Hospital-acquired infections in two district hospitals in Kenya

Introduction: Little is known about hospital-acquired infections (HAI) in developing countries although surgical site infections (SSI) are thought to be a particular problem. The aim of the work in this thesis was to describe three different forms of HAI (SSI, hospital-acquired bacteraemia in children, transmission of MRSA in hospital inpatients) in hospitals in sub-Saharan Africa and to make changes, where possible, to prevent their occurrence. Methods: A literature review on the subject of SSI in sub-Saharan Africa was conducted as part of the preliminary investigation. To study the occurrence of SSI in Thika Hospital in Kenya, SSI surveillance was established at this site and we subsequently implemented a change in the use of surgical antibiotic prophylaxis at this hospital. The occurrence of MRSA amongst inpatients in Thika Hospital was measured in a cross-sectional study and the occurrence of hospital-acquired bacteraemia in children in Kilifi Hospital, Kenya was measured using surveillance data from 2002-2009. Results: The epidemiological characteristics of the SSI surveillance programme in Thika Hospital were examined including: the consistency of parameter scoring by surgeons and anaesthetists; the sensitivity and specificity of telephone-based post-discharge surveillance; the performance of risk indicators in predicting SSI after major Obstetric+Gynaecological surgery. The process, outcome and balancing effects of changing the use of surgical antibiotic prophylaxis at Thika Hospital were evaluated, showing that there was rapid and sustained uptake of pre-operative antibiotic prophylaxis use and a more gradual reduction in use of post-operative antibiotics. There was evidence of a modest reduction in the risk of superficial SSI, and an overall reduction in the use of antibiotics, with accompanying cost and time savings. The risk, rate, aetiology and morbidity and mortality impacts associated with paediatric hospital- acquired bacteraemia in Kilifi Hospital were examined. In a subsequently published correspondence questions regarding Coagulase-negative staphylococci, premature infants and competing risks were addressed. MRSA carriage rate amongst inpatients in Thika Hospital was estimated. This organism was relatively rare, and carriage was largely confined to patients with bums. All MRSA isolates obtained were in the ST239-t037 clone, suggesting within-hospital transmission. Conclusion: The work of this thesis suggests that the problem of hospital-acquired infections in sub- Saharan Africa is substantial, although there are some simple and achievable steps that can be taken to reduce their occurrence

Singular Sylvester equation and its applications

This thesis concerns singular Sylvester operator equations, that is, equations of the form AX-XB=C, under the premise that they are either unsolvable or have infinitely many solutions. The equation is studied in different cases, first in the matrix case, then in the case when A, B and C are bounded linear operators on Banach spaces, and finally in the case when A and B are closed linear operators defined on Banach or Hilbert spaces. In each of these cases, solvability conditions are derived and then, under those conditions, the initial equation is solved. Exact solutions are obtained in their closed forms, and their classification is conducted. It is shown that all solutions are obtained in the manner illustrated in this thesis. Special attention is dedicated to approximation schemes of the solutions. Obtained results are illustrated on some contemporary problems from operator theory, among which are spectral problems of bounded and unbounded linear operators, Sturm-Liouville inverse problems and some operator equations from quantum mechanics

Termination and Productivity

Klop, J.W. [Promotor]Vrijer, R.C. de [Copromotor

Combinatorics of Pisot Substitutions

Siirretty Doriast

Number Theory, Analysis and Geometry: In Memory of Serge Lang

Serge Lang was an iconic figure in mathematics, both for his own important work and for the indelible impact he left on the field of mathematics, on his students, and on his colleagues. Over the course of his career, Lang traversed a tremendous amount of mathematical ground. As he moved from subject to subject, he found analogies that led to important questions in such areas as number theory, arithmetic geometry and the theory of negatively curved spaces. Lang's conjectures will keep many mathematicians occupied far into the future. In the spirit of Lang’s vast contribution to mathematics, this memorial volume contains articles by prominent mathematicians in a variety of areas, namely number theory, analysis and geometry, representing Lang’s own breadth of interests. A special introduction by John Tate includes a brief and engaging account of Serge Lang’s life

On Musical Self-Similarity : Intersemiosis as Synecdoche and Analogy

Self-similarity, a concept borrowed from mathematics, is gradually becoming a keyword in musicology. Although a polysemic term, self-similarity often refers to the multi-scalar feature repetition in a set of relationships, and it is commonly valued as an indication for musical ‘coherence’ and ‘consistency’. In this study, Gabriel Pareyon presents a theory of musical meaning formation in the context of intersemiosis, that is, the translation of meaning from one cognitive domain to another cognitive domain (e.g. from mathematics to music, or to speech or graphic forms). From this perspective, the degree of coherence of a musical system relies on a synecdochic intersemiosis: a system of related signs within other comparable and correlated systems. The author analyzes the modalities of such correlations, exploring their general and particular traits, and their operational bounds. Accordingly, the notion of analogy is used as a rich concept through its two definitions quoted by the Classical literature—proportion and paradigm, enormously valuable in establishing measurement, likeness and affinity criteria. At the same time, original arguments by Benoît B. Mandelbrot (1924–2010) are revised, alongside a systematic critique of the literature on the subject. In fact, connecting Charles S. Peirce’s ‘synechism’ with Mandelbrot’s ‘fractality’ is one of the main developments of the present study