354 research outputs found
A study of soil formation rates using 10Be in the wet-dry tropics of northern Australia
A catchment level study to obtain soil formation rates using beryllium-10 (10Be) tracers has been undertaken in the Daly River Basin in the wet-dry tropics of northern Australia. Three soil cores have been collected to bedrock, with depths ranging from
Seabird species vary in behavioural response to drone census
This is the final version of the article. Available from the publisher via the DOI in this record.Unmanned aerial vehicles (UAVs) provide an opportunity to rapidly census wildlife in remote areas while removing some of the hazards. However, wildlife may respond negatively to the UAVs, thereby skewing counts. We surveyed four species of Arctic cliff-nesting seabirds (glaucous gull Larus hyperboreus, Iceland gull Larus glaucoides, common murre Uria aalge and thick-billed murre Uria lomvia) using a UAV and compared censusing techniques to ground photography. An average of 8.5% of murres flew off in response to the UAV, but >99% of those birds were non-breeders. We were unable to detect any impact of the UAV on breeding success of murres, except at a site where aerial predators were abundant and several birds lost their eggs to predators following UAV flights. Furthermore, we found little evidence for habituation by murres to the UAV. Most gulls flew off in response to the UAV, but returned to the nest within five minutes. Counts of gull nests and adults were similar between UAV and ground photography, however the UAV detected up to 52.4% more chicks because chicks were camouflaged and invisible to ground observers. UAVs provide a less hazardous and potentially more accurate method for surveying wildlife. We provide some simple recommendations for their use.We thank T. Leonard and the Seabird Ecological Reserves Advisory Committee for permission to work at Witless
Bay, the Canadian Wildlife Service for permits to work at Newfoundland and Nunavut and the Government of
Nunavut for permits to work in Nunavut. Newfoundland and Labrador Murre Fund, Bird Studies Canada and
the Molson Foundation directly funded the work. An NSERC Discovery Grant, the Canada Research Chair in
Arctic Ecology and Polar Continental Shelf Project also helped fund the project. We thank T. Burke, G. Sorenson,
T. Lazarus and M. Guigueno for their help and J. Nakoolak for keeping us safe from bear
Hospital wards and modular construction: Summertime overheating and energy efficiency
The UK National Health Service (NHS) is continually under pressure to provide more bed spaces and to do this within a tight budget. Therefore, NHS Trusts may turn to modular buildings, which promise faster construction and low energy demands helping the NHS meet its stringent energy targets. However, there is growing evidence that thermally lightweight, well insulated and naturally ventilated dwellings are at risk of overheating during warm UK summers.
This paper examines the energy demands and internal temperatures in two 16-bed hospital wards built in 2008?at Bradford Royal Infirmary in northern England using modular fast track methods. The two-storey building used ceiling-mounted radiant panels and a mix of natural and mechanical ventilation with heat recovery to condition patients' rooms. Monitoring showed that the annual energy demand was 289?kWh/m2 ±16%, which is below the NHS guidelines for new hospital buildings.
It was observed that the criterion given in Department of Health Technical Memorandum HTM03-01 can lead to the incorrect diagnosis of overheating risk in existing buildings. Assessment using other static and adaptive overheating criteria showed that patient rooms and the nurses' station overheated in summer. To maintain patient safety, temporary air conditioning units had to be installed during the warmest weather.
It is concluded that thermally lightweight, well insulated, naturally ventilated hospital wards can be low-energy but are at risk of overheating even in relatively cool UK summer conditions and that this needs to be addressed before such buildings can be recommended for wider adoption
Continuous transport of Pacific-derived anthropogenic radionuclides towards the Indian Ocean
Unusually high concentrations of americium and plutonium have been observed in a sediment core collected from the eastern Lombok Basin between Sumba and Sumbawa Islands in the Indonesian Archipelago. Gamma spectrometry and accelerator mass spectrometry data together with radiometric dating of the core provide a high-resolution record of ongoing deposition of anthropogenic radionuclides. A plutonium signature characteristic of the Pacific Proving Grounds (PPG) dominates in the first two decades after the start of the high yield atmospheric tests in 1950’s. Approximately 40–70% of plutonium at this site in the post 1970 period originates from the PPG. This sediment record of transuranic isotopes deposition over the last 55 years provides evidence for the continuous long-distance transport of particle-reactive radionuclides from the Pacific Ocean towards the Indian Ocean
No Fukushima Dai-ichi derived plutonium signal in marine sediments collected 1.5-57km from the reactors
Based on AMS analysis, it is shown that no Pu signals from the Fukushima accident could be discerned in marine sediments collected 1.5-57km away from the Fukushima Da-ichi power plant (FDNPP), which were clearly influenced by accident-derived radiocesium. The 240Pu/239Pu atom ratios (0.21-0.28) were significantly higher than terrestrial global fallout (0.182 ± 0.005), but still in agreement with pre-FDNPP accident baseline data for Pu in near coastal seawaters influenced by global fallout and long-range transport of Pu from the Pacific Proving Grounds.This study has been funded by the Norwegian Research Council through its Centre of Excellence (CoE) funding scheme (Project No. 223268/F50)
An Empirical Study of the I2P Anonymity Network and its Censorship Resistance
Tor and I2P are well-known anonymity networks used by many individuals to
protect their online privacy and anonymity. Tor's centralized directory
services facilitate the understanding of the Tor network, as well as the
measurement and visualization of its structure through the Tor Metrics project.
