of comprehensive planning and create a legitimate process. To this end, the study will analyse how three municipalities of varying sizes have worked with children's perspectives within their comprehensive plan according to their different conditions. In the study a series of documents, concerning the work of municipalities with children’s perspectives within their comprehensive plan were examined and interviews with officials having insight into the processes were conducted. The work of municipalities has then been analysed based on models of participation, different approaches to children, planning theories and a model of legitimacy. The study indicates a discrepancy in the conditions and knowledge of working with children's perspectives within the comprehensive plan across the three municipalities. The opportunities have been greatest in Gothenburg, which has notably had more experience of working with the issue. In Lund, the conditions have been somewhat poorer. In Lysekil, which is the smallest of the three municipalities, there have been other challenges that were not found in Gothenburg and Lund. Lund and Gothenburg worked with children's perspective through dialogues and workshops, while Lysekil carried out the work by utilising the method children´s maps in GIS.  The findings of the study indicate that municipal planning departments often lack the requisite competence to work with children's perspectives. It can therefore be beneficial to seek support from other municipal departments with the necessary competence to pursue the work. However, the study also demonstrates involving planners in work with children's perspective, as essential to ensure that the children's opinions are taken into account in the plan. It is also shown to be of significance to reconnect with the participating children at a later stage, to elucidate which of their opinions were incorporated and which were not, as well as to provide an explanation for the rationale behind the decision-making process. The study also reveals that children's comprehension of the process and the rationale behind their inclusion is crucial. Furthermore, the study highlights the significance of establishing appropriate boundaries while maintaining a flexible approach. All these aspects are shown to be of utter importance in the work with children’s perspectives, in order to ensure legitimacy in the process and enhance the level of participation. The study also shows that there is a purpose to at least try to run processes with a children's perspective as it can contribute to higher ambitions and more knowledge regardless of the outcome.

When children have a say in comprehensive planning : Key learnings from three Swedish municipalities

Under flera decennier har barn fått stå tillbaka när städer har utvecklats utefter andra intressen. Barnkonventionen blev lag i Sverige år 2020 och efterföljdes av allmänna val år 2022. Därmed har det funnits anledning för många kommuner att revidera sina översiktsplaner och vid den revideringen arbeta med barns perspektiv och delaktighet. Frågan om barns perspektiv kan däremot urskiljas vara en utmaning för planerare på kommunerna. Denna studie har därför haft som syfte att undersöka hur kommuner kan arbeta med barns perspektiv i översiktlig planering för att skapa legitimitet för processen. Detta har gjorts genom att undersöka hur tre olika stora kommuner har gått till väga efter sina förutsättningar.  I studien har kommunernas dialograpporter och översiktsplaner studerats samt kompletteras med intervjuer av tjänstepersoner med inblick i processerna. Kommunernas arbete har därefter analyserats utifrån delaktighetsmodeller, olika synsätt på barn, planeringsteorier och en legitimitetsmodell.  Studien har visat att det råder stor skillnad i förutsättningarna för att hantera frågan i de tre undersökta kommunerna. Möjligheterna har varit störst i Göteborg, som märkbart också har haft en längre erfarenhet av att arbeta med frågan. I Lund har förutsättningarna varit något sämre och i Lysekil, som är den minsta av de tre kommunerna, har det funnits andra utmaningar som inte återfunnits i Göteborg och Lund. I Lysekil genomfördes ett arbete med barnkartor i GIS medan i Lund och Göteborg arbetades det främst med workshopar och dialoger för att få tillgång till barnens synpunkter. Slutsatser som kan dras från studien är att de planerande förvaltningarna på de studerade kommunerna har saknat rätt kompetenser för att arbeta med barn vilket har gjort stöttning utifrån vital. Rätt kompetens har antingen kunnat hittas inom andra förvaltningar eller inom andra pedagogiska institutioner inom kommunen. Samtidigt har det visat sig att det varit av stor vikt för att barns synpunkter skulle få genomslag i översiktsplanen, att personer på planavdelningarna varit direkt delaktiga i dialogerna med barn. När arbetet varit transparent, effektivt med återkoppling och översiktsplanen färgats av barns synpunkter har det inneburit en ökad nivå av delaktighet och legitimitet för de delaktiga barnen. Studien visar även att det finns ett syfte att åtminstone försöka driva processer med barns perspektiv då det kan bidra till högre ambitioner och mer kunskap oavsett utfall.For several decades, children have had to stand back when cities have developed according to the interests of other stakeholders. The Convention on the Rights of the Child became law in Sweden in 2020 and was followed by a general election in 2022, which means that municipalities have had reason to revise their comprehensive plans and include children's perspectives when doing so. Children's participation has however been shown to be something that urban planners find challenging. The objective of this study is to examine the manner in which municipalities can engage with children's perspectives in the context of comprehensive planning and create a legitimate process. To this end, the study will analyse how three municipalities of varying sizes have worked with children's perspectives within their comprehensive plan according to their different conditions. In the study a series of documents, concerning the work of municipalities with children’s perspectives within their comprehensive plan were examined and interviews with officials having insight into the processes were conducted. The work of municipalities has then been analysed based on models of participation, different approaches to children, planning theories and a model of legitimacy. The study indicates a discrepancy in the conditions and knowledge of working with children's perspectives within the comprehensive plan across the three municipalities. The opportunities have been greatest in Gothenburg, which has notably had more experience of working with the issue. In Lund, the conditions have been somewhat poorer. In Lysekil, which is the smallest of the three municipalities, there have been other challenges that were not found in Gothenburg and Lund. Lund and Gothenburg worked with children's perspective through dialogues and workshops, while Lysekil carried out the work by utilising the method children´s maps in GIS.  The findings of the study indicate that municipal planning departments often lack the requisite competence to work with children's perspectives. It can therefore be beneficial to seek support from other municipal departments with the necessary competence to pursue the work. However, the study also demonstrates involving planners in work with children's perspective, as essential to ensure that the children's opinions are taken into account in the plan. It is also shown to be of significance to reconnect with the participating children at a later stage, to elucidate which of their opinions were incorporated and which were not, as well as to provide an explanation for the rationale behind the decision-making process. The study also reveals that children's comprehension of the process and the rationale behind their inclusion is crucial. Furthermore, the study highlights the significance of establishing appropriate boundaries while maintaining a flexible approach. All these aspects are shown to be of utter importance in the work with children’s perspectives, in order to ensure legitimacy in the process and enhance the level of participation. The study also shows that there is a purpose to at least try to run processes with a children's perspective as it can contribute to higher ambitions and more knowledge regardless of the outcome.

