京都大学 / 新制・課程博士 / 博士(医学) / 甲第24838号 / 医博第5006号 / 新制||医||1068(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 大森, 孝一, 教授 中山, 健夫, 教授 後藤, 慎平 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Introduktion Fysisk aktivitet hos barn under fem år är ett område som saknar grundlig forskning. Nyligen har rekommendationer på fysisk aktivitet för denna åldersgrupp publicerats men det finns fortfarande många delar av detta område som inte är studerade.  Syfte Syfte med denna studie var att undersöka om det finns några skillnader i mängden fysisk aktivitet på veckodagar jämfört med helgdagar och även om en skillnad finns mellan pojkar och flickors fysiska aktivitet bland treåriga barn i Västerbotten. Metod Accelerometern (Motion watch 8/MW8) placerades på handleden på de treåriga barn vars föräldrar gett sitt medgivande till ett projekt inom Northpop-kohorten. Barnen (n=15) fick bära accelerometern i 8 dygn. Under dessa dagar antecknade föräldrarna barnens sovtimmar, skärmtid och aktiviteter utomhus och inomhus i en dagbok. Utifrån accelerometrarnas rådata analyserades activity counts med avseende på skillnader i fysisk aktivitet mellan vardagar och helgdagar och mellan pojkar och flickor med Wilcoxon W och Mann-Whitney U test. Resultat  Ingen signifikant skillnad påvisades gällande fysiska aktivitet på veckodagar jämfört med helgdagar (p=0.330) eller mellan pojkar och flickor (p=0.397).   Konklusion I denna studie kunde ingen signifikant skillnad i fysisk aktivitet påvisas mellan helg- och veckodagar eller mellan pojkar och flickor bland treåriga barn i Västerbotten. Det behövs mer forskning för att kartlägga barnens olika intensitetsnivåer, skolans påverkan på den fysiska aktiviteten och skillnader mellan könen.

The Jupiter Icy Moons Explorer is a planetary exploration mission that aims to study the moons of Jupiter in the planet’s vast magnetosphere. Among the various instruments on board is the Particle Environment Package (PEP), that is led by the Swedish Institute of Space Physics (IRF) in Kiruna. The Jovian plasma Dynamics and Composition analyzer (JDC) is one of six sensors within PEP and focuses on the characterization of positive ions. To be able to measure their three-dimensional distribution and composition, in-situ and in high time resolution, JDC has to cover a large field of view of 2π sr, for the desired energy range, in just a couple of seconds. An electrostatic analyzer within the sensor determines the energy per charge of such particles and a time-of-flight mass spectrometer measures their mass per charge. Constraints on weight and the radiation environment of Jupiter drive the design of the sensor: small and lightweight to allow extra shielding, but still large enough to accomplish measurements in the harsh radiation environment of Jupiter. This work focuses on a new type of compact, electrostatic analyzer using spherical wedges and the start signal generation for the time-of-flight measurement using new venetian blind-type surfaces. Simulations on the electrostatic analyzer showed that the most promising design is a hybrid variant, using an inner shell with spherical wedges and a spheroidal outer shell. A prototype sensor was built and tested with successful results. A reflectron-type time-of-flight cell measures the time it takes for a particle to pass a linear electric field. The time measurement has to be very accurate and requires that all ions enter the reflectron from the same start position. Commonly this is achieved with thin carbon foils of some nanometer thickness to provide a very accurate start position. Upon impact and after leaving a foil, ions generate secondary electrons that act as start signals for the time measurement. Foils require a substantial pre-acceleration of several kilovolts for the ions to penetrate the foil, thus increasing the size and mass of the instrument. When incident ions are reflected at grazing angles from a surface, secondary electrons are released in the same way as with foils. To increase position accuracy during this reflection process, venetian blind-type start surfaces are investigated, where many smaller surfaces replace a large flat surface. The most promising sample was found to be micro pore optics, that were initially designed to focus gamma rays. In several experiments it could be shown that micro pore optics show good reflection properties when used as start surfaces in the time-of-flight measurement. Both improvements allow a more compact and lightweight sensor that can be better shielded against the harsh radiation environment in Jupiter’s system. Jupiter hosts the strongest radiation environment in the solar system, that could kill an unprotected human thousand times over. / JUICE, PEP

In this thesis, new methods for proving concentration inequalities for Poisson functionals are developed. The focus is on techniques that are based on logarithmic Sobolev inequalities, but also results that are based on the convex distance for Poisson processes are presented. The general methods are applied to a variety of functionals associated with random geometric graphs. In particular, concentration inequalities for subgraph and component counts are proved. Finally, the established concentration results are used to derive strong laws of large numbers for subgraph and component counts associated with random geometric graphs.

