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Peter Wilson Tom C. Lord Matt W. Telfer Timothy T. Barrows Peter J. Vincent 《Geology Today》2013,29(1):16-22
The Craven Dales of North Yorkshire contain some of the finest examples of limestone geology and landscape in the UK. The extensive limestone pavements with their clints, grikes and other water‐worn features, are a key attraction for both scientists and recreational visitors. Likewise the cave systems attract attention with their remarkable sediment accumulations, some of which are in excess of 500 000 years old and others contain the bones of mammals that are either extinct or no longer present in the British Isles. The glacial erratic boulders at Norber and the loessic sediments that, in places, mask the limestone have also provided stimulus for investigation. Summarized below are the findings of several recent studies that focussed on establishing the age of various features. Whilst the reports answer some long‐standing questions, they also demonstrate that there is still much that can be learned about this seemingly familiar territory. 相似文献
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Mary Gleason Scott McCreary Melissa Miller-Henson John Ugoretz Evan Fox Matt Merrifield Will McClintock Paulo Serpa Kathryn Hoffman 《Ocean & Coastal Management》2010,53(2):52-68
The planning process for California's Marine Life Protection Act in north central California represents a case study in the design of a regional component of a statewide network of marine protected areas (MPAs) for improved ecosystem protection. We describe enabling factors, such as a legislative mandate, political will, and adequate capacity and funding that fostered a successful planning process. We identify strategic principles that guided the design of a transparent public planning process that delivered regional MPA network proposals, which both met science guidelines and achieved a high level of support among stakeholders. We also describe key decision support elements (spatial data, planning tools, and scientific evaluation) that were essential for designing, evaluating, and refining alternative MPA network proposals and for informing decision-makers. 相似文献
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Matt?A.?KingEmail author Michael?Bevis Terry?Wilson Bjorn?Johns Frederick?Blume 《Journal of Geodesy》2012,86(1):53-63
We examine the electromagnetic coupling of a GPS antenna–monument pair in terms of its simulated affect on long GPS coordinate
time series. We focus on the Earth and Polar Observing System (POLENET) monument design widely deployed in Antarctica and
Greenland in projects interested particularly in vertical velocities. We base our tests on an absolute robot calibration that
included the top ~0.15 m of the monument and use simulations to assess its effect on site coordinate time series at eight
representative POLENET sites in Antarctica over the period 2000.0–2011.0. We show that the neglect of this calibration would
introduce mean coordinate bias, and most importantly for velocity estimation, coordinate noise which is highly sensitive to
observation geometry and hence site location and observation period. Considering only sub-periods longer than 2.5 years, we
show vertical site velocities may be biased by up to ±0.4 mm/year, and biases up to 0.2 mm/year may persist for observation
spans of 8 years. Changing between uniform and elevation-dependent observation weighting alters the time series but does not
remove the velocity biases, nor does ambiguity fixing. The effect on the horizontal coordinates is negligible. The ambiguities
fixed series spectra show noise between flicker and random walk with near-white noise at the highest frequencies, with mean
spectral indices (frequencies <20 cycles per year) of approximately −1.3 (uniform weighting) and −1.4 (elevation-dependent
weighting). While the results are likely highly monument specific, they highlight the importance of accounting for monument
effects when analysing vertical coordinate time series and velocities for the highest precision and accuracy geophysical studies. 相似文献
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T. Di Salvo A. D'Aí R. Iaria L. Burderi M. Doviak V. Karas G. Matt A. Papitto S. Piraino A. Riggio N. R. Robba A. Santangelo 《Monthly notices of the Royal Astronomical Society》2009,398(4):2022-2027
Iron emission lines at 6.4–6.97 keV, identified with fluorescent Kα transitions, are among the strongest discrete features in the X-ray band. These are therefore one of the most powerful probes to infer the properties of the plasma in the innermost part of the accretion disc around a compact object. In this paper, we present a recent XMM–Newton observation of the X-ray burster 4U 1705−44, where we clearly detect a relativistically smeared iron line at about 6.7 keV, testifying with high statistical significance that the line profile is distorted by high-velocity motion in the accretion disc. As expected from disc reflection models, we also find a significant absorption edge at about 8.3 keV; this feature appears to be smeared, and is compatible with being produced in the same region where the iron line is produced. From the line profile, we derive the physical parameters of the inner accretion disc with large precision. The line is identified with the Kα transition of highly ionized iron, Fe xxv , the inner disc radius is R in = 14 ± 2 R g (where R g is the Gravitational radius, GM / c 2 ), the emissivity dependence from the disc radius is r −2.27±0.08 , the inclination angle with respect to the line of sight is i = 39°± 1° . Finally, the XMM–Newton spectrum shows evidences of other low-energy emission lines, which again appear broad and their profiles are compatible with being produced in the same region where the iron line is produced. 相似文献
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Matt Bradshaw 《The Australian geographer》2001,32(2):241-257
The focus in this paper is on the shifting optimum location for a newsprint mill in Australia, factors influencing this shift, and the implications for a particular manufacturing site that is becoming increasingly outdated and out-of-place. Shipping times and schedules for high-volume, high-density tonnages of commodities such as newsprint have altered insufficiently over the last 60 years to affect competitive relations among various newsprint manufacturers around the world. With sea transport held roughly constant, changes in other aspects of the international newsprint industry can be investigated as part of unpacking the concept of globalisation. Globalisation for the former Australian Newsprint Mills Ltd meant becoming more open to new and closer competition, as well as becoming more exposed to acquisition by increasingly transnational enterprises. In the global newsprint industry at least, the world is less a smaller place than a more open one, with tonnes of newsprint moving at similar speeds to 60 years ago but among different and changing locations in terms of geography, ownership and market preference. 相似文献