Water in Crystals : A Database for ML and a Knowledge Base for Vibrational Prediction

Hydrate crystals are excellent reference systems to learnaboutaqueous systems. We have created a database of density functionaltheory (DFT)-optimized (optPBE-vdW) structures and vibrational frequenciesfor 101 crystalline hydrate and hydroxide bulk systems and over 300unique oscillators and use it to explore and discuss the tradeoffbetween prediction accuracy and insight. Starting from a machine-learninggeometrical descriptor, we gradually include more physics/chemistryflavor in the descriptor and examine how the frequency predictionpower varies. The most accurate models are the machine-learned model(of modest insight) and a physically motivated model containing theelectric field and field gradient. Furthermore, detailed comparisonswith experimental correlations show that, where available data exists,our DFT results largely overlap with the experiment. A small blind-testshowed that our machine-learned (ML) descriptor model can be usedto predict experimental vibrational frequencies based only on theexperimental structures and our best-regressed model, with encouragingresults

Predicting Frequency from the External Chemical Environment: OH Vibrations on Hydrated and Hydroxylated Surfaces

Robust correlation curves are essential to decipher structural information from IR-vibrational spectra. However, for surface-adsorbed water and hydroxides, few such correlations have been presented in the literature. In this paper, OH vibrational frequencies are correlated against 12 structural descriptors representing the quantum mechanical or geometrical environment, focusing on those external to the vibrating molecule. A nonbiased fitting procedure based on Gaussian process regression (GPR) was used alongside simple analytical functional forms. The training data consist of 217 structurally unique OH groups from 38 water/metal oxide interface systems for MgO, CaO and CeO2, all optimized at the DFT level, and the fully anharmonic and uncoupled OH vibrational signatures were calculated. Among our results, we find the following: (i) The intermolecular R(H···O) hydrogen bond distance is particularly strong, indicating the primary cause of the frequency shift. (ii) Similarly, the electric field along the H-bond vector is also a good descriptor. (iii) Highly detailed machine learning descriptors (ACSF, SOAP) are less intuitive but were found to be more capable descriptors. (iv) Combinations of geometric and QM descriptors give the best predictions, supplying complementary information