Please read the abstract in the section 00front of this document / Thesis (DPhil)--University of Pretoria, 2000. / Veterinary Tropical Diseases / unrestricted

Myokardscintigrafi är en nuklearmedicinsk metod som används för att kartlägga och visuellt bedöma blodflödet till hjärtat. Vid undersökningen används radiofarmakan Myoview, som består av radionukliden 99mTechnetium som vid sönderfall avger gammastrålning som kan registreras med en gammakamera. StarGuide är en modern gammakamera som implenterades i verksamheten på Skånes universitetssjukhus år 2022. Skillnaden mellan konventionella kamerasystem och StarGuide är främst utformningen och uppbyggnaden av detektorerna, vilket även påverkar hur bilderna framställs. Det här gör att det inte finns några riktlinjer på kliniken gällande kvalitetssäkring i myokardscintigrafi-bilder tagna med StarGuide. Syftet med studien var att undersöka om det finns korrelation mellan counts och kroppsvikt i myokardscintigrafibilder tagna med StarGuide. Retrospektiva data från totalt 60 patienter användes till studien. Medelcounts/s/MBq sattes mot vikt i en scatterplot samt utfördes även en korrelationsanalys. Korrelationsanalysen för hela populationen gav ett värde på -0,790. Könsfördelade korrelationsanalyser utfördes även och gav värdena -0,784 för kvinnor och -0,706 för män. Slutsatsen är att det finns en märkbar korrelation mellan counts och vikt tagna på StarGuide men att det behövs vidare arbete för att stärka studiens fynd. Framför allt behövs insamling av mer data från patienter med en lägre vikt då de var underrepresenterade i studien. / Myocardial perfusion SPECT is a nuclear test used to map and visually assess blood flow to the heart. In the test, the radiopharmaceutical Myoview is used, which consists of the radionuclide 99mTechnetium, which when decaying emits gamma radiation that can be registered with a gamma camera. StarGuide is a modern gamma camera that was implemented in the clinics at Skåne University Hospital in 2022. The difference between conventional camera systems and StarGuide is primarily the design and construction of the detectors, which also affects how the images are produced. This means that there are no guidelines in the clinic regarding quality assurance in myocardial scintigraphy images taken with StarGuide. The purpose of the study was to investigate whether there is a correlation between counts and body weight in myocardial scintigraphy images taken with StarGuide. Retrospective data from a total of 60 patients were used for the study. Mean counts/s/MBq were plotted against weight in a scatter plot and a correlation analysis was also performed. The correlation analysis for the whole population gave a rsvalue of -0.790. Gender-distributed correlation analyzes were also performed and yielded rsvalues ​​of -0.784 for women and -0.706 for men. The conclusion is that there is a noticeable correlation between counts and weight taken on the StarGuide, but that further work is needed to strengthen the study's findings. Above all, the collection of more data is needed from patients with a lower weight as they were underrepresented in the study.

<p>Haematology instruments using optical and fluorescence techniques have improved the platelet count in domestic animals. There are still some difficulties present, especially when counting cat thrombocytes due to their ability to aggregate and the occurrence of large platelets.</p><p>The objective of this study was to evaluate and compare the platelet count, mean platelet volume and platelet crit in dogs, horses and cats on Advia 2120 and Sysmex XT-2000iV.</p><p>Fresh blood samples from 64 dogs, 40 horses and 39 cats with various medical conditions were analysed on both instruments. Manual blood smears of all feline samples were scrutiniously analysed to evaluate the aggregation warning flag from Advia.</p><p>There was good agreement between the instruments for the optical platelet count in dogs and cats. Slightly higher values were reported from Advia. Samples from horses presented poor correlations for all studied parameters. Platelet clumps appeared in 70% of the 37 scrutinized feline blood smears, while 46% of the samples generated aggregation warning flags from the Advia instrument.</p><p>Advia and Sysmex showed good agreement for platelet counts in blood from dogs and cats. Mean platelet volume and platelet crit need further evaluation before conclusions can be made concerning their clinical relevance. The sensitivity of the platelet aggregation warning flag from the Advia instument needs further elevation.</p>

An emerging trend towards non-laboratory based biological and microbiological marker analysis is occurring in multiple sectors of science and industry. In the medical sector, these trends have demonstrated that conducting sample analyses away from centralised laboratories not only makes analyses quicker and more convenient (e.g. a home pregnancy test), but can offer services that are otherwise impractical (e.g. mobile laboratories to diagnose disease in the developing world). In the environmental sector, similar benefits, plus the ability to develop and test hypotheses, protocols and sampling strategies within a field campaign, are possible with in-field analyses. Icy environments in particular would benefit from in situ or in-field life detection as they are typically remote, and hence impart high logistical costs for repeated field campaigns and associated sample return with the implication that the efficiency of scientific return is poor. Unfortunately, most equipment and protocols developed for microbiological analyses in other sectors of science and industry are unsuitable for direct application to in-field use in icy environments because of poor compatibility with icy environment sample matrices and frequently inappropriate microbiological targets. Hence within this work, two hypotheses were tested: that (i) microbiological detection infield in icy environments is possible and through this (ii) unique and more efficient scientific studies can be conducted. Cont/d.

The human sense of touch integrates feedback from a multitude of touch receptors, but how this information is represented in the neural responses such that it can be extracted quickly and reliably is still largely an open question. At the same time, dexterous robots equipped with touch sensors are becoming more common, necessitating better methods for representing sequentially updated information and new control strategies that aid in extracting relevant features for object manipulation from the data. This thesis uses information theoretic methods for two main aims: First, the neural code for tactile processing in humans is analyzed with respect to how much information is transmitted about tactile features. Second, machine learning approaches are used in order to influence both what data is gathered by a robot and how it is represented by maximizing information theoretic quantities. The first part of this thesis contains an information theoretic analysis of data recorded from primary tactile neurons in the human peripheral somatosensory system. We examine the differences in information content of two coding schemes, namely spike timing and spike counts, along with their spatial and temporal characteristics. It is found that estimates of the neurons’ information content based on the precise timing of spikes are considerably larger than for spikes counts. Moreover, the information estimated based on the timing of the very first elicited spike is at least as high as that provided by spike counts, but in many cases considerably higher. This suggests that first spike latencies can serve as a powerful mechanism to transmit information quickly. However, in natural object manipulation tasks, different tactile impressions follow each other quickly, so we asked whether the hysteretic properties of the human fingertip affect neural responses and information transmission. We find that past stimuli affect both the precise timing of spikes and spike counts of peripheral tactile neurons, resulting in increased neural noise and decreased information about ongoing stimuli. Interestingly, the first spike latencies of a subset of afferents convey information primarily about past stimulation, hinting at a mechanism to resolve ambiguity resulting from mechanical skin properties. The second part of this thesis focuses on using machine learning approaches in a robotics context in order to influence both what data is gathered and how it is represented by maximizing information theoretic quantities. During robotic object manipulation, often not all relevant object features are known, but have to be acquired from sensor data. Touch is an inherently active process and the question arises of how to best control the robot’s movements so as to maximize incoming information about the features of interest. To this end, we develop a framework that uses active learning to help with the sequential gathering of data samples by finding highly informative actions. The viability of this approach is demonstrated on a robotic hand-arm setup, where the task involves shaking bottles of different liquids in order to determine the liquid’s viscosity from tactile feedback only. The shaking frequency and the rotation angle of shaking are optimized online. Additionally, we consider the problem of how to better represent complex probability distributions that are sequentially updated, as approaches for minimizing uncertainty depend on an accurate representation of that uncertainty. A mixture of Gaussians representation is proposed and optimized using a deterministic sampling approach. We show how our method improves on similar approaches and demonstrate its usefulness in active learning scenarios. The results presented in this thesis highlight how information theory can provide a principled approach for both investigating how much information is contained in sensory data and suggesting ways for optimization, either by using better representations or actively influencing the environment.

This thesis mainly concerns the cohomology of the moduli spaces ℳ3[2] and ℳ3,1[2] of genus 3 curves with level 2 structure without respectively with a marked point and some of their natural subspaces. A genus 3 curve which is not hyperelliptic can be realized as a plane quartic and the moduli spaces 𝒬[2] and 𝒬1[2] of plane quartics without respectively with a marked point are given special attention. The spaces considered come with a natural action of the symplectic group Sp(6,𝔽2) and their cohomology groups thus become Sp(6,𝔽2)-representations. All computations are therefore Sp(6,𝔽2)-equivariant. We also study the mixed Hodge structures of these cohomology groups. The computations for ℳ3[2] are mainly via point counts over finite fields while the computations for ℳ3,1[2] primarily uses a description due to Looijenga in terms of arrangements associated to root systems. This leads us to the computation of the cohomology of complements of toric arrangements associated to root systems. These varieties come with an action of the corresponding Weyl group and the computations are equivariant with respect to this action.