Mindfully Resisting the Bandwagon – IT Implementation and Its Consequences in the Financial Crisis

Although the ”financial meltdown” between 2007 and 2009 can be substantially attributed to herding behaviour in the subprime market for credit default swaps, a “mindless” IT implementation of participating financial services providers played a major role in the facilitation of the underlying bandwagon. The problem was a discrepancy between two core complementary capabilities: (1.) the (economic-rationalistic) ability to execute financial transactions (to comply with the herd) in milliseconds and (2.) the required contextualized mindfulness capabilities to comprehend the implications of the transactions being executed and the associated IT innovation decisions that enabled these transactions

Electron Energy-Loss Spectroscopy: A versatile tool for the investigations of plasmonic excitations

The inelastic scattering of electrons is one route to study the vibrational and electronic properties of materials. Such experiments, also called electron energy-loss spectroscopy, are particularly useful for the investigation of the collective excitations in metals, the charge carrier plasmons. These plasmons are characterized by a specific dispersion (energy-momentum relationship), which contains information on the sometimes complex nature of the conduction electrons in topical materials. In this review we highlight the improvements of the electron energy-loss spectrometer in the last years, summarize current possibilities with this technique, and give examples where the investigation of the plasmon dispersion allows insight into the interplay of the conduction electrons with other degrees of freedom

On the blocks of the walled Brauer algebra

We determine the blocks of the walled Brauer algebra in characteristic zero. These can be described in terms of orbits of the action of a Weyl group of type $A$ on a certain set of weights. In positive characteristic we give a linkage principle in terms of orbits of the corresponding affine Weyl group. We also classify the semisimple walled Brauer algebras in all characteristics.Comment: 40 pages, 16 figure

APP Expression in Primary Neuronal Cell Cultures fromP6 Mice during in vitro Differentiation

Primary neuronal cell cultures from P6 mice were investigated in order to study amyloid protein precursor (APP) gene expression in differentiating neurons. Cerebellar granule cells which strongly express APP 695 allowed the identification of three distinct isoforms of neuronal APP 695. The high-molecular-weight form of APP 695 is sialylated. The expression pattern of neuronal APP 695 changes during in vitro differentiation. Sialylated forms become more abundant upon longer cultivation time. The secreted forms of sialylated, neuronal APP 695 are shown to comigrate with APP isolated from cerebrospinal fluid. We suggest that the different sialylation states of APP 695 may reflect the modulation of cell-cell and cell-substrate interactions during in vitro differentiation and regeneration

Enlarged symmetry algebras of spin chains, loop models, and S-matrices

The symmetry algebras of certain families of quantum spin chains are considered in detail. The simplest examples possess m states per site (m\geq2), with nearest-neighbor interactions with U(m) symmetry, under which the sites transform alternately along the chain in the fundamental m and its conjugate representation \bar{m}. We find that these spin chains, even with {\em arbitrary} coefficients of these interactions, have a symmetry algebra A_m much larger than U(m), which implies that the energy eigenstates fall into sectors that for open chains (i.e., free boundary conditions) can be labeled by j=0, 1, >..., L, for the 2L-site chain, such that the degeneracies of all eigenvalues in the jth sector are generically the same and increase rapidly with j. For large j, these degeneracies are much larger than those that would be expected from the U(m) symmetry alone. The enlarged symmetry algebra A_m(2L) consists of operators that commute in this space of states with the Temperley-Lieb algebra that is generated by the set of nearest-neighbor interaction terms; A_m(2L) is not a Yangian. There are similar results for supersymmetric chains with gl(m+n|n) symmetry of nearest-neighbor interactions, and a richer representation structure for closed chains (i.e., periodic boundary conditions). The symmetries also apply to the loop models that can be obtained from the spin chains in a spacetime or transfer matrix picture. In the loop language, the symmetries arise because the loops cannot cross. We further define tensor products of representations (for the open chains) by joining chains end to end. The fusion rules for decomposing the tensor product of representations labeled j_1 and j_2 take the same form as the Clebsch-Gordan series for SU(2). This and other structures turn the symmetry algebra \cA_m into a ribbon Hopf algebra, and we show that this is ``Morita equivalent'' to the quantum group U_q(sl_2) for m=q+q^{-1}. The open-chain results are extended to the cases |m|< 2 for which the algebras are no longer semisimple; these possess continuum limits that are critical (conformal) field theories, or massive perturbations thereof. Such models, for open and closed boundary conditions, arise in connection with disordered fermions, percolation, and polymers (self-avoiding walks), and certain non-linear sigma models, all in two dimensions. A product operation is defined in a related way for the Temperley-Lieb representations also, and the fusion rules for this are related to those for A_m or U_q(sl_2) representations; this is useful for the continuum limits also, as we discuss in a companion paper

