Direct and inverse transient eddy current problems

Die vorliegende Arbeit behandelt Vorwärts- sowie Rückwärtstheorie transienter Wirbelstromprobleme. Transiente Anregungsströme induzieren elektromagnetische Felder, welche sogenannte Wirbelströme in leitfähigen Objekten erzeugen. Im Falle von sich langsam ändernden Feldern kann diese Wechselwirkung durch die Wirbelstromgleichung, einer Approximation an die Maxwell-Gleichungen, beschrieben werden. Diese ist eine lineare partielle Differentialgleichung mit nicht-glatten Koeffizientenfunktionen von gemischt parabolisch-elliptischem Typ. Das Vorwärtsproblem besteht darin, zu gegebener Anregung sowie den umgebungsbeschreibenden Koeffizientenfunktionen das elektrische Feld als distributionelle Lösung der Gleichung zu bestimmen. Umgekehrt können die Felder mit Messspulen gemessen werden. Das Ziel des Rückwärtsproblems ist es, aus diesen Messungen Informationen über leitfähige Objekte, also über die Koeffizientenfunktion, die diese beschreibt, zu gewinnen. In dieser Arbeit wird eine variationelle Lösungstheorie vorgestellt und die Wohlgestelltheit der Gleichung diskutiert. Darauf aufbauend wird das Verhalten der Lösung für verschwindende Leitfähigkeit studiert und die Linearisierbarkeit der Gleichung ohne leitfähiges Objekt in Richtung des Auftauchens eines leitfähigen Objektes gezeigt. Zur Regularisierung der Gleichung werden Modifikationen vorgeschlagen, welche ein voll parabolisches bzw. elliptisches Problem liefern. Diese werden verifiziert, indem die Konvergenz der Lösungen gezeigt wird. Zuletzt wird gezeigt, dass unter der Annahme von sonst homogenen Umgebungsparametern leitfähige Objekte eindeutig durch die Messungen lokalisiert werden können. Hierzu werden die Linear Sampling Methode sowie die Faktorisierungsmethode angewendet.

Is computer-assisted telephone triage safe? A prospective surveillance study in walk-in patients with non-life-threatening medical conditions

Background Patients often establish initial contact with healthcare institutions by telephone. During this process they are frequently medically triaged. Purpose To investigate the safety of computer-assisted telephone triage for walk-in patients with non-life-threatening medical conditions at an emergency unit of a Swiss university hospital. Methods This prospective surveillance study compared the urgency assessments of three different types of personnel (call centre nurses, hospital physicians, primary care physicians) who were involved in the patients' care process. Based on the urgency recommendations of the hospital and primary care physicians, cases which could potentially have resulted in an avoidable hazardous situation (AHS) were identified. Subsequently, the records of patients with a potential AHS were assessed for risk to health or life by an expert panel. Results 208 patients were enrolled in the study, of whom 153 were assessed by all three types of personnel. Congruence between the three assessments was low. The weighted κ values were 0.115 (95% CI 0.038 to 0.192) (hospital physicians vs call centre), 0.159 (95% CI 0.073 to 0.242) (primary care physicians vs call centre) and 0.377 (95% CI 0.279 to 0.480) (hospital vs primary care physicians). Seven of 153 cases (4.57%; 95% CI 1.85% to 9.20%) were classified as a potentially AHS. A risk to health or life was adjudged in one case (0.65%; 95% CI 0.02% to 3.58%). Conclusion Medical telephone counselling is a demanding task requiring competent specialists with dedicated training in communication supported by suitable computer technology. Provided these conditions are in place, computer-assisted telephone triage can be considered to be a safe method of assessing the potential clinical risks of patients' medical conditions.

Verifying Harder's Conjecture for Classical and Siegel Modular Forms

A conjecture by Harder shows a surprising congruence between the coefficients of “classical” modular forms and the Hecke eigenvalues of corresponding Siegel modular forms, contigent upon “large primes” dividing the critical values of the given classical modular form. Harder’s Conjecture has already been verified for one-dimensional spaces of classical and Siegel modular forms (along with some two-dimensional cases), and for primes p 37. We verify the conjecture for higher-dimensional spaces, and up to a comparable prime p.

Public Speaking Anxiety, Test Anxiety, and Academic Achievement in Undergraduate Students

Public speaking anxiety and test anxiety are both psychological difficulties which may adversely influence academic achievement in undergraduate students. Previous research has indicated that both public speaking anxiety and test anxiety are negatively correlated with academic performance, usually measured by grade point average. The purpose of this study was to assess the prevalence of public speaking anxiety, test anxiety, and their effects on academic achievement in a sample of undergraduate students, and to determine if certain groups of students are more likely to be affected than others. Although test anxiety and public speaking anxiety were both found to be negatively correlated with grade point average, these correlations were not statistically significant. Potential reasons for the lack of statistical congruence with previous studies, as well as implications for future research and treatment, are discussed.

