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L'IRM de diffusion (IRMd) est une modalité d'imagerie qui permet d'étudier in vivo la structure des faisceaux de la substance blanche grâce à la caractérisation des propriétés de diffusion des molécules d'eau dans le cerveau. Les travaux de cette thèse se sont concentrés sur la comparaison de groupes d'individus en IRMd. Le but est d'identifier les zones de la substance blanche dont les propriétés structurelles sont statistiquement différentes entre les deux populations ou significativement corrélées avec certaines variables explicatives. L’enjeu est de pouvoir localiser et caractériser les lésions causées par une pathologie et de comprendre les mécanismes sous-jacents. Pour ce faire, nous avons proposé dans cette thèse des méthodes d'analyse basées voxel reposant sur le Modèle Linéaire Général (MLG) et ses extensions multivariées et sur des variétés, qui permettent d'effectuer des tests statistiques intégrant explicitement des variables explicatives. En IRMd, la diffusion des molécules d'eau peut être modélisée par un tenseur d'ordre deux représenté par une matrice symétrique définie-positive de dimension trois. La principale contribution de cette thèse a été de montrer la plus-value de considérer, dans le MLG, l'information complète du tenseur par rapport à un unique descripteur scalaire caractérisant la diffusion (fraction d’anisotropie ou diffusion moyenne), comme cela est généralement fait dans les études en neuro-imagerie. Plusieurs stratégies d’extension du MLG aux tenseurs ont été comparées, que ce soit en termes d’hypothèse statistique (homoscédasticité vs hétéroscédasticité), de métrique utilisée pour l’estimation des paramètres (Euclidienne, Log-Euclidienne et Riemannienne), ou de prise en compte de l’information du voisinage spatial. Nous avons également étudié l'influence de certains prétraitements comme le filtrage et le recalage. Enfin, nous avons proposé une méthode de caractérisation des zones détectées afin d’en faciliter l’interprétation physiopathologique. Les validations ont été menées sur données synthétiques ainsi que sur une base d’images issues d’une cohorte de patients atteints de Neuromyélite optique de Devic. / Diffusion Tensor MRI (DT-MRI) is an imaging modality that allows to study in vivo the structure of white matter fibers through the characterization of diffusion properties of water molecules in the brain. This work focused on group comparison in DT-MRI. The aim is to identify white matter regions whose structural properties are statistically different between two populations or significantly correlated with some explanatory variables. The challenge is to locate and characterize lesions caused by a disease and to understand the underlying mechanisms. To this end, we proposed several voxel-based strategies that rely on the General Linear Model (GLM) and its multivariate and manifold-based extensions, to perform statistical tests that explicitly incorporate explanatory variables. In DT-MRI, diffusion of water molecules can be modeled by a second order tensor represented by a three dimensional symmetric and positive definite matrix. The main contribution of this thesis was to demonstrate the added value of considering the full tensor information as compared to a single scalar index characterizing some diffusion properties (fractional anisotropy or mean diffusion) in the GLM, as it is usually done in neuroimaging studies. Several strategies for extending the GLM to tensor were compared, either in terms of statistical hypothesis (homoscedasticity vs heteroscedasticity), or metrics used for parameter estimation (Euclidean, Log-Euclidean and Riemannian), or the way to take into account the spatial neighborhood information. We also studied the influence of some pre-processing such as filtering and registration. Finally, we proposed a method for characterizing the detected regions in order to facilitate their physiopathological interpretation. Validations have been conducted on synthetic data as well as on a cohort of patients suffering from Neuromyelitis Optica.

