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191.
Helen Mavromichalaki George Souvatzoglou Christos Sarlanis George Mariatos Athanasios Papaioannou Anatoly Belov Eugenia Eroshenko Victor Yanke 《New Astronomy》2010,15(8):744-748
The European Commission is supporting the real-time database for high-resolution neutron monitor measurements (NMDB) as an e-Infrastructures project in the Seventh Framework Programme in the Capacities section. The realization of the NMDB will provide the opportunity for several applications most of which will be implemented in real-time. An important application will be the establishment of an Alert signal when dangerous solar particle events are heading to the Earth, resulting into a ground level enhancement (GLE) registered by neutron monitors (NMs). The cosmic ray community has been occupied with the question of establishing such an Alert for many years and recently several groups succeeded in creating a proper algorithm capable of detecting space weather threats in an off-line mode. A lot of original work has been done to this direction and every group working in this field performed routine runs for all GLE cases, resulting into statistical analyses of GLE events. The next step was to make this algorithm as accurate as possible and most importantly, working in real-time. This was achieved when, during the last GLE observed so far, a real-time GLE Alert signal was produced. In this work, the steps of this procedure as well as the functionality of this algorithm for both the scientific community and users are being discussed. Nevertheless, the transition of the Alert algorithm to the NMDB is also being discussed. 相似文献
192.
Izvestiya, Atmospheric and Oceanic Physics - An open software implementation of the algorithm for retrieving the land surface temperature (LST) from Landsat 8 remote sensing satellite data is... 相似文献
193.
Anastassia Y. Borisova Rémi Freydier Mireille Polvé Klaus Peter Jochum Frederic Candaudap 《Geostandards and Geoanalytical Research》2010,34(3):245-255
This paper reports on the application of variants of LA-ICP-MS – including infrared femtosecond laser ablation (fs-LA) inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) and nanosecond laser ablation (ns-LA) coupled with single-collector sector-field (SF-) ICP-MS – to the in situ determination of trace elements in different splits of the reference material (RM) ATHO-G (MPI-DING). Analyses of the materials performed by fs- and ns-LA-ICP-MS demonstrated the efficiency of the techniques with typical accuracy at a level of ≤ ± 20%. One ‘anomalous’ split, however, displayed a significant discrepancy from the reference concentrations for B, V, Zn, Mo, Sn, Sb, Cs, W and Pb. Three- to six-fold enrichment of V, Mo, Cs and Pt relative to the reference contents in this split is likely to have been due to direct contact of the silicate melt with Pt crucible walls and ceramics. Boron, Zn, Sn, Sb, W and Pb depletion relative to the reference concentrations is probably due to siderophile element adsorption by the Pt walls and/or related to the formation of volatile-depleted compositional cords during the preparation process. Our results imply that additional precautions should be taken against volatile/siderophile element heterogeneity in marginal/surface layers (≤ 10 mm) during the preparation of RMs by the fusion technique. 相似文献
194.
David L. Jauncey Helen M. Johnston Hayley E. Bignall J.E.J. Lovell Lucyna Kedziora-Chudczer A.K. Tzioumis Jean-Pierre Macquart 《Astrophysics and Space Science》2003,288(1-2):63-68
We have measured annual cycles in the time scales of the rapid, intra-day variability of the total and circularly polarized flux density, of the unusual BL Lac source PKS 1519–273 at 4.8 and 8.6 GHz. This data was collected at the ATCA over the last seven years, and establishes unequivocally interstellar scintillation as the principal mechanism responsible for this cm-wavelength intra-day variability. 相似文献
195.
Garret Cotter Helen J. Buttery Rhiju Das† Michael E. Jones Keith Grainge G. G. Pooley Richard Saunders 《Monthly notices of the Royal Astronomical Society》2002,334(2):323-326
We have observed the z =0.78 cluster MS 1137.5+6625 with the Ryle Telescope (RT) at 15 GHz. After subtraction of contaminating radio sources in the field, we find a Sunyaev–Zel'dovich flux decrement of -421±60 μJy on the ≈0.65 k λ baseline of the RT, spatially coincident with the optical and X-ray positions for the cluster core.