Comparative Czech and Polish Perspectives and Policies on the Eastern Enlargement of the EU and the Prominence of the German Factor

With the end of the Cold War, which for central and eastern Europe in many respects meant the real political end to the Second World War, Germany regained its central position in the region. The Federal Republic quickly established itself as a major political and economic partner for both the Czech Republic and Poland. More importantly, due to its support for the idea of EU and NATO enlargement. Germany also became the most active western advocate of the Czech and Polish 'return to Europe'. The question remains, however, of whether Germany's relations with Poland and the Czech Republic can mature into a close axis like that enjoyed between Paris and Bonn/Berlin, or whether they will continue to develop along the lines of 'strategic congruence' but 'emotional mistrust and reserve'. The research here looked at three aspects of this question. First it considered the idea of a link between perceptions of Germany and broader considerations of European integration in Poland and the Czech Republic and outlined the ways in which Germany has motivated Czech and Polish activities and policies on EU membership. The team then focused upon on-going Czech and Polish EU integration strategies and sought to identify the actual ways in which Germany's advocacy of EU enlargement in manifest in cooperation 'on the ground'. The group concluded by considering prospects for Czech/German and Polish/German cooperation in the context of the enlarged European Union.

Genetic relatedness within the genus Campylobacter inferred from rpoB sequences

The genus Campylobacter comprises 17 species, some of which are important animal and human pathogens. To gain more insight into the genetic relatedness of this genus and to improve the molecular tools available for diagnosis, a universal sequencing approach was established for the gene encoding the beta-subunit of RNA polymerase (rpoB) for the genus Campylobacter. A total of 59 strains, including the type strains of currently recognized species as well as field isolates, were investigated in the study. A primer set specific for Campylobacter species enabled straightforward amplification and sequencing of a 530 bp fragment of the rpoB gene. The 16S rRNA gene sequences of all of the strains were determined in parallel. A good congruence was obtained between 16S rRNA and rpoB gene sequence-based trees within the genus Campylobacter. The branching of the rpoB tree was similar to that of the 16S rRNA gene tree, even though a few discrepancies were observed for certain species. The resolution of the rpoB gene within the genus Campylobacter was generally much higher than that of the 16S rRNA gene sequence, resulting in a clear separation of most species and even some subspecies. The universally applicable amplification and sequencing approach for partial rpoB gene sequence determination provides a powerful tool for DNA sequence-based discrimination of Campylobacter species.

[Medium-term results after m. vastus medialis obliquus-plasty for lateral patellar dislocation]

Progressive retropatellar arthrosis is often seen in dated rigid distal realignment (i.e. osteotomy of tuberositas) at long-term follow-ups. Therefore, operations for lateral dislocation of the patella are still discussed controversially. Dynamic, proximal realignments seem to have lower rates of arthrosis but higher rates of redislocation. Recently, in anatomic and biomechanic studies, the m. vastus medialis obliquus (vmo) was found to be one of the most important proximal restraints to lateral dislocation of the patella.A total of 28 patients (mean age 21.5 years) were treated between 1994 and 2003 with a plasty of the vmo for lateral patellar dislocation. The technique was performed for most etiologies of femoropatellar instability.For this proximal soft tissue technique, the muscle tendon is detached from its patellar insertion. Subsequently, the tendon is reinserted at the patella 10-15 mm more distally and fixed with Mitek anchors. Full weight bearing in extension is possible immediately after surgery. An active vastus medialis training is started after 6 weeks.Of the patients, 27 were evaluated clinically and radiologically in 2004 (a mean of 5 years postoperatively). A total of 83% of the patients estimated the result to be good or excellent, 10% were satisfied and 7% were discontent. The mean Lysholm-Knee-Score was 83.1 points. Two patients suffered a patella redislocation (7%). A statistically significant improvement of the congruence angle was noted in the radiographs, even in medium-term controls. In 89% of the cases no or only little retropatellar arthrosis was observed. These 5 year results are comparable to those of other techniques for distal or proximal realignments. The rate of redislocation was below average. Compared to the rate of retropatellar arthrosis in long-term results of rigid distal realignment, our patients demonstrated a relative low rate after 5 years. We attribute this to the minimal interference in physiological joint mechanics and to the restored anatomy. In terms of future long-term results, our findings are promising. The idea of a proximal dynamic stabilization and the causal operative approach at the origin of pathology using vmo-plasty was confirmed in recent anatomic and biomechanic studies. Over or under correction of soft tissues could be adapted. More rigid techniques of distal realignment do not allow an adaptation to this extent and can lead to prearthrotic hyperpression in the medial femoropatellar and femorotibial joints.