Representation theory of towers of recollement: Theory, notes, and examples

We give an axiomatic framework for studying the representation theory of towers of algebras. We introduce a new class of algebras, contour algebras, generalising (and interpolating between) blob algebras and cyclotomic Temperley–Lieb algebras. We demonstrate the utility of our formalism by applying it to this class

Asymmetry of charge relaxation times in quantum dots: The influence of degeneracy

Using time-resolved transconductance spectroscopy, we study the tunneling dynamics between a two-dimensional electron gas (2DEG) and self-assembled quantum dots (QDs), embedded in a field-effect transistor structure. We find that the tunneling of electrons from the 2DEG into the QDs is governed by a different time constant than the reverse process, i.e., tunneling from the QDs to the 2DEG. This asymmetry is a clear signature of Coulomb interaction and makes it possible to determine the degeneracy of the quantum dot orbitals even when the individual states cannot be resolved energetically because of inhomogeneous broadening. Our experimental data can be qualitatively explained within a master-equation approach

Free Cooling in der Klimakälte, Untersuchung des Potentials in der Schweiz

Auftraggeber der Studie ist das Bundesamt für Energie BFEIn dieser Arbeit wurde das Potential von Free Cooling (direkte Rückkühlung des Kühlmediums mit Einbezug der Umgebung) in der Klimakälte bezogen auf die Schweiz untersucht. Die zahl-reichen Ergebnisse und Diagramme aus dieser Arbeit ermöglichen dem Leser anhand weniger Schritte das Free Cooling Potential in Abhängigkeit von Vorlauftemperatur, Anwendungsart, Standort, Schaltung und Art der Rückkühlung abzuschätzen und so die Sinnhaftigkeit von Free Cooling oder das Optimierungspotential zu beurteilen. Eine Beschreibung dieses Vorgehens inkl. zahlreicher Hilfestellungen ist im Anhang ersichtlich. Die Ergebnisse zeigen, dass der einflussreichste Parameter die benötigte Vorlauftemperatur des Kühlmediums ist. Werden vom Verbraucher Temperaturen unterhalb von 14°C benötigt, fällt das Free Cooling Potential bis auf ein paar wenige Prozent zusammen und ist daher nicht zu empfehlen, sofern keine grösseren internen Lasten (z.B. Rechenzentrum) vorhanden sind. Weiter ist das Potential stark von den klimatischen Verhältnissen am Standort abhängig. Kältere Regionen wie die Alpen ermöglichen über das Jahr einen längeren Free Cooling Betrieb als ver-gleichsweise wärmere Regionen wie das Mittelland oder das Tessin. Nutzt man trockene oder hybride Rückkühler nur zur Vorkühlung, kann sich das Potential verdoppeln. Die weitaus grössten Potentiale bieten Wasseranbindungen (See-, Fluss- oder Grundwasser) oder Erdsonden. Jedoch müssen die Potentiale dieser Anbindungen von Fall zu Fall separat beurteilt werden, denn Boden- resp. Grundwassertemperaturen sind stark vom Ort abhängig und bei der einfachen Modellrechnung in dieser Arbeit wurden keine dynamischen Effekte bei der Abga-be von Wärme an den Boden berücksichtigt. Bei der Anbindung einer Erdwärmesonde muss zudem beachtet werden, dass das Free Cooling eine mögliche Sondenregeneration konkurriert. Weiter müssen die Gesetze bezüglich Grundwassernutzung hinsichtlich Erwärmung eingehalten werden. Da eine Wärmenutzung der Kältemaschine einer Wärmeabgabe an die Umgebung (Free Cooling Betrieb) klar vorzuziehen ist, muss immer geprüft werden, ob ein Free Cooling Betrieb nicht die Kapazität einer möglichen Wärmenutzung gefährdet

Examining trade-offs between social, psychological, and energy potential of urban form

Urban planners are often challenged with the task of developing design solutions which must meet multiple, and often contradictory, criteria. In this paper, we investigated the trade-offs between social, psychological, and energy potential of the fundamental elements of urban form: the street network and the building massing. Since formal methods to evaluate urban form from the psychological and social point of view are not readily available, we developed a methodological framework to quantify these criteria as the first contribution in this paper. To evaluate the psychological potential, we conducted a three-tiered empirical study starting from real world environments and then abstracting them to virtual environments. In each context, the implicit (physiological) response and explicit (subjective) response of pedestrians were measured. To quantify the social potential, we developed a street network centrality-based measure of social accessibility. For the energy potential, we created an energy model to analyze the impact of pure geometric form on the energy demand of the building stock. The second contribution of this work is a method to identify distinct clusters of urban form and, for each, explore the trade-offs between the select design criteria. We applied this method to two case studies identifying nine types of urban form and their respective potential trade-offs, which are directly applicable for the assessment of strategic decisions regarding urban form during the early planning stages