315 research outputs found
A critical look at power law modelling of the Internet
This paper takes a critical look at the usefulness of power law models of the
Internet. The twin focuses of the paper are Internet traffic and topology
generation. The aim of the paper is twofold. Firstly it summarises the state of
the art in power law modelling particularly giving attention to existing open
research questions. Secondly it provides insight into the failings of such
models and where progress needs to be made for power law research to feed
through to actual improvements in network performance.Comment: To appear Computer Communication
Iodine monoxide in the Antarctic snowpack
Recent ground-based and space borne observations suggest the presence of significant amounts of iodine monoxide in the boundary layer of Antarctica, which are expected to have an impact on the ozone budget and might contribute to the formation of new airborne particles. So far, the source of these iodine radicals has been unknown. This paper presents long-term measurements of iodine monoxide at the German Antarctic research station Neumayer, which indicate that high IO concentrations in the order of 50 ppb are present in the snow interstitial air. The measurements have been performed using multi-axis differential optical absorption spectroscopy (MAX-DOAS). Using a coupled atmosphere snowpack radiative transfer model, the comparison of the signals observed from scattered skylight and from light reflected by the snowpack yields several ppb of iodine monoxide in the upper layers of the sunlit snowpack throughout the year. Snow pit samples from Neumayer Station contain up to 700 ng/l of total iodine, representing a sufficient reservoir for these extraordinarily high IO concentrations
Aspects of the distribution, phytosociology, ecology and management of Danthonia popinensis D.I. Morris, an endangered wallaby grass from Tasmania
Danthonia popinensis is a recently discovered, nationally endangered tussock grass, originally known from only one roadside population at Kempton, Tasmania. Six populations have been recorded, all from flat land with mildly acid non-rocky soils, and all in small roadside or paddock remnants, badly invaded by exotic plants. However, one site has recently been destroyed through roadworks. The species germinates best at temperatures of 10°e, indicating a winter germination strategy. Autumn burning at Kempton resulted in an increased cover of D. popinensis two years after the burn, but also resulted in an increased cover of competitive exotics. The future of the species needs to be secured by ex situ plantings, as almost all of its original habitat has been converted to crops or improved pasture
Native Grasslands in Northwest Tasmania and the Role of Forest Managers in Their Conservation and Management
First records of Silver Gull Larus (Chroicocephalus) novaehollandiae for Bali and Oriental Region
The distribution, ecology and management of two rare Tasmanian sedges - Schoenus absconditus Kuk. and Carex tasmanica Kuk
The sedges, Carex tasmanica and Schoenus absconditus, were considered to be threatened species at the national level. They are species of grassland and grassy woodland in the driest parts of Tasmania, C. tasmanica being associated with drainafe lines, and S. absconditus characteristically occurring in Themeda triandra grassland, in situations where there is a large amount of intertussock space. Both species proved
much more common than previously thought, and both species have been downlisted. They are both well-adapted to mechanical disturbance and sheep grazing. C. tasmanica is also herbicide resistant. However, mowing and cattle grazing deleteriously affect C. tasmanica. S. absconditus can no longer be regarded as a rare or threatened species. However, C. tasmanica has disappeared from two localities out of 30 in the past four years and has no substantial populations in any secure reserve. Secure reservation is needed for this vulnerable species
The grasshoppers and the great cattle: an exploration of participation in the ASB's standard-setting process
This paper presents the results of a research study of participation in the Accounting Standards Boardâs (âthe ASBâ) standard setting processes. It replicates studies of a similar nature carried out in the US and Australia or in specific contexts (e.g. Operating and Financial Review) in the UK. The study considers the 1,519 responses to the ASBâs proposals for accounting standards. Consistent with the findings of other studies, the study finds that there is a high level of preparer participation in the ASBâs consultation process. Drawing on Positive Accounting
Theory to develop its hypotheses, the paper then examines the characteristics of the preparer corporations which formally lobbied the ASB. The research evidence supports the hypotheses that those firms who become involved in the lobbying process tend to be larger and more highly geared than non-lobbying firms. The paper concludes by considering the implications of these findings in the light of the ASBâs objectives
The flora of Township Lagoon Nature Reserve and its management, Tunbridge, Tasmania
Township Lagoon Nature Reserve is 16 ha of remnant native grassland in the lowest rainfall area of Tasmania. A high proportion of rare and threatened species occurs within the reserve. They comprise four endangered species, including three endangered at the national level, four vulnerable species and eight rare species, seven of the above being daisies. There is a strong floristic affinity with the semi-arid mallee ground flora in northwestern Victoria and western New South Wales. The small grassland remnant comprises five floristic communities, the principal influences on floristic variation being exerted by soil factors, such as geology, pH and drainage, and past history of mechanical disturbance and rubbish dumping. Active conservation management, that is favourable to the continued existence of vulnerable and rare
species, promotes normal ecosystem functions and prevents threatening processes, is essential
- âŠ