Secondary resurfacing of the patella in total knee arthroplasty

Anterior knee pain following primary total knee arthroplasty is common and can be difficult to treat satisfactorily. We reviewed 28 consecutive patients (29 knees) who underwent secondary resurfacing of the patella for persistent anterior knee pain and report on the results. Mean follow-up was 28 months (range12-61) with no cases lost to follow-up. Oxford knee scores, range of motion, the patient's assessment of outcome and overall satisfaction were recorded. Seventeen out of 19 (59%) felt their knee was better following patellar resurfacing, 10 out of 29 (34%) felt it was the same and two out of 29 (7%) felt it was worse. There was a significant improvement in Oxford knee scores (p < 0.001) and significant increase in patient satisfaction (p < 0.001) following secondary resurfacing. While secondary resurfacing of the patella does not provide the solution for every case of anterior knee pain following total knee joint replacement, in greater than 50% of cases it can be effective at relieving symptoms and in this series carries a low risk of worsening symptoms or complications

Modeling and Detection of Ice Particle Accretion in Aircraft Engine Compression Systems

The accretion of ice particles in the core of commercial aircraft engines has been an ongoing aviation safety challenge. While no accidents have resulted from this phenomenon to date, numerous engine power loss events ranging from uneventful recoveries to forced landings have been recorded. As a first step to enabling mitigation strategies during ice accretion, a detection scheme must be developed that is capable of being implemented on board modern engines. In this paper, a simple detection scheme is developed and tested using a realistic engine simulation with approximate ice accretion models based on data from a compressor design tool. These accretion models are implemented as modified Low Pressure Compressor maps and have the capability to shift engine performance based on a specified level of ice blockage. Based on results from this model, it is possible to detect the accretion of ice in the engine core by observing shifts in the typical sensed engine outputs. Results are presented in which, for a 0.1 percent false positive rate, a true positive detection rate of 98 percent is achieved

Constraints in Production and Marketing of Arecanut in Salem District of Tamil Nadu, India

Arecanut is an important cash crop in our country. The study was carried out to ascertain the constraints faced by arecanut farmers in Salem district of Tamil Nadu with a sample size of 120, by employing proportionate random sampling technique. Majority of the respondents expressed lack of specific grading of nuts in marketing as a constraint. More than three-fourths of the respondents suggested that there should be a mechanism to regulate import of nuts from other countries and to create market potential for nuts in the local markets

Investigating the machining of tungsten (W) using finite element analysis

Tungsten is extensively used as a plasma facing material in fusion energy reactors. A finite element model was created to simulate the machining of tungsten for the first time by estimating the cutting forces and observing the impact of the variation in tool rake angle. The model was validated through machining experiments involving a specially designed single flute fly cutter which indicated errors of 6% – 34%, depending on the rake angle. This investigation is the first step in understanding the impact of cutting parameters on machining of tungsten. However, the model is affected by the unpredictable impact of tungsten’s deformation behaviour and especially the effects of its brittle nature and low fracture toughness

How is your health in general? : qualitative and quantitative studies on self-assessed health and socioeconomic differences here

Measuring perceived health status through the single item "How is your health in general?" has appealed to many researchers. Understandably, as it is an easy to administer, highly reliable measure, 'vith strong predictive validity and -at the individual level- high content validity. However, although many (mostly quantitative) studies have been conducted on the single-item measure of self-assessed health, investigators have not been able to determine all dimensions which are involved in health-assessments. This illustrates that the greatest advantage of the single-item measure on self-assessed health over other measures of perceived health, the fact that it is fully individualised, is at the same time its greatest disadvantage; the process of health assessment is more or less a "black box". We still need to find out which dimensions are involved in answering this questio

Stability of the quantum supermembrane in a manifold with boundary

We point out an effect which may stabilize a supersymmetric membrane moving on a manifold with boundary, and lead to a light-cone Hamiltonian with a discrete spectrum of eigenvalues. The analysis is carried out explicitly for a closed supermembrane in the regularized $SU(N)$ matrix model version.Comment: 10 pages, harvmac (references added, minor changes

Power, norms and institutional change in the European Union: the protection of the free movement of goods

How do institutions of the European Union change? Using an institutionalist approach, this article highlights the interplay between power, cognitive limits, and the normative order that underpins institutional settings and assesses their impact upon the process of institutional change. Empirical evidence from recent attempts to reinforce the protection of the free movement of goods in the EU suggests that, under conditions of uncertainty, actors with ambiguous preferences assess attempts at institutional change on the basis of the historically defined normative order which holds a given institutional structure together. Hence, path dependent and incremental change occurs even when more ambitious and functionally superior proposals are on offer