The use of MRI for patient examinations has constantly increased as technical development has lead to faster image acquisitions and higher image quality. Nevertheless, an MR-examination still takes relatively long time and yet another way of speeding up the process is to employ parallel imaging. In this thesis, one of these parallel imaging techniques, called SENSE, is described and examined more closely. When SENSE is employed, the number of spatial encoding steps can be reduced thanks to the use of several receiving coils. A reduction of the number of phase encoding steps not only leads to faster image acquisition, but also to superimposed pixel values in image space. In order to be able to separate the aliased pixels, knowledge about the spatial sensitivity of the coils is required. There are several different alternatives to how and when information about the sensitivities of the coils should be collected, but in this thesis, focus is on the method of performing a reference measurement before the actual scan. The reference measurement consists of a fast, low-resolution sequence which either is collected with both the body coil and the parallel imaging coil or only with the parallel imaging coil. A comparison of these two methods by simulations in program written MATLAB leads to the conclusion that even if the scan time of the reference measurement is doubled it seems like there are numerous advantages of also collecting data with the body coil: • the images are more homogeneous which facilitates the establishment of a diagnose • the noise levels in the reconstructed images are somewhat lower • images collected with a reduced sampling density show better agreement with those collected without reduction. Furthermore, it is shown that the reference measurement preferably should be a 3D sequence covering all the volume of interest. If a 2D sequence is used it is absolutely necessary that it can be performed in any plane and it has to be repeated for every plane that is imaged.