Harm reduction in Bern: from outreach to heroin maintenance

In Switzerland, harm-reduction programs have the support of the national government and many localities, in congruence with much of the rest of Europe and in contrast with the United States, and take place in public settings. The threat of AIDS is recognized as the greater harm. This paper describes the overall national program and highlights the experience from one city; the program is noteworthy because it is aimed at gathering comparative data from controlled trials.

A Diagnostic Test for the Mixing Distribution in a Generalised Linear Mixed Model

We introduce a diagnostic test for the mixing distribution in a generalised linear mixed model. The test is based on the difference between the marginal maximum likelihood and conditional maximum likelihood estimates of a subset of the fixed effects in the model. We derive the asymptotic variance of this difference, and propose a test statistic that has a limiting chi-square distribution under the null hypothesis that the mixing distribution is correctly specified. For the important special case of the logistic regression model with random intercepts, we evaluate via simulation the power of the test in finite samples under several alternative distributional forms for the mixing distribution. We illustrate the method by applying it to data from a clinical trial investigating the effects of hormonal contraceptives in women.

Bayesian Hierarchical Distributed Lag Models for Summer Ozone Exposure and Cardio-Respiratory Mortality

In this paper, we develop Bayesian hierarchical distributed lag models for estimating associations between daily variations in summer ozone levels and daily variations in cardiovascular and respiratory (CVDRESP) mortality counts for 19 U.S. large cities included in the National Morbidity Mortality Air Pollution Study (NMMAPS) for the period 1987 - 1994. At the first stage, we define a semi-parametric distributed lag Poisson regression model to estimate city-specific relative rates of CVDRESP associated with short-term exposure to summer ozone. At the second stage, we specify a class of distributions for the true city-specific relative rates to estimate an overall effect by taking into account the variability within and across cities. We perform the calculations with respect to several random effects distributions (normal, t-student, and mixture of normal), thus relaxing the common assumption of a two-stage normal-normal hierarchical model. We assess the sensitivity of the results to: 1) lag structure for ozone exposure; 2) degree of adjustment for long-term trends; 3) inclusion of other pollutants in the model;4) heat waves; 5) random effects distributions; and 6) prior hyperparameters. On average across cities, we found that a 10ppb increase in summer ozone level for every day in the previous week is associated with 1.25 percent increase in CVDRESP mortality (95% posterior regions: 0.47, 2.03). The relative rate estimates are also positive and statistically significant at lags 0, 1, and 2. We found that associations between summer ozone and CVDRESP mortality are sensitive to the confounding adjustment for PM_10, but are robust to: 1) the adjustment for long-term trends, other gaseous pollutants (NO_2, SO_2, and CO); 2) the distributional assumptions at the second stage of the hierarchical model; and 3) the prior distributions on all unknown parameters. Bayesian hierarchical distributed lag models and their application to the NMMAPS data allow us estimation of an acute health effect associated with exposure to ambient air pollution in the last few days on average across several locations. The application of these methods and the systematic assessment of the sensitivity of findings to model assumptions provide important epidemiological evidence for future air quality regulations.

A Mechanistic Latent Variable Model for Estimating Drug Concentrations in the Male Genital Tract

The purpose of this study is to develop statistical methodology to facilitate indirect estimation of the concentration of antiretroviral drugs and viral loads in the prostate gland and the seminal vesicle. The differences in antiretroviral drug concentrations in these organs may lead to suboptimal concentrations in one gland compared to the other. Suboptimal levels of the antiretroviral drugs will not be able to fully suppress the virus in that gland, lead to a source of sexually transmissible virus and increase the chance of selecting for drug resistant virus. This information may be useful selecting antiretroviral drug regimen that will achieve optimal concentrations in most of male genital tract glands. Using fractionally collected semen ejaculates, Lundquist (1949) measured levels of surrogate markers in each fraction that are uniquely produced by specific male accessory glands. To determine the original glandular concentrations of the surrogate markers, Lundquist solved a simultaneous series of linear equations. This method has several limitations. In particular, it does not yield a unique solution, it does not address measurement error, and it disregards inter-subject variability in the parameters. To cope with these limitations, we developed a mechanistic latent variable model based on the physiology of the male genital tract and surrogate markers. We employ a Bayesian approach and perform a sensitivity analysis with regard to the distributional assumptions on the random effects and priors. The model and Bayesian approach is validated on experimental data where the concentration of a drug should be (biologically) differentially distributed between the two glands. In this example, the Bayesian model-based conclusions are found to be robust to model specification and this hierarchical approach leads to more scientifically valid conclusions than the original methodology. In particular, unlike existing methods, the proposed model based approach was not affected by a common form of outliers.

