Designing a Compensated–Kidney Donation System

Osteochondral lesions of the talus (OLTs) are the third most common type of osteochondral lesion and can cause pain and instability of the ankle joint. Episurf Medical AB is a medical technology company that develops individualized implants for patients who are suffering from focal cartilage lesions. Episurf have recently started a project that aims to implement their implantation technique in the treatment of OLTs. This master thesis was a part of Episurf’s talus project and the main goal of the thesis was to find the optimal implantation angle of the Episurf implant when treating OLTs. The optimal implantation angle was defined as the angle that minimized the maximum equivalent (von Mises) strain acting on the implant shaft during the stance phase of a normal gait cycle. It is desirable to minimize the strain acting on the implant shaft, since a reduction of the strain can improve the longevity of the implant. To find the optimal implantation angle a finite element model of an ankle joint treated with the Episurf implant was developed. In the model an implant with a diameter of 12 millimeters was placed in the middle part of the medial side of the talar dome. An optimization algorithm was designed to find the implantation angle, which minimized the maximum equivalent strain acting on the implant shaft. The optimal implantation angle was found to be a sagittal angle of 12.5 degrees and a coronal angle of 0 degrees. Both the magnitude and the direction of the force applied to the ankle joint in the simulated stance phase seemed to influence the maximum equivalent strain acting on the implant shaft. A number of simplifications have been done in the simulation of this project, which might affect the accuracy of the results. Therefore it is recommended that further, more detailed, simulations based on this project are performed in order to improve the result accuracy.Fokala broskskador på talusbenet är den tredje vanligaste typen av fokala broskskador och kan ge upphov till smärta och instabilitet av fotleden. Episurf Medical AB är ett medicintekniskt företag som utvecklar individanpassade implantat för patienter med fokala broskskador. Episurf har nyligen påbörjat ett projekt där deras teknik ska användas i behandlingen av fokala broskskador på talusbenet. Den här masteruppsatsen var en del i Episurfs talusprojekt och dess huvudmål var att finna den optimala implantationsvinkeln av Episurfs implantat i behandlingen av fokala broskskador på talusbenet. Den optimala implanteringsvinkeln definierades som den vinkel som minimerade den effektiva von Mises-töjningen som verkade på implantatskaftet under stance-fasen i en normal gångcykel. Det är eftersträvansvärt att minimera belastningen på implantatskaftet eftersom en reducering av belastningen kan förbättra implantatets livslängd. En finita element-modell av en fotled behandlad med Episurfs implantat utvecklades för att för att finna den optimala implantationsvinkeln. I modellen placerades ett implantat med en diameter på 12 millimeter på mittendelen av talus mediala sida. En optimeringsalgoritm utformades för att finna implantationsvinkeln som minimerade den effektiva von Mises-töjningen på implantatskaftet. Den funna optimala implantationsvinkeln bestod av en vinkel på 12.5 grader i sagittalplan och en vinkel på 0 grader i koronalplan. Både storleken och riktningen på kraften som applicerats på fotleden under den simulerade stance-fasen av gångcykeln verkade påverka belastningen på implantatskaftet. Ett antal förenklingar har gjorts i projektets simuleringar, vilket kan påverka noggrannheten i resultatet. Därför rekommenderas att ytterligare, mer detaljerade simuleringar baserade på det här projektet görs för att förbättra resultatets noggrannhet

Russian Economic Reform: Is Economics Helpful?

This paper examines how issues ranging from inflation to monopolization in the former Soviet Union are occasionally misdiagnosed, leading to sub-optimal prescriptions for reform. The misdiagnosis occurs because the pre-reform state of the Russian economy is often taken at face value as a centrally-planned economy, Russian official statistics are accepted uncritically, and the actual effects of changes in the former Soviet Union are frequently taken to be equivalent to their measured effects. The theme that emerges when an attempt is made to apply basic economic principles to Russian economic reform is that problems that are often attributed to reform are already present in the current, partially-reformed Russian economy.

Why the Rich May Favor Poor Protection of Property Rights

Abstract In unequal societies, the rich may benefit from shaping economic institutions in their favor. This paper analyzes the dynamics of institutional subversion by focusing on the public protection of property rights. If this institution functions imperfectly, agents have incentives to invest in private protection of property rights. The ability to maintain private protection systems makes the rich natural opponents of public property rights and precludes grass-roots demand to drive the development of the market-friendly institution. The economy becomes stuck in a bad equilibrium with low growth rates, high inequality of income, and wide-spread rent-seeking. The Russian oligarchs of 1990s, who controlled large stakes of newly privatized property, provide motivation for this paper

<i>Hamlet</i> and Rational Choice

A standard interpretation of the character of Hamlet is that he is indecisive, even pathologically so, and that his indecisiveness is manifested by the lengthy passage of time between when Hamlet is told that his father’s death was a murder and when he kills the perpetrator. Rational choice in economics concerns the connection between means and ends. A person is rational if, given her ends (her goals), she chooses reasonable means to achieve those ends. With uncertainty, a bad (or tragic) outcome can occur even when the best decision is taken. A reasonable approach to achieving one’s goal does not imply that the goal is attained. In Shakespeare’s Hamlet, the fact that most of the main characters, including Hamlet, meet untimely deaths is, therefore, not sufficient to conclude that Hamlet (or any other character) engages in less-than-rational behavior. This article examines Hamlet’s actions through the lens of rational choice. Hamlet’s delay in seeking revenge, combined with his interest in collecting more evidence of the alleged assailant’s guilt, comports well with economic rationality. The common view of Hamlet as indecisive, as someone who incorrectly substitutes deliberation for action, is unwarranted

Athens or London? The Parthenon Marbles and economic efficiency

In the early part of the 19th century sculptures on the Parthenon in Athens were removed under the direction of the Earl of Elgin, then the British ambassador to the Ottoman Empire, which at the time included Greece. The sculptures were brought to Britain, finding their way to the custody of the British Museum in London in 1816, where they are viewed by millions of visitors annually. A debate long has simmered as to whether these Parthenon Marbles, which date from the 5th century BCE, should be returned to Athens or remain in the United Kingdom. Much of the debate concerns the legitimacy of Elgin's original transfer of the Marbles and, relatedly, their current rightful owner. This article employs a Law-and-Economics, efficiency-based lens to examine the “property dispute” surrounding the Marbles. The efficiency inquiry centers on what location for the Marbles will do the best job of satisfying human preferences, which depend to a large extent on access to the Marbles and the quality of that access. Coase-like reasoning is applied to the question of the “highest-valued” location of the Marbles, supplemented with behavioral economics concepts involving cultural identity and endowment effects. The article concludes by offering some contours for a potentially Pareto-improving agreement that would result in the reunification of the Parthenon Marbles in Greece.</p