Diffusion of myosin V on microtubules

Organelle transport in eukaryotes employs both microtubule and actin tracks to deliver cargo effectively to their destinations, but the question of how the two systems cooperate is still largely unanswered. Recently, in vitro studies revealed that the actin-based processive motor myosin V also binds to, and diffuses along microtubules. This biophysical trick enables cells to exploit both tracks for the same transport process without switching motors. The detailed mechanisms underlying this behavior remain to be solved. By means of single molecule Total Internal Reflection Microscopy (TIRFM), we show here that electrostatic tethering between the positively charged loop 2 and the negatively charged C-terminal E-hooks of microtubules is dispensable. Furthermore, our data indicate that in addition to charge-charge interactions, other interaction forces such as non-ionic attraction might account for myosin V diffusion. These findings provide evidence for a novel way of myosin tethering to microtubules that does not interfere with other E-hook-dependent processes

IT Sourcing Portfolio Management for IT Services Providers - A Risk/Cost Perspective

Utilizing a global IT sourcing strategy bears enormous growth potential. With the main focus on cost reduction in valuation of sourcing alternatives, risk and risk diversification effects are often inadequately considered or completely neglected. This systematically results in wrong decisions about global sourcing. Correct decisions are in particular important for the success of IT services providers (ITSP), which are the major beneficiaries of the market growth, though being faced with intensifying competition. This paper proposes a decision model for allocating software development projects of an ITSP to available sites in a risk/cost efficient way by adapting Markowitz’s Modern Portfolio Theory to IT sourcing decision making. The suggested approach covers not only costs and sourcing risks but also interdependencies between both sites and projects. Additionally, we propose methods for quantifying the necessary input parameters. We demonstrate the practicability of our approach in a case study with data from a major ITSP

A sampling-based optimization algorithm for solution spaces with pair-wise-coupled design variables

Solution spaces are sets of good designs that satisfy all design goals. They serve as target regions for robust and independent component development in a distributed design process. So-called solution boxes provide best decoupling; however, they are often small and therefore impractical. This article proposes an algorithm that computes two-dimensional permissible regions for pairs of design variables that are substantially larger than solution boxes. This is accomplished by modifying the existing sampling-based optimization algorithm for boxes and extending it by box-rotation

Verbesserung der Prozesskette zur Herstellung mikrostrukturierter Linsen für automobile Scheinwerfer

Diese Arbeit befasst sich mit der Auslegung, Herstellung und Qualitätskontrolle mikrostrukturierter Linsen für Scheinwerfer-Projektionssysteme. Es wird ein Algorithmus beschrieben, um glatte Linsenflächen zu strukturieren. Die Datenweitergabe zur Herstellung von Stahlwerkzeugen für den Spritzgussprozess werden erläutert. Um die Werkzeuge zu qualifizieren wird ein „Reverse Engineering“-Prozess vorgestellt

A real options approach for valuating intertemporal interdependencies within a value-based IT portfolio management - A risk-return perspective

Value-based IT portfolio management requires the consideration of intertemporal interdependencies that may exist among IT projects. Therefore, several papers suggest adopting the real options approach in order to include intertemporal interdependencies within the valuation of IT projects. However, this paper shows that the standard Black-Scholes model, which is often used for valuating real options, is not appropriate to correctly account for project-specific private risks due to its restrictive assumptions. Since this can have major impacts on the value of IT projects, we develop an approach – based on the Black-Scholes model – to consider private risks properly within project valuation. A comparison of the results of the standard Black-Scholes model used today and our approach finally reveals that the neglect of private risks results in a systematic underestimation of both risk and return of IT projects, which may lead to wrong investment decisions

How do Different Sources of the Variance of Consumer Ratings Matter?

We examine the effect of the variance of consumer ratings on product pricing and sales using an analytical model, which considers goods that are characterized by experience attributes and informed search attributes (i.e., experience attributes that were transformed in search attributes by consumer ratings). For pure informed search goods, equilibrium price increases and demand decreases in variance. For pure experience goods, equilibrium price and demand decrease in variance. For hybrid goods with low total variance, equilibrium price and demand increase with an increasing relative share of variance caused by informed search attributes when the average rating and total variance of ratings are held constant. Hence, risk-averse consumers may prefer a more expensive good with a higher variance of ratings out of two similar goods with the same average rating. Moreover, our analytical model provides a theoretical foundation for the empirically observed j-shaped distribution of consumer ratings in electronic commerce

COMPETITION AT LAST? AN ECONOMIC ANALYSIS OF CURRENT MOBILE DATA ROAMING REGULATIONS IN EUROPE

The mobile data roaming market in the European Union is characterized by a lack of competition which is one of the main reasons for wholesale and retail prices being well above cost-based prices. In 2012, the European Commission has enacted new regulatory measures such as allowing for more players competing in the wholesale data roaming market and forcing mobile network operators to unbundle roaming services from domestic offers by 2014. Moreover, the European Commission recently proposed the elimination of roaming charges by 2016. Nevertheless, it remains unclear whether these measures will ultimately result in more competition and, thus, in increased social welfare. Drawing on existing research from IS, telecommunications and regulation domains, we propose the development of an analytical model to evaluate the economic implications of these regulatory measures