A new business model?

The paper delivers an analysis of the “New Economy” focussing on the roles of new business models, the capital market and venture capital. The capital market created a double standard in the 1990s: A high return on capital was required from old economy firms whereas money was thrown at new economy firms which had a business idea that stimulated the fantasies of financial investors but no earnings. Through the gradual burst of the tech stock bubble since spring 2000 it has come to the eyes of the public that many new economy start ups were unable to recover their costs. This paper shows that business models related to the internet can only work under certain conditions. The sectoral distribution of power, for example, determines the prospects of the single firms to realise e-commerce in a profitable way. Digital technologies do not necessarily enhance profitability. On the contrary, they can increase competition and lead to lower profit rates. The limitation of competition appears to be a central condition of successful cost recovery. The venture capital cycle has been an important driving force of the new economy boom, but it can also be momentum of a longer crisis. Enormous amounts of money have been channeled to new economy start ups hoping that successful IPOs will one day give venture capitalists a high return. But the burst of the bubble has brought down the IPO activity and interrupted the valorisation cycle of venture capital. Financial investors have reacted to the crisis by shifting their capital to even riskier investments, as the come-back of hedge funds indicates. --

A coupled mitral valve - left ventricle model with fluid-structure interaction

Understanding the interaction between the valves and walls of the heart is important in assessing and subsequently treating heart dysfunction. This study presents an integrated model of the mitral valve (MV) coupled to the left ventricle (LV), with the geometry derived from in vivo clinical magnetic resonance images. Numerical simulations using this coupled MV–LV model are developed using an immersed boundary/finite element method. The model incorporates detailed valvular features, left ventricular contraction, nonlinear soft tissue mechanics, and fluid-mediated interactions between the MV and LV wall. We use the model to simulate cardiac function from diastole to systole. Numerically predicted LV pump function agrees well with in vivo data of the imaged healthy volunteer, including the peak aortic flow rate, the systolic ejection duration, and the LV ejection fraction. In vivo MV dynamics are qualitatively captured. We further demonstrate that the diastolic filling pressure increases significantly with impaired myocardial active relaxation to maintain a normal cardiac output. This is consistent with clinical observations. The coupled model has the potential to advance our fundamental knowledge of mechanisms underlying MV–LV interaction, and help in risk stratification and optimisation of therapies for heart diseases

Modelling mitral valvular dynamics–current trend and future directions

Dysfunction of mitral valve causes morbidity and premature mortality and remains a leading medical problem worldwide. Computational modelling aims to understand the biomechanics of human mitral valve and could lead to the development of new treatment, prevention and diagnosis of mitral valve diseases. Compared with the aortic valve, the mitral valve has been much less studied owing to its highly complex structure and strong interaction with the blood flow and the ventricles. However, the interest in mitral valve modelling is growing, and the sophistication level is increasing with the advanced development of computational technology and imaging tools. This review summarises the state-of-the-art modelling of the mitral valve, including static and dynamics models, models with fluid-structure interaction, and models with the left ventricle interaction. Challenges and future directions are also discussed