Fossil insects from the Middle Ecca (Lower permian) of southern Africa

Main articleThree insects are recorded from carbonaceous shales of Middle Ecca age from Hammanskraal, near Pretoria. Thaumalophora pranotalis gen. et sp. nov., is an aquatic nymph of the Paraplecoptera showing lateral abdominal gills. Sysciophlebia kovacsae sp. nov. is a tegmen of a spiloblattinid cockroach. The third specimen is a small protopsyllidiid nymph. Only three insects of greater age are known from southern Africa.Non

An unusual mayfly (Insecta: Ephemeroptera) from the Triassic of South Africa

Main articleAn unusual mayfly from the Upper Triassic near Dordrecht in the Cape Province of South Africa is described as Xenophlebia optata gen. et sp. nov., and is ascribed to a new family, the Xenophlebiidae, as its sole representative.Non

A FOSSIL INSECT FROM THE DWYKA SERIES OF RHODESIA

Hadenlomoides dwykensis, gen. et sp. nov. (Paraplecoptera: Hadentomidael is the oldest recorded insect in the southern hemisphere. It is similar to Hadenlomum americanum from the Upper Carboniferous of North America. The close relationship between these two species tends to support the view that at least part of the Dwyka Series extends below the Permian into the Upper Carboniferous

UPPER TRIASSIC INSECTS FROM THE MOLTENO "FORMATION", SOUTH AFRICA.

Insects are recorded from eight plant fossil localities in the Molteno "Formation", but only heavily sclerotized species (Blattodea and Coleoptera) have been obtained from six of them. A small mecopteron was found at another locality, and only at Birds River, near Dordrecht, has a more diverse fauna, with representatives of the Orthoptera, ?Mantodea, Blattodea, Homoptera and Megaloptera, been obtained. The known fauna is closely comparable with the Triassic faunas of Australia. Thirteen species, nine of which are described as new, are recorded from the Molteno. Six of the new species, and one described species, are referred to Hagla, Mesorthopteron, Triassoblatta, Dysmorphoptiloides and Ademosyne, genera represented in or previously restricted to the Australian Triassic faunas. The new monotypic genera, Prosbolomorpha (type species clara: Homoptera) and Afristella (type species delicatula: Mecoptera), are similar to genera recorded from the Triassic of Australia. Euchauliodes distinctus, gen. et sp. nov., is the earliest known Corydaloidean wing (Megaloptera); it is referred to a new family

Quarkonia and Heavy-Quark Relaxation Times in the Quark-Gluon Plasma

A thermodynamic T-matrix approach for elastic 2-body interactions is employed to calculate spectral functions of open and hidden heavy-quark systems in the Quark-Gluon Plasma. This enables the evaluation of quarkonium bound-state properties and heavy-quark diffusion on a common basis and thus to obtain mutual constraints. The two-body interaction kernel is approximated within a potential picture for spacelike momentum transfers. An effective field-theoretical model combining color-Coulomb and confining terms is implemented with relativistic corrections and for different color channels. Four pertinent model parameters, characterizing the coupling strengths and screening, are adjusted to reproduce the color-average heavy-quark free energy as computed in thermal lattice QCD. The approach is tested against vacuum spectroscopy in the open (D, B) and hidden (Psi and Upsilon) flavor sectors, as well as in the high-energy limit of elastic perturbative QCD scattering. Theoretical uncertainties in the static reduction scheme of the 4-dimensional Bethe-Salpeter equation are elucidated. The quarkonium spectral functions are used to calculate Euclidean correlators which are discussed in light of lattice QCD results, while heavy-quark relaxation rates and diffusion coefficients are extracted utilizing a Fokker-Planck equation.Comment: 33 pages, 28 figure

Debye mass and heavy quark potential in a PNJL quark plasma

We calculate the Debye mass for the screening of the heavy quark potential in a plasma of massless quarks coupled to the temporal gluon background governed by the Polyakov loop potential within the PNJL model in RPA approximation. We give a physical motivation for a recent phenomenological fit of lattice data by applying the calculated Debye mass with its suppression in the confined phase due to the Polyakov-loop to a description of the temperature dependence of the singlet free energy for QCD with a heavy quark pair at infinite separation. We compare the result to lattice data.Comment: 6 pages, 1 figure, contribution to Proceedings of the 6th International Conference on "Critical Point and Onset of Deconfinement", to appear in Phys. At. Nucl., vol. 7

Dynamics of Resonances in Strongly Interacting Systems

The effects of the propagation of particles which have a finite life-time and an according broad distribution in their mass spectrum are discussed in the context of a transport descriptions. In the first part some example cases of mesonic modes in nuclear matter at finite densities and temperatures are presented. These equilibrium calculations illustrate the dynamical range of spectral distributions to be adequately covered by non-equilibrium description of the dynamics of two nuclei colliding at high energies. The second part addresses the problem of transport descriptions which properly account for the damping width of the particles. A systematic and general gradient approximation is presented in the form of diagrammatic rules which permit to derive a self-consistent transport scheme from the Kadanoff--Baym equation. The scheme is conserving and thermodynamically consistent provided the self-energies are obtained within the Phi-derivable two-particle irreducible (2PI) method of Baym. The merits, the limitations and partial cures of the limitations of this transport scheme are discussed in detail.Comment: To appear in the proceedings of the International Conference "Progress in Nonequilibrium Green's Functions III", Kiel, 22.-26. August 200

Characterisation of sugar beet (Beta vulgaris L. ssp. vulgaris) varieties using microsatellite markers

<p>Abstract</p> <p>Background</p> <p>Sugar beet is an obligate outcrossing species. Varieties consist of mixtures of plants from various parental combinations. As the number of informative morphological characteristics is limited, this leads to some problems in variety registration research.</p> <p>Results</p> <p>We have developed 25 new microsatellite markers for sugar beet. A selection of 12 markers with high quality patterns was used to characterise 40 diploid and triploid varieties. For each variety 30 individual plants were genotyped. The markers amplified 3-21 different alleles. Varieties had up to 7 different alleles at one marker locus. All varieties could be distinguished. For the diploid varieties, the expected heterozygosity ranged from 0.458 to 0.744. The average inbreeding coefficient F_iswas 0.282 ± 0.124, but it varied widely among marker loci, from F_is= +0.876 (heterozygote deficiency) to F_is= -0.350 (excess of heterozygotes). The genetic differentiation among diploid varieties was relatively constant among markers (F_st= 0.232 ± 0.027). Among triploid varieties the genetic differentiation was much lower (F_st= 0.100 ± 0.010). The overall genetic differentiation between diploid and triploid varieties was F_st= 0.133 across all loci. Part of this differentiation may coincide with the differentiation among breeders' gene pools, which was F_st= 0.063.</p> <p>Conclusions</p> <p>Based on a combination of scores for individual plants all varieties can be distinguished using the 12 markers developed here. The markers may also be used for mapping and in molecular breeding. In addition, they may be employed in studying gene flow from crop to wild populations.</p