Becoming most fully ourselves : gender, voice, and ritual in dissertations

The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher. Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse. The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse. The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse. The writing and defense of the dissertation serve both as demonstration one is able to do the work of a scholar and as a rite of initiation. In contrast to much academic writing, dissertations generally adhere to narrowly conceived notions of academic discourse. I explore this within the context of an academic community in which under-representation remains a serious issue. This dissertation is about women writing dissertations. I draw from conversations with fifteen women, in or beyond, the process; friends’ anecdotes; published accounts; and, autobiographically, my experience. I suggest the dissertation’s initiatory role is at least as important as its scholarly role; during the process one establishes a sense of self as scholar, writer, and researcher Students come to the dissertation with some notion of self as writer and scholar – a culturally negotiated sense that is more, or less, congruent with the culturally established self required for successful completion of the dissertation. The degree of congruence (or alternatively, harmony and dissonance) shapes the process of doing a dissertation. I argue that both the community and the language in which dissertations must generally be written are gendered masculine. Negotiating a voice that is acceptable in a dissertation while maintain fidelity to a sense of who one is seems more problematic as one’s distance from the center of dominant culture increases. Believing that agency lies in altering the reiteration of such processes, I worked with my committee to find ways to alter the process yet still do a dissertation I write in a variety of voices – essay and poetry as well as analytical – play with visual qualities of text, and experiment with non-verbal interpretations. These don’t exhaust possibilities, but do give a sense of how the rich variety of expression found in academe cam be brought into the dissertation. I thus demonstrate that one need not reconstitute herself through characteristic academic discourse in order to be initiated into the community of scholars. I suggest both the desirability of encouraging flexibility in the language, form, and process, of dissertations, and the theoretical necessity for such flexibility if the academic community is to become diverse.

Benson's Theorem for Partial Geometries

In 1970 Clark Benson published a theorem in the Journal of Algebra stating a congruence for generalized quadrangles. Since then this theorem has been expanded to other specific geometries. In this thesis the theorem for partial geometries is extended to develop new divisibility conditions for the existence of a partial geometry in Chapter 2. Then in Chapter 3 the theorem is applied to higher dimensional arcs resulting in parameter restrictions on geometries derived from these structures. In Chapter 4 we look at extending previous work with partial geometries with α = 2 to uncover potential partial geometries with higher values of α. Finally the theorem is extended to strongly regular graphs in Chapter 5. In addition we obtain expressions for the multiplicities of the eigenvalues of matrices related to the adjacency matrices of these graphs. Finally, a four lesson high school level enrichment unit is included to provide students at this level with an introduction to partial geometries, strongly regular graphs, and an opportunity to develop proof skills in this new context.

Polarity correspondence in comparative number magnitude judgments

When asked which of two digits is greater, participants respond more quickly if physical size corresponds to number magnitude, such as in 3 7, than when the two attributes contradict each other, such as in 3 7. This size congruence effect in comparative number judgments is a well-documented phenomenon. We extended existing findings by showing that this effect does not depend on physical size of the number alone but can be observed with number symmetry. In addition, we observed that symmetric numbers are judged as being smaller than asymmetric numbers, which renders an interpretation of the number symmetry congruence effect in terms of physical size implausible. We refer to the polarity correspondence principle (Proctor & Cho, 2006) to explain the present findings.

Comparative phylogenies of the housekeeping genes atpD, infB and rpoB and the 16S rRNA gene within the Pasteurellaceae

Phylogenies of housekeeping gene and 16S rRNA gene sequences were compared to improve the classification of the bacterial family Pasteurellaceae and knowledge of the evolutionary relationships of its members. Deduced partial protein sequences of the housekeeping genes atpD, infB and rpoB were compared in 28, 36 and 28 representative taxa of the Pasteurellaceae, respectively. The monophyly of representatives of the genus Gallibacterium was recognized by analysis of all housekeeping genes, while members of Mannheimia, Actinobacillus sensu stricto and the core group of Pasteurella sensu stricto formed monophyletic groups with two out of three housekeeping genes. Representatives of Mannheimia, Actinobacillus sensu stricto, [Haemophilus] ducreyi and [Pasteurella] trehalosi formed a monophyletic unit by analysis of all three housekeeping genes, which was in contrast to the 16S rRNA gene-derived phylogeny, where these taxa occurred at separate positions in the phylogenetic tree. Representatives of the Rodent, Avian and Aphrophilus-Haemophilus 16S rRNA gene groups were weakly supported by phylogenetic analysis of housekeeping genes. Phylogenies derived by comparison of the housekeeping genes diverged significantly from the 16S rRNA gene-derived phylogeny as evaluated by the likelihood ratio test. A low degree of congruence was also observed between the individual housekeeping gene-derived phylogenies. Estimates on speciation derived from 16S rRNA and housekeeping gene sequence comparisons resulted in quite different evolutionary scenarios for members of the Pasteurellaceae. The phylogeny based on the housekeeping genes supported observed host associations between Mannheimia, Actinobacillus sensu stricto and [Pasteurella] trehalosi and animals with paired hooves.