For a spherical King-profile cluster model, the best fit to our flux measurement has a core radius θC =20 arcsec , consistent with previous X-ray observations, and a central temperature decrement Δ T =650±92 μK .
Using this model, we calculate that the cluster has a gas mass inside a radius of 2.9×1013 M⊙ for an Ω M =1 universe and 1.6×1013 M⊙ for Ω M =0.3 , ΩΛ =0.7 . We compare this model with existing measurements of the total mass of the cluster, based on gravitational lensing, and estimate a gas fraction for MS 1137.5+6625 of ≈8 per cent. 相似文献
For a spherical King-profile cluster model, the best fit to our flux measurement has a core radius θ
Using this model, we calculate that the cluster has a gas mass inside a radius of 2.9×10
196.
197.
Richard W. Battarbee Gavin L. Simpson Helen Bennion Christopher Curtis 《Journal of Paleolimnology》2011,45(4):489-505
This paper has two aims: (1) to show for the first time how a natural typology can be established using palaeoecological methods;
and (2) to show how it can be used in lake restoration studies with respect to the definition of recovery targets for acidified
lakes. By defining the characteristic reference assemblages for low alkalinity site types rather than for a specific site
it allows success to be measured more broadly, unconstrained by the specific composition of the pre-acidification flora. We
analyse statistically the pre-acidification diatom assemblages of sediment cores from 121 low alkalinity lakes in the UK in
order to assess whether a reference typology for such lakes can be defined on the basis of their diatom floras. We use samples
dating to ~1850 AD to represent pre-acidification conditions. The results show that three main clusters can be identified,
two dominated by benthic taxa (Clusters 1 and 3) and one dominated by planktonic taxa (Cluster 2). Cluster 1 is characterised
by taxa such as Brachysira vitrea, Cymbella microcephala and Fragilaria spp., Cluster 2 by Cyclotella comensis, C. radiosa, Asterionella formosa, Aulacoseira subarctica and Achnanthes minutissima and Cluster 3 by Eunotia incisa, Frustulia rhomboides var. saxonica, Fragilaria virescens var. exigua, and Cymbella perpusilla. Although environmental data for 1850 AD are not available it is apparent from the contemporary distribution of the taxa
in the different clusters that Cluster 2 represents the most alkaline pre-acidification conditions. Some sites in this cluster
have been acidified, but some, especially the larger, deeper lakes have been enriched. Cluster 1 includes sites that contain
diatoms with relatively high pH optima (pH 6.4–7.4) whereas Cluster 3 sites contain diatoms with the lowest pre-acidification
pH conditions in the data-set. Sites in this cluster also have the lowest base cation concentrations at the present day and
include the sites in the UK that have been most affected by acid deposition. 相似文献
198.
This Special Issue was produced as an output from the EU Integrated Project Euro-limpacs which aimed to evaluate the impacts of global change on European freshwater ecosystems using a combination of approaches,
including monitoring, experiments, modelling and palaeolimnology. The papers focus on the last of these approaches. They examine
the role of lake sediment records in determining reference conditions for a range of environmental pressures including acidification,
eutrophication, metal pollution, organic carbon and sediment accumulation rates. The findings are especially relevant to the
European Union’s Water Framework Directive which requires an assessment of lake ecological status based on deviation from
reference conditions. The contributions consider a range of issues relating to the use of palaeolimnological data in defining
reference conditions and lake status including human versus natural variability, concepts of pristine and reference conditions,
shifting baselines, and quantification of degree of change. This introductory paper sets the context for the volume by briefly
describing how palaeolimnology has evolved as a science, able now to contribute uniquely to the understanding of lake ecosystem
change, especially with respect to the role of human activity over recent decades and centuries. 相似文献
199.
200.
The original article to which this Erratum refers was published in Journal of Quaternary Science 16 (3) 2001, 201‐220. 相似文献