vorgelegt von

Towards a precise measurement of the cosmic-ray positron fraction Von der Fakultät für Mathematik, Informatik und Naturwissenschaften de

vorgelegt von Diplom-Biologin

Immunomodulatory function of astrocytes: characterization and regulation of prostanoid metabolism and cytokine synthesis Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades eines Doktors de

Search for Cosmic-Ray Antiparticles with Balloon-borne and Space-borne Experiments

This thesis discusses two different approaches for the measurement of cosmic-ray antiparticles in the GeV to TeV energy range. The first part studies the prospects of antiparticle flux measurements with the proposed PEBS detector. The project allots long duration balloon flights at one of Earth’s poles at an altitude of 40 km. The detector consists of a transition radiation detector, a time of flight system, a combined silicon and scintillating fiber tracker and an electromagnetic calorimeter. All detectors are placed in a superconducting magnet which creates a field of 0.8 T. Several flights are discussed starting from 2012 to get a total of 100 days measurement time with an acceptance of 0.4 m 2 sr. This work calculates the systematic effects due to interactions of cosmic rays in the atmosphere. GEANT4 simulations were carried out which determine the atmospheric background and attenuation especially for antiparticles. Projected results taking the effects of the atmosphere and the detector properties into account are discussed. The second part covers the AMS-02 experiment which will be installed in 2010 on the International Space Station at an altitude of about 400 km for about three years to measure cosmi

Contents Abbreviations

Cytochrome c oxidase mediates the regulation of mitochondrial function in an in vitro model of Huntington’s disease Von der Fakultät für Mathematik, Informatik und Naturwissenschaften der RWTH Aachen University zur Erlangung des akademischen Grades eines Doktors de

Type-Inference Based Deforestation of Functional Programs

In lazy functional programming modularity is often achieved by using intermediate data structures to combine separate parts of a program. Each intermediate data structure is produced by one part and consumed by another one. Deforestation optimises a functional program by transformation into a program which does not produce such intermediate data structures. In this thesis we present a new method for deforestation, which combines a known method,short cut deforestation, with a new analysis that is based on type inference. Short cut deforestation eliminates an intermediate list by a single, local transformation. In return, short cut deforestation expects both producer and consumer of the intermediate list in a certain form. Whereas the required form of the consumer is generally considered desirable in a well-structured program anyway, the required form of the producer is only a crutch to enable deforestation. Hence only the list-producing functions of the standard libraries were defined in the desired form and short cut deforestation has been confined to compositions of these functions. Here, we present an algorithm which transforms an arbitrary producer into the required form. Starting from the observation that short cut deforestation is based on a parametricity theorem of the second-order typed lambda-calculus, we show how the construction of the required form can be reduced to a type inference problem. Typability for the second-order typed lambda-calculus is undecidable, but we only need to solve a partial type inference problem. For this problem we develop an algorithm based on the well-known Hindley-Milner type inference algorithm. The transformation of a producer often requires inlining of some function definitions. Type inference even indicates which function definitions need to be inlined. However, only limited inlining across module boundaries is practically feasible. Therefore, we extend the previously developed algorithm to split a function definition into a worker definition and a wrapper definition. We only need to inline the small wrapper definition, which transfers all information required for deforestation. The flexibility of type inference allows us to remove intermediate lists which original short cut deforestation cannot remove, even with hand-crafted producers. In contrast to most previous work on deforestation, we give a detailed proof of completeness and semantic correctness of our transformation