Predictions for ASKAP Neutral Hydrogen Surveys

The Australian Square Kilometer Array Pathfinder (ASKAP) will revolutionise our knowledge of gas-rich galaxies in the Universe. Here we present predictions for two proposed extragalactic ASKAP neutral hydrogen (HI) emission-line surveys, based on semi-analytic models applied to cosmological N-body simulations. The ASKAP HI All-Sky Survey, known as WALLABY, is a shallow 3 Pi survey (z = 0 - 0.26) which will probe the mass and dynamics of over 600,000 galaxies. A much deeper small-area HI survey, called DINGO, aims to trace the evolution of HI from z = 0 - 0.43, a cosmological volume of 40 million Mpc^3, detecting potentially 100,000 galaxies. The high-sensitivity 30 antenna ASKAP core (diameter ~2 km) will provide an angular resolution of 30 arcsec (at z=0). Our simulations show that the majority of galaxies detected in WALLABY (87.5%) will be resolved. About 5000 galaxies will be well resolved, i.e. more than five beams (2.5 arcmin) across the major axis, enabling kinematic studies of their gaseous disks. This number would rise to 160,000 galaxies if all 36 ASKAP antennas could be used; the additional six antennas provide baselines up to 6 km, resulting in an angular resolution of 10 arcsec. For DINGO this increased resolution is highly desirable to minimise source confusion; reducing confusion rates from a maximum of 10% of sources at the survey edge to 3%. We estimate that the sources detected by WALLABY and DINGO will span four orders of magnitude in total halo mass (from 10^{11} to 10^{15} Msol) and nearly seven orders of magnitude in stellar mass (from 10^{5} to 10^{12} Msol), allowing us to investigate the process of galaxy formation across the last four billion years.Comment: 21 pages, accepted for publication in MNRAS, minor updates to published version and fixed links. Movies and images available at http://ict.icrar.org/store/Movies/Duffy12c

Taphonomy of very ancient microfossils from the ∼3400Ma Strelley Pool Formation and ∼1900Ma Gunflint Formation:New insights using a focused ion beam

Focused ion beam (FIB) milling permits the accurate extraction of ultrathin (c. 100. nm) cross sectional lamellae from microfossils found in geological thin sections. Subsequent TEM analysis of these lamellae can provide unique insights into the ultrastructure, chemistry and taphonomy of Precambrian microfossils at the micrometer to nanometer scale. Combining serial FIB milling with SEM imaging extends this capability to three dimensional (3D) tomographic reconstruction and visualization of Precambrian microfossils, revealing information not available in light microscopy.Here we apply these techniques to two iconic silicified microfossil assemblages, from the ∼3400. Ma Strelley Pool Formation of Western Australia and the ∼1900. Ma Gunflint Formation of Canada. All the examined microfossils have carbonaceous walls surrounded by pure silica. Impregnation of microfossil walls by nano-grains of silica is common, together with variable degrees of wall displacement and replacement by silica. All microfossils are rigidly preserved in 3D and show little or no folding or compression. However, there are also notable differences in taphonomic preservation. Our examples of the spheroidal Gunflint microfossil Huroniospora showed the highest fidelity of preservation with a continuous carbonaceous wall fossilized by spheroidal nano-silica grains that resemble those found on bacterial surfaces in modern silicifying hot-spring environments. The nucleation of these silica nano-spheres on the microfossil walls has induced an artificial 'saw-tooth-like' ridged wall texture that may subsequently hinder species-level identification. The Strelley Pool microfossils in comparison show a lower fidelity of preservation with small parts of the microfossil walls completely replaced by silica, plus extensive recrystallization of spheroidal silica nano-grains to angular micro-quartz. Our examples of the sheath-like filamentous Gunflint microfossil Siphonophycus showed the lowest fidelity of preservation with many gaps in the carbonaceous walls and significant redistribution of carbon by recrystallizing silica grains. A model is presented to explain these observations.Criteria for distinguishing highly probable microfossils from non-cellular carbonaceous microstructures (e.g., botryoids and grain coatings) using FIB-based imaging are put forward for the first time here, using examples drawn from the Strelley Pool Formation and comparisons with younger Gunflint material.The combined in situ techniques of FIB-TEM and FIB-SEM nano-tomography potentially provide a wealth of new nano-scale information regarding the biogenicity, antiquity and taphonomy of Precambrian microfossils. However, the destructive nature of both techniques makes their application to unique palaeontological specimens problematical. © 2012 Elsevier B.V.David Wacey, Sarath Menon, Leonard Green, Derek Gerstmann, Charlie Kong, Nicola Mcloughlin, Martin Saunders, Martin Brasie

uic-evl/omegalib: v15.0

Major changes added support for warping and edge blending (thanks @voidcycles) added support for XCode (thanks @koosha94) modules now do not need to be registered with a hub repository. It is possible to tell omegalib omegalib to use any github repository containing an omegalib module. added new OpenGL3 GPU API (GpuProgram, GpuBuffer, Uniform, etc) added support for using external python distributions on Windows Fixes fixed module dependency solver fixed cmake files for including omegalib into external applications several fixes to opengl core profile support improved packaging scripts including support for packaging installers on OSX Full changelog: https://github.com/uic-evl/omegalib/compare/v13.1...v15.

GHSI EMERGENCY RADIONUCLIDE BIOASSAY LABORATORY NETWORK: SUMMARY OF A RECENT EXERCISE

The Global Health Security Initiative (GHSI) established a laboratory network within the GHSI community to develop theircollective surge capacity for radionuclide bioassay in response to a radiological or nuclear emergency. A recent exercise was conductedto test the participating laboratories for their capabilities in screening and in vitro assay of biological samples, performinginternal dose assessment and providing advice on medical intervention, if necessary, using a urine sample spiked with a singleradionuclide, 241Am. The laboratories were required to submit their reports according to the exercise schedule and using pre-formattedtemplates. Generally, the participating laboratories were found to be capable with respect to rapidly screening samplesfor radionuclide contamination, measuring the radionuclide in the samples, assessing the intake and radiation dose, and providingadvice on medical intervention. However, gaps in bioassay measurement and dose assessment have been identified. Thenetwork may take steps to ensure that procedures and practices within this network be harmonised and a follow-up exercise beorganised on a larger scale, with potential participation of laboratories from the networks coordinated by the InternationalAtomic Energy Agency and theWorld Health Organization