Änderung des femoralen Offset durch Implantation handelsüblicher Hüftprothesen

Ziel: Untersuchung von Auftreten/Ausmass von Offsetaenderung durch auf dem deutschen Markt angebotene Hueftgelenkendoprothesen. 90 Modelle (594 div. Groessen), wurden virtuell bei 50 Patienten unter Beachtung von Passform und Beinlaenge implantiert (4500 virtuelle OP). Es zeigte sich sehr unterschiedliches Einsetzverhalten der TEP. Fuer einen Teil der Patienten ist es sehr schwer, eine geeignete TEP zu finden, die das Offset nicht veraendert. Die TEP liessen sich bei 2 bis 40 Patienten (MW=17) einsetzen. Der Betrag der mittleren Abweichung betraegt in diesem Fall fuer das gesamte TEP-Kollektiv 0,27cm, nur fuer Faelle mit Abweichung 0,56cm. Die Analyse TEP-Gesamtkollektiv bezogen auf einzelne Patienten zeigt, dass im Mittel nur 30 (1-67) der 90 TEP einzupassen sind. Hier betraegt die Offsets-Aenderung 0,4cm (-1,04 bis +1,54cm) im Betrag, nur bei Faellen mit Abweichung 0,64cm.Mit einem Grossteil der auf dem Markt befindlichen TEP kann das individuelle Offset nicht rekonstruiert werden

Convergence analysis of a multigrid algorithm for the acoustic single layer equation

We present and analyze a multigrid algorithm for the acoustic single layer equation in two dimensions. The boundary element formulation of the equation is based on piecewise constant test functions and we make use of a weak inner product in the multigrid scheme as proposed in \cite{BLP94}. A full error analysis of the algorithm is presented. We also conduct a numerical study of the effect of the weak inner product on the oscillatory behavior of the eigenfunctions for the Laplace single layer operator

Mediation in the Law Curriculum

Cited by Lord Neuberger in ‘Educating Future Mediators’ at the 4th Civil Mediation Council National Conference, May 201

Sprint start kinetics of amputee and non-amputee sprinters

The purpose of this study was to explore the relationship between the forces applied to the starting blocks and the start performances (SPs) of amputee sprinters (ASs) and non-amputee sprinters (NASs). SPs of 154 male and female NASs (100-m personal records [PRs], 9.58–14.00 s) and 7 male ASs (3 unilateral above knee, 3 unilateral below knee, 1 bilateral below knee; 100 m PRs, 11.70–12.70 s) with running specific prostheses (RSPs) were analysed during full-effort sprint starts using instrumented starting blocks that measured the applied forces in 3D. Using the NAS dataset and a combination of factor analysis and multiple regression techniques, we explored the relationship between force characteristics and SP (quantified by normalized average horizontal block power). Start kinetics were subsequently compared between ASs and NASs who were matched based on their absolute 100 m PR and their 100 m PR relative to the world record in their starting class. In NASs, 86% of the variance in SP was shared with five latent factors on which measured parameters related to force application to the rear and front blocks and the respective push-off directions in the sagittal plane of motion were loaded. Mediolateral force application had little influence on SP. The SP of ASs was significantly reduced compared to that of NASs matched on the basis of relative 100-m PR (−33.8%; d = 2.11, p < 0.001), while a non-significant performance reduction was observed when absolute 100-m PRs were used (−17.7%; d = 0.79, p = 0.09). These results are at least partially explained by the fact that force application to the rear block was clearly impaired in the affected legs of ASs

A Housing Affordability Standard for the UK

Since 1990 there has been extensive exploration of the meaning of housing affordability by members of the academic, professional and advocacy communities in Britain. These debates have revealed weaknesses in the traditional ratio standard of affordability and led to arguments in support of an alternative, residual income concept of affordability. However, so far there has been only limited success in operationalising and applying the residual income approach in the UK. In the US, by contrast, arguments in support of a residual income approach to housing affordability emerged in the late 1960s and early 1970s, culminating in the formulation of operational standards utilising normative family budgets. This paper draws upon the US experience to formulate a residual income housing affordability standard for the UK that utilises the non-shelter components of the Family Budget Unit (FBU) ‘Low Cost but Acceptable’ budgets as the normative standard for minimum adequate residual income. The paper concludes by suggesting how use of such a ‘shelter’ poverty standard to assess housing affordability problems and needs in the UK might yield results that differ from those based on the ratio standard

The BPX Preconditioner for the Single Layer Potential Operator

In this paper we discuss the BPX preconditioner for the single layer potential operator. We find that the extrem eigenvalues of the preconditioner applied to the single layer potential operator are bounded independent of the number of unknowns. A description of an efficient implementation of the BPX algorithm is given. Subject Classifications: AMS(MOS) Key words: 1 Introduction It was shown in [1] that the BPX preconditioner is a very efficient preconditioner for iterative solvers of finite element discretizations of elliptic boundary value problems. The goal of this paper is to apply the BPX preconditioner B to the integral operator V of the single layer potential, which is a pseudo differential operator of order minus one. We prove the efficiency of this preconditioner by showing that the condition number of BV is independent of the number of unknowns. In Section 2 we review the mapping properties of the integral operator V and comment on the behaviour of the eigenvalues of the c..

Hierarchical Basis Preconditioners for Coupled FEM-BEM Equations

this paper is to present a nearly optimal preconditioned iterative method to solve indefinite linear systems of equations arising from h-adaptive procedures for the symmetric coupling of Finite Elements and Boundary Elements. This solver is nearly optimal in the sense, that its convergence rate grows only logarithmically with the number of unknowns. The algorithm is based on the conjugate residual method with block-diagonal preconditioning, where no Schur complement construction is required. This method uses different hierarchical basis preconditioners for the positive semi--definite FEM block belonging to an interior Neumann problem and the negative definite boundary element block belonging to the single layer potential. The efficiency of the hierarchical basis solvers is underlined by a numerical experiment showing fast convergence