Extragalactic transients, such as gamma-ray bursts (GRBs), represent the most energetic phenomena in the Universe. They are characterized by their intense radiation within short timescales. In recent years, significant advances have been made in understanding the emission mechanism of GRBs, with the detection of very-high-energy (VHE; >100 GeV) gamma rays. These observations have improved our understanding of VHE gamma-ray emissions in such extreme environments. So far, five GRBs have been detected in VHE gamma rays, intensifying the search for more such detections. The observation of extragalactic sources in VHE gamma rays is challenging due to extragalactic background light (EBL) absorption, which results in softening the source spectrum to energies below a few TeV.

To address these challenges, the ALTO/CoMET R&D project is proposed. This project aims to design a wide field-of-view observatory to observe soft-spectrum sources continuously in VHE gamma rays. To achieve this goal, a dedicated Monte Carlo simulation study is conducted to optimize the configuration of the proposed detectors. An important part of the simulation study is the development of an analysis method called SEMLA (Signal Extraction using Machine learning for ALTO/CoMET), which enables the proposed array to detect gamma rays at energies down to a few hundred GeV. The results from the simulated data analysis demonstrate that ALTO/CoMET is capable of detecting extragalactic transients like GRBs. 

This thesis presents the analysis methods developed, and the results obtained from the ALTO/CoMET R&D project in detecting extragalactic transients, with a focus on GRBs. The lessons learned from these ALTO/CoMET simulation studies and prototype activities are useful for other future extensive air shower detectors, concerning the observation of soft-spectrum VHE gamma-ray sources.

Additionally, the search for GRB emission is explored using the H.E.S.S. array, analysing follow-up observations of GRBs recorded from its construction in 2004 until 2019 (excluding the two significantly detected GRBs by H.E.S.S.).

Microalgal solutions use microalgae, photosynthetic unicellular microorganisms (2-50 μm), to efficiently recover nutrients and CO2 into a valuable algal biomass, containing lipids, fatty acids, proteins, amino acids, carbohydrates, vitamins, and more. Autotrophic mode, the most traditional microalgal cultivation method, relies entirely on photosynthesis, resulting in low biomass productivity in low light seasons, such as during Nordic autumns and winters. Mixotrophic mode, that supports both photosynthesis and heterotrophy using organic carbon (OC) for growth, yields higher biomass productivity and nutrient recovery.Whey permeate and cheese whey, dairy processing wastewaters, have been tested as OC sources for mixotrophic algal production in small-scale controlled laboratory conditions. This thesis investigates the potential for using these wastewaters as sources of phosphorus and OC, in combination with landfill leachate or fluegas condensate water as a nitrogen source, for sustainable mixotrophic algal cultivations under outdoor Nordic conditions. Monocultures and polycultures of local green algae were cultivated in mixotrophic mode on glucose, whey permeate or cheese whey and autotrophic mode in pilot-scale raceway ponds during the spring and autumn in southern Sweden. The coexistence of algae and bacteria, the algal gene expression, and the metabolite profile of algal biomass in response to mixotrophic mode were studied to optimize the operations and suggest suitable applications of mixotrophic algal biomass.The results demonstrated enhanced algal productions in mixotrophic mode under both high and low light conditions, with higher algal growth rates, productivity, and nutrient removal and recovery rates compared to autotrophic mode. Mixotrophic mode offers the potential for year-round algal cultivations in Nordic conditions. Additionally, cheese whey mitigated night algal biomass loss when added at sufficient concentrations.The eukaryotic and prokaryotic composition of polycultures varied more in mixotrophic mode than autotrophic mode. In the polycultures, most enzymes involved in carbon metabolism were upregulated, while those related to photosynthesis were downregulated in mixotrophic mode on glucose compared to autotrophic mode. Mixotrophic mode did not affect the biochemical composition in polycultures, but resulted in higher carbohydrate, and lower protein and lipid content in monocultures. Metabolite profiles of polycultures and monocultures were species-specific and differed between cultivation modes, favoring carbohydrate accumulation in mixotrophic mode. Therefore, the selection of algal species and cultivation mode is crucial for specific applications of algal biomass and when targeting specific metabolites.

