Radio-continuum observations of a giant radio source QSO J0443.8-6141

We report the discovery of a giant double-lobed (lobe-core-lobe) radio-continuum structure associated with QSO J0443.8-6141 at z=0.72. This QSO was originally identified during the follow-up of a sample of ROSAT All Sky Survey sources at radio and optical frequencies. With a linear size of ~0.77 Mpc, QSO J0443.8-6141 is classified as a giant radio source (GRS); based on its physical properties, we classify QSO J0443.8-6141 as a FR II radio galaxy. High-resolution observations are required to reliably identify GRSs; the next generation of southern sky radio and optical surveys will be crucial to increasing our sample of these objects

Infrared-faint radio sources: A new population of high-redshift radio galaxies

We present a sample of 1317 Infrared-faint radio sources (IFRSs) that, for the first time, are reliably detected in the infrared, generated by cross-correlating the Wide-field Infrared Survey Explorer (WISE) all-sky survey with major radio surveys. Our IFRSs are brighter in both radio and infrared than the first-generation IFRSs that were undetected in the infrared by the Spitzer Space Telescope. We present the first spectroscopic redshifts of IFRSs, and find that all but one of the IFRSs with spectroscopy have z > 2. We also report the first X-ray counterparts of IFRSs, and present an analysis of radio spectra and polarization, and show that they include gigahertz peaked-spectrum, compact steep-spectrum and ultra-steep-spectrum sources. These results, together with their WISE infrared colours and radio morphologies, imply that our sample of IFRSs represents a population of radio-loud active galactic nuclei at z > 2. We conclude that our sample consists of lower redshift counterparts of the extreme first-generation IFRSs, suggesting that the fainter IFRSs are at even higher redshift

Genetic resources and fodder quality in sesbania

The International Livestock Centre for Africa has a genetic base of 300 accessions from 20 species of Sesbania. The largest number of these are represented by the perennials S. sesban (207), S. goetzii (18), and S. keniensis (8) and the short-lived perennial S. macrantha (97). Almost all of this collection is under evaluation in Ethiopia at Debre Zeit (1850 m altitude, 850 mm rainfall) and at Addis Ababa (2380 m altitude, 1100 mm rainfall), both on seasonally waterlogged Vertisols. There is considerable variation both within and between accessions of S. sesban in vigour of growth, growth form, dry season survival, growth response to cutting, stem color, tannins, and related polyphenolic compounds, and possibly nematode resistance and beetle (Mesoplatys ochroptera) attack. Over a wide range of accessions N contents have been found to range from 2.6 to 4.0 percent. Sheep fed S. sesban grew at 50 g/day which equalled the best legume hay (Vicia dasycarpa), which was twice that from equivalent levels of natural multi-purpose trees (MPTs), e.g., Acacia seyal

A Multi-Frequency Study of the Milky Way-Like Spiral Galaxy NGC 6744

We present a multi-frequency study of the intermediate spiral SAB(r)bc type galaxy NGC 6744, using available data from the Chandra X-Ray telescope, radio continuum data from the Australia Telescope Compact Array and Murchison Widefield Array, and Wide-field Infrared Survey Explorer infrared observations. We identify 117 X-ray sources and 280 radio sources. Of these, we find nine sources in common between the X-ray and radio catalogues, one of which is a faint central black hole with a bolometric radio luminosity similar to the Milky Way’s central black hole. We classify 5 objects as supernova remnant (SNR) candidates, 2 objects as likely SNRs, 17 as H ii regions, 1 source as an AGN; the remaining 255 radio sources are categorised as background objects and one X-ray source is classified as a foreground star. We find the star-formation rate (SFR) of NGC 6744 to be in the range 2.8–4.7 M⊙~yr − 1 signifying the galaxy is still actively forming stars. The specific SFR of NGC 6744 is greater than that of late-type spirals such as the Milky Way, but considerably less that that of a typical starburst galaxy.ADK acknowledges the financial support from the ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO) through project number CE110001020. MZP acknowledges support from the Ministry of Education, Science and Technological Development of the Republic of Serbia through project No. 176005

Land resources in darfur region, Sudan: Prisoners' dilemma or coase outcome?

The article tests institutional models of environmental pressure, for example, the Tragedy of the Commons, against evidence from Darfur region, Sudan. Three aspects are considered in detail: rangeland degradation, rangeland enclosure and the implicit rent gained from range destocking. A methodology to estimate the latter is presented and demonstrated using survey data. It is concluded that strong circumstantial evidence of a Tragedy of the Commons -famine, drought and insecurity - is misleading. Social institutions such as land tenure are both adapted to the existing resource endowment and flexible enough to accommodate changes in it.

Radio continuum sources behind the Large Magellanic Cloud

We present a comprehensive multifrequency catalogue of radio sources behind the Large Magellanic Cloud (LMC) between 0.2 and 20 GHz, gathered from a combination of new and legacy radio continuum surveys. This catalogue covers an area of ∼144 deg(2) at angular resolutions from 45 arcsec to ∼3 arcmin. We find 6434 discrete radio sources in total, of which 3789 are detected at two or more radio frequencies. We estimate the median spectral index (α; where S(v) ∼ ν(α)) of α = −0.89 and mean of −0.88 ± 0.48 for 3636 sources detected exclusively at two frequencies (0.843 and 1.384 GHz) with similar resolution [full width at half-maximum (FWHM) ∼40–45 arcsec]. The large frequency range of the surveys makes it an effective tool to investigate Gigahertz Peak Spectrum (GPS), Compact Steep Spectrum (CSS), and Infrared Faint Radio Source (IFRS) populations within our sample. We find 10 GPS candidates with peak frequencies near 5 GHz, from which we estimate their linear size. 1866 sources from our catalogue are CSS candidates with α  < −0.8. We found six candidates for High Frequency Peaker (HFP) sources, whose radio fluxes peak above 5 GHz and no sources with unconstrained peaks and α  > 0.5. We found optical counterparts for 343 of the radio continuum sources, of which 128 have a redshift measurement. Finally, we investigate the population of 123 IFRSs found in this study.M D Filipović … G. Rowell … et al