Surrogates of spider diversity, leveraging the conservation of a poorly known group in the Savanna Biome of South Africa (Arachnida : Araneae)

The inclusion of spiders in conservation planning initiatives is confounded by several factors. Surrogates could facilitate their incorporation. In this paper we investigate the performance of a number of surrogate measures, such as higher taxa (genus, family), cross-taxon surrogates that are subsets of the spider assemblages (certain spider families) or non-overlapping groups (woody vegetation and birds), and the use of morphospecies. Birds and woody vegetation were included because they often form the focus of conservation planning initiatives. We assessed the surrogate measures based on their predictive power for species richness and extent to which conservation planning that maximizes representation of the surrogate is effective in representing spider diversity. A measure for the latter is the Species Accumulation Index (SAI). Generic richness as a higher taxon surrogate and the combined richness of the families Thomisidae and Salticidae were the best estimators of total species richness. Based on the surrogacy efficiency criterion, genera and the family Salticidae had species accumulation indices (SAIs) that were significantly larger than 95% confidence intervals of a random curve, while woody vegetation and birds turned out to be poor surrogates for spider diversity. The use of morphospecies as estimators is cautiously supported (adjusted R2 = 0.85, for species richness, SAI = 0.73). The surrogates identified here provide a viable alternative to whole assemblage analysis but should be used with caution. The use of genera is confounded by unstable taxonomy and the difficulty of identifying specimens up to genus level. Geographic location and varying sampling effort between surveys did not have an effect on the surrogate performance of the two spider families, viz. Salticidae and Thomisidae. The former family has seen a flood of recent systematic work, whereas the latter’s taxonomy is fairly well developed. These two families comprise ca. 20% of spider species observed in the Savanna Biome of South Africa and could provide a viable handle on spider diversity in this region.This research was funded by the University of Venda and an NRF grant (GUN 2054390) to the first author. SHF also acknowledges support from the DST-NRF Centre of Excellence for Invasion Biology.http://www.elsevier.com/ locate/bioconhb201

Energy Levels and Transition Probabilities for Nitrogen-Like Fe xx

Energies of the 700 lowest levels in Fexx have been obtained using the multiconfiguration Dirac-Fock method. Configuration interaction method on the basis set of transformed radial orbitals with variable parameters taking into account relativistic corrections in the Breit-Pauli approximation was used to crosscheck our presented results. Transition probabilities, oscillator and line strengths are presented for electric dipole (E1), electric quadrupole (E2) and magnetic dipole (M1) transitions among these levels. The total radiative transition probabilities from each level are also provided. Results are compared with data compiled by NIST and with other theoretical work

Impurity generation during intense lower hybrid heating experiments on the Alcator C tokamak

and disposal, in whole or in part by or for the United States govern-ment is permitted. By acceptance of this article, the publisher and/or recipient ac-knowledges the U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright covering this paper. Experiments are underway on the Alcator C Tokamak with over 1 MW of RF power injected into the plasma at a frequency of 4.6 GHz to study both heating and current drive effects. During these studies, impurity genera-tion from limiter structures has been observed. The RF induced impurity influx is a strongly nonlinear function of net injected power. For Prf < 500 kW, only small effects are seen. As Prf approaches 1 MW, however, sharp increases in impurity influxes and Zeff are observed. Three different lim-iter materials have been used during these studies: molybdenum, graphite, and silicon-carbide coated graphite. In each case, the materials of the limiter structure are seen to dominate the increased impurity influx. In a typical case, with Prf = 1.0 MW e = 1.3 x 1014 cm- 3, and the SiC coated limiters, Zeff is seen to increase from 1.5 before the RF pulse to about 4 during the heating. At the same time, central Te increases from 2000 eV to 3000 eV and central Ti from 1200 eV to 1800 eV. Similar effects are seen in both H2 and D2 working gas discharges. The contribution to impurity genera-tion of nonthermal electrons, which are produced by the RF, is under investi-gation. Changes in edge plasma temperature and density, as well as the possibility that the particle transport is affected by the RF, are also being examined. Results of the experiments with the three different limiter materials are compared, and contributions of impurity radiation to the overall power balance are estimated

