We present deep near-infrared $K_\textrm{s}$-band imaging for 35 of the 53 sources from the high-redshift ($z \gt 2$) radio galaxy candidate sample defined in Broderick et al. (2022, PASA, 39, e061). These images were obtained using the High-Acuity Widefield K-band Imager (HAWK-I) on the Very Large Telescope. Host galaxies are detected for 27 of the sources, with $K_\textrm{s} \approx 21.6$–23.0 mag (2$^{\prime\prime}$ diameter apertures; AB). The remaining eight targets are not detected to a median $3\unicode{x03C3}$ depth of $K_\textrm{s} \approx 23.3$ mag (2$^{\prime\prime}$ diameter apertures). We examine the radio and near-infrared flux densities of the 35 sources, comparing them to the known $z \gt 3$ powerful radio galaxies with 500-MHz radio luminosities $L_{500\,\textrm{MHz}} \gt 10^{27}$ W Hz$^{-1}$. By plotting 150-MHz flux density versus $K_\textrm{s}$-band flux density, we find that, similar to the sources from the literature, these new targets have large radio to near-infrared flux density ratios, but extending the distribution to fainter flux densities. Five of the eight HAWK-I deep non-detections have a median $3\unicode{x03C3}$ lower limit of $K_\textrm{s} \gtrsim 23.8$ mag (1$.\!^{\prime\prime}$5 diameter apertures); these five targets, along with a further source from Broderick et al. (2022, PASA, 39, e061) with a deep non-detection ($K_\textrm{s} \gtrsim 23.7$ mag; $3\unicode{x03C3}$; 2$^{\prime\prime}$ diameter aperture) in the Southern H-ATLAS Regions $K_\textrm{s}$-band Survey, are considered candidates to be ultra-high-redshift ($z \gt 5$) radio galaxies. The extreme radio to near-infrared flux density ratios ($\gt 10^5$) for these six sources are comparable to TN J0924$-$2201, GLEAM J0856$+$0223 and TGSS J1530$+$1049, the three known powerful radio galaxies at $z \gt 5$. For a selection of galaxy templates with different stellar masses, we show that $z \gtrsim 4.2$ is a plausible scenario for our ultra-high-redshift candidates if the stellar mass $M_\textrm{*} \gtrsim 10^{10.5}$ M$_\odot$. In general, the 35 targets studied have properties consistent with the previously known class of infrared-faint radio sources. We also discuss the prospects for finding more UHzRG candidates from wide and deep near-infrared surveys.

Colonial rule in West Africa initiated the incorporation of mobile people, particularly pastoralists, into Western territorial states. This article reports on the early period of French colonial rule of the area that is now South-Western Niger – a strategically important area with respect to territorial competition among the French colonies of Dahomey and Soudan (later the colonies of Senegambia and Niger) as well as the British colony of Nigeria. Building from the study of contemporary patterns of livestock mobility and their logics, archival and secondary literatures are used to develop an understanding of dominant herd mobility patterns at the time (transhumance for grazing and trekking to distant markets); the importance of livestock as a source of tax revenue; colonial anxieties about the loss of livestock from within their borders; and efforts of colonial administrators to reduce the potential loss of livestock from their territories. This case illustrates the limitations of the territorial state model where the state lacks sufficient power over mobile subjects utilizing a sparse and fluctuating resource base. The actions of French administrators and Fulɓe pastoralists worked as a form of ‘hands-off’ negotiation, with each group monitoring and reacting to the actions of the other. Due to the limitations of colonial state control, the existence of boundaries elicited greater monitoring of livestock movements by colonial administrators but also increased the leverage held by mobile pastoralists as the French sought to increase the attractiveness of their territory to the principal managers of its wealth (livestock). The proximity of borders to the study area complicated the task of French colonial administrators, who necessarily became increasingly focused on monitoring the movements of their subjects (labour and capital) to avoid their possible escape as they moved within the borderlands of what is now South-Western Niger. The limits of colonial power to monitor and control these movements led administrators to initiate policies favouring pastoralists.

Objectives: Treatments for childhood brain tumors (BT) confer substantial risks to neurological development and contribute to neuropsychological deficits in young adulthood. Evidence suggests that individuals who experience more significant neurological insult may lack insight into their neurocognitive limitations. The present study compared survivor, mother, and performance-based estimates of executive functioning (EF), and their associations with treatment intensity history in a subsample of young adult survivors of childhood BTs. Methods: Thirty-four survivors (52.9% female), aged 18 to 30 years (M=23.5; SD=3.4), 16.1 years post-diagnosis (SD=5.9), were administered self-report and performance-based EF measures. Mothers also rated survivor EF skills. Survivors were classified by treatment intensity history into Minimal, Average/Moderate, or Intensive/Most-Intensive groups. Discrepancies among survivor, mother, and performance-based EF estimates were compared. Results: Survivor-reported and performance-based measures were not correlated, although significant associations were found between mother-reported and performance measures. Survivors in the Intensive/Most-Intensive treatment group evidenced the greatest score discrepancies, reporting less executive dysfunction relative to mother-reported F(2,31)=7.81, p<.01, and performance-based measures F(14,50)=2.54, p<.05. Conversely, survivors in the Minimal treatment group reported greater EF difficulties relative to mothers t(8)=2.82, p<.05, but not performance-based estimates (ps>.05). Conclusions: There may be a lack of agreement among survivor, mother, and performance-based estimates of EF skills in young adult survivors of childhood BT, and these discrepancies may be associated with treatment intensity history. Neuropsychologists should use a multi-method, multi-reporter approach to assessment of EF in this population. Providers also should be aware of these discrepancies as they may be a barrier to intervention efforts. (JINS, 2016, 22, 900–910)

The electronic properties of ThO2 single crystals were studied using x-ray photoemission spectroscopy (XPS). The XPS results show that the Th 4f core level is in an oxidation state that is consistent with that expected for Th in ThO2. The effective Debye temperature is estimated from the temperature dependent photoemission intensities of the Th 4f core level over the temperature range of 290 to 360 K. A Debye temperature of 468±32 K has been determined.

The spreading and diffusion of two-dimensional vortices subject to weak external random strain fields is examined. The response to such a field of given angular frequency depends on the profile of the vortex and can be calculated numerically. An effective diffusivity can be determined as a function of radius and may be used to evolve the profile over a long time scale, using a diffusion equation that is both nonlinear and non-local. This equation, containing an additional smoothing parameter, is simulated starting with a Gaussian vortex. Fine scale steps in the vorticity profile develop at the periphery of the vortex and these form a vorticity staircase. The effective diffusivity is high in the steps where the vorticity gradient is low: between the steps are barriers characterized by low effective diffusivity and high vorticity gradient. The steps then merge before the vorticity is finally swept out and this leaves a vortex with a compact core and a sharp edge. There is also an increase in the effective diffusion within an encircling surf zone.

In order to understand the properties of the evolution of the Gaussian vortex, an asymptotic model first proposed by Balmforth, Llewellyn Smith & Young (J. Fluid Mech., vol. 426, 2001, p. 95) is employed. The model is based on a vorticity distribution that consists of a compact vortex core surrounded by a skirt of relatively weak vorticity. Again simulations show the formation of fine scale vorticity steps within the skirt, followed by merger. The diffusion equation we develop has a tendency to generate vorticity steps on arbitrarily fine scales; these are limited in our numerical simulations by smoothing the effective diffusivity over small spatial scales.