4,616 research outputs found
Chronology, Uncertainty and GIS: A Methodology for Characterising and understanding Landscapes of the Ancient Near East
Modern archaeological research is confronted with a legacy of projects which stretch back to the early 20th century. Alongside this, massive amounts of disparate data are being generated by on-going excavation and survey. Scholars are also beginning to use satellite imagery to interpret and re-interpret archaeological data-sets both old and new. In the Near East this disparity is compounded by the diversity of dating schemes and interpretative frameworks used by archaeologists studying the region. Faced with these issues, how is it possible to combine such data into a coherent and comprehensive format, adding value to both old and on-going research projects? The Fragile Crescent (AHRC) and Vanishing Landscape (Leverhulme) Projects (Durham University) aim to draw together data derived from archaeological surveys and satellite imagery analysis into a single analytical framework. The projects have developed a methodology for understanding, analysing and presenting disparate chronological, morphological and methodological data across the Ancient Near East. This paper will illustrate how researchers have been able to revitalise old data, adding value through new approaches towards archaeological sites and landscapes via satellite imagery, remote sensing and spatial analyses. We will examine how integrating multiple chronological systems and concepts of ‘uncertainty’ into a single GIS/Database framework can allow for a robust and detailed multi-scalar archaeological landscape analysis. Using case studies from the Fragile Crescent/Vanishing Landscape Projects we will discuss how this methodology has led to new interpretations of urban and non-urban landscapes of the Ancient Near East
Carbon flux on coral reefs: effects of large shifts in community structure
The effect of replacement of live coral cover by epilithic algae on patterns and magnitudes
of carbon flux is examined for the shallow front slope of a midshelf reef in the Great Barrier Reef (GBR)
complex of Australia. A steady-state network of carbon exchange among 19 trophic compartments is
constructed for the coral-dominated state. From this, 2 scenarios for patterns of carbon flux when algae
dominate are derived, viz. (1) the increase in algal production is channeled to detrital pathways
(grazers do not respond), and (2) grazers utilise the increase in production of algal carbon so that
transfers to detritus and grazers are in the same proportion as occurs when coral cover is high. The
3 models summarise current knowledge of carbon flux on GBR reef fronts and are compared using
network analysis. Because fluxes in the reef front zone are dominated by exogenous imports and
exports as a result of the high volume of water passing around and over the reef, the analyses ignore
advective fluxes across the zone that are not internalised.The shift in structure to an algae-dominated
system realises lower rates of benthic primary production, and thus system slze and activity (i.e. total
system throughput, internal throughput, development capacity and ascendancy) are reduced, suggest-
ing a disturbed system. With loss of coral cover, the proportion of the total flow that is recycled and
transferred to the detritus pool increases (although the structure of recycling is not affected), and the
balance of pathways in the network is changed: average path length increases, while the average
trophic level of most of the second order consumers, and trophic efiiciencies of most trophic categories,
decreases. Also, there are marked changes in dependencies of particular trophic groups on others. The
analysis shows that, in the coral-dominated state, carbon fixed by zooxanthellae is used indirectly by
most organisms in the system, even those seemingly remotely connected. Differences between the
coral- and algae-dominated systems were much greater than differences between the 2 scenarios for
the algae-dominated state. However, the exact fate of additional algae-derived carbon In the system is
an important consideration since the 2 scenarios for the algae-dominated state yielded dissimilar values
for some parameters (e.g. flow diversity, trophic dependencies and effective trophic levels of some com-
partments, relative importance of recycling, trophic efficiency of some trophic categories)
Exploiting tightly-coupled cores
This is the published manuscript. It was first published by Springer in the Journal of Signal Processing Systems here: http://link.springer.com/article/10.1007%2Fs11265-014-0944-6.The individual processors of a chip-multiprocessor
traditionally have rigid boundaries. Inter-core communication is
only possible via memory and control over a core’s resources is
localised. Specialisation necessary to meet today’s challenging
energy targets is typically provided through the provision of
a range of processor types and accelerators. An alternative
approach is to permit specialisation by tailoring the way a large
number of homogeneous cores are used. The approach here
is to relax processor boundaries, create a richer mix of intercore
communication mechanisms and provide finer-grain control
over, and access to, the resources of each core. We evaluate one
such design, called Loki, that aims to support specialisation in
software on a homogeneous many-core architecture. We focus
on the design of a single 8-core tile, conceived as the building
block for a larger many-core system. We explore the tile’s ability
to support a range of parallelisation opportunities and detail
the control and communication mechanisms needed to exploit
each core’s resources in a flexible manner. Performance and a
detailed breakdown of energy usage is provided for a range of
benchmarks and configurations.This work was supported by EPSRC grant EP/G033110/1
Short-term disturbance by a commercial two-dimensional seismic survey does not lead to long-term displacement of harbour porpoises
Peer reviewedPublisher PD
Multiwavelength Observations of a Flare from Markarian 501
We present multiwavelength observations of the BL Lacertae object Markarian
501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated
variability is seen in very high energy (VHE, E > 350 GeV) gamma-ray
observations taken with the Whipple Observatory gamma-ray telescope, data from
the Oriented Scintillation Spectrometer Experiment of the Compton Gamma-Ray
Observatory, and quicklook results from the All-Sky Monitor of the Rossi X-ray
Timing Explorer while the Energetic Gamma-Ray Experiment Telescope did not
detect Mrk 501. Short term optical correlations are not conclusive but the
U-band flux observed with the 1.2m telescope of the Whipple Observatory was 10%
higher than in March. The average energy output of Mrk 501 appears to peak in
the 2 keV to 100 keV range suggesting an extension of the synchrotron emission
to at least 100 keV, the highest observed in a blazar and ~100 times higher
than that seen in the other TeV-emitting BL Lac object, Mrk 421. The VHE
gamma-ray flux observed during this period is the highest ever detected from
this object. The VHE gamma-ray energy output is somewhat lower than the 2-100
keV range but the variability amplitude is larger. The correlations seen here
do not require relativistic beaming of the emission unless the VHE spectrum
extends to >5 TeV.Comment: 10 pages, 2 figures, accepted for publication in ApJ Letter
Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises
Acknowledgements We would like to thank Erik Rexstad and Rob Williams for useful reviews of this manuscript. The collection of visual and acoustic data was funded by the UK Department of Energy & Climate Change, the Scottish Government, Collaborative Offshore Wind Research into the Environment (COWRIE) and Oil & Gas UK. Digital aerial surveys were funded by Moray Offshore Renewables Ltd and additional funding for analysis of the combined datasets was provided by Marine Scotland. Collaboration between the University of Aberdeen and Marine Scotland was supported by MarCRF. We thank colleagues at the University of Aberdeen, Moray First Marine, NERI, Hi-Def Aerial Surveying Ltd and Ravenair for essential support in the field, particularly Tim Barton, Bill Ruck, Rasmus Nielson and Dave Rutter. Thanks also to Andy Webb, David Borchers, Len Thomas, Kelly McLeod, David L. Miller, Dinara Sadykova and Thomas Cornulier for advice on survey design and statistical approache. Data Accessibility Data are available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.cf04gPeer reviewedPublisher PD
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