Photon density of states for deformed surfaces

A new approach to the Helmholtz spectrum for arbitrarily shaped boundaries and a rather general class of boundary conditions is introduced. We derive the boundary induced change of the density of states in terms of the free Green's function from which we obtain both perturbative and non-perturbative results for the Casimir interaction between deformed surfaces. As an example, we compute the lateral electrodynamic Casimir force between two corrugated surfaces over a wide parameter range. Universal behavior, fixed only by the largest wavelength component of the surface shape, is identified at large surface separations. This complements known short distance expansions which are also reproduced.Comment: 8 pages, J Phys A Special Issue QFEXT0

Networking in regions:potential analysis of the integration of North Rhine-Westphalian cities outside the Rhine-Ruhr-region into the project FLOW.NRW

Abstract. Tourists nowadays search for authentic and interesting experiences and acitivities in a destination. The project FLOW.NRW wants to present the federal state North Rhine-Westphalia as an attractive urban destination and as a living space with a high quality of life in international competition. It aims to attract people to discover the numerous facets of the various cities with its cultural, creative and digital potential. In contrast to the previous project #urbanana, the project approach in FLOW.NRW is now extended to the regional centres outside the Rhine-Ruhr region. The objective of this study therefore is to investigate the potential of the regional centers included, how an integration into the project can be successful and what potential for the future of the project can result from this. The data is collected via a short preliminary study with the three project partners Köln Tourismus, Düsseldorf Tourismus and Ruhr Tourismus as well with qualitative guideline-interviews with seven experts from the regional centers. After the evaluation with the method GABEK it turns out that the regional centers offer a lot of potential which can be communicated into the project. Especially within the threads Culture and Design exist many linkages, whereby the digital scene is still developable. The study has practical implications since it highlights the potentials of the cities and helps the project management to develop the project further, get better connections to the cities and thus to create a working network which strengthens the whole federal state NRW as a travel destination

Identification of grapevine cultivars by DNA analyses: Ptfalls of random amplified polymorphic DNA techniques using 10mer primers

Research Not

Evidence for an Excited Hyperon State in pp -> p K^+ Y^{0*}

Indications for the production of a neutral excited hyperon in the reaction pp -> p K^+ Y^{0*} are observed in an experiment performed with the ANKE spectrometer at COSY-J\"ulich at a beam momentum of 3.65 GeV/c. Two final states were investigated simultaneously, viz. Y^{0*} -> pi^+X^- and pi^-X^+, and consistent results were obtained in spite of the quite different experimental conditions. The parameters of the hyperon state are M(Y^{0*})= (1480 +/- 15) MeV/c^2 and Gamma(Y^{0*})= (60 +/- 15) MeV/c^2. The production cross section is of the order of few hundred nanobarns. Since the isospin of the Y^{0*} has not been determined here, it could either be an observation of the Sigma(1480), a one-star resonance of the PDG tables, or alternatively a Lambda hyperon. Relativistic quark models for the baryon spectrum do not predict any excited hyperon in this mass range and so the Y^{0*} may be of exotic nature.Comment: 4 pages, 3 figures, accepted for publication in Phys.Rev.Let

On the origin of the grapevine variety Müller-Thurgau as investigated by the inheritance of random amplified polymorphic DNA (RAPD)

Random amplified polymorphic DNA obtained with 10 different primers and peroxidase isoenzymes of Riesling, Silvaner and Müller-Thurgau were analyzed for genetic relationships between these grapevine varieties. It can be concluded that Müller-Thurgau is not a progenitor of a cross Riesling x Silvaner as generally assumed, but of Riesling and an unknown cultivar

The frequency of wing damage in a migrating butterfly

The ability to fly is crucial for migratory insects. Consequently, the accumulation of damage on the wings over time can affect survival, especially for species that travel long distances. We examined the frequency of irreversible wing damage in the migratory butterfly Vanessa cardui to explore the effect of wing structure on wing damage frequency, as well as the mechanisms that might mitigate wing damage. An exceptionally high migration rate driven by high precipitation levels in their larval habitats in the winter of 2018–2019 provided us with an excellent opportunity to collect data on the frequency of naturally occurring wing damage associated with long-distance flights. Digital images of 135 individuals of V. cardui were collected and analyzed in Germany. The results show that the hindwings experienced a greater frequency of damage than the forewings. Moreover, forewings experienced more severe damage on the lateral margin, whereas hindwings experienced more damage on the trailing margin. The frequency of wing margin damage was higher in the painted lady butterfly than in the migrating monarch butterfly and in the butterfly Pontia occidentalis following artificially induced wing collisions. The results of this study could be used in future comparative studies of patterns of wing damage in butterflies and other insects. Additional studies are needed to clarify whether the strategies for coping with wing damage differ between migratory and non-migratory species

The ABC Effect in Double-Pionic Nuclear Fusion and a pn Resonance as its Possible Origin

The ABC effect -- a long-standing puzzle in double-pionic fusion -- has been reexamined by the first exclusive and kinematically complete measurements of solid statistics for the fusion reactions $pn \to d\pi^0\pi^0$, $pd \to ^3$He$\pi\pi$ and $dd \to ^4$He$\pi\pi$ using the WASA detector, first at CELSIUS and recently at COSY -- the latter with a statistics increased by another two orders of magnitude. In all cases we observe a huge low-mass enhancement in the $\pi\pi$-invariant mass accompanied by a pronounced $\Delta\Delta$ excitation. For the most basic fusion reaction, the $pn \to d\pi^0\pi^0$ reaction, we observe in addition a very pronounced resonance-like energy dependence in the total cross section with a maximum 90 MeV below the $\Delta\Delta$ mass and a width of only 50 MeV, which is five times smaller than expected from a conventional $t$-channel $\Delta\Delta$ excitation. This reveals the ABC effect to be the consequence of a s-channel resonance with the formfactor of this dibaryonic state being reflected in the low-mass enhancement of the $\pi\pi$-invariant mass. From the fusion reactions to $^3$He and $^4$He we learn that this resonance is robust enough to survive even in nuclei.Comment: conference proceedings PANIC 0

Production of a0a_0-mesons in pp and pn reactions

We investigate the cross section for the reaction $NN \to NNa_0$ near threshold and at medium energies. An effective Lagrangian approach with one-pion exchange is applied to analyze different contributions to the cross section for different isospin channels. The Reggeon exchange mechanism is also considered. The results are used to calculate the contribution of the $a_0$ meson to the cross sections and invariant $K \bar K$ mass distributions of the reactions $pp\to pn K^+\bar K^0$ and $pp\to pp K^+K^-$. It is found that the experimental observation of $a_0^+$ mesons in the reaction $pp\to pn K^+\bar K^0$ is much more promising than the observation of $a_0^0$ mesons in the reaction $pp\to pp K^+K^-$.Comment: 26 pages, including 11 eps figures, to be bublished in J. Phys.