In contrast, I2P does not rely on centralized directory servers, and thus
obtaining a complete view of the network is challenging. In this work, we
conduct an empirical study of the I2P network, in which we measure properties
including population, churn rate, router type, and the geographic distribution
of I2P peers. We find that there are currently around 32K active I2P peers in
the network on a daily basis. Of these peers, 14K are located behind NAT or
firewalls.
Using the collected network data, we examine the blocking resistance of I2P
against a censor that wants to prevent access to I2P using address-based
blocking techniques. Despite the decentralized characteristics of I2P, we
discover that a censor can block more than 95% of peer IP addresses known by a
stable I2P client by operating only 10 routers in the network. This amounts to
severe network impairment: a blocking rate of more than 70% is enough to cause
significant latency in web browsing activities, while blocking more than 90% of
peer IP addresses can make the network unusable. Finally, we discuss the
security consequences of the network being blocked, and directions for
potential approaches to make I2P more resistant to blocking.Comment: 14 pages, To appear in the 2018 Internet Measurement Conference
(IMC'18
Beyond Cookie Monster Amnesia:Real World Persistent Online Tracking
Browser fingerprinting is a relatively new method of uniquely identifying
browsers that can be used to track web users. In some ways it is more
privacy-threatening than tracking via cookies, as users have no direct control
over it. A number of authors have considered the wide variety of techniques
that can be used to fingerprint browsers; however, relatively little
information is available on how widespread browser fingerprinting is, and what
information is collected to create these fingerprints in the real world. To
help address this gap, we crawled the 10,000 most popular websites; this gave
insights into the number of websites that are using the technique, which
websites are collecting fingerprinting information, and exactly what
information is being retrieved. We found that approximately 69\% of websites
are, potentially, involved in first-party or third-party browser
fingerprinting. We further found that third-party browser fingerprinting, which
is potentially more privacy-damaging, appears to be predominant in practice. We
also describe \textit{FingerprintAlert}, a freely available browser extension
we developed that detects and, optionally, blocks fingerprinting attempts by
visited websites
Exposure-age constraints on the extent, timing and rate of retreat of the last Irish Sea ice stream
We report 23 cosmogenic isotope exposure ages (10Be and 36Cl) relating to the maximum extent and deglaciation chronology of the Irish Sea Ice Stream (ISIS), which drained the SW sector of the last British-Irish Ice Sheet. These show that the ISIS failed to reach the Preseli Hills of North Pembrokeshire yet extended southwards to impinge on northern Isles of Scilly (50°N) during the last glacial maximum. Four samples from western Anglesey demonstrate deglaciation of the southern Irish Sea Basin by c. 20-18 ka, and two from the Llŷn Peninsula in northwest Wales, if valid, suggest deglaciation by c. 23-22 ka followed by gradual oscillatory northwards retreat of the ice margin for over 3000 years. An alternative interpretation of our data suggests that ice reached Scilly as late as 22-21 ka then retreated 450 km northwards within the following three millennia, possibly in response to sea level rise and/or intrinsic reorganisation within the last British-Irish Ice Sheet. Samples from upland source areas of the ISIS in NW England and SW Scotland produced exposure ages ≤14.3 ka, suggesting possible persistence of ice in such areas into the Lateglacial Interstade of 14.7-12.9 ka
The Search for Supernova-produced Radionuclides in Terrestrial Deep-sea Archives
An enhanced concentration of 60Fe was found in a deep ocean's crust in 2004
in a layer corresponding to an age of ~2 Myr. The confirmation of this signal
in terrestrial archives as supernova-induced and detection of other
supernova-produced radionuclides is of great interest. We have identified two
suitable marine sediment cores from the South Australian Basin and estimated
the intensity of a possible signal of the supernova-produced radionuclides
26Al, 53Mn, 60Fe and the pure r-process element 244Pu in these cores. A finding
of these radionuclides in a sediment core might allow to improve the time
resolution of the signal and thus to link the signal to a supernova event in
the solar vicinity ~2 Myr ago. Furthermore, it gives an insight on
nucleosynthesis scenarios in massive stars, the condensation into dust grains
and transport mechanisms from the supernova shell into the solar system
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