Michael Kettner

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OBJECTIVES This study sought to assess the feasibility and safety of a recently described technique of mechanical recanalization with the help of a stent-like device. BACKGROUND In the special group of acute stroke patients with an intracranial large vessel occlusion, intravenous tissue-type plasminogen activator on its own leads to a good clinical(More)
In this paper we consider the problem of bounding the Betti numbers , b i (S), of a semi-algebraic set S ⊂ R k defined by polynomial inequalities b i (S) ≤ 1 2 + (k − s) + 1 2 · min{s+1,k−i} X j=0 2 j " s + 1 j " " k j − 1 " ≤ 3 2 · " 6ek s « s + k. This improves the bound of k O(s) proved by Barvinok in [2]. This improvement is made possible by a new(More)
In this paper, we present a new algorithm for computing in a very efficient way the real intersection of three quadric surfaces. Our approach is based on the cylindrical decomposition ([4]) and the TOP algorithm ([10]) for analyzing the topology of a planar curve. We preform a symbolic pre-processing that allows us later to execute all numerical(More)
We prove a nearly optimal bound on the number of stable homo-topy types occurring in a k-parameter semi-algebraic family of sets in R , each defined in terms of m quadratic inequalities. Our bound is exponential in k and m, but polynomial in. More precisely, we prove the following. Let R be a real closed field and let k be the projection on the last k(More)
Spinal dural arteriovenous fistulas are rare spinal vascular malformations which can cause progressive paraparesis and paraplegia if not treated. As symptoms are unspecific diagnosis is often delayed and clinical outcome is dependent on early therapy. While magnetic resonance imaging (MRI) is the first choice imaging procedure, selective spinal digital(More)
Simvastatin (MK733), derived from lovastatin by substituting CH3 for H at the 2' position, is a potent hydroxymethylglutaryl coenzyme A (HMG CoA) reductase inhibitor. Its cholesterol-lowering effect in 40 patients with heterozygous familial hypercholesterolaemia was more pronounced (an LDL-cholesterol reduction of 43%) than that of cholestyramine(More)
In this paper, we present a new algorithm for computing in a very efficient way the real intersection of three cubic surfaces. Our approach is based on the cylindrical decomposition ([8]) and the TOP algorithm ([10]) for analyzing the topology of a planar curve. We perform a symbolic pre-processing that allows us later to execute all numerical computations(More)
For my Mum and the memory of my Dad iii ACKNOWLEDGEMENTS The writing of this thesis has been one of the most significant academic challenges I have had to face. Without the support, patience and guidance of the following people and institutes, this study would not have been completed. It is to them that I owe my deepest gratitude. In the first place I would(More)
Verbal interactive behavior of 10 male patients diagnosed as schizophrenic, but not acutely psychotic, and of their non-schizophrenic ('normal') and non-informed dialogue-partners are studied in dialogical conversations about political problems. A control group of ten dyads of 'normal' dialogue partners is used for comparisons. Quantitative text-properties(More)