The remnant phase of a radio galaxy begins when the jets launched from an active galactic nucleus are switched off. To study the fraction of radio galaxies in a remnant phase, we take advantage of a $8.31$ deg$^2$ subregion of the GAMA 23 field which comprises of surveys covering the frequency range 0.1–9 GHz. We present a sample of 104 radio galaxies compiled from observations conducted by the Murchison Widefield Array (216 MHz), the Australia Square Kilometer Array Pathfinder (887 MHz), and the Australia Telescope Compact Array (5.5 GHz). We adopt an ‘absent radio core’ criterion to identify 10 radio galaxies showing no evidence for an active nucleus. We classify these as new candidate remnant radio galaxies. Seven of these objects still display compact emitting regions within the lobes at 5.5 GHz; at this frequency the emission is short-lived, implying a recent jet switch off. On the other hand, only three show evidence of aged lobe plasma by the presence of an ultra-steep-spectrum ($\alpha<-1.2$) and a diffuse, low surface brightness radio morphology. The predominant fraction of young remnants is consistent with a rapid fading during the remnant phase. Within our sample of radio galaxies, our observations constrain the remnant fraction to $4\%\lesssim f_{\mathrm{rem}} \lesssim 10\%$; the lower limit comes from the limiting case in which all remnant candidates with hotspots are simply active radio galaxies with faint, undetected radio cores. Finally, we model the synchrotron spectrum arising from a hotspot to show they can persist for 5–10 Myr at 5.5 GHz after the jets switch of—radio emission arising from such hotspots can therefore be expected in an appreciable fraction of genuine remnants.

We present a detailed analysis of the radio galaxy PKS $2250{-}351$ , a giant of 1.2 Mpc projected size, its host galaxy, and its environment. We use radio data from the Murchison Widefield Array, the upgraded Giant Metre-wavelength Radio Telescope, the Australian Square Kilometre Array Pathfinder, and the Australia Telescope Compact Array to model the jet power and age. Optical and IR data come from the Galaxy And Mass Assembly (GAMA) survey and provide information on the host galaxy and environment. GAMA spectroscopy confirms that PKS $2250{-}351$ lies at $z=0.2115$ in the irregular, and likely unrelaxed, cluster Abell 3936. We find its host is a massive, ‘red and dead’ elliptical galaxy with negligible star formation but with a highly obscured active galactic nucleus dominating the mid-IR emission. Assuming it lies on the local M– $\sigma$ relation, it has an Eddington accretion rate of $\lambda_{\rm EDD}\sim 0.014$ . We find that the lobe-derived jet power (a time-averaged measure) is an order of magnitude greater than the hotspot-derived jet power (an instantaneous measure). We propose that over the lifetime of the observed radio emission ( ${\sim} 300\,$ Myr), the accretion has switched from an inefficient advection-dominated mode to a thin disc efficient mode, consistent with the decrease in jet power. We also suggest that the asymmetric radio morphology is due to its environment, with the host of PKS $2250{-}351$ lying to the west of the densest concentration of galaxies in Abell 3936.

We examine whether political corruption impedes innovation. Using a comprehensive sample of U.S. firms, we find that corruption has a substantial, negative relation with the quantity and quality of innovation. These results are robust to using various fixed effects, proxies for corruption and innovation, and subsamples. To establish causality, we employ 2 instruments for corruption: local ethnic diversity and the corruption of the state a firm’s founder grew up in. Corruption appears to reduce innovation output both on average and for the most innovative firms. Overall, this evidence is consistent with the notion that corruption reduces social welfare by impeding innovation.

I examine the ability of the U.S. investor protection regime to limit insider trading returns, absent Section 16(b) of the Securities Exchange Act of 1934 (the short-swing rule). I find that in this setting, U.S. insiders execute short-swing trades that i) beat the market by approximately 15 basis points per day and ii) systematically divest ahead of disappointing earnings announcements. These results indicate that the bright-line rule restricting short-horizon round-trip insider trading plays a substantial role in protecting outside investors from privately informed insiders in the United States.

To solve the problem of induction we had first better know what it is. Some ways of formulating the worry about induction are underwhelming as they depend on assumptions that don't survive much scrutiny. Perhaps the most disturbing argument for inductive skepticism appeals to the claim that we could not possibly be justified in taking our inductive methods to be reliable independently of our use of those methods. And the use of inductive methods cannot give us justification to suppose that they are reliable. I argue for a new way to escape the first horn of this dilemma.

Examining data for 79 immigrant source countries and six OECD member destination countries during the years 1975–2000, we find that source-destination cultural differences inhibit international migration. We also report that existing immigrant stocks act to offset, at least in part, the migration-inhibiting effects of cultural differences. Employing educational attainment as a proxy for skill, we find variation across low-, medium-, and high-skilled immigrant cohorts both with respect to the cultural distance-migration relationship and in terms of the extent to which existing immigrant stocks offset the influence of cultural differences. Our results appear robust to econometric techniques, sample composition, and endogeneity issues.

In this paper we consider near inclusions $A\,{{\subseteq }_{\gamma }}\,B$ of ${{\text{C}}^{*}}$ -algebras. We show that if $B$ is a separable type $\text{I}$ ${{\text{C}}^{*}}$ -algebra and $A$ satisfies Kadison's similarity problem, then $A$ is also type $\text{I}$ . We then use this to obtain an embedding of $A$ into $B$ .

The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are?

In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life.

The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole.

EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates.