Thermodynamically Stable One-Component Metallic Quasicrystals

Classical density-functional theory is employed to study finite-temperature trends in the relative stabilities of one-component quasicrystals interacting via effective metallic pair potentials derived from pseudopotential theory. Comparing the free energies of several periodic crystals and rational approximant models of quasicrystals over a range of pseudopotential parameters, thermodynamically stable quasicrystals are predicted for parameters approaching the limits of mechanical stability of the crystalline structures. The results support and significantly extend conclusions of previous ground-state lattice-sum studies.Comment: REVTeX, 13 pages + 2 figures, to appear, Europhys. Let

New results for the degree/diameter problem

The results of computer searches for large graphs with given (small) degree and diameter are presented. The new graphs are Cayley graphs of semidirect products of cyclic groups and related groups. One fundamental use of our ``dense graphs'' is in the design of efficient communication network topologies.Comment: 15 page

Regulating Television and the Case of Football World Cup

This paper deals with EU-Directive 89/552/EEC "Television Without Frontiers", which enables each EU-country to set up a list of major events that are not allowed to be transmitted in Pay-TV. We analyze this kind of regulation using instruments of game-theory and monopoly-theory. We compare the market results of the EU-Regulation with two alternative arrangements, namely with a general ban of Pay-TV and with a 'laisser-faire'-solution. Our model shows that a selective ban may be welfare-superior to both other forms of Pay-TV treatment. Finally we show that there are good arguments to forbid Pay-TV-broadcasting of major football events. -- Dieses Paper beschäftigt sich mit der Frage, ob sportliche Großereignisse im Pay-TV oder im Free-TV übertragen werden sollten. Aktueller Anlaß für eine breite Diskussion dieses Themas ist der Kauf der Übertragungsrechte für die Fußballweltmeisterschaften 2002 und 2006 durch die ISL/Kirch-Gruppe. Verfechter einer weit-reichenden Regulierung des Fernsehmarktes befürworten Maßnahmen, die bis zu einem Verbot von Pay-TV reichen. Andere wollen hingegen der ISL/Kirch-Gruppe die freie Vermarktung ihrer Rechte belassen. Unsere Analyse nähert sich dem Problem aus ökonomischer Sicht. Wir gehen dabei von einem dreistufigen Fernsehmarkt aus, in dem ein Erstrechteinhaber als Monopolanbieter die Übertragungslizenz vergibt. Auf einer zweiten Stufe entscheidet der Lizenznehmer über die Ausstrahlungsform. Die unterste Ebene ist von fußballbegeisterten Fernsehzuschauern geprägt, die eine wertvolle Zielgruppe für die Werbewirtschaft darstellen. In einem einfachen monopoltheoretischen Modell werden Bedingungen abgeleitet, unter denen eine Regulie-rung des Fernsehmarktes erfolgen sollte. Unsere Empfehlungen stützen sich dabei auf eine wohlfahrtsökonomische Bewertung der Modellergebnisse.Pay-TV,Football,Media economics,Advertising,Applied Game Theory,EU-Directive 89/552/EEC

Econometric analysis of volatile art markets

A new heteroskedastic hedonic regression model is suggested which takes into account time-varying volatility and is applied to a blue chips art market. A nonparametric local likelihood estimator is proposed, and this is more precise than the often used dummy variables method. The empirical analysis reveals that errors are considerably non-Gaussian, and that a student distribution with time-varying scale and degrees of freedom does well in explaining deviations of prices from their expectation. The art price index is a smooth function of time and has a variability that is comparable to the volatility of stock indices.Volatility, art markets, hedonic regression, semiparametric estimation

Super-resolution imaging and estimation of protein copy numbers at single synapses with DNA-PAINT

In the brain, the strength of each individual synapse is defined by the complement of proteins present or the "local proteome." Activity-dependent changes in synaptic strength are the result of changes in this local proteome and posttranslational protein modifications. Although most synaptic proteins have been identified, we still know little about protein copy numbers in individual synapses and variations between synapses. We use DNA-point accumulation for imaging in nanoscale topography as a single-molecule super-resolution imaging technique to visualize and quantify protein copy numbers in single synapses. The imaging technique provides near-molecular spatial resolution, is unaffected by photobleaching, enables imaging of large field of views, and provides quantitative molecular information. We demonstrate these benefits by accessing copy numbers of surface AMPA-type receptors at single synapses of rat hippocampal neurons along dendritic segments

Systemic epidermal nevus with involvement of the oral mucosa due to FGFR3 mutation

Our results show that activating FGFR3 mutations can also affect the oral mucosa and that extracutaneous manifestations of EN syndrome can be subtle. We highlight the theoretical risk of the patient having an offspring with thanatophoric dysplasia as gonadal mosaicism for the R248C mutation cannot be excluded

The Structure of Barium in the hcp Phase Under High Pressure

Recent experimental results on two hcp phases of barium under high pressure show interesting variation of the lattice parameters. They are here interpreted in terms of electronic structure calculation by using the LMTO method and generalized pseudopotential theory (GPT) with a NFE-TBB approach. In phase II the dramatic drop in c/a is an instability analogous to that in the group II metals but with the transfer of s to d electrons playing a crucial role in Ba. Meanwhile in phase V, the instability decrease a lot due to the core repulsion at very high pressure. PACS numbers: 62.50+p, 61.66Bi, 71.15.Ap, 71.15Hx, 71.15LaComment: 29 pages, 8 figure

Generalized van der Waals theory of liquid-liquid phase transitions

In the framework of the thermodynamic perturbation theory for fluids we study how the phase diagram of an isotropic repulsive soft-core attractive potential, where a liquid-liquid phase transition exists in addition to the standard gas-liquid phase transition, changes by varying the parameters of the potential. We show that existence of the liquid-liquid transition is determined by the interplay of the parameters of the potential and the structure of a reference liquid.Comment: 5 pages, 6 figure