Quaternionic Projective Theory and Hadron Transformation Laws

A quaternionic projective theory based on the symmetry group Sl(2,H) allows one to identify various hadron models and many well-known particle transformation laws in its subgroup chains. Identifying the 16-dimensional Dirac algebra {} with Sl(2,H), we use a well-established group-theoretic framework as well as the framework of projective geometry to classify elementary particles and describe their interactions at low energies. It is straightforward to derive Chiral Dynamics and explain the spinorial ('quark') structure of hadrons. Spontaneous symmetry breaking occurs naturally by coset reductions, whereas 'classical' physics is obtained via well-defined limits in terms of a group contraction. The Dirac equation can be identified within a Riemannian globally symmetric space and thus allows one to investigate the fermionic mass as a well-defined parameter. In addition, we suggest an identification of the second quantization scheme and an approach to sum up the perturbation series.     

Bestimmung der 15N Häufigkeit bei nichtstatistischer 15N-verteilung in N2 sowie bei N2O in Bodenluftproben mittels GC-R-IRMS-Kopplung in einem Probenlauf

Abstract

An analysis technique based on GC-R-IRMS coupling (Gas-Chromatography-Reduction-Isotope Ratio Mass Spectrometry) is demonstrated. The ¹⁵N abundance of N² and N²O in atmospheric air or soil atmosphere from nitrification or denitrification processes with nonrandom distribution is determined in one run. The 12 ml sample is separated from CO² and transported by a helium gas stream through a cooling trap. The N²O is trapped in the cooling trap while the N² passes through it and enters the GC. After GC separation and O² removal in a reduction column, part of the N² enters an isotope mass spectrometer to determine the masses m/z 28,29 and 30. The interferences on mass 30 by the formation of NO in the ion source of the mass spectrometer are eliminated by a calibration and a correction procedure. Upon removing the cooling trap, the N²O is injected into the GC, where it is separated and then quantitatively reduced to N² in a reduction column. The measurement of one sample takes 16 minutes. The detection limit of the ³⁰R_t in alteration N₂ is Δ³⁰R_t = 5 · 10^?7. The detection limit of the N₂O is 3.6 nl.     

My agents love to conform: Norms and emotion in the micro-macro link

This contribution investigates the function of emotion in relation to norms, both in natural and artificial societies. We illustrate that unintentional behavior can be normative and socially functional at the same time, thereby highlighting the role of emotion. Conceiving of norms as mental objects we then examine the role of emotion in maintaining and enforcing such propositional attitudes. The findings are subsequently related to social structural dynamics and questions concerning micro-macro linkage, in natural societies as well as in artificial systems. Finally, we outline the possibilities of an application to the socionic multi-agent architecture SONAR. Christian von Scheve graduated in Sociology with minors in Psychology, Economics, and Political Science at the University of Hamburg, where he also worked as a research assistant at the Institute of Sociology. Currently, he is a 3rd year PhD student at the University of Hamburg. He was a Fellow of the Research Group “Emotions as Bio-Cultural Processes” at the Center for Interdisciplinary Research (ZiF) at Bielefeld University. In his doctoral thesis he develops an interdisciplinary approach to emotion and social structural dynamics, integrating emotion theories from the neurosciences, psychology, and the social sciences. He has published on the role of emotion in large-scale social systems, human-computer interaction, and multi-agent systems. He is co-editor of a forthcoming volume on emotion regulation. Daniel Moldt received his BSc in Computer Science/Software Engineering from the University of Birmingham (England) in 1984, graduated in Informatics at the University of Hamburg, with a minor in Economics in 1990. He received his PhD in Informatics from the University of Hamburg in 1996, where he has been a researcher and lecturer at the Department of Informatics since 1990. Daniel Moldt is also the head of the Laboratory for Agent-Oriented Systems (LAOS) of the theoretical foundations group at the Department of Informatics. His research interests focus on theoretical foundations, software engineering and distributed systems with an emphasis on agent technology, Petri nets, specification languages, intra- and inter-organizational application development, Socionics and emotion in informatics. Julia Fix is currently a PhD student at the Theoretical Foundations of Computer Science Group, Department for Informatics at the University of Hamburg. She studied Informatics and Psychology at the University of Hamburg, with an emphasis on theoretical foundations of multi-agent systems and wrote her diploma theses about emotional agent systems. Her current research interests focus on conceptual challenges and theoretical foundations of modelling emotions in multi-agent systems, emotion-based norm enforcement and maintenance, and Socionics. A further research focus are Petri nets, in particular the use of Petri-net modelling formalisms for representing different aspects of emotion in agent systems. Rolf von Lüde is a professor of Sociology at the University of Hamburg with a focus in teaching and research in Sociology of Organizations, Work and Industry since 1996. He graduated in Economics, Sociology, and Psychology, and received his doctorate in Economics and the venia legendi in Sociology from the University of Dortmund. His current research focuses on labor conditions, the organization of production, social change and the educational system, the organizational structures of university, Socionics as a new approach to distributed artificial intelligence in cooperation with computer scientists, new public management, and emotions and social structures. Rolf von Lüde is currently Head of Department of Social Sciences and Vice Dean of the School of Business, Economics and Social Sciences, University of Hamburg.     

Eine kinematische Integralformel für konvexe Körper

Ohne Zusammenfassung     

Das Christoffel-Problem für Polytope

Ohne Zusammenfassung     

Using Single-Channel Blind Deconvolution to Choose the Most Realistic Pharmacokinetic Model in Dynamic Contrast-Enhanced MR Imaging

In dynamic contrast-enhanced magnetic resonance imaging, there has been no consensus in the choice of the pharmacokinetic model. In this paper, a new approach for assessment of the most realistic model for a given tissue is presented. Non-blind and single-channel blind deconvolution algorithms were used in quantitative magnetic resonance dynamic contrast-enhanced imaging of the mouse masseter muscle to compare the realism of two different pharmacokinetic models for the tissue residue function. The first was the adiabatic approximation tissue homogeneity model (aaJW) and the second, the two-compartment exchange model (2CXM). Normals and mice treated with the substance C48/80 were studied. C48/80 increases both blood flow and contrast leakage in muscle substantially. The obtained approximation accuracy was evaluated for both pharmacokinetic models. In addition, the arterial input functions (aifs) estimated using blind deconvolution were compared to the corresponding observed aifs. The hypothesis is that the most realistic model of the tissue residue function leads to the best fits. The non-blind deconvolution did not result in any clear answer. For blind deconvolution, the aifs of the aaJW model were very similar to the corresponding observed aifs, and clearly more so than the aifs of the 2CXM model. Also, the approximation of the observed tracer time sequences was more accurate for the aaJW than the 2CXM model. The realism of different pharmacokinetic models in describing the passage of a tracer through a microvascular bed of a single tissue could be assessed using single-channel blind deconvolution.     

Conjugacy classes of non-normal subgroups of finite p-groups

Let G be a finite p-group, and let ν(G) denote the number of conjugacy classes of non-normal subgroups of G. It is known that either ν(G) ≤ 1 or ν(G) ≥ p. We determine all p-groups G with ν(G) ≤ p + 1.     

A characterization of the duality mapping for convex bodies

We characterize the duality of convex bodies in d-dimensional Euclidean vector space, viewed as a mapping from the space of convex bodies containing the origin in the interior into the same space. The question for such a characterization was posed by Vitali Milman. The property that the duality interchanges pairwise intersections and convex hulls of unions is sufficient for a characterization, up to a trivial exception and the composition with a linear transformation. Received: March 2007, Accepted: April 2007