Ethische Aspekte der Regularisierung ärztlichen Handelns

Zusammenfassung.   Die Ressourcenknappheit hat zu einer progredienten Regularisierung ?rztlichen Handelns geführt, überwiegend durch staatliche und institutionelle Richt- und Leitlinien. Aber nicht nur der Spardruck, sondern ebenso „offiziell” instrumentierte Wissenschaft kann ?rztliches Denken und damit ethische Reflexion behindern – selbst wenn sie in der optimalen Form evidenzbasierter Leitlinien auftritt. ”Futility” als Begriff ist in den USA l?ngst aus einer andauernden theoretischen Diskussion in die klinische Praxis eingedrungen. Vor allem bei bedrohlichen Erkrankungen am Ende des Lebens gibt es formalisierte Entscheidungswege; etwa im Sinne der prozeduralen Festlegung einer ”Do-Not-Attempt-Resuscitation Order” (DNAR). Unentrinnbar ist die Frage nach dem Sinn und der Vergeblichkeit ?rztlichen Handelns mit derjenigen nach der Entscheidungsmacht im medizinischen Alltag verknüpft. Regularisierungsversuche, die von der Makroebene der Gesundheits?konomie ausgehen, interferieren mit den h?ufig ebenso machtf?rmigen Entscheidungsprozessen in der unmittelbaren Patientenversorgung. Das gilt auch bei der Balance der Interessen von Patienten einschlie?lich ihrer pers?nlichen und juristischen Vertreter mit den fachlichen Ansprüchen der ?rzte. Die schlichte übernahme des Konzeptes der ”Futility” aus den USA ist angesichts der ungel?sten Komplexit?t der Interferenzen von Makro- und Mikroebene in Deutschland wenig sinnvoll, da es zu sehr auf die spezifischen Verh?ltnisse der amerikanischen Medizin zugeschnitten ist. Andererseits helfen die konkret praktikablen Kategorien der ”Futility” gegen das Ausufern von Grundsatzdiskussionen im europ?ischen Stil.      

A FE/BE coupling for the 3D time-dependent eddy current problem. Part I: a priori error estimates

In this paper the discontinuous Galerkin method in time for the coupling of conforming finite element and boundary element methods is established. We derive quasi-optimal a priori error estimates. Numerical examples prove the new scheme to be useful in practice. A posteriori error control and an adaptive algorithm are studied in Part II of this paper.     

Applications for stochastic optimization in the power industry

A survey on present applications of stochastic optimization in the power industry is presented. In particular, the motivation for changing over from deterministic to stochastic optimization models, the theory of stochastic optimization and the implementation of risk aversion is described. Furthermore, several characteristic applications in the power industry, such as short-term unit commitment, middle-term portfolio optimization, long-term investment planning and emissions-trading, are discussed.

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Assessment of edema using STIR+ via 3D cardiovascular magnetic resonance imaging in patients with suspected myocarditis

Objective

To evaluate three-dimensional T2-weighted fast spin echo triple inversion recovery sequences (STIR+) for the diagnosis of myocardial edema in patients with suspected early myocarditis after respiratory or gastrointestinal tract viral infection and at follow-up.

Materials and methods

We prospectively examined 28 patients with suspected myocarditis and 37 controls matched for gender and age. An ECG-triggered STIR+ was used to cover the entire left ventricle in short-axis images with 10-mm slice thickness and no interslice gap. The global signal intensity ratio (heart muscle in relation to skeletal muscle) was calculated (global STIR+ ratio) to evaluate edema. All patients had repeat examinations at follow-up (mean interval 4.9 months, 1–12 months).

Results

The mean global STIR+ ratio was 2.15 ± 0.4 in the initial examination of patients as compared to 1.78 ± 0.3 in controls (p < 0.0001) and 1.89 ± 0.3 in patients at follow-up (p = 0.0001 vs. first visit). Left ventricular ejection fraction did not differ between patients and controls at baseline and at follow-up.

Conclusion

We could identify a significantly higher global STIR+ ratio in patients with suspected myocarditis compared to controls, and a dynamic change during follow-up. The global STIR+ ratio may, therefore, be useful for the diagnosis of myocarditis and should be further explored.

     

Comprehensive modeling of electrochemical metallization memory cells

This paper reviews our previous theoretical studies on the simulation and modeling of resistively switching electrochemical metallization memory devices. The focus is on the current understanding of the dynamic behavior of this type of memory cells. A wide range of simulation scales is presented ranging from atomistic kinetic Monte Carlo models to 1D compact and analytical models. While these models show consistent results in the mean dynamic behavior, they address different aspects of the device behavior. With the compact and analytical models, the dynamic behavior on timescales ranging from nanoseconds to thousands of seconds can be investigated. The computationally more expensive multidimensional continuum models and kinetic Monte Carlo models, in contrast, give additional information on the detailed filamentary growth and dissolution mechanism, which is the origin of the resistance switching effect in electrochemical metallization memory cells. Using the different models, the different aspects of the resistance switching effect such as switching dynamics, multilevel programming, filament shape, polyfilamentary switching, variability, quantized conduction and polarity-independent filament dissolution are addressed. Moreover, it will be discussed how the models need to be extended in order to address further properties of the switching process.     

Two-beam cross-correlation: a method to characterize transport phenomena in micrometer-sized structures

To determine flow properties, namely, the velocity and angle of the flow in microstructured channels, an experimental realization based on fluorescence correlation spectroscopy is described. For this purpose, two micrometer-sized spatially separated volume elements have been created. The cross-correlation signal from these has been recorded and evaluated mathematically. In addition to previous results, two-beam cross-correlation allows for fast and easy determination of even small (down to 200 μm/s) flow velocities, as well as simultaneous measurement of diffusion properties of single dye molecules within a rather short detection time of 5-100 s and an error rate of less than 20%. The spatial flow resolution is around 1-2 μm, limited by the diameter of the volume element. Furthermore, vectorial flow data can be obtained and evaluated. A discussion of the theoretical background and an experimental verification of the theoretical results is performed. The feasibility of fast and easy data processing is shown if the flow time is the only desired information. Possible applications of this precise and simple method are the determination of transportation effects within artificial microstructures for CE and HPLC, fast chemical kinetics, and high-throughput screening.     

Cache Aware Pre-Runtime Scheduling

We present a novel pre-runtime scheduling method for uniprocessors which precisely takes the effects of task switching on the processor cache into consideration. Tasks are modelled as a sequence of non preemptable segments with precedence constraints. The cache behavior of each task segment is statically determined by abstract interpretation. For the sake of efficiency, the scheduling algorithm uses a heuristically guided search strategy. Each time a new task segment is added to a partial schedule, its worst case execution time is calculated based on the cache state at the end of the preceding partial schedule.