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[en] Previous research to assess impacts from aggregate dredging has focussed on infaunal species with few studies made of fish entrainment. Entrainment evidence from hydraulic dredging studies is reviewed to develop a sensitivity index for benthic fish. Environmental monitoring attendant with the granting of new licences in the Eastern Channel Region (ECR) in 2006 offers a unique opportunity to assess the effects of dredging upon fish. Projected theoretical fish entrainment rates are calculated based upon: abundance data from 4m beam trawl sampling of fish species over the period 2005–2008; sensitivity data; and dredging activity and footprint derived from Electronic monitoring System (EMS) data. Results have been compared with actual entrainment rates and also against summary results from independent analysis of the changes in fish population over the period 2005–2008 (). The case is made for entrainment surveys to form part of impact monitoring for marine aggregate dredging.
[en] Complete text of publication follows. Deception Island forms the emergent part of a young active shield volcano (less than 1 Ma). It lies in the south-western part of Bransfield Strait between the Antarctic Peninsula and the South Shetland archipelago. This volcanic island has been very active during its entire evolution and its possible to distinguish different episodes of volcanic activity. Particularly, its last eruptions took place in 1967, 1969 and 1970. Its last active episode took place during the 1998-1999 Antarctic summer, when the pattern of seismic activity at Deception Island volcano changed significantly. A magmatic injection in depth is widely consider as the most probable hypothesis that explains the generation of this last seismic crisis. First magnetic surveys at Deception Island surroundings kicked-off during late 80's of the past century. Particularly, in 1988 was carried out the first magnetic survey ever performed of Port Foster (Deception volcano inner's bay). These studies continued during the period which goes from 1988 to 1991. In December 1999, January-February 2002, and December 2008, the Royal Naval Observatory of the Spanish Navy performed additional geophysical campaigns where new marine magnetic data were always recorded. In fact, Deception inner's bay was surveyed again in December 1999, and December 2008. Nowadays all this information provide us the chance of analysing the volcano and its evolution from different perspectives: a) The study and comparation of these three magnetic anomaly pictures of Deception island's inner bay (1988, 1999 and 2008). b) The study of its offshore magnetic anomalies. In this communication we will present and discuss all these results.
[en] Highlights: • AI as a support system for radiology is welcomed by students and radiologists. • Medical students see AI as a potential threat to diagnostic radiology. • Better education about this supposed fear of AI seems to be necessary. • Radiologists fear other disciplines in terms of “turf losses”. - Abstract: PurposeTo evaluate the opinion and assessment of radiologists, surgeons and medical students on a number of important topics regarding the future of radiology, such as artificial intelligence (AI), turf battles, teleradiology and 3D-printing.
[en] Complete text of publication follows. The National Geophysical Data Center (NGDC) and the co-located World Data Centers for Solar Terrestrial Physics (STP, Boulder) and Geophysics and Marine Geology (GMG) steward the data and information describing the geomagnetic environment from the surface of the sun to the core of the Earth. We accomplish this task through the interactions with geomagnetic data providers contributing magnetic observatory, variation, repeat station, airborne, ship track, and satellite data. In turn, these data are made available, as permitted, to magnetic field modelers for navigation charting and to the scientific research community. The WDC on-line archives include the annual, daily and hourly magnetic averages (means) from numerous geomagnetic stations covering a period from 1813 to the present, historical survey reports, and thousands of marine and airborne trackline surveys. Additional geomagnetic means are contained in data books stored in our climate controlled library which have not yet been converted to digital form. We provide an overview of the NGDC geomagnetic data holdings plus discuss various ongoing activities within the WDCs to facilitate user access to the data and to encourage the use of descriptive metadata by the data providers.
[en] Complete text of publication follows. While high-degree global models of the gravity field have been produced for decades, the break-through for magnetic models has only been achieved in the last few years. This is primarily due to three reasons: (1) Long wavelength control for a global model requires highly accurate satellite measurements at low orbital altitudes. These have only recently become available with the ongoing CHAMP mission. (2) Due to the secular change of the Earth's core field, marine and airborne magnetic surveys have unknown offsets which make it difficult to integrate 60 years of surveys into a common global field model. (3) The geopotential can conveniently be inferred from measurements of the gravity acceleration by direct integration. In contrast, the magnetic potential is not completely determined by measurements of the anomaly of the total intensity, and it has to be estimated in an iterative scheme. Here, we present our modeling approach starting with the determination of the long-wavelength lithospheric field from CHAMP data then merging the marine and aeromagnetic data into the EMAG2 global magnetic anomaly grid which then provides the basis for the estimation of the NGDC-720 model (http://geomag.org).
[en] Complete text of publication follows. During the last years, the geographical coverage of magnetic fields improved thanks to the release of old and new data acquired from the Earth's surface to the satellite altitudes. Concerted international efforts to compile and publish these data in a digital format, like the World Digital Magnetic Anomaly Map (WDMAM) project, represented a key motivation for also improving our methods for interpreting and modelling marine, airborne and satellite data. Thus, these unprecedented high spatial resolution data also challenged our ability 1) to extract accurately the contribution of the lithospheric field from the total measurements, 2) to represent the data with potential field modelling technique capable of merging locally all kinds of data, 3) and to interpret these models in terms of sources distribution and depth, heat flow, etc... I will first briefly review recent advances made towards improving the marine and aeromagnetic compilations at the worldwide scale. Then, I will focus on the other end of the lithospheric magnetic field spectrum and discuss the consistency of various recent satellite-based lithospheric field models. This will allow me to illustrate the ambiguities and compatibility issues that remain to be addressed before we can successfully merge near surface and satellite data. Then, I will report on different studies carried out to interpret lithospheric magnetic field models in terms of tectonic, and discuss some original methods employed to estimate local and average properties of the Earth's magnetic crust.
[en] This paper introduces and describes the data cubes from GHIGLS, deep Green Bank Telescope (GBT) surveys of