As average global temperatures rise, cool-season C3 turfgrasses, such as the most commonly grown Kentucky bluegrass (Poa pratensis L.; KBG), struggle to tolerate extreme summer heat and increase their water consumption. Hybrid Bermudagrass (Cynodon dactylon [L.] Pers. × Cynodon transvaalensis Burtt Davy; HBG) is a warm-season C4 grass that may be increasingly suited for northern ecosystems traditionally classified as transition or cool-season climate zones. Glasshouse and field studies were conducted to compare HBG and KBG water use. The objective of the glasshouse study was to evaluate plant health and growth for two HBG cultivars (‘DT-1’ and ‘NorthBridge’) compared to a blend of KBG cultivars in all combinations of deficit, moderate, and high irrigation at optimum or short mowing height. The study was conducted in a glasshouse at Provo, UT, USA from 2020-2021. Grass was grown in pots arranged in a randomized complete block, full factorial design, with four replications of each treatment. The moderate KBG was also significantly different from both high and deficit for verdure and for the last half of NDVI. The objective of the field study was to evaluate two HBG cultivars (‘Tahoma 31’ and ‘Latitude 36’) compared to a blend of KBG cultivars for water loss and canopy health, temperature, and growth when subjected to deficit, moderate, and high irrigation. The study was arranged in a randomized complete block, full factorial design with three replications per treatment, and was conducted at Provo, UT, USA throughout the summer of 2021. In both the glasshouse and field trials, the deficit irrigated KBG consistently scored lower for NDVI and visual turf quality than all other treatments, including moderate and high KBG. This same trend was seen in the field study for percent cover. Although not observed in the glasshouse trial, it was observed in the field trial that the different irrigation levels of HBG resulted in no significant differences for any measurements but the HBG regularly scored better than KBG. The canopy temperatures of deficit irrigated KBG were also higher than all other treatments on most dates. The shoot mass, thatch mass, and total biomass of KBG were significantly less than either HBG cultivar. In the glasshouse trial it was observed that all deficit grasses were significantly lower than the other irrigation treatments and HBG had significantly deeper roots than KBG, although these results were not seen in the field trial. The data suggest that irrigation needs will be less for HBG than KBG and that HBG could provide a water-saving turfgrass alternative to KBG in semi-arid, cool-season regions with increasing water scarcity.

This thesis presents how a non-destructive method allows for analysis of archeological material, using three Neolithic anthropomorphic figurines attributed to the Pitted Ware Culture. Anthropomorphic figurines from this period are rare in Sweden and traditional destructive methods, such as thin section petrography is therefore not an option. Using µCT – Micro-Computed tomography as an archaeological method, information can be produced regarding the ceramic composition, forming technique and ornamentation of these figurines. Furthermore, this thesis shows how new advancements in computer imaging technology, such as 3D volume rendering of µCT-data, allows for the reconstruction of organic inclusions.

Neurotoxlns represent unique chemical tools, providing a means to 1) gain insight into cellular mechanisms of apopotosis and necrosis, 2) achieve a morphological template for studies otherwise unattainable, 3) specifically produce a singular phenotype of denervation, and 4) provide the starting point to delve into processes and mechanisms of nerve regeneration and sprouting. There are many other notable uses of neurotoxins in neuroscience research, and ever more being discovered each year. The objective of this review paper is to highlight the broad areas of neuroscience in which neurotoxins and neurotoxicity mechanism come into play. This shifts the focus away from neurotoxins per se, and onto the major problems under study today. Neurotoxins broadly defined are used to explore neurodegenerative disorders, psychiatric disorders and substance use disorders. Neurotoxic mechanisms relating to protein aggregates are indigenous to Alzheimer disease, Parkinson's disease. NeuroAIDS is a disorder in which microglia and macrophages have enormous import. The gap between the immune system and nervous system has been bridged, as neuroinflammation is now considered to be part of the neurodegenerative process. Related mechanisms now arise in the process of neurogenesis. Accordingly, the entire spectrum of neuroscience is within the purview of neurotoxins and neurotoxicity mechanisms. Highlights on discoveries in the areas noted, and on selective neurotoxins, are included, mainly from the past 2 to 3 years.

