Quantum phase transitions in magnetic systems: application of coupled cluster method

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2009

Competition and well-being

We study the effects of competition in a context in which people's actions can not be contractually fixed. We find that in such an environment the very presence of competition does neither increase efficiency nor does it yield any payoff gains for the short side of the market. We also find that competition has a strong negative impact on social well-being, the disposition towards others, and individually experienced well-being, the emotional state, of those on the long side of the market. We conjecture that this limits the possibilities of satisfactory interaction in the future and, hence, has negative implications for efficiency in the longer-run

The Well

Combined media on paper. 110" x 40", Private Collection

Propietats d'absorció bifotònica del tetrafenilporficè i el seu complex de palladi: potencials sensibilitzadors per a Teràpia Fotodinàmica bifotònica.

Estudi elaborat a partir d’una estada a la Universitat de Aarhus, Dinamarca, durant juliol 2006. En el present treball s’investiguen, per primer cop, les propietats de absorció bifotòniques del fotosensibilitzador 2,7,12,17-tetrafenilporficè (TPPo) i del seu complex de pal•ladi (II) (PdTPPo). Ambos compostos han rebut molta atenció com a possibles otosensibilitzadors per a Teràpia Fotodinàmica (TFD). S’utilitza la detecció de la fosforescència de l’oxigen singlet, centrada a 1270 nm i produïda per l’absorció de dos fotons, per quantificar la magnitud de la secció d’absorció bifotònica, "delta", dels porficèns estudiats. Els experiments se han dut a terme en el marge espectral 750-850 nm i a l’infraroig proper a 1100nm. Aquestes longituds d’ona corresponen a les zones d’absorció bifotònica en les bandes de Soret i Q. Les propietats bifotòniques obtingudes es comparen i contrasten amb les dades conegudes de la tetrafenilporfirina (TPP), isòmer estructural del tetrafenilporficè però amb més gran simetria, i es troba que en la banda de Soret (que coincideix amb la regió de la pell més transparent) els valors de delta per el TPPo i PdTPPo son aproximadament 2000 GM en el màxim, pràcticament cent vegades més grans que per la TPP. A més a més, aquestos valors son dos ordres de magnitud més grans que els obtinguts a l’irradiar a 1100 nm (bandes Q). Aquestes observacions es poden explicar mitjançant la amplificació per ressonància deguda a la presència de transicions monofotòniques ressonants en la regió de les bandes Q. Els elevats valors de "delta" obtinguts per els tetrafenilporficèns estudiats junt a les principals característiques que aquestos presenten (elevat rendiment de formació d’oxigen singlet, estabilitat química i fotoquímica, absència de citotoxicitat,...) qualifiquen al TPPo y PdTPPo com a possibles fotosensibilitzadors per a Teràpia Fotodinàmica Bifotònica.

On punishment and well-being

The existence of punishment opportunities has been shown to cause efficiency in public goods experiments to increase considerably. In this paper we ask whether punishment also has a downside in terms of process dissatisfaction. We conduct an experiment to study the conjecture that an environment with stronger punishment possibilities leads to higher material but lower subjective well-being. The more general motivation for our study stems from the notion that people??s subjective well-being may be affected by the institutional environment they find themselves in. Our findings show that harsher punishment possibilities lead to signficantly higher well-being, controlling for earnings and other relevant variables. People derive independent satisfaction from interacting under the protection of strong punishment possibilities. These results complement the evidence on the neural basis of altruistic punishment reported in de Quervain et al. (2004).

Well-posedness and invariant measures for HJM models with deterministic volatility and Lévy noise

We give sufficient conditions for existence, uniqueness and ergodicity of invariant measures for Musiela's stochastic partial differential equation with deterministic volatility and a Hilbert space valued driving Lévy noise. Conditions for the absence of arbitrage and for the existence of mild solutions are also discussed.

Quantum symmetries for exceptional SU(4) modular invariants associated with conformal embeddings

Three exceptional modular invariants of SU(4) exist at levels 4, 6 and 8. They can be obtained from appropriate conformal embeddings and the corresponding graphs have self-fusion. From these embeddings, or from their associated modular invariants, we determine the algebras of quantum symmetries, obtain their generators,and, as a by-product, recover the known graphs E4, E6 and E8 describing exceptional quantum subgroups of type SU(4). We also obtain characteristic numbers (quantum cardinalities, dimensions) for each of them and for their associated quantum groupoïds.

Identification of a novel determinant for membrane association in hepatitis C virus nonstructural protein 4B.

Nonstructural protein 4B (NS4B) plays an essential role in the formation of the hepatitis C virus (HCV) replication complex. It is a relatively poorly characterized integral membrane protein predicted to comprise four transmembrane segments in its central portion. Here, we describe a novel determinant for membrane association represented by amino acids (aa) 40 to 69 in the N-terminal portion of NS4B. This segment was sufficient to target and tightly anchor the green fluorescent protein to cellular membranes, as assessed by fluorescence microscopy as well as membrane extraction and flotation analyses. Circular dichroism and nuclear magnetic resonance structural analyses showed that this segment comprises an amphipathic alpha-helix extending from aa 42 to 66. Attenuated total reflection infrared spectroscopy and glycosylation acceptor site tagging revealed that this amphipathic alpha-helix has the potential to traverse the phospholipid bilayer as a transmembrane segment, likely upon oligomerization. Alanine substitution of the fully conserved aromatic residues on the hydrophobic helix side abrogated membrane association of the segment comprising aa 40 to 69 and disrupted the formation of a functional replication complex. These results provide the first atomic resolution structure of an essential membrane-associated determinant of HCV NS4B.

Neuroscience, quantum indeterminism and the Cartesian soul.

Quantum indeterminism is frequently invoked as a solution to the problem of how a disembodied soul might interact with the brain (as Descartes proposed), and is sometimes invoked in theories of libertarian free will even when they do not involve dualistic assumptions. Taking as example the Eccles-Beck model of interaction between self (or soul) and brain at the level of synaptic exocytosis, I here evaluate the plausibility of these approaches. I conclude that Heisenbergian uncertainty is too small to affect synaptic function, and that amplification by chaos or by other means does not provide a solution to this problem. Furthermore, even if Heisenbergian effects did modify brain functioning, the changes would be swamped by those due to thermal noise. Cells and neural circuits have powerful noise-resistance mechanisms, that are adequate protection against thermal noise and must therefore be more than sufficient to buffer against Heisenbergian effects. Other forms of quantum indeterminism must be considered, because these can be much greater than Heisenbergian uncertainty, but these have not so far been shown to play a role in the brain.

Genuine savings and future well-being in Germany, 1850-2000

Genuine Savings (GS), also known as ‘net adjusted savings’, is a composite indicator of the sustainability of economic development. Genuine Savings reflects year-on-year changes in the total wealth or capital of a country, including net investment in produced capita, investment in human capital, depletion of natural resources, and damage caused by pollution. A negative Genuine Savings rate suggests that the stock of national wealth is declining and that future utility must be less than current utility, indicating that economic development is non-sustainable (Hamilton and Clemens, 1999). We make use of data over a 150 year period to examine the relationship between Genuine Savings and a number of indicators of well-being over time, and compare the relative changes in human, produced, and components of natural capital over the period. Overall, we find that the magnitude of genuine savings is positively related to changes in future consumption, with some evidence of a cointegrating relationship. However, the relationships between genuine savings and infant mortality or average heights are less clear.