As disturbed binocular functions in small children may lead to severe amblyopia it is of interest to detect it as early as possible. Most tests for binocular functions, however, demand active cooperation and may be unreliable in children up to 4-5 years of age. This study therefore aims to employ visual evoked potentials (VEP) to enable the examiner to evaluate the binocular function in a subject without need of active cooperation from the subject. Initially we studied the relation of suprathreshold contrast to the latency of the transient pattern VEP (tpVEP). Although suprathreshold contrast independently influenced the tpVEP latency, interindividual variation was too large to suggest tpVEP as a possible method for objectively measuring contrast sensitivity in a subject. The tpVEP latency in normal and microstrabismic adult subjects was examined. It was significantly shorter with binocular viewing in normals, but not in the microstrabismic group. Contrast sensitivity and tpVEP latency was examined in adults, both with normal binocularity and with microstrabismus, using both luminance (black-and-white) contrast and colour contrast patterns. The tpVEP latency to colour contrast, like that to luminance contrast, is shorter in normal subjects who view the stimulus binocularly. Interindividual variation or overlap between the normal and microstrabismic groups did not improve with colour contrast. The most significant features of the tpVEP are amplitude and latency. Depending on stimulus conditions, the response may show variations in configuration, amplitude and, to a lesser degree, latency. To decrease the influence of such variations steady-state VEP (ssVEP) can be used. The stimulus is presented in a fast repetitive manner, yielding a VEP response shaped as a continuous curve. The frequency components of this curve can be analysed using Fast Fourier Analysis. Fast Fourier analysis of ssVEP in children aged 8-15 years with normal binocularity and with microstrabismus showed that the power of the second harmonic (the double frequency of stimulus frequency) of the response with binocular viewing was larger than with monocular viewing, both in normals and microstrabismic subjects. For higher stimulus frequencies, microstrabismic subjects showed a significantly lower power of the second harmonic compared with subjects with normal binocularity, when the stimulus was presented binocularly. Finally, Fast Fourier analysed ssVEP in pre-school children aged 4-5 years was studied. A normal group was compared with a group with microstrabismus and a group with significant amblyopia. Amblyopic subjects had significant interocular differences in the first harmonic. We confirmed the significant difference found between microstrabismic subjects and subjects with normal binocularity regarding the second harmonic’s power with higher temporal frequency binocular stimulation, although at a slightly lower frequency than for older children. A low power of the second harmonic in the ssVEP to a binocular stimulus with high temporal frequency is a strong indicator of disturbed binocular function. / För att förhindra amblyopi (ensidig synsvaghet) hos barn är det viktigt att upptäcka störningar i samsynsfunktionerna så tidigt som möjligt. Samsynstester kräver dock aktiv medverkan och kan ge osäkra resultat hos barn upp till 4-5 års ålder. Den här avhandlingen studerar möjligheterna att utifrån tidsmässiga (temporala) egenskaper hos visual evoked potentials (VEP) undersöka samsynsfunktioner objektivt, utan att den undersökte behöver medverka aktivt. Första delstudien visar att ett synstimulus kontrastnivå i relation till kontrastkänslighetströskeln oberoende påverkar latensen i VEP, men variationer mellan individer gör metoden olämplig som objektiv kontrastkänslighetstest. Andra delstudien jämför latensen i VEP hos individer med normal samsyn med den hos personer med mikroskelning. Stimulering av båda ögonen gav signifikant kortare latens än stimulering av ett öga hos normala, men inte hos mikroskelare. I den tredje delstudien jämfördes känslighet för luminanskontrast och färgkontrast hos individer med normal samsyn och personer med mikroskelning. Både luminansmönster (svart-vita) och färgkontrastmönster upptäcktes vid lägre kontrast om båda ögonen stimulerades istället för ett i taget hos normalseende. Mikroskelare uppfattade mönstren sämre med båda ögonen än med ett öga (det dominanta). Latensen i VEP mättes i båda grupperna för både luminans- och färgkontrastmönster. Båda typerna av kontrast gav förkortning av latensen när båda ögonen stimulerades vid normal samsyn, men denna förkortning uteblev hos mikroskelare. Både luminans- och färgkontrast gav för varierande resultat för att utnyttja metoden för objektiv undersökning av samsynen. Fourier-analys innebär att en kurvform delas upp i sinuskurvor med olika frekvens, amplitud och fas. Om ett stimulus växlar hastigt får man ett steady-state VEP (ssVEP), dvs en kontinuerligt vågformad VEP-kurva, som kan delas upp i delsinuskurvor med Fourieranalys. Detta gör att man särskilt kan studera frekvenser som är relaterade till stimuleringsfrekvensen, till exempel grundton och övertoner (multipler av grundtonsfrekvensen). Barn 8-15 år gamla, med normal samsyn och med mikroskelning undersöktes med ssVEP i det fjärde delarbetet. Den första övertonen (= ”second harmonic”) var statistiskt signifikant svagare hos mikroskelare jämfört med normala individer, när stimuleringsfrekvensen var hög. Det femte och sista delarbetet undersökte ssVEP hos 4-5 år gamla förskolebarn på motsvarande sätt. I denna studie deltog också en grupp barn med amblyopi (synsvaghet) på ena ögat. På en något lägre stimuleringsfrekvens bekräftades den svagare första övertonen hos barnen med mikroskelning jämfört med barnen med normal samsyn. De amblyopa barnen visade tydligast förändringar vid lägre stimuleringsfrekvenser och i ssVEP:s grundtonsfrekvens (= ”first harmonic” eller ”fundamental harmonic”). Resultaten i de olika grupperna är så pass åtskilda att metoden verkar lämpa sig för objektiv undersökning av samsynsfunktioner, i det att en svag första överton i binokulärt ssVEP utlöst av hög stimuleringsfrekvens inger en stark misstanke om störd samsyn, medan en stor skillnad i grundtonens styrka i höger respektive vänster ögas ssVEP tyder på amblyopi.

This thesis consists of two separate parts. The first part consists of one paper and considers problems concerning spatial point processes and the second part includes three papers in the field of bioinformatics. The first part of the thesis is based on a forestry problem of estimating the number of trees in a region by using the information in an aerial photo, showing the area covered by the trees. The positions of the trees are assumed to follow either a binomial point process or a hard-core Strauss process. Furthermore, discs of equal size are used to represent the tree-crowns. We provide formulas for the expectation and the variance of the relative vacancy for both processes. The formulas are approximate for the hard-core Strauss process. Simulations indicate that the approximations are accurate.  The second part of this thesis focuses on pre-processing of microarray data. The microarray technology can be used to measure the expression of thousands of genes simultaneously in a single experiment. The technique is used to identify genes that are differentially expressed between two populations, e.g. diseased versus healthy individuals. This information can be used in several different ways, for example as diagnostic tools and in drug discovery. The microarray technique involves a number of complex experimental steps, where each step introduces variability in the data. Pre-processing aims to reduce this variation and is a crucial part of the data analysis. Paper II gives a review over several pre-processing methods. Spike-in data are used to describe how the different methods affect the sensitivity and bias of the experi­ment. An important step in pre-processing is dye-normalization. This normalization aims to re­move the systematic differences due to the use of different dyes for coloring the samples. In Paper III a novel dye-normalization, the MC-normalization, is proposed. The idea behind this normaliza­tion is to let the channels’ individual intensities determine the cor­rection, rather than the aver­age intensity which is the case for the commonly used MA-normali­zation. Spike-in data showed that  the MC-normalization reduced the bias for the differentially expressed genes compared to the MA-normalization. The standard method for preserving patient samples for diagnostic purposes is fixation in formalin followed by embedding in paraffin (FFPE). In Paper IV we used tongue-cancer micro­RNA-microarray data to study the effect of FFPE-storage. We suggest that the microRNAs are not equally affected by the storage time and propose a novel procedure to remove this bias. The procedure improves the ability of the analysis to detect differentially expressed microRNAs.