Corynebacterium diphtheriae, Pseudomonas aeruginosa, Ricinus communis, Shigella dysentariae, and Vibrio cholerae produce AB toxins which share the same basic structural characteristics: a catalytic A subunit attached to a cell-binding B subunit. All AB toxins have cytosolic targets despite an initial extracellular location. AB toxins use different methods to reach the cytosol and have different effects on the target cell. Broad-spectrum inhibitors against these toxins are therefore hard to develop because they use different surface receptors, entry mechanisms, enzyme activities, and cytosolic targets. We have found that grape seed extract provides resistance to five different AB toxins: diphtheria toxin (DT), P. aeruginosa exotoxin A (ETA), ricin, Shiga toxin, and cholera toxin (CT). To identify individual compounds in grape seed extract that are capable of inhibiting the activities of these AB toxins, we screened twenty common phenolic compounds of grape seed extract for anti-toxin properties. Three compounds inhibited DT, four inhibited ETA, one inhibited ricin, and twelve inhibited CT. Additional studies were performed to determine the mechanism of inhibition against CT. Two compounds inhibited CT binding to the cell surface and even stripped bound CT off the plasma membrane of a target cell. Two other compounds inhibited the enzymatic activity of CT. We have thus identified individual toxin inhibitors from grape seed extract and some of their mechanisms of inhibition against CT. This work will help to formulate a defined mixture of phenolic compounds that could potentially be used as a therapeutic against a broad range of AB toxins.

In recent years, digital twins (DT) have gained traction in enhancing operation and maintenance procedures across various industrial sectors, such as manufacturing, energy, and aerospace. Yet their utilization remains more limited in the built environment. The aim of this paper is to investigate the current conceptualizations of DTs within the context of the Swedish built environment, shedding light on the maturity of DTs for built assets and the key value drivers influencing their adoption. The study reveals that DTs for built assets are in early developmental stages, lacking the maturity required to encompass the full spectrum of attributes inherent in a conventional DT. Despite stakeholders labeling these initiatives as DTs, our findings indicate a closer alignment with the concept of BIM-based digital models. This observation resonates with existing literature, highlighting the absence of a universally accepted definition for DTs. Within the Operations and Maintenance (O&M) phase, we have identified the following four primary value drivers shaping the adoption of BIM-based DTs: 1) commercial transparency and trusted transactions, 2) efficiency and cost reduction in routine operations, 3) operational continuity, and 4) added services. These findings contribute to the ongoing discourse surrounding the convergence of BIM and DTs, offering insights into the practical implications and value propositions that drive the integration of these technologies within the built environment. / Under de senaste åren har användningen av digitala tvillingar (DT:ar) blivit allt vanligare för drift- och underhållsförfaranden inom olika industrisektorer, såsom tillverkning, energi och flyg- och rymdindustrin. Användningen är dock fortfarande begränsad inom bygg- och fastighetsbranschen. Syftet med denna studie är att undersöka de nuvarande konceptualiseringarna av DT:ar inom ramen för den svenska fastighetsbranschen, belysa mognaden hos tekniken och undersöka de viktigaste värdedrivande faktorerna som påverkar utvecklingen och användningen i drift- och underhåll av fastigheter. Studien visar att användningen av DT:ar i fastighetsbranschen befinner sig i ett tidigt utvecklingsstadie och att begreppet inom industrin inte helt överensstämmer med visionen kring konceptet. Resultaten stämmer överens med befintlig litteratur, som belyser avsaknaden av en allmänt accepterad definition för DT:ar. I drift- och underhållsfasen har vi också identifierat följande fyra primära värdedrivande faktorer för användingen av BIM-baserade DT:ar: 1) kommersiell transparens och pålitliga transaktioner, 2) kostnadsbesparingar i rutinmässigt drift- och underhållsarbete, 3) kontinuerligt driftsarbete, samt 4) tilläggstjänster. Resultaten från denna studie bidrar till den pågående diskussionen om koncepten BIM och DT, och ger ytterligare insikt i de praktiska värdeskapande processerna och belyser användningsområden av DT:ar i fastighetsbranschen.

