1,102 research outputs found
A study to examine the operation and function of a virtual UK environmental specimen bank (UK-ESB). Final report
Executive Summary:
1. Environmental specimen banking is recognised internationally as an integral part of long-term environmental research and monitoring. Analysis of preserved environmental samples is often needed to detect and quantify patterns and rate of environmental change, and the emergence and progression of environmental hazards and risks.
2. National Environmental Specimen Banks have been established in several countries; they vary in scope and breadth. There are a few specialised environmental specimen holdings in the UK but no national-scale catalogue of holdings, despite an estimated annual spend of £16 million to store specimens. This lack of information results in under-exploitation of archived specimens and is a lost opportunity to facilitate world-class science and identify emerging pressures and threats on the environment.
3. An earlier project had identified key stakeholder organisations either engaged in archiving nationally important environmental specimens or who wished to utilise such specimens. These stakeholders had agreed there was a need for a national metadata catalogue of environmental specimens (subsequently termed a virtual UK-ESB). The objective of the current project was to further develop a virtual UK-ESB. Specifically, the aim was to work with stakeholders to establish the correct metadata entry fields, the search capabilities, the functionality and the nature of the hosting website of a virtual UK-ESB.
4. More than 80 stakeholder organisations that had previously expressed an interest in a UK-ESB were approached to provide feedback either electronically or by attending a stakeholder workshop. Thirty eight organisations responded. All remained interested in the UK-ESB concept and seventeen answered the survey questions.
5. Mock-ups of data entry screens, search screens and ideas around the functionality of a UK-ESB were developed by the CEH project team. These were mailed to stakeholders for feedback. Initial feedback was incorporated into the mock-ups which were then presented for discussion at a workshop comprising 15 attendees from across the specimen archiving community, CEH and the UK-EOF.
6. Workshop participants reviewed and agreed the format of 23 mandatory or optional data-entry fields for a virtual UK-ESB that, in the absence of standard for material samples and archives, were aligned with ISO19115 (geospatial metadata standard) and DublinCore (metadata standard). These fields were sub-divided into the following headings: Sample description, Categorisation, keywords and links, Storage Information and Contact information. Workshop participants also made a number of recommendations as to the format of the data entry screens and inclusion of extra fields.
7. Workshop participants reviewed options for search capabilities and made recommendations as to simple and advanced searching methods and their formats. It was also recommended that search facilities of the ESBs of other countries be examined to determine what is used, ease of use, and how they match the recommendations from the workshop.
8. Workshop participants reviewed options for functionality and agreed a detailed list of prioritised requirements.
9. Workshop participants agreed that a virtual UK-ESB should be hosted through a dedicated website that would also provide wider information, such as recently updated or added specimen holdings, most downloaded information, links to other groups, standard operating procedures, etc.
10. The next step for the development of a virtual UK-ESB is to implement the design and development ideas captured in the current report and build a test version of a virtual UK-ESB. This would be tested and refined, and could then be launched on a specifically designed website. This would need to be accompanied by a communication strategy. There is potential to link and co-brand a virtual UK-ESB with the UK-Environmental Observation Framework (UK-EOF)
La ley de derechos humanos bajo amenaza. El desafÃo a la ley de derechos humanos en el Reino Unido. Human Rights Law under Threat – the Challenge to Human Rights Law in the United Kingdom.
Solar Stereoscopy with STEREO/EUVI A and B spacecraft from small (6 deg) to large (170 deg) spacecraft separation angles
We performed for the first time stereoscopic triangulation of coronal loops
in active regions over the entire range of spacecraft separation angles
(, and
). The accuracy of stereoscopic correlation depends mostly on the
viewing angle with respect to the solar surface for each spacecraft, which
affects the stereoscopic correspondence identification of loops in image pairs.
