Basal channels, which are troughs carved into the undersides of ice shelves by buoyant plumes of water, are modulators of ice-shelf basal melt and structural stability. In this study, we track the evolution of 12 large basal channels beneath ice shelves of the Amundsen and Bellingshausen seas region in West Antarctica using the Landsat record since its start in the 1970s through 2020. We observe examples of channel growth, interactions with ice-shelf features, and systematic changes in sinuosity that give insight into the life cycles of basal channels. We use the last two decades of the record, combined with contemporary ice-flow velocity datasets, to separate channel-path evolution into components related to advection by ice flow and those controlled by other forcings, such as ocean melt or surface accumulation. Our results show that ice-flow-independent lateral channel migration is overwhelmingly to the left when viewed down-flow, suggesting that it is dominated by Coriolis-influenced ocean melt. By applying a model of channel-path evolution dominantly controlled by ice flow and ocean melt, we show that the majority of channels surveyed exhibit non-steady behavior that serves as a novel proxy for increased ocean forcing in West Antarctica starting at least in the early 1970s.

The calving of icebergs accounts for a significant fraction of the mass loss from both the Antarctic and Greenland ice sheets. Iceberg melting affects the water properties impacting sea ice formation, local circulation and biological activity. Laboratory experiments have investigated the effects of the Earth’s rotation on iceberg melting and the possible formation of Taylor columns (TCs) underneath icebergs. It is found that at high Rossby number, $Ro$, when rotation is weak compared to advection, iceberg melting is unaffected by the background rotation. As $Ro$ decreases, the melt rate shows an increasing trend, which is expected to reverse for very low $Ro$. This behaviour is explained by considering the integrated horizontal velocity at the base of the iceberg. For moderate $Ro$, a partial TC is formed and its effective blocking accelerates the flow under the remainder of the iceberg, which increases the melt rate since the melting is proportional to the flow velocity. It is expected that for very low $Ro$ the melt rate decreases because, with the expansion of the TC, the region of flow acceleration occurs away from the base of the iceberg. For low free stream velocity the freshwater produced by the ice melting introduces another dynamical effect. It is observed that there is a threshold free stream velocity below which the melt rate is constant. This is explained with the formation of a gravity current at the base of the iceberg that insulates it from the free flow and controls its melting.

We present the first results of a dedicated search for Diffuse Interstellar Bands that have profiles with FWHM > 6 Å. Broad DIBs have been noticed in past surveys using averages of multiple sight lines (e.g. Jenniskens & Désert, 1994), but careful detection, measurement, and cataloguing for individual sight lines has not been done since the pioneering work of Herbig (1995). We have initiated an observing campaign using the Apache Point Observatory in order to obtain low-resolution spectra to search for such broad DIBs and monitor their behaviour from star to star. A first sample of 21 stars with 0.3 < E(B-V) < 3.3 mag, along with 15 matched low-reddening stars, were observed with the APO/DIS B400 (R ~ 450) and R300 (R ~ 1000) gratings to obtain spectra having S/N > 500.

Anomalously broad diffuse interstellar bands (DIBs) at 5780.5, 5797.1, 6196.0, and 6613.6 Å are found in absorption along the line of sight to Herschel 36, an O star system next to the bright Hourglass nebula of the Hii region Messier 8. Excited lines of CH and CH+ are seen as well. We show that the region is very compact and itemize other anomalies of the gas. An infrared-bright star within 400 AU is noted. The combination of these effects produces anomalous DIBs, interpreted by Oka et al. (2013, see also this volume) as being caused predominantly by infrared pumping of rotational levels of relatively small molecules.

Alcohol use is common in older adults and is associated with numerous health and social problems. Recent evidence suggests that in addition to level of alcohol consumption, drinking pattern may also be important. Moderate alcohol intake may confer some cardiac benefits, while heavy episodic drinking seems particularly problematic. Detecting alcohol misuse in older adults is difficult since clinical acumen is often poor, screening questionnaires have serious limitations and laboratory tests are not diagnostic. Brief alcohol interventions to reduce alcohol consumption appear useful in younger populations, but are less studied in older adults. While there is increasing research into the issue of alcohol use among older adults, clinicians and policy-makers must rely on limited evidence when making clinical decisions.

The nature, frequency and causes of reproductive loss were investigated in populations of Glossina pallidipes Aust. in western and coastal localities in Kenya. Daily collections from biconical traps in which females were trapped for varying periods up to 30 h were followed by a series of hourly captures which gave less biased data. Ovarian abnormalities and insemination failure were rare, and abortion was the only major source of loss of fecundity. Total reproductive loss was within the range 1·60–1·97% (0·23% ovarian loss plus 1·37% abortions or 1·74% total empty uteri) in western Kenya (Lambwe Valley) and 0·99–1·71% from less comprehensive data at the coast. The incidence of empty uteri was higher in daily than in hourly collections, due mainly to premature parturitions brought about by the stressful effects of prolonged confinement in traps and handling. Abortions were significantly more frequent in females which had ovulated but were not yet parous than in older, parous flies. No relationship between the frequency of abortion and climate, tsetse density or pathogen or parasite infection could be demonstrated.