172 research outputs found
E/V Nautilus EM302 Multibeam Echosounder System Review
Introduction
The E/V Nautilus undertook leg NA040 to perform a review of the vessel’s Kongsberg EM302 multibeam echosounder in the vicinity of the continental shelf break offshore of St. Petersburg, Florida, from May 4-9, 2014 (Fig. 1). Paul Johnson and Kevin Jerram provided logistical and technical support for data collection and analysis. This report:
• Describes the data collected.
• Provides an overview of the processing methods used on the data
• Presents the EM302 system performance for accuracy and coverage over the expected operational depth range.
• Documents changes made to the system configuration prior to the 2014 field season.
• Plots the EM302 transducer impedance data to document transducer health
Does landscape-scale conservation management enhance the provision of ecosystem services?
Biodiversity conservation approaches are increasingly being implemented at the landscape-scale to support the maintenance
of metapopulations and metacommunities. However, the impact of such interventions on the provision of ecosystem services
is less well defined. Here we examine the potential impacts of landscape-scale conservation initiatives on ecosystem
services, through analysis of five case study areas in England and Wales. The provision of multiple ecosystem services was
projected according to current management plans and compared with a baseline scenario. Multicriteria analysis indicated
that in most cases landscape-scale approaches lead to an overall increase in service provision. Consistent increases were
projected in carbon storage, recreation and aesthetic value, as well as biodiversity value. However, most study areas
provided evidence of trade-offs, particularly between provisioning services and other types of service. Results differed
markedly between study areas, highlighting the importance of local context. These results suggest that landscape-scale
conservation approaches are likely to be effective in increasing ecosystem service provision, but also indicate that associated
costs can be significant, particularly in lowland areas
Development of EM-CCD-based X-ray detector for synchrotron applications
A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved
Photon counting strategies with low light level CCDs
Low light level charge coupled devices (L3CCDs) have recently been developed,
incorporating on-chip gain. They may be operated to give an effective readout
noise much less than one electron by implementing an on-chip gain process
allowing the detection of individual photons. However, the gain mechanism is
stochastic and so introduces significant extra noise into the system. In this
paper we examine how best to process the output signal from an L3CCD so as to
minimize the contribution of stochastic noise, while still maintaining
photometric accuracy.
We achieve this by optimising a transfer function which translates the
digitised output signal levels from the L3CCD into a value approximating the
photon input as closely as possible by applying thresholding techniques. We
identify several thresholding strategies and quantify their impact on photon
counting accuracy and effective signal-to-noise.
We find that it is possible to eliminate the noise introduced by the gain
process at the lowest light levels. Reduced improvements are achieved as the
light level increases up to about twenty photons per pixel and above this there
is negligible improvement. Operating L3CCDs at very high speeds will keep the
photon flux low, giving the best improvements in signal-to-noise ratio.Comment: 7 pages, accepted by MNRA
Three-Dimensional Seismic Imaging of Ancient Submarine Lava Flows : An Example From the Southern Australian Margin
This work comprises a part of the Great Australian Bight Deepwater Marine Program (GABDMP) for funding this project. The GABDMP is a CSIRO research program, sponsored by Chevron Australia the results of which will be made publicly available. 3D seismic data was gratefully provided by TGS. IHS are thanked for access to seismic interpretation software. Spectral decomposition was carried out using Foster-Findlay Associates Geoteric Software. Sverre Planke and Tracy Gregg are thanked for constructive reviews.Peer reviewedPublisher PD
Improving clinical utility of GAD65 autoantibodies by electrochemiluminescence assay and clinical phenotype when identifying autoimmune adult-onset diabetes
Electron Multiplying CCDs
Electron multiplying CCD (EMCCD) technology has found important initial applications in low light surveillance and photon starved scientific instrumentation. This paper provides a description of the technology and discusses the attributes of the EMCCD which may make it useful for other detectors, particularly those which are photon starve
Compact CMOS camera demonstrator (C3D) for Ukube-1
The Open University, in collaboration with e2v technologies and XCAM Ltd, have been selected to fly an EO (Earth Observation) technology demonstrator and in-orbit radiation damage characterisation instrument on board the UK Space Agency's UKube-1 pilot Cubesat programme. Cubesat payloads offer a unique opportunity to rapidly build and fly space hardware for minimal cost, providing easy access to the space environment. Based around the e2v 1.3 MPixel 0.18 micron process eye-on-Si CMOS devices, the instrument consists of a radiation characterisation imager as well as a narrow field imager (NFI) and a wide field imager (WFI). The narrow and wide field imagers are expected to achieve resolutions of 25 m and 350 m respectively from a 650 km orbit, providing sufficient swathe width to view the southern UK with the WFI and London with the NFI. The radiation characterisation experiment has been designed to verify and reinforce ground based testing that has been conducted on the e2v eye-on-Si family of devices and includes TEC temperature control circuitry as well as RADFET in-orbit dosimetry. Of particular interest are SEU and SEL effects. The novel instrument design allows for a wide range of capabilities within highly constrained mass, power and space budgets providing a model for future use on similarly constrained missions, such as planetary rovers. Scheduled for launch in December 2011, this 1 year low cost programme should not only provide valuable data and outreach opportunities but also help to prove flight heritage for future missions
Combining thermal imaging with photogrammetry of an active volcano using UAV : an example from Stromboli, Italy
The authors would like to thank the Istituto Nazionale di Geofisica e Vulcanologia – Sezione di Catania (INGV‐CT) for granting permission to conduct the UAV surveys over the Stromboli volcano. This work was supported by the School for Early Career Researchers at the University of Aberdeen, UK. Dougal Jerram is partly funded through a Norwegian Research Council Centres of Excellence project (project number 223272, CEED). The team would like to thank Angelo Cristaudo for logistical help during the fieldwork efforts on Stromboli.Peer reviewedPostprin
The Interface Region Imaging Spectrograph (IRIS)
The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft
provides simultaneous spectra and images of the photosphere, chromosphere,
transition region, and corona with 0.33-0.4 arcsec spatial resolution, 2 s
temporal resolution and 1 km/s velocity resolution over a field-of-view of up
to 175 arcsec x 175 arcsec. IRIS was launched into a Sun-synchronous orbit on
27 June 2013 using a Pegasus-XL rocket and consists of a 19-cm UV telescope
that feeds a slit-based dual-bandpass imaging spectrograph. IRIS obtains
spectra in passbands from 1332-1358, 1389-1407 and 2783-2834 Angstrom including
bright spectral lines formed in the chromosphere (Mg II h 2803 Angstrom and Mg
II k 2796 Angstrom) and transition region (C II 1334/1335 Angstrom and Si IV
1394/1403 Angstrom). Slit-jaw images in four different passbands (C II 1330, Si
IV 1400, Mg II k 2796 and Mg II wing 2830 Angstrom) can be taken simultaneously
with spectral rasters that sample regions up to 130 arcsec x 175 arcsec at a
variety of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to
emission from plasma at temperatures between 5000 K and 10 MK and will advance
our understanding of the flow of mass and energy through an interface region,
formed by the chromosphere and transition region, between the photosphere and
corona. This highly structured and dynamic region not only acts as the conduit
of all mass and energy feeding into the corona and solar wind, it also requires
an order of magnitude more energy to heat than the corona and solar wind
combined. The IRIS investigation includes a strong numerical modeling component
based on advanced radiative-MHD codes to facilitate interpretation of
observations of this complex region. Approximately eight Gbytes of data (after
compression) are acquired by IRIS each day and made available for unrestricted
use within a few days of the observation.Comment: 53 pages, 15 figure
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