From a simple theoretical model we predict an optimum range of , which is also experimentally confirmed. The best
accuracy is generally obtained when an active region passes the central
meridian (viewed from Earth), which yields a symmetric view for both STEREO
spacecraft and causes minimum horizontal foreshortening. For the extended
angular range of we find a mean 3D
misalignment angle of of stereoscopically
triangulated loops with magnetic potential field models, and for a force-free field model, which is partly caused by
stereoscopic uncertainties . We predict optimum
conditions for solar stereoscopy during the time intervals of 2012--2014,
2016--2017, and 2021--2023.Comment: Solar Physics, (in press), 22 pages, 9 figure
The use of uplift modelling in the reconstruction of drainage development and landscape evolution in the repeatedly glaciated Trent catchment, English Midlands, UK
The Trent Valley Palaeolithic Project has recently investigated the Quaternary evolution of the River Trent, the northernmost river system in western Europe with a documented long-timescale terrace staircase. The uppermost and lowermost reaches of the Trent, which drains the English Midlands, were glaciated during Marine oxygen Isotope Stage (MIS) 2, but older fluvial terraces dating back to MIS 8 are preserved in the remainder of the catchment, delineating the former course through the Lincoln Gap and across the Fen Basin (the modern course to the Humber estuary dating only from the latest Pleistocene). Numerical modelling enables lateral variations in uplift across the catchment to be deduced from differences in height of these fluvial terraces above the modern valley floor. Uplift rates thus indicated over the last two climate cycles attain values of ∼0.08 mm a−1 around Nottingham and Derby in the middle reach of the Trent, but are significantly lower elsewhere in the catchment; these variations are shown to relate to lateral variations in crustal properties, primarily variations in radioactive heat production in the underlying continental crust. Glaciation during the late Middle Pleistocene (MIS 8) caused significant changes to the Trent catchment, including the integration of the modern Upper Trent with the rest of the system. Older sedimentary evidence is much more fragmentary, but is used along with the results of the uplift modelling to reconstruct the earlier drainage. It is thus inferred that between the Anglian (MIS 12) and Wragby (MIS 8) glaciations the Trent already flowed into the Fen Basin via the Lincoln Gap, but the smaller-than-present catchment, indicated by gravel lithology, resulted in a much steeper longitudinal gradient, such that during interglacials (MIS 11 and 9) an elongated estuary would have developed, extending inland almost to the present location of Newark. Prior to the Anglian, much of the modern Trent catchment, including the rivers Derwent and Dove, drained into the former Bytham River. The modern Middle Trent catchment downstream of Nottingham was drained by a relatively small ‘Ancaster Trent’ river, which flowed above the Ancaster Gap; analysis of gravel lithology suggests that it probably joined the Bytham in the area that now forms the Fen Basin
Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere
A method for the full three-dimensional (3-D) reconstruction of the
trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations
Observatory (STEREO) data is presented. Four CMEs that were simultaneously
observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and
Behind STEREO satellites were analysed. These observations were used to derive
CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data
support a radial propagation model. Assuming pseudo-radial propagation at large
distances from the Sun (15-240Rsun), the CME positions were extrapolated into
the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in
the different fields-of-view. It was found that CMEs slower than the solar wind
were accelerated, while CMEs faster than the solar wind were decelerated, with
both tending to the solar wind velocity.Comment: 17 pages, 10 figures, 1 appendi
Exact first-order density matrix for a d-dimensional harmonically confined Fermi gas at finite temperature
We present an exact closed form expression for the {\em finite temperature}
first-order density matrix of a harmonically trapped ideal Fermi gas in any
dimension. This constitutes a much sought after generalization of the recent
results in the literature, where exact expressions have been limited to
quantities derived from the {\em diagonal} first-order density matrix. We
compare our exact results with the Thomas-Fermi approximation (TFA) and
demonstrate numerically that the TFA provides an excellent description of the
first-order density matrix in the large-N limit. As an interesting application,
we derive a closed form expression for the finite temperature Hartree-Fock
exchange energy of a two-dimensional parabolically confined quantum dot. We
numerically test this exact result against the 2D TF exchange functional, and
comment on the applicability of the local-density approximation (LDA) to the
exchange energy of an inhomogeneous 2D Fermi gas.Comment: 12 pages, 3 figures included in the text, RevTeX4. Text before
Eq.(25) corrected. Additional equation following Eq.(25) has been adde
Nonuniversality in the pair contact process with diffusion
We study the static and dynamic behavior of the one dimensional pair contact
process with diffusion. Several critical exponents are found to vary with the
diffusion rate, while the order-parameter moment ratio m=\bar{rho^2}
/\bar{rho}^2 grows logarithmically with the system size. The anomalous behavior
of m is traced to a violation of scaling in the order parameter probability
density, which in turn reflects the presence of two distinct sectors, one
purely diffusive, the other reactive, within the active phase. Studies
restricted to the reactive sector yield precise estimates for exponents beta
and nu_perp, and confirm finite size scaling of the order parameter. In the
course of our study we determine, for the first time, the universal value m_c =
1.334 associated with the parity-conserving universality class in one
dimension.Comment: 9 pages, 5 figure
Universality in the pair contact process with diffusion
The pair contact process with diffusion is studied by means of multispin
Monte Carlo simulations and density matrix renormalization group calculations.
Effective critical exponents are found to behave nonmonotonically as functions
of time or of system length and extrapolate asymptotically towards values
consistent with the directed percolation universality class. We argue that an
intermediate regime exists where the effective critical dynamics resembles that
of a parity conserving process.Comment: 8 Pages, 9 figures, final version as publishe
Reaction-controlled diffusion
The dynamics of a coupled two-component nonequilibrium system is examined by
means of continuum field theory representing the corresponding master equation.
Particles of species A may perform hopping processes only when particles of
different type B are present in their environment. Species B is subject to
diffusion-limited reactions. If the density of B particles attains a finite
asymptotic value (active state), the A species displays normal diffusion. On
the other hand, if the B density decays algebraically ~t^{-a} at long times
(inactive state), the effective attractive A-B interaction is weakened. The
combination of B decay and activated A hopping processes gives rise to
anomalous diffusion, with mean-square displacement ~ t^{1-a} for a
< 1. Such algebraic subdiffusive behavior ensues for n-th order B annihilation
reactions (n B -> 0) with n >=3, and n = 2 for d < 2. The mean-square
displacement of the A particles grows only logarithmically with time in the
case of B pair annihilation (n = 2) and d >= 2 dimensions. For radioactive B
decay (n = 1), the A particles remain localized. If the A particles may hop
spontaneously as well, or if additional random forces are present, the A-B
coupling becomes irrelevant, and conventional diffusion is recovered in the
long-time limit.Comment: 7 pages, revtex, no figures; latest revised versio
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