Phylogeny of Geomydoecus and Thomomydoecus pocket gopher lice (phthiraptera, trichodectidae) inferred from cladistic analysis of adult and first instar morphology

The phylogeny for all 122 species and subspecies of chewing lice of the genera Geomydoecus and Thomomydoecus (Phthiraptera: Trichodectidae) hosted by pocket gophers (Rodentia: Geomyidae) is estimated by a cladistic analysis of fifty-eight morphological characters obtained from adults and first instars. The data set has considerable homoplasy, but still contains phylogenetic information. The phylogeny obtained is moderately resolved and, with some notable exceptions, supports the species complexes proposed by Hellenthal and Price over the the last two decades. The subgenera G. (Thaelerius) and T. (Thomomydoecus) are both shown to be monophyletic, but the monophly of subgenus T. (Jamespattonius) could not be confirmed, perhaps due to the lack of first-instar data for one of its component species. The nominate subgenus of Geomydoecus may be monophyletic, but our cladogram was insufficiently resolved to corroborate this. Mapping the pocket gopher hosts onto the phylogeny reveals a consistent pattern of louse clades being restricted to particular genera or subgenera of gophers, but the history of the host-parasite association appears complex and will require considerable effort to resolve

On the rate of convergence of the Hamiltonian particle-mesh method

The Hamiltonian Particle-Mesh (HPM) method is a particle-in-cell method for compressible fluid flow with Hamiltonian structure. We present a numer- ical short-time study of the rate of convergence of HPM in terms of its three main governing parameters. We find that the rate of convergence is much better than the best available theoretical estimates. Our results indicate that HPM performs best when the number of particles is on the order of the number of grid cells, the HPM global smoothing kernel has fast decay in Fourier space, and the HPM local interpolation kernel is a cubic spline

Scalar Synchrotron Radiation in the Schwarzschild-anti-de Sitter Geometry

We present a complete relativistic analysis for the scalar radiation emitted by a particle in circular orbit around a Schwarzschild-anti-de Sitter black hole. If the black hole is large, then the radiation is concentrated in narrow angles- high multipolar distribution- i.e., the radiation is synchrotronic. However, small black holes exhibit a totally different behavior: in the small black hole regime, the radiation is concentrated in low multipoles. There is a transition mass at $M=0.427 R$, where $R$ is the AdS radius. This behavior is new, it is not present in asymptotically flat spacetimes.Comment: 13 pages, 6 figures, published version. References adde

Close limit evolution of Kerr-Schild type initial data for binary black holes

We evolve the binary black hole initial data family proposed by Bishop {\em et al.} in the limit in which the black holes are close to each other. We present an exact solution of the linearized initial value problem based on their proposal and make use of a recently introduced generalized formalism for studying perturbations of Schwarzschild black holes in arbitrary coordinates to perform the evolution. We clarify the meaning of the free parameters of the initial data family through the results for the radiated energy and waveforms from the black hole collision.Comment: 8 pages, RevTex, four eps figure

Das bandkeramische Gräberfeld vom „Viesenhäuser Hof“ bei Stuttgart-Mühlhausen: Neue Untersuchungsergebnisse zum Migrationsverhalten im frühen Neolithikum

Einleitung: Gegenstand des vorliegenden Beitrags ist die Rolle der Mobilität im Leben der frühen Ackerbauern und Viehzüchter in Südwestdeutschland. Seit Jahrzehnten werden wissenschaftliche Auseinandersetzungen über die Bedeutung von Wanderungsbewegungen bei der Ausbreitung der produzierenden Wirtschaftsweise in Europa zwischen 7000 und 4000 v. Chr. geführt. Dabei gehen traditionelle Überlegungen davon aus, dass die ersten Ackerbauern in Mitteleuropa Zuwanderer waren, die ein ‚Paket‘ neuer Errungenschaften und Ideen mit sich führten, das u. a. Haustiere, dauerhafte Siedlungen, Keramik und den Ackerbau enthielt.1 Neuere Untersuchungen und Überlegungen gestehen dagegen der einheimischen Bevölkerung eine maßgebliche Bedeutung bei der Übernahme der neolithischen Wirtschaftsweise zu.2 Die Mobilität des Menschen ist aber nicht nur für die Erklärung des Neolithisierungsprozesses, sondern auch für das Verständnis der Lebens- und Wirtschaftsweise der Menschen in den mittleren und späteren Abschnitten der Linearbandkeramik von höchstem Interesse. Die bisherige Forschungsdiskussion basierte in diesem Zusammenhang überwiegend auf indirekten Argumenten, d. h. auf Artefakten, die auch getauscht oder gestohlen worden sein konnten, aber nicht auf den Überresten der potenziellen Zuwanderer selbst, die in Form von Knochen und Zähnen erhalten sind. Die vorliegende Studie bedient sich der direkten Analyse menschlicher Skelettreste der bandkeramischen Gräber vom ‚Viesenhäuser Hof‘, Stuttgart-Mühlhausen, mittels anthropologischer Untersuchungen und Strontiumisotopenanalysen. Nachfolgend werden der Fundplatz in seinem archäologischen Kontext der Linearbandkeramik sowie die Ergebnisse der anthropologischen Untersuchungen und Strontiumisotopenanalysen vorgestellt und dann die Rolle der Mobilität im Leben der frühen Ackerbauern und Viehzüchter sowie für die Ausbreitung der neolithischen Wirtschaftsweise diskutiert. Stuttgart-Mühlhausen ist eines der ältesten bandkeramischen Gräberfelder, die bislang für derartige Untersuchungen zur Verfügung standen

