Electron Transfer in Porphyrin Complexes in Different Solvents

The electron transfer in different solvents is investigated for systems consisting of donor, bridge and acceptor. It is assumed that vibrational relaxation is much faster than the electron transfer. Electron transfer rates and final populations of the acceptor state are calculated numerically and in an approximate fashion analytically. In wide parameter regimes these solutions are in very good agreement. The theory is applied to the electron transfer in ${\rm H_2P-ZnP-Q}$ with free-base porphyrin (${\rm H_2P}$) being the donor, zinc porphyrin (${\rm ZnP}$) the bridge, and quinone (${\rm Q}$) the acceptor. It is shown that the electron transfer rates can be controlled efficiently by changing the energy of the bridging level which can be done by changing the solvent. The effect of the solvent is determined for different models.Comment: 28 pages + 5 figures, submitted to J. Phys. Chem. For more details see the Ph. D. thesis in quant-ph archive http://xxx.lanl.gov/abs/quant-ph/000100

T-Duality from super Lie n-algebra cocycles for super p-branes

We compute the $L_\infty$-theoretic dimensional reduction of the F1/D$p$-brane super $L_\infty$-cocycles with coefficients in rationalized twisted K-theory from the 10d type IIA and type IIB super Lie algebras down to 9d. We show that the two resulting coefficient $L_\infty$-algebras are naturally related by an $L_\infty$-isomorphism which we find to act on the super $p$-brane cocycles by the infinitesimal version of the rules of topological T-duality and inducing an isomorphism between $K^0$ and $K^1$, rationally. In particular this is a derivation of the Buscher rules for RR-fields (Hori's formula) from first principles. Moreover, we show that these $L_\infty$-algebras are the homotopy quotients of the RR-charge coefficients by the "T-duality Lie 2-algebra". We find that the induced L_\infty$-extension is a gerby extension of a 9+(1+1) dimensional (i.e. "doubled") T-duality correspondence super-spacetime, which serves as a local model for T-folds. We observe that this still extends, via the D0-brane cocycle of its type IIA factor, to a 10+(1+1)-dimensional super Lie algebra. Finally we observe that this satisfies expected properties of a local model space for F-theory elliptic fibrations

Central extensions of mapping class groups from characteristic classes

Tangential structures on smooth manifolds, and the extension of mapping class groups they induce, admit a natural formulation in terms of higher (stacky) differential geometry. This is the literal translation of a classical construction in differential topology to a sophisticated language, but it has the advantage of emphasizing how the whole construction naturally emerges from the basic idea of working in slice categories. We characterize, for every higher smooth stack equipped with tangential structure, the induced higher group extension of the geometric realization of its higher automor- phism stack. We show that when restricted to smooth manifolds equipped with higher degree topological structures, this produces higher extensions of homotopy types of diffeomorphism groups. Passing to the groups of connected components, we obtain abelian extensions of mapping class groups and we derive sufficient conditions for these being central. We show as a special case that this provides an elegant re-construction of Segal’s approach to $\mathbb{Z}$ -extensions of mapping class groups of surfaces that provides the anomaly cancellation of the modular functor in Chern-Simons theory. Our construction generalizes Segal’s approach to higher central extensions of mapping class groups of higher dimensional manifolds with higher tangential structures, expected to provide the analogous anomaly cancellation for higher dimensional TQFTs

On Integrity Constraints for a Waste Management Information System

There is a waste problem in nearly every country. A model of a waste generating system and an efficient waste management information system are the first steps to control this problem. Some countries have already enacted laws which force communities and enterprises to report annually the amounts of wastes produced. For example, the German federal state, Lower Saxony, enacted such a law in 1992. This YSSP-Project deals with a case study on the development of a waste management information system for this state. The quality of the system essentially depends on the consistency of the underlying database system. Therefore, the point of view of a database designer is given. The design of the data structures and the support of integrity constraints in the underlying database system is thereby especially emphasized. The data structures are modelled using an extended entity relationship model. They are implemented with a relational database management system. In contrast to the traditional way of supporting integrity constraints in the application program, we define triggers which are implemented in the database system itself to enforce main consistency rules. In the final chapter some conclusions about further steps are given

DDF and Pohlmeyer invariants of (super)string

We show how the Pohlmeyer invariants of the bosonic string are expressible in terms of DDF invariants. Quantization of the DDF observables in the usual way yields a consistent quantization of the algebra of Pohlmeyer invariants. Furthermore it becomes straightforward to generalize the Pohlmeyer invariants to the superstring as well as to all backgrounds which allow a free field realization of the worldsheet theory.Comment: 17 pp, minor typos corrected, references to papers by Isaev and Borodulin added, which contain essentially the same results as reported her

Evaluation of a commercially available rapid urinary porphobilinogen test

Background: Demonstration of substantially increased urinary excretion of porphobilinogen is the cornerstone of diagnosing acute porphyria crisis. Because porphobilinogen testing is not implemented on clinical chemistry analysers, respective analyses are available in rather few clinical laboratories. The aim of this study was to critically describe and to evaluate a semi-quantitative rapid test for urinary porphobilinogen determination which is commercially available and recommended by the American Porphyria Foundation. Methods: Urinary samples from patients with acute intermittent porphyria and control samples were analysed and the semi-quantitative results were compared with the results obtained by a manual quantitative spectrophotometric method. Results: In all 32 samples studied, acceptable agreement between the results of the rapid test and the quantitative test was observed. Handling of the test was found to be convenient. Conclusions: The assay was found to be reliable and has the potential to increase the availability of porphobilinogen testing in the field

Literarische Kommunikation:zur rekursiven Operativität des Literatursystems

Die Systemtheorie Niklas Luhmanns gehört zu den festen Bestandteilen des literaturwissenschaftlichen Theoriebestandes. Trotzdem blieb für die Literaturwissenschaft bislang die Frage offen, wie das literarische System im Unterschied zu anderen Systemen die Anschlussfähigkeit seiner Kommunikationen sicherstellt. Ausgehend von Luhmanns Kommunikationsbegriff untersucht der Beitrag die komplexe Operationsweise des literarischen Systems und seinen Umgang mit Information, Mitteilung und Verstehen. Die Erörterung des Problems, dass literarische Kommunikation auf der Basis von Texten abläuft, führt zu einer neuen Perspektive auf die Autopoiesis und die Selbstorganisation des Literatursystems. Anhand dieses systemtheoretischen Modells erklärt sich erstens, wie das System trotz fortwährender Existenzbedrohung seine Operativität aufrecht erhält, und zweitens, wie es zur Einteilung in Gattungen und Epochen kommt