Cross-Laminated Timber (CLT) is a pre-engineered timber product that has gainedmuch popularity over the last three decades as a sustainable construction material.CLT has excellent mechanical properties, and connections between CLT elementsand other structural elements in CLT structures are often critical in the engineeringdesign. The aim of this thesis is to develop a Finite Element Method (FEM)model for connections with dowel-type fasteners in CLT structures. Through athorough analysis from the embedment behaviour of timber to the simulation ofCLT structures with connections, this thesis aims to deepen the understandingof the load transfer and deformation behaviour of connections. Papers I and IIinvestigate with own and previous experiments the embedment behaviour ofdowel-type fasteners in timber and CLT. A non-linear analytical spring model forthe prediction of CLT embedment behaviour from the embedment behaviour ofthe constituent layers is proposed and shows good agreement with experiments.A Finite Element Method (FEM) model for the non-linear force-displacementbehaviour of single-fastener CLT connections is presented in Papers III andIV. A ‘Beam-on-Foundation’ (BoF) model is implemented in the FEM modelfor simulating the connection behaviour. The BoF model is validated withexperiments on steel-to-CLT and concrete-to-CLT connections, before it is usedto investigate the influence of various parameters on both the strength and slipmodulus of CLT connections. In Paper V, several single-fastener BoF models areintegrated into a multiple-fastener CLT connection model. The FEM model isvalidated with experiments on laterally loaded multiple-fastener steel-to-CLTconnections and used to investigate the influence of various parameters on thestrength and slip modulus of multiple-fastener CLT connections. From theresulting database, a design equation for the group effect in the slip modulusof steel-to-CLT connections with multiple-fasteners is derived. In Paper VI, theFEM model is applied to simulate angle bracket and hold-down bracket CLTconnections, as well as full-scale CLT shear walls with multiple connections.Due to the integrated BoF models, the FEM model provides insight into theload distribution between various connections. The developed FEM model is aneffective tool for the prediction of the force-displacement behaviour, the ductilestrength and the slip modulus of CLT connections with dowel-type fasteners.As it is implemented using a parametrised python script, the FEM model ishighly adaptable to accommodate numerous material and geometrical parameters.In addition to the effectiveness of the developed FEM model, the study alsohighlights the need for further developments in the simulation of the interactionof loading conditions and experimental validation.

Even though teachers of the language of schooling and of foreign languages all teach writing in their respective language classrooms, research has shown that few cross-curricular connections are made in their teaching practices (Forbes, 2020; Haukås, 2016; Vikøy & Haukås, 2023). The present PhD project attends to this gap, aiming at (1) showcasing and explaining the complexity of teaching writing in different languages taught at school, and (2) exploring whether and how teachers of different languages may align their teaching approaches to writing. Data were collected at two secondary schools in Berlin, Germany, where German is the language of schooling, English the first foreign language and French or Spanish the second foreign language. 

Nexus analysis (Scollon & Scollon, 2004) served as the theoretical and methodological framework for this study. Theoretically, nexus analysis provided an understanding of teachers’ social actions as mediated by circulating discourses, among which were the Discourses of Writing (DoW) (Ivanič, 2004). Methodologically, nexus analysis provided concepts to divide the research design into two phases: an ethnographic and a design phase. 

The ethnographic observation phase revealed that teachers of German, English, French and Spanish had divergent teaching approaches: the Genre DoW was foregrounded in most German classrooms while writing tasks in the foreign language classrooms were predominantly motivated by the Skills DoW. In both cases, assessment and upcoming examinations often motivated writing tasks. Multilingual teaching practices happened in the form of grammar and vocabulary comparisons while cross-curricular practices meant that teachers drew on or even coordinated teaching content from other language subjects. However, such practices were few and far between and were more opportunistic than systematic. 

In an attempt to systematize these practices, the design phase involved the development of teaching materials. The materials incorporated already circulating discourses (Genre, Skills, assessment among others) but additionally foregrounded the Social Practice DoW. This discourse promotes writing as a social practice with a communicative purpose and encouraged cross-curricular teaching practices because the same or similar materials were used in all language subjects. The materials were multilingual in German, English, French and Spanish and, where appropriate, left space for any additional languages that students might know. This dissertation discusses to what extent teacher–researcher collaborations can foster change in teaching approaches to writing from autonomous to multilingual and cross-curricular ones. 

Keywords: writing, multilingualism, teaching practice, cross-curricular collaboration, nexus analysis, discourse, educational linguistics

This dissertation investigates how metascientific approaches can enhance the quality and reliability of evidence syntheses in educational psychology. Prompted by the replication crisis, widespread questionable research practices, and the growing dependence on systematic reviews and meta-analyses in education, this work critically examines current research standards and advances innovative solutions rooted in open science.

Study I evaluates the methodological validity and reproducibility of the influential research synthesis Visible Learning by John Hattie. The study reveals several methodological flaws that contest the assumptions of the findings and the failure of being able to reproduce the statistics serves as a warning example of the presence of the replication crisis. 

Study II evaluates the risk of bias and transparency in systematic reviews conducted in educational psychology. Alarmingly, most included systematic reviews were judged as high risk of bias and across the entire sample, there was a lack of data sharing, preregistered protocols, and reproducible primary research data. 

Study III is a proof of concept of a registered report in educational psychology, the study aims to investigate the evidence of a writing intervention by conducting a systematic review. By adhering to the state-of-the-art conducting standards in systematic reviews, this protocol covers all aspects needed to produce reliable evidence as well as being reproducible. 

In Study IV, an innovative open-source Community-Augmented Meta-Analysis combined with a database is developed. The study presents solutions to several well-known problems in systematic reviews by allowing the research community to update, store, calculate, and share educational interventional data in a convenient way.

The findings of the included studies highlight significant gaps in research rigor and transparency, underscoring the necessity of fundamental change to adhere to current standards and modern research practices. 

By incorporating methodological tools such as preregistration, open science, risk of bias assessments and FAIR data principles, this dissertation calls for a paradigm shift in the synthesis and application of evidence in educational psychology. Ultimately, it seeks to promote more trustworthy, transparent, and impactful research to better inform educational policy and practice.