This doctoral thesis presents results of literature review on classical and contemporary aspects of stripping, as well as experimental investigations on moisture damage as influenced by bituminous materials. Previous research in the area of moisture damage was reviewed and synthesized into a state-of-the-art. Important parameters linked to moisture sensitivity, like bituminous material characteristics, dynamic loads from heavy vehicles, environmental factors, construction practice and nature of anti-stripping additives, are presented. The state-of-the-art in current test methods is summarized and given. The experimental work involved investigations of the influence of bitumen and aggregate composition on water susceptibility. The influence of aggregate mineralogy and chemistry was evaluated using eleven aggregates and one bitumen, followed by studying the interactive effect of four bitumens and four aggregates. Moisture sensitivity was evaluated in accordance with (EN 12697-12:2003) for conditioning, ASTM D 4123 for resilient modulus determination, and (EN 12697-23:2003) for indirect tensile strength testing. Furthermore, thermal stability of two liquid amine anti-stripping additives mixed with two bitumens of varied acidity was investigated using potentiometric titration and Fourier Transform Infrared (FTIR) Spectroscopy. Lastly, a technique based on Fourier Transform Infrared Spectroscopy-Attenuated Total Reflectance (FTIR-ATR) was developed and used for studying transport of water across thin bitumen films, as well as stripping at bitumen/substrate interfaces. Bitumens from different sources and three substrates (silicon, germanium and zinc selenide crystals) were used. Based on the results obtained, it was concluded that aggregates containing sodium and potassium in alkali feldspars generally showed high moisture sensitivity. In contrast, presence of calcium, magnesium and iron was associated with aggregates with low moisture sensitivity. Contrary to several previous findings, one aggregate with practically 100% quartz exhibited low moisture sensitivity. No linear relationship between moisture sensitivity and the contents of SiO2 and Al2O3 in the aggregates studied was established. Results of the interactive influence of bitumen and aggregate composition showed that high acid and low penetration bitumens exhibited high dry strength for all the aggregates studied. On the other hand, for a given bitumen, the wet strengths were found to be aggregate specific. The results of tests on thermal stability of amine additives showed that usefulness of these additives reduces considerably, when the more alkaline additive was mixed with the high acid bitumen, followed by storing the blends under pronounced conditions of time and temperature (24 hours and 140ºC, or more, in this study). Much less interaction occurred when the less alkaline additive was blended with the low acid bitumen. Even if a correlation was found between the results of potentiometric titration and Fourier Transform Infrared spectroscopy, the latter was not considered good enough at detecting amine additives, especially at low dosages. The technique based on FTIR-ATR developed in this study distinguished between good and bad bitumens with regard to stripping. The effectiveness of amine-based additives in reducing stripping was also shown by the method. Three likely processes occurred during the test, namely water diffusion, film break, and displacement (stripping) of bitumen from the substrate surface. The results also indicated that the diffusion process of water into the bitumen/substrate interface does not obey Fick’s law. / QC 20100831

The dynamic behaviour in the audible frequency range of magneto-sensitive (MS) rubber is the focus of this thesis consisting of five papers A-E. Paper A presents results drawn from experiments on samples subjected to different constant shear strains over varying frequencies and magnetic fields. Main features observed are the existence of an amplitude dependence of the shear modulus referred to as the Fletcher-Gent effect for even small displacements, and the appearance of large MS effects. These results are subsequently used in Paper B and C to model two magneto-sensitive rubber isolators, serving to demonstrate how, effectively, by means of MS rubber, these can be readily improved. The first model calculates the transfer stiffness of a torsionally excited isolator, and the second one, the energy flow into the foundation for a bushing inserted between a vibrating mass and an infinite plate. In both examples, notable improvements in isolation are obtainable. Paper D presents a non-linear constitutive model of MS rubber in the audible frequency range. Characteristics inherent to magneto-sensitive rubber within this dynamic regime are defined: magnetic sensitivity, amplitude dependence, elasticity and viscoelasticity. A very good agreement with experimental values is obtained. In Paper E, the magneto-sensitive rubber bushing stiffness for varying degrees of magnetization is predicted by incorporating the non-linear magneto-sensitive audio frequency rubber model developed in Paper D, into an effective engineering formula for the torsional stiffness of a rubber bushing. The results predict, and clearly display, the possibility of controlling over a large range through the application of a magnetic field, the magneto-sensitive rubber bushing stiffness. / QC 20100816

The purpose of this thesis is to investigate if the trade flows within the European Union are affected by the environmental policies within the union. An environmental sensitivity index (IESP) is used as explanatory variable, with export and import shares respectively as dependent variables. The trade flow data is collected from the OECD database for the years 1995 to 1998, and is used in a regression analysis together with IESP data from the same years. The analysis covers 15 European Union member countries. The result from the regression analysis shows a positive relationship between IESP and trade flows. However, our values did not turn out to be significant, much due to the low number of observations and too few explanatory variables. / Syftet med denna uppsats är att undersöka om handelsflödena inom den Europeiska Unionen påverkas av miljöpolitiken inom unionen. Ett index som mäter miljökänslighet (IESP) används som förklarande variabel, med export respektive import som beroende variabler. Data om handelsflöden är hämtade från OECDs databas och täcker åren 1995-1998. Dessa data används i en regressionsanalys tillsammans med IESP data från samma period. Analysen täcker 15 medlemsländer från den Europeiska Unionen. Resultaten från regressionsanalysen pekar på ett positivt samband mellan handelsflöden och IESP. Tyvärr blev våra värden ej signifikanta, mycket beroende på för få observationer och förklarande variabler.

<p>This dissertation explores the role of executive compensation in determining the capital structure decisions of a firm. CEOs experience a large personal cost of default that interacts through the risk adjusted probability of default with their compensation contract. Since default happens in a particularly costly state of the world for a CEO whose compensation contract consists primarily of pay for performance elements, i.e. a CEO who has a large personal equity stake in the firm, a large pay performance sensitivity is negatively and significantly associated with firm leverage choice. I document this effect in detail for the first time, and I show that it is both statistically robust and significant in magnitude, approximately 1\% of firm value. I show that this effect is driven by the stock holdings of the CEO, not the option holdings. I provide a simple principal agent model that explains the observed negative relationship and makes additional predictions on the relationship of other firm characteristics to pay performance sensitivity and leverage. I then test and confirm these predictions empirically using a standard OLS framework and an instrumental variable approach to control for endogeneity in the compensation contract. I also look at leverage adjustment speeds and show that CEOs with higher pay performance sensitivity adjust leverage upwards towards target values more slowly and downwards more quickly than their peers, and I interpret this as direct evidence that CEOs are actively managing personal risk through firm leverage choice.</p> / Dissertation

This paper examines the interest rate sensitivity of Business Development Companies (BDCs). The results of this study are intended to lend insight to investors about the viability and timing of investments in BDCs during the business cycle. Similar to previous research that has examined interest rate sensitivity of financial companies, this paper employs a two-factor market model to see whether BDCs are responsive to changes in short, medium, and long-term interest rates. My particular interest in BDCs is motivated by their unique asset-liability structure and requirements, as well as their high dividend payouts. Monthly data is drawn from the period ranging from January 2004 through December 2012. Using a sample of 30 BDCs, I estimate the sensitivity of BDC stock returns to stock market and interest rate changes in general. I then proceed to test whether size and Small Business Investment Company (SBIC) licensure status affect these sensitivities.

The papers collected in this volume were presented at a Graduate/Postgraduate Student Conference with the title Information Structure: Empirical Perspectives on Theory held on December 2 and 3, 2011 at Potsdam-Griebnitzsee. The main goal of the conference was to connect young researchers working on information structure (IS) related topics and to discuss various IS categories such as givenness, focus, topic, and contrast. The aim of the conference was to find at least partial answers to the following questions: What IS categories are necessary? Are they gradient/continuous? How can one deal with optionality or redundancy? How are IS categories encoded grammatically? How do different empirical methods contribute to distinguishing between the influence of different IS categories on language comprehension and production? To answer these questions, a range of languages (Avatime, Chinese, German, Ishkashimi, Modern Greek, Old Saxon, Russian, Russian Sign Language and Sign Language of the Netherlands) and a range of phenomena from phonology, semantics, and syntax were investigated. The presented theories and data were based on different kinds of linguistic evidence: syntactic and semantic fieldwork, corpus studies, and phonological experiments. The six papers presented in this volume discuss a variety of IS categories, such as emphasis and contrast (Stavropoulous, Titov), association with focus and topics (van Putten, Karvovskaya), and givenness and backgrounding (Kimmelmann, Röhr).

The overall aim of this thesis is twofold: first, to develop and validate questionnaires that could be used for investigating relationships between perceptions of conscience, moral sensitivity and burnout and second, to describe patterns of self-comfort used to ease stress and illuminate meanings of living with a troubled conscience. The thesis comprises five studies and is based on both quantitative and qualitative data. In study I, a questionnaire was constructed to assess perceptions of conscience; the Perceptions of Conscience Questionnaire (PCQ). This 15 item-questionnaire was distributed to 444 care providers. Statistical analyses of responses showed sufficient distribution and a stable six factor solution congruent with reviewed literature. The six factors were labelled: ‘the voice of authority’, ‘warning signal’, ‘demanding sensitivity’, ‘asset’, ‘burden’ and ‘depending on culture’. The findings suggest that the PCQ is a valid questionnaire. The aim of study II was further development of an existing questionnaire assessing care providers’ moral sensitivity, enabling its use in various care contexts. The revised nine-item questionnaire, the Moral Sensitivity Questionnaire Revised version (MSQ-R), was distributed to 278 care providers with various professional backgrounds. Statistical analyses of responses showed sufficient distribution and a three-factor solution congruent with reviewed literature. The three factors were labelled: ‘sense of moral burden’, ‘sense of moral strength,’ and ‘sense of moral responsibility.’ The findings suggest that MSQ-R is valid for use in various healthcare contexts. In study III, the PCQ, the MSQ-R and the Maslach Burnout Inventory (MBI) were distributed to a population of psychiatric care providers (n=101) to investigate relationships between perceptions of conscience and moral sensitivity and levels of burnout. The hierarchical cluster analysis shows two clusters with Pearson’s r &gt;.50. Cluster A comprising items such as: being sensitive, interpreting and following the voice of conscience that warns us against hurting other or ourselves and developing as human beings was labelled ‘experiencing a sense of moral integrity’. Cluster B comprising items such as: feeling inadequate, doing more than one has strengths for, feeling always responsible, having difficulties to deal with wearing feelings, perceiving that conscience gives wrong signals and express social values, having to deaden one’ conscience, were all related to scores of the MBI subscales emotional exhaustion (EE) and depersonalisation (DP). Cluster B was labelled ‘experiencing a burdening accountability’. The results show that levels of ‘experiencing a burdening accountability’ are closely related to levels of being at risk of burnout. The aim of study IV was to describe patterns of self-comforting measures used to ease stress. The written accounts of 168 care providers and healthcare students were analysed by means of qualitative content analysis. The findings disclose two dimensions: an ability to use early learned measures to take care of oneself (ingression) and an ability to feel intimately related to life, other human beings and universe or God (transcendence). The findings provide valuable knowledge about self-comfort as a coping strategy. The aim of study V was to illuminate meanings of living with a troubled conscience. Ten psychiatric care providers, respondents of study III with various perceptions of conscience were interviewed. The interviews were interpreted using a phenomenological - hermeneutical method. The findings show that one meaning of living with a troubled conscience is being confronted with inadequacy and struggling to view oneself as ‘good enough.’ The comprehensive understanding indicates that inadequacy, both one’s own and that of organization one represents, infuse feelings of shame rather than feelings of guilt. Shame concerns one’s identity and need of reconciliation. Conclusions: The results reveal two ways of encountering a troubled conscience. One is being unable to interpret the ethical demand from a troubled conscience. This is indicated by connections between levels of moral burden and levels of burnout. The other way is being able to interpret the ethical demand and using one’s troubled conscience to develop practical wisdom. This means facing shame of feeling inadequate, reconciling images of the ideal self and self-contempt, and becoming realistic about what one can do. In this process comfort seems to be a mediator of reconciliation.