Non-linear instability of Kerr-type Cauchy horizons

Using the general solution to the Einstein equations on intersecting null surfaces developed by Hayward, we investigate the non-linear instability of the Cauchy horizon inside a realistic black hole. Making a minimal assumption about the free gravitational data allows us to solve the field equations along a null surface crossing the Cauchy Horizon. As in the spherical case, the results indicate that a diverging influx of gravitational energy, in concert with an outflux across the CH, is responsible for the singularity. The spacetime is asymptotically Petrov type N, the same algebraic type as a gravitational shock wave. Implications for the continuation of spacetime through the singularity are briefly discussed.Comment: 11 pages RevTeX, two postscript figures included using epsf.st

Seismic data reveal eastern Black Sea Basin structure

Rifted continental margins are formed by progressive extension of the lithosphere. The development of these margins plays an integral role in the plate tectonic cycle, and an understanding of the extensional process underpins much hydrocarbon exploration. A key issue is whether the lithosphere extends uniformly, or whether extension varies\ud with depth. Crustal extension may be determined using seismic techniques. Lithospheric extension may be inferred from the waterloaded subsidence history, determined from\ud the pattern of sedimentation during and after rifting. Unfortunately, however, many rifted margins are sediment-starved, so the subsidence history is poorly known.\ud To test whether extension varies between the crust and the mantle, a major seismic experiment was conducted in February–March 2005 in the eastern Black Sea Basin (Figure 1), a deep basin where the subsidence history is recorded\ud by a thick, post-rift sedimentary sequence. The seismic data from the experiment indicate the presence of a thick, low-velocity zone, possibly representing overpressured sediments. They also indicate that the basement and\ud Moho in the center of the basin are both several kilometers shallower than previously inferred. These initial observations may have considerable impact on thermal models of the petroleum system in the basin. Understanding\ud the thermal history of potential source rocks is key to reducing hydrocarbon exploration risk. The experiment, which involved collaboration between university groups in the United Kingdom, Ireland, and Turkey, and BP and\ud Turkish Petroleum (TPAO), formed part of a larger project that also is using deep seismic reflection and other geophysical data held by the industry partners to determine the subsidence history and hence the strain evolution of\ud the basin

Design and Testing of High Current, High Voltage, Hexapolar Flexible Cables for Pulsed Power Applications

Under Defense Advanced Research Projects Agency (DARPA) and U. S. Army sponsorship, the Center for Electromechanics has designed and is constructing highly flexible, high current and voltage, magnetically compensated (hexapolar) cables and cable terminations as component interconnect buswork for a stand-alone, Compulsator-driven electromagnetic (EM) gun system. Flexible cables under development are rated at 300 kA peak current and peak voltage of 15 kV. Cable construction in this configuration provides several advantages; high flexibility, outstanding insulation integrity, ease in termination, and large conductor net cross sectional area (fig. 1). Standardized modular cable terminations are also being developed featuring compact construction, small footprint, a unique single-bolt (per polarity) high contact area/pressure electrical terminal, and electromagnetically self supporting high voltage insulated casing. The cable termination mates to a simply machined receptacle. Presented are cable and termination design criteria, cable parallel operation simulations and preliminary performance test data collected. A list of vendors capable of manufacturing the cables and terminations is also included.Center for Electromechanic

Decay of charged scalar field around a black hole: quasinormal modes of R-N, R-N-AdS and dilaton black holes

It is well known that the charged scalar perturbations of the Reissner-Nordstrom metric will decay slower at very late times than the neutral ones, thereby dominating in the late time signal. We show that at the stage of quasinormal ringing, on the contrary, the neutral perturbations will decay slower for RN, RNAdS and dilaton black holes. The QN frequencies of the nearly extreme RN black hole have the same imaginary parts (damping times) for charged and neutral perturbations. An explanation of this fact is not clear but, possibly, is connected with the Choptuik scaling.Comment: 10 pages, LaTeX, 4 figures, considerable changes made and wrong interpretation of computations correcte

Response of Vegetation to Livestock Grazing at the Texas Experimental Ranch.

40 p