Expeditionen ins Pilzreich Panamas : Pionierarbeit in einer der artenreichsten Regionen unserer Erde

Als Bindeglied zwischen Nord- und Südamerika ist Panama ein »Biodiversitäts-Hotspot« – es beherbergt eine außerordentlich hohe Artenvielfalt an Pflanzen, Tieren und Pilzen. Pilze übernehmen in tropischen Ökosystemen wichtige Aufgaben: Sie zersetzen totes organisches Material, helfen den Pflanzen bei der Aufnahme von Wasser und Mineralstoffen aus dem Boden, und sie leisten sogar als Parasiten einen Beitrag zum Erhalt einer großen Artenvielfalt. Aufgrund einzelner Stichproben wissen wir, dass die Anzahl der Pilzarten in den Tropen diejenige der Pflanzen um ein Vielfaches übertrifft. Doch während für Panama zirka 9500 verschiedene Arten von Gefäßpflanzen bekannt sind, zählt eine im Rahmen unserer Arbeit erstellte Checkliste der Pilze nur zirka 1800 Arten. Das zeigt, dass für die Erforschung der Pilze noch umfangreiche Pionierarbeit geleistet werden muss. Zwischen 2003 und 2006 geschah dies im Rahmen einer Universitätspartnerschaft der Universität Frankfurt mit der Universidad Autónoma de Chiriquí, die durch den Deutschen Akademischen Austauschdienst (DAAD) gefördert wurde. Im Zentrum eines Projekts der Deutschen Forschungsgemeinschaft (DFG) steht die Erforschung der Vielfalt und Ökologie pflanzenparasitischer Pilze. Des Weiteren untersucht unsere Arbeitsgruppe Pilze an Insekten sowie an menschlichen Haut- und Nagelläsionen

Sur les limites d'application du modèle de Stephens

Les conséquences de l'hypothèse de la conservation de j dans le modèle de Stephens sont analysées. Les conditions de l'applicabilité de cette hypothèse dans le cas des sous-couches isolées (l'extension est faite à N = 4 et N = 3) sont discutées et des explications en sont données. Dans les autres cas, un traitement exact des états propres du mouvement intrinsèque permet néanmoins l'extension du modèle de Stephens sans élargissement de la base de diagonalisation

Self-consistent collective subspaces and diabatic/adiabatic motion in nuclei

We discuss the application of a theory of large-amplitude collective motion to a simple model mimicking the pairing-plus-quadrupole model of nuclear physics.Comment: 4 pages, RevTex using graphicx.sty, 1 postscript figures included. Talk presented at Conference on "Nuclear structure at the extremes" (June 17 - 19, 1998, Lewes, UK

SU(2) × SU(2) × U(1) basis for symmetric SO(6) representations : matrix elements of the generators

Matrix elements of the group generators for the symmetric irreducible representations of SO(6) are explicitly calculated in a closed form employing the decomposition chain SO(6) ⊃ SU(2) x SU(2) x U(1) (which is different from the well known Wigner supermultiplet scheme). The relation to the Gel'fand Tsetlin method using SO(6) ⊃ SO(5) ⊃ ... ⊃ SO(2) is indicated. An example of a physical application is given