Water on ceria{111} : Comparison between 23 experimental vibrational studies in the literature and new modeling

Theoretical and experimental vibrational signatures of H2O and OH- (dissociated water) adsorbed on stoichiometric ceria{111} surfaces are compared. The experimental ones were collected from low-coverage experiments in the literature, and the theoretical anharmonic frequencies were generated using density functional theory calculations employing the optPBE-vdW functional for coverages from 0.5 to a few monolayers. It is found that (i) the experiments and our calculations overall agree well, lending credibility to both; (ii) the calculations manage to resolve the large class of H-bonded motifs into frequency classes that can guide experimental assignments; (iii) it is possible to find a geometrical H-bond definition that also captures the OH vibrational frequency downshifts well: R(H center dot center dot center dot O) <= 2.5 angstrom and the O-H center dot center dot center dot O angle theta >= 100 degrees; and (iv) the frequency vs electric field relations for water and hydroxides (i.e., dissociated water) follow different and well-separated curves

The water/ceria(111) interface : Computational overview and new structures

Thin film structures of water on the CeO2(111) surface for coverages between 0.5 and 2.0 water monolayers have been optimized and analyzed using density functional theory (optPBE-vdW functional). We present a new 1.0 ML structure that is both the lowest in energy published and features a hydrogen-bond network extending the surface in one-dimension, contrary to what has been found in the literature, and contrary to what has been expected due to the large bulk ceria cell dimension. The adsorption energies for the monolayer and multilayered water structures agree well with experimental temperature programmed desorption results from the literature, and we discuss the stability window of CeO2(111) surfaces covered with 0.5-2.0 ML of water.

Environmental, nutritional and endocrine regulation of metabolic processes in fish

Due to seasonal variations in temperature and food availability, fish in temperate regions should be able to make metabolic adjustments to ensure that enough energy is available for the maintenance of basal processes. The major aim of this thesis was to elucidate how the physiology and lipid metabolism of salmonid fish is affected by temperature and food availability, and to clarify aspects of the endocrine control of lipid metabolism. In this thesis, the effects of increased temperature or reduced food availability were studied in salmonids by employing a non-prejudiced metabolomics approach to assess the physiological responses. Detailed information on the abundance of specific amino acids, lipid classes, fatty acids and other metabolites in tissue extracts and plasma was obtained by nuclear magnetic resonance (NMR) based metabolomics. NMR-based metabolomics were successfully employed and proved to be applicable to studying metabolic fluxes in fish, providing data on novel and integrated responses. The results show similar changes in lipid metabolism during food deprivation and elevated temperature. The observed responses included increased plasma very-low-density lipoprotein (VLDL) and unsaturated fatty acids (FAs) concurrent with decreased high-density lipoprotein (HDL) and choline. The changes during starvation also involved changes in amino acids and glycogen that indicate that amino acids are used for gluconeogenesis in the liver to preserve glycogen stores. Growth hormone (GH) has both lipolytic and lipogenic effects. To further elucidate the mechanisms of GH action on salmonid lipid metabolism, the effects of GH in vivo on the transcription of several key lipid metabolism enzymes in various tissues were investigated. GH inhibited the hepatic expression of lipoprotein lipase (LPL) thereby decreasing hepatic lipid uptake. Hormone-sensitive lipase (HSL) mRNA expression was not increased by GH in any of the studied tissues, suggesting that the well-known GHinduced lipolysis is regulated on posttranslational levels in rainbow trout. The regulation lipid metabolism in salmonids was further investigated by studying direct effects of FAs and ghrelin on freshly isolated cells from mesenteric adipose tissue and liver. FAs elicited acute negative effects on lipid storage by decreasing lipid uptake via LPL activity in adipose cells as well as by stimulating lipolysis of stored triglycerides (TG) in liver cells. Together the results presented in this thesis shows that elevated, suboptimal temperature and nutritional may have propound effects on important processes as growth, food intake and the metabolome of salmonid fish, and may lead to a negative energy balance. Metabolic changes may be mediated by hormonal and nutrient factors acting at gene expression or enzyme activity level. The results may contribute to better understand lipid deposition patterns in farmed fish and potential effects of climate change on salmonids in the wild and in aquaculture