The promise of the affordable artist's studio: Governing creative spaces in London

The role of artists' organisations in populating and popularising postindustrial urban areas is well documented. However, what are less apparent are analyses of how spaces of artistic production are organised and governed in these areas. This paper explores, via an analysis of organisational documents and practices, the techniques used by London-based affordable studio providers to imagine, calculate, and make material low-cost workspace for artists. The argument made is that the negotiation of competing agendas around the production of cultural, economic, and social benefit by affordable studio providers has led to the emergence of a specific form of affordable studio. This analysis will thus show how configurations of creative space emerge from mundane techniques of measurement and governance. © 2013 Pion and its Licensors

X-ray Astronomy in the Laboratory with a Miniature Compact Object Produced by Laser-Driven Implosion

Laboratory spectroscopy of non-thermal equilibrium plasmas photoionized by intense radiation is a key to understanding compact objects, such as black holes, based on astronomical observations. This paper describes an experiment to study photoionizing plasmas in laboratory under well-defined and genuine conditions. Photoionized plasma is here generated using a 0.5-keV Planckian x-ray source created by means of a laser-driven implosion. The measured x-ray spectrum from the photoionized silicon plasma resembles those observed from the binary stars Cygnus X-3 and Vela X-1 with the Chandra x-ray satellite. This demonstrates that an extreme radiation field was produced in the laboratory, however, the theoretical interpretation of the laboratory spectrum significantly contradicts the generally accepted explanations in x-ray astronomy. This model experiment offers a novel test bed for validation and verification of computational codes used in x-ray astronomy.Comment: 5 pages, 4 figures are included. This is the original submitted version of the manuscript to be published in Nature Physic

Radiation Science Using Z-Pinch X-Rays

Present-day Z-pinch experiments generate 200 TW peak power, 5–10 ns duration x-ray bursts that provide new possibilities to advance radiation science. The experiments support both the underlying atomic and plasma physics, as well as inertial confinement fusion and astrophysics applications. A typical configuration consists of a sample located 1–10 cm away from the pinch, where it is heated to 10–100 eV temperatures by the pinch radiation. The spectrally-resolved sample-plasma absorption is measured by aiming x-ray spectrographs through the sample at the pinch. The pinch plasma thus both heats the sample and serves as a backlighter. Opacitymeasurements with this source are promising because of the large sample size, the relatively long radiation duration, and the possibility to measureopacities at temperatures above 100 eV. Initial opacity experiments are under way with CH-tamped NaBr foil samples. The Na serves as a thermometer and absorption spectra are recorded to determine the opacity of Br with a partially-filled M-shell. The large sample size and brightness of the Z pinch as a backlighter are also exploited in a novel method measuring re-emission from radiation-heated gold plasmas. The method uses a CH-tamped layered foil with Al+MgF2 facing the radiationsource. A gold backing layer that covers a portion of the foil absorbs radiation from the source and provides re-emission that further heats the Al+MgF2. The Al and Mg heating is measured using space-resolved Kα absorption spectroscopy and the difference between the two regions enables a determination of the gold re-emission. Measurements are also performed at lower densities where photoionization is expected to dominate over collisions. Absorption spectra have been obtained for both Ne-like Fe and He-like Ne, confirming production of the relevant charge states needed to benchmark atomic kinetics models. Refinement of the methods described here is in progress to address multiple issues for radiation science

