Plantaris excision reduces pain in Mid-portion Achilles tendinopathy even in the absence of plantaris tendinosis

Background It is becoming increasingly apparent that the plantaris can contribute to symptoms in at least a subset of patients with mid-portion Achilles tendinopathy. However the nature of its involvement remains unclear. Hypothesis / Purpose To determine whether excised plantaris tendons from patients with mid-portion Achilles tendinopathy display tendinopathic changes and whether the presence of such changes affect clinical outcomes. Methods Sixteen plantaris tendons patients with mid-portion Achilles tendinopathy recalcitrant to conservative management underwent histological examination for the presence of tendinopathic changes. All patients had imaging to confirm the presence of the plantaris tendon adherent to or invaginated into the focal area of Achilles tendinosis. Visual analogue scores (VAS) and foot and ankle outcome scores (FAOS) were recorded pre and post-operatively. Results Sixteen patients (mean age 26.2; 18-47 years) underwent surgery with a mean follow-up of 14 months (range 6-20 months). The plantaris tendon was histologically normal in 13/16 cases (81%). Inflammatory changes in the loose peritendinous connective tissue surrounding the plantaris tendon were evident in all cases. There was significant improvement in mean VAS scores (p<0.05) and all domains of the FAOS post-operatively (p<0.05). Conclusions The absence of any tendinopathic changes in the excised plantaris of 13 patients who clinically improved suggests plantaris involvement with Achilles tendinopathy may not yet be fully understood and supports the concept that this may be a compressive or a frictional phenomenon rather than purely tendinopathic. Clinical Relevance There is increasing evidence to support that the excision of plantaris results in improved clinical outcomes in a sub-set of patients with mid-portion Achilles tendinopathy. Prior findings have reported that excised plantaris tendons from these patients display tendinopathic changes. However these findings suggest the role of plantaris in the pathology of these patients could be biomechanical since patients improved even when the excised plantaris was not tendinopathic

Maps, agents and dialogue for exploring a virtual world

In previous years we have been involved in several projects in which users (or visitors) had to find their way in information-rich virtual environments. 'Information-rich' means that the users do not know beforehand what is available in the environment, where to go in the environment to find the information and, moreover, users or visitors do not necessarily know exactly what they are looking for. Information-rich means also that the information may change during time. A second visit to the same environment will require different behavior of the visitor in order for him or her to obtain similar information than was available during a previous visit. In this paper we report about two projects and discuss our attempts to generalize from the different approaches and application domains to obtain a library of methods and tools to design and implement intelligent agents that inhabit virtual environments and where the agents support the navigation of the user/visitor

Musical Multimodal Child Computer Interaction

In this project an interactive computer system is designed that envisions to contribute to young children's musical education. From literature, requirements for musical interaction were derived. In this paper these requirements and the design of the system are described

Monotonicity and error bounds for networks of Erlang loss queues

Networks of Erlang loss queues naturally arise when modelling finite communication systems without delays, among which, most notably are (i) classical circuit switch telephone networks (loss networks) and (ii) present-day wireless mobile networks. Performance measures of interest such as loss probabilities or throughputs can be obtained from the steady state distribution. However, while this steady state distribution has a closed product form expression in the first case (loss networks), it does not have one in the second case due to blocked (and lost) handovers. Product form approximations are therefore suggested. These approximations are obtained by a combined modification of both the state space (by a hypercubic expansion) and the transition rates (by extra redial rates). It will be shown that these product form approximations lead to (1) upper bounds for loss probabilities and \ud (2) analytic error bounds for the accuracy of the approximation for various performance measures.\ud The proofs of these results rely upon both monotonicity results and an analytic error bound method as based on Markov reward theory. This combination and its technicalities are of interest by themselves. The technical conditions are worked out and verified for two specific applications:\ud (1)• pure loss networks as under (2)• GSM networks with fixed channel allocation as under.\ud The results are of practical interest for computational simplifications and, particularly, to guarantee that blocking probabilities do not exceed a given threshold such as for network dimensioning

Firm relocation: state of the art and research prospects

This paper deals with firm relocation. Firm relocation is a particular form of locational adjustment of the firm and one of the possible ways to adjust to changes in markets, preferences of consumers, environmental regulations, technological progress etc. In section 2 we will treat the neo-classical, the behavioural, and the institutional approaches respectively. Next, a historical review of firm relocation research is presented, in section 3. It starts with the "classical studies" of the first post-war period, followed by a description of what can be called the golden era of firm relocation studies according to the large number of studies: the nineteen sixties and seventies. This section ends with an overview of firm relocation studies of the last decades of the previous century. In section 4 we present an example an empirical study that addresses relevant firm relocation for the present era by means of a statistical model estimated on data for individual firms of the Netherlands. We conclude the chapter with a discussion of why and how the firm relocation research frontier can be pushed forward and give suggestions for further research also in relation with policy.