Nuklearmedicin är en specialitet där Flour18-fluorodeoxyglukos positronemissionstomografi/datortomografi (18F-FDG PET/DT) är en vanligt förekommande undersökning. Den vanligaste indikationen för att genomgå undersökningen är misstänkt eller känd cancer. Syfte: Syftet var att studera patienters upplevelse av information i samband med en 18F-FDG PET/DT-undersökning. Metod: En kvantitativ tvärsnittsstudie genomfördes på nuklearmedicinska avdelningen där 100 patienter som uppfyllde inklusionskriterierna tillfrågades om medverkan i studien. Efter undersökningen ombads studiedeltagarna att besvara en enkät innehållande nio studiespecifika frågor gällande informationen med fem tillhörande svarsalternativ. Resultat: Studiens resultat visar att 93,4% av studiedeltagarna upplevde den skriftliga informationen som tydlig och lättförståelig. Samtliga enkätfrågor erhöll en median på 4 vilket överensstämmer med svarsalternativet 5 “Instämmer helt”. Resultatet visar att 86 studiedeltagare (94,5%) var nöjda med den muntliga informationen samt att 78 studiedeltagare (88,7%) var nöjda med den skriftliga informationen. Resultatet påvisade att informationen gällande den radioaktiva isotopen erhöll 7 "Instämmer i låg grad" och informationen efter undersökningen erhöll 3 "Instämmer inte alls". Slutsats: Majoriteten av patienter som genomgår en 18F-FDG PET/DT-undersökning är nöjda med informationsinnehållet i samband med undersökningen. Informationen gällande den radioaktiva isotopen samt informationen efter undersökningen behöver dock förbättras. En mer omfattande studie som inkluderar fler studiedeltagare under en längre tidsperiod bör genomföras för ett mer generaliserbart resultat hos den aktuella patientgruppen. / Nuclear Medicine is a speciality in which Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is a common examination. The most common indication for undergoing the examination is known or suspected cancer. Aim: Our aim was to study patients’ experiences regarding the information during an 18F-FDG PET/CT examination. Method: A quantitative cross-sectional study was carried out at the Nuclear Medicine department in which 100 patients who met the inclusion criteria were asked to participate. The participants were asked to answer a questionnaire regarding the information containing of nine study-specific questions with five options. Results: The results of our study showed that 93,4% of the participants perceived the written information as direct and easily comprehensible. All questions received a median score of 4, which corresponds with alternative 5 “Strongly agree”. The result shows that 86 participants (94,5%) were satisfied with the verbal information and that 78 participants (88,7%) were satisfied with the written information. The results showed that the information regarding the radioactive isotope received 7 “Disagree” and the information after the examination received 3 “Strongly disagree”. Conclusion: The majority of patients who undergo an 18F-FDG PET/CT examination are satisfied with the information during the examination. However, the information regarding the radioactive tracer and the information after the examination needs to be improved. A larger study that includes more participants over a longer period of time is suggested to be conducted for more generalized results.

Bakgrund: Antalet datortomografiundersökningar (DT-undersökningar) har ökat kraftigt i Sverige och den kollektiva stråldosen till befolkningen blir allt högre. DT-undersökningar av buken är en av de undersökningarna som ger högst stråldos till patienten, därför är det viktigt att de endast görs när det krävs för att ställa diagnos. Därmed kan det vara relevant att undersöka huruvida antalet undersökningar också lett till ökat antal patologiska fynd hos patienter. Syfte: Undersöka hur många akuta DT-undersökningar med intravenös kontrast av buken som gjordes vid två sjukhus och hur stor andel av dessa som påvisade patologiska fynd. Metod: För att besvara syftet gjordes en kvantitativ retrospektiv studie där röntgenremisser och röntgensvar från mars 2013, mars 2018 och mars 2023 analyserades. Resultat: Antalet akuta DT-bukundersökningar med intravenös kontrast har ökat vid sjukhusen med i genomsnitt 49,5% mellan 2018–2023. Den mest markanta ökningen sågs i åldrarna 50–80 år. Vid Sjukhus 1 hade andelen fynd ökat från 57,5% i mars 2013 till 72,4% i mars 2023, samtidigt som andelen fynd vid Sjukhus 2 i stället minskat från 54% i mars 2018 till 46,3% i mars 2023. De vanligaste fynden vid de två sjukhusen var ileus/subileus, appendicit och kolecystit/gallsten/vidgade gallvägar. Könsfördelningen visade att något fler kvinnor än män genomgick akut DT buk med iv. kontrast, (Sjukhus 1: 54% kvinnor och Sjukhus 2: 55% kvinnor). Slutsatser: Det har vid båda sjukhusen skett en ökning av antalet undersökningar men utvecklingen av andelen fynd har gått i två olika riktningar. De vanligaste patologiska fynden som görs skulle kunna ställas med hjälp av andra modaliteter med låg eller ingen stråldos, såsom konventionell röntgen eller ultraljud. Ökningen av antalet akut DT-buk med iv. kontrast har medfört en ökad arbetsbelastning för röntgensjuksköterskor.