Molecular evidence of Ebola Reston virus infection in Philippine bats

Background: In 2008-09, evidence of Reston ebolavirus (RESTV) infection was found in domestic pigs and pig workers in the Philippines. With species of bats having been shown to be the cryptic reservoir of filoviruses elsewhere, the Philippine government, in conjunction with the Food and Agriculture Organization of the United Nations, assembled a multi-disciplinary and multi-institutional team to investigate Philippine bats as the possible reservoir of RESTV. Methods: The team undertook surveillance of bat populations at multiple locations during 2010 using both serology and molecular assays. Results: A total of 464 bats from 21 species were sampled. We found both molecular and serologic evidence of RESTV infection in multiple bat species. RNA was detected with quantitative PCR (qPCR) in oropharyngeal swabs taken from Miniopterus schreibersii, with three samples yielding a product on conventional hemi-nested PCR whose sequences differed from a Philippine pig isolate by a single nucleotide. Uncorroborated qPCR detections may indicate RESTV nucleic acid in several additional bat species (M. australis, C. brachyotis and Ch. plicata). We also detected anti-RESTV antibodies in three bats (Acerodon jubatus) using both Western blot and ELISA. Conclusions: The findings suggest that ebolavirus infection is taxonomically widespread in Philippine bats, but the evident low prevalence and low viral load warrants expanded surveillance to elaborate the findings, and more broadly, to determine the taxonomic and geographic occurrence of ebolaviruses in bats in the region. © 2015 Jayme et al

Developing the Physics Basis of Fast Ignition Experiments at Future Large Fusion-class lasers

The Fast Ignition (FI) concept for Inertial Confinement Fusion (ICF) has the potential to provide a significant advance in the technical attractiveness of Inertial Fusion Energy (IFE) reactors. FI differs from conventional 'central hot spot' (CHS) target ignition by using one driver (laser, heavy ion beam or Z-pinch) to create a dense fuel and a separate ultra-short, ultra-intense laser beam to ignite the dense core. FI targets can burn with {approx} 3X lower density fuel than CHS targets, resulting in (all other things being equal) lower required compression energy, relaxed drive symmetry, relaxed target smoothness tolerances, and, importantly, higher gain. The short, intense ignition pulse that drives this process interacts with extremely high energy density plasmas; the physics that controls this interaction is only now becoming accessible in the lab, and is still not well understood. The attraction of obtaining higher gains in smaller facilities has led to a worldwide explosion of effort in the studies of FI. In particular, two new US facilities to be completed in 2009/2010, OMEGA/OMEGA EP and NIF-ARC (as well as others overseas) will include FI investigations as part of their program. These new facilities will be able to approach FI conditions much more closely than heretofore using direct drive (dd) for OMEGA/OMEGA EP and indirect drive (id) for NIF-ARC. This LDRD has provided the physics basis for the development of the detailed design for integrated Fast ignition experiments on these facilities on the 2010/2011 timescale. A strategic initiative LDRD has now been formed to carry out integrated experiments using NIF ARC beams to heat a full scale FI assembled core by the end of 2010

Modelling, Design And Diagnostics For A Photoionised Plasma Experiment

Photoionised plasmas are common in astrophysical environments and new high resolution spectra from such sources have been recorded in recent years by the Chandra and XMM-Newton satellites. These provide a wealth of spectroscopic information and have motivated recent efforts aimed at obtaining a detailed understanding of the atomic-kinetic and radiative characteristics of photoionised plasmas. The Z-pinch facility at the Sandia National Laboratories is the most powerful terrestrial source of X-rays and provides an opportunity to produce photoionised plasmas in a well characterised radiation environment. We present modelling work and experimental design considerations for a forthcoming experiment at Sandia in which X-rays from a collapsing Z-pinch will be used to photoionise low density neon contained in a gas cell. View factor calculations were used to evaluate the radiation environment at the gas cell; the hydrodynamic characteristics of the gas cell were examined using the Helios-CR code, in particular looking at the heating, temperature and ionisation of the neon and the absorption of radiation. Emission and absorption spectra were also computed, giving estimates of spectra likely to be observed experimentally