Macquarie University

About: Macquarie University is a education organization based out in Sydney, New South Wales, Australia. It is known for research contribution in the topics: Population & Context (language use). The organization has 14075 authors who have published 47673 publications receiving 1416184 citations. The organization is also known as: Macquarie uni.

The VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS

Abstract: The VST Photometric HSurvey of the Southern Galactic Plane and Bulge (VPHAS+) is surveying the southern Milky Way in u,g,r,i and Hat �1 arcsec angular resolution. Its footprint spans the Galactic latitude range 5 o < b < +5 o at all longitudes south of the celestial equator. Extensions around the Galactic Centre to Galactic latitudes ±10 ◦ bring in much of the Galactic Bulge. This ESO public sur- vey, begun on 28th December 2011, reaches down to �20th magnitude (10�) and will provide single-epoch digital optical photometry for �300 million stars. The observing strategy and data pipelining is described, and an appraisal of the segmented narrow- band Hfilter in use is presented. Using model atmospheres and library spectra, we compute main-sequence (u g), (g r), (r i) and (r H�) stellar colours in the Vega system. We report on a preliminary validation of the photometry using test data obtained from two pointings overlapping the Sloan Digital Sky Survey. An example of the (u g,g r) and (r H�,r i) diagrams for a full VPHAS+ survey field is given. Attention is drawn to the opportunities for studies of compact nebulae and nebular morphologies that arise from the image quality being achieved. The value of the u band as the means to identify planetary-nebula central stars is demonstrated by the discovery of the central star of NGC 2899 in survey data. Thanks to its excellent imaging performance, the VST/OmegaCam combination used by this survey is a per- fect vehicle for automated searches for reddened early-type stars, and will allow the discovery and analysis of compact binaries, white dwarfs and transient sources.

Antarctic Bottom Water production by intense sea-ice formation in the Cape Darnley polynya

Abstract: Antarctic Bottom Water fills much of the global abyssal ocean, and is known to form in three main sites in the Southern Ocean. Data from instrumented elephant seals and moorings suggest an additional source of bottom-water formation in the Cape Darnley polynya that is driven by sea-ice production.

The Costs of keeping cool in a warming world : implications of high temperatures for foraging, thermoregulation and body condition of an arid-zone bird

Abstract: Recent mass mortalities of bats, birds and even humans highlight the substantial threats that rising global temperatures pose for endotherms. Although less dramatic, sublethal fitness costs of high temperatures may be considerable and result in changing population demographics. Endothermic animals exposed to high environmental temperatures can adjust their behaviour (e.g. reducing activity) or physiology (e.g. elevating rates of evaporative water loss) to maintain body temperatures within tolerable limits. The fitness consequences of these adjustments, in terms of the ability to balance water and energy budgets and therefore maintain body condition, are poorly known. We investigated the effects of daily maximum temperature on foraging and thermoregulatory behaviour as well as maintenance of body condition in a wild, habituated population of Southern Pied Babblers Turdoides bicolor. These birds inhabit a hot, arid area of southern Africa where they commonly experience environmental temperatures exceeding optimal body temperatures. Repeated measurements of individual behaviour and body mass were taken across days varying in maximum air temperature. Contrary to expectations, foraging effort was unaffected by daily maximum temperature. Foraging efficiency, however, was lower on hotter days and this was reflected in a drop in body mass on hotter days. When maximum air temperatures exceeded 35.5 °C, individuals no longer gained sufficient weight to counter typical overnight weight loss. This reduction in foraging efficiency is likely driven, in part, by a trade-off with the need to engage in heat-dissipation behaviours. When we controlled for temperature, individuals that actively dissipated heat while continuing to forage experienced a dramatic decrease in their foraging efficiency. This study demonstrates the value of investigations of temperature-dependent behaviour in the context of impacts on body condition, and suggests that increasingly high temperatures will have negative implications for the fitness of these arid-zone birds.