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Broadly speaking, an engineer's constant aim is the creation of something which serves mankind. In order to achieve his aim the engineer has to tackle numerous problems arising between the time of conception and the final bringing into service of the product. To this end it is convenient to picture the process as divided into three stages. The first stage is to recognise the existence of the real problem, with its multitude of complexities and details, all at varying levels of importance. The real problem is always too difficult to handle directly, and as an aid to thinking, great simplifications are made. The simplified problem may be called the physical model, in which only the more important aspects of the real problem are defined. The setting up of a physical model requires skill, judgement and, in most cases, experience with similar situations. It follows that the first physical model may at times be subject to subsequent variations and revisions. Finally, a mathematical model is formulated this model attempts to describe, by means of mathematical equations, the behaviour of the physical model. For example, if the real problem is one of structural design, the unknowns in the final equations are usually design parameters such as stress, deflection, beam depth and so on. Thus the solution of the equations defines the behaviour of the physical model in terms of design parameters, but the degree to which these apply to the real problem depends on how well the physical model represents the real structure. Final design is achieved only after many cycles of appraisal, modifications to the physical model, refinements, re-evaluation, and so on. The above philosophy is generally applicable, indeed it is believed to be the only successful method of problem solving in any field, especially in engineering. This thesis is concerned with the problem of the behaviour of framed structures. Throughout the work, emphasis is placed on the geometry of the deformations of the frame. Although it is often not appreciated, the geometric approach has dominated throughout the history of structural engineering development. The reason for this is obvious, because once the deformations of a structure are known, other quantities like stresses, strains, bending moments and so on, are easily calculated. Another reason is that deformations, unlike forces (the alternative to a geometric approach is a force approach), can be pictured and drawn to scale or sketched. Such a picture is readily obtained from experiments and one is always pleasantly surprised at how much information can be drawn from but the simplest measurements of deformations. The author has experienced most success from simply constructed, light and flexible models which, apart from being inexpensive, are easily deformed by hand, and the deformed models are quickly sketched or traced. Frequently a wire or cardboard model may be used in order to gain a preliminary understanding of the deformations.

INTRODUCTION: The previously reported randomised controlled trial of a consensus regimen of pulse cyclophosphamide suggested that it was as effective as a daily oral (DO) cyclophosphamide for remission induction of antineutrophil cytoplasm autoantibodies-associated systemic vasculitis when both were combined with the same glucocorticoid protocol (CYCLOPS study (Randomised trial of daily oral versus pulse Cyclophosphamide as therapy for ANCA-associated Systemic Vasculitis published de groot K, harper L et al Ann Int Med 2009)). The study had limited power to detect a difference in relapse. This study describes the long-term outcomes of patients in the CYCLOPS study. METHODS: Long-term outcomes were ascertained retrospectively from 148 patients previously recruited to the CYCLOPS Trial. Data on survival, relapse, immunosuppressive treatment, cancer incidence, bone fractures, thromboembolic disease and cardiovascular morbidity were collected from physician records retrospectively. All patients were analysed according to the group to which they were randomised. RESULTS: Median duration of follow-up was 4.3 years (IQR, 2.95-5.44 years). There was no difference in survival between the two limbs (p=0.92). Fifteen (20.8%) DO and 30 (39.5%) pulse patients had at least one relapse. The risk of relapse was significantly lower in the DO limb than the pulse limb (HR=0.50, 95% CI 0.26 to 0.93; p=0.029). Despite the increased risk of relapse in pulse-treated patients, there was no difference in renal function at study end (p=0.82). There were no differences in adverse events between the treatment limbs. DISCUSSION: Pulse cyclophosphamide is associated with a higher relapse risk than DO cyclophosphamide. However, this is not associated with increased mortality or long-term morbidity. Although the study was retrospective, data was returned in 90% of patients from the original trial.