Computing convex hulls and counting integer points with <Emphasis FontCategory="NonProportional">polymake</Emphasis>

The main purpose of this paper is to report on the state of the art of computing integer hulls and their facets as well as counting lattice points in convex polytopes. Using the polymake system we explore various algorithms and implementations. Our experience in this area is summarized in ten “rules of thumb”.     

Quantum: Einstein,Bohr and the Great Debate About the Nature of Reality,by Manjit Kumar

The history of absolute measurements of gravity is mentioned and the reasons for making absolute measurements are indicated. The principles and main advantages and difficulties of the main method—reversible pendulum, free fall, symmetrical free motion—are discussed and examples of each method are described. Problems of comparison of different determinations and of estimating systematic errors are considered.     

Model building and molecular mechanics calculations of mitoxantrone-deoxytetranucleotide complexes: Molecular foundations of DNA intercalation as cytostatic active principle

Summary Several intercalation complexes of the antitumor-active drug mitoxantrone with base paired tetranucleotides were constructed by molecular modeling using computer graphics and molecular mechanics calculations. The mitoxantrone molecule favours DNA binding into CG intercalation site. The two side chains of the drug are orientated into the major groove and fixed by hydrogen bonds with the nucleotide bases. This molecular study can be helpful for understanding the mode of action of cytostatically active compounds and to design new structurally related compounds of the anthraquinone drug type.Dedicated to Prof. Dr. Dr. h.c. mult.H. Oelschläger on the occasion of his 75^th birthday     

Interband critical-point symmetry from electroreflectance spectra

The theoretical basis for electroreflectance symmetry analysis is reviewed, with emphasis on its application to common diamond, zinc blende, rock salt, and wurtzite type materials. Both longitudinal and transverse geometries are considered. The use of atomic-state selection rules in determining electroreflectance polarization dependences is reviewed. Symmetry analysis of excitonic transitions and transitions involving degenerate states is discussed, along with the importance of low-field spectra, and the roles of thermal and lifetime broadening. The phenomenological theory of linear and quadratic low-field electroreflectance is presented for both longitudinal and transverse geometries, and the expected polarization dependences of these are analyzed in detail. The relationship of tensorial polarization dependence to symmetry analysis is also examined along with the measurement of individual tensor components. Experimental considerations such as photocarriers and surface barriers are reviewed, as are techniques for separately observing linear and quadratic low-field spectra. The utility of linear low-field spectra in symmetry analysis of wurtzite type materials is pointed out.     

Real-time non-linear spatial filtering with a leaky OASLM

In this paper we demonstrate image processing techniques such as edge enhancement and phase contrast by using an optically addressed liquid crystal spatial light modulator (OASLM) in the frequency plane of an optical 4f processor. The transfer function of the device is derived on the basis of the Jones formalism. Faced with a lack of a general theory for such non-linear optical processors, we show that an analogy to the propagation of optical pulses in fibres is helpful for the understanding of the image processing operation.