<p>This dissertation consists of three major chapters. The first chapter is dedicated to testing a novel gravity model of international trade, while the last two chapters explore cross-country commitment and implementation behavior within the World Trade Organization’s Trade Facilitation Agreement. </p> <p><strong>Chapter 1:</strong> I test a novel theoretical gravity model of international trade on firm-level export data from Colombia in 2018. The model assumes a power law relationship between trade flows and distance, with the distance elasticity resulting from two dynamic processes: firm-export growth captured in a Pareto distribution; and the growth of the distance over which those exports are sold. Although the model has been shown to work well in French data, its usefulness for interpreting data from other countries remains unexplored. I find evidence that the model fails in Colombia because some large firms contradict its assumptions by exhibiting shorter export distances compared to smaller firms in the sample. I hypothesize that these large firms are branches of foreign multinational corporations (MNCs). MNCs’ headquarters constraint the export growth of its affiliates as well as the markets they reach. While I cannot prove firms’ MNC affiliation, I use export sophistication as an imperfect metric to reflect MNC presence. When MNC affiliates are excluded from the sample, firm export distance rises faster with firm size, leading to improved predictions of the distance elasticity of trade in Colombia by the model. These findings have implications not only for the tested model but also for other theories that explain gravity in international trade through firm-level behavior.</p> <p><strong>Chapter 2:</strong> We use a new database of commitments made during the process of ratifying the Trade Facilitation Agreement (TFA) to study variation in countries’ commitment behavior. The TFA is a novel World Trade Organization agreement because it allows developing countries to select commitments from a menu of best practices in trade facilitation, rather than to consent, or not, to a comprehensive package of negotiated commitments. The operation of this <em>à la carte</em> approach to concluding trade agreements is worthy of study in its own right, but the commitment data also offer a high-level description of progress in an international effort to improve border management procedures around the globe. Our study uses data on TFA commitments to describe progress across subcomponents of the agreement. A regression model shows that the number of Type A trade facilitation commitments that a country made in the TFA ratification process depends on its level of development, population size, ability to control corruption, and foreign aid received to support trade facilitation. We use multidimensional scaling techniques to study differences in the content of national commitment bundles. This approach demonstrates that variation in the content of countries’ commitments is closely tied to the number of commitments made.</p> <p><strong>Chapter 3:</strong> This chapter examines the implementation progress of the Trade Facilitation Agreement (TFA) from 2019 to 2023. The TFA, which is the latest World Trade Organization agreement, came into force in 2017. In its novelty, it allows developing countries to set their own implementation schedule and adjust it if needed. This flexibility aligns implementation requirements with the capabilities of signatory countries, but introduces uncertainties in achieving complete global implementation and fully realizing the potential benefits of the agreement. Using data on the notified implementation dates for each measure of the TFA, this study describes the progress made in implementing different subcomponents of the agreement over a period of five years. A regression analysis suggests that the annual rate of progress towards achieving full TFA implementation does not vary based on country characteristics such as GDP per capita, population size, or landlocked status. Assuming that the tendency at which countries implement measures remains unchanged, I project that 95% of developing countries will achieve 95% TFA implementation between the years 2036 and 2047.</p>