New records and host plants of fly-speck fungi from Panama

Fly-speck fungi are inconspicuous Ascomycota mainly found in the tropics and subtropics. They form small scutellate fruiting bodies, called thyriothecia, on the surface of host organs. They are plant parasites on living leaves and stems (Theissen, 1913; Stevens and Ryan, 1939), saprobes on dead leaves and stems (Ellis, 1976) or commensals (fungal epiphylls) on living leaves (Gilbert et al., 2006). Saprobes are found in temperate zones as well as in the tropics or subtropics. True plant parasites and commensals, which are thought to be species-rich, are delimited to tropical or subtropical regions of the world. Most fly-speck fungi belong to one of two subclasses of bitunicate Ascomycota: Chaetothyriomycetidae or Dothideomycetidae (Kirk et al., 2001). The systematic relationships between families, genera and species are not solved yet, as complete phylogenetic studies are lacking for this group, except for some members of Chaetothyriomycetidae (Berbee, 1996; Liu and Hall, 2004) and Dothideomycetidae (e.g. Tam et al., 2003). In the past, many authors described tropical fly-speck fungi (e.g. Theissen, 1913; Sydow, 1927; Hansford, 1946). During the last decades 55 members of fly-speck fungi have been described from many tropical and subtropical regions: Africa (Mibey and Hawksworth, 1997), Asia (e.g. Hosagoudar and Abraham, 1998; Song et al., 2004), Australia (Reynolds and Gilbert, 2005) and North America (e.g. Ahn and Crane, 2004). However, only Batista (1959), Batista et al. (1963) and Farr (1986, 1987) published morphologic and taxonomic studies on this group in the neotropics, and only from Brazil. As the diversity of fly-speck fungi is very high in tropical latitudes (Batista, 1959), our knowledge is still very incomplete. During recent field work in Panama, many tropical fly-speck fungi were observed. Only the flyspeck fungi Chaetothyrina panamensis (F. Stevens & Dorman) Arx (Dennis, 1970), Chaetothyriopsis panamensis F. Stevens & Dorman (Stevens, 1927), Micropeltis bakeri Syd. & P. Syd. (Cash and Watson, 1955), Yamamotoa carludovicae (Bat.) Arx & E. Müll. (Sivanesan, 1984), Scolecopeltidium bakeri (Syd. & P. Syd.) F. Stevens & Manter (Batista, 1959) and Scolecopeltidium mayteni Bat. & I.H. Lima (Gilbert et al., 1997) are known so far from Panama. In the present study six species new for Panama on several new host plants are described and illustrated. We are convinced that many more species will be found in Panama during future field work

Multi-Phonon γ\gamma-Vibrational Bands and the Triaxial Projected Shell Model

We present a fully quantum-mechanical, microscopic, unified treatment of ground-state band and multi-phonon $\gamma$-vibrational bands using shell model diagonalization with the triaxial projected shell model. The results agree very well with data on the g- and $\gamma$-band spectra in $^{156-170}$Er, as well as with recently measured $4^+$ 2-phonon $\gamma$-bandhead energies in $^{166}$Er and $^{168}$Er. Multi-phonon $\gamma$-excitation energies are predicted.Comment: 4 pages, 4 figures, submitted to Phys. Lett.

HONGOS ENTOMOPATÓGENOS ASOCIADOS A INSECTOS RECOLECTADOS EN PLANTACIONES DE CAFÉ EN EL OESTE DE PANAMÁ

This study was carried out in order to determine the diversity of native entomopathogenic fungi associated to insects present in coffee plantations in Boquete (without the presence of Hipothenemus hampei Ferrari). Fieldwork was conducted between October and November 2005. Insects were collected with the symptoms of entomopathogenic fungi attack and were isolated and identified. A total of 33 fungal cultures were obtained from the isolation of mycelia present in samples of insects collected in the field. The cultures correspond to 7 species in 5 genera of pathogenic fungi: Acremonium charticola, A. crassum, Beauveria bassiana, B. brongniartii, Fusarium oxysporum, Lecanicillium tenuipes, Metarhizium anisopliae and Torrubiella tenuis, which were found on insects of the orders Dermaptera and Hemiptera. Of these species, only Beauveria and Acremonium have been documented in other studies as natural enemies of H. hampei. T. tenuis was the only teleomorph found infesting scale insects.  Este estudio se realizó con la finalidad de determinar la diversidad de hongos entomopatógenos nativos asociados a insectos presentes en plantaciones de café en Boquete (sin la presencia de Hypothenemus hampei Ferrari).  El trabajo de campo se realizó entre octubre y noviembre de 2005. Se recolectaron insectos con la sintomatología del ataque de hongos entomopatógenos y se aislaron e identificaron. Un total de 33 cultivos de hongos se obtuvieron del aislamiento de micelio presente en las muestras de insectos. Los cultivos corresponden a siete especies en cinco géneros de hongos patógenos: Acremonium charticola, A. crassum, Beauveria bassiana, B. brongniartii, Fusarium oxysporum, Lecanicillium tenuipes, Metarhizium anisopliae y Torrubiella tenuis, los cuales se encontraron en insectos de los órdenes Dermáptera y Hemiptera. De éstas especies, solo Acremonium y Beauveria han sido documentadas en otros estudios como enemigos naturales de H. hampei. Torrubiella tenuis fue el único teleomorfo encontrado parasitando insectos escamas

Parametrization of the octupole degrees of freedom

A simple parametrization for the octupole collective variables is proposed and the symmetries of the wave functions are discussed in terms of the solutions corresponding to the vibrational limit. [PACS: 21.60Ev, 21.60.Fw, 21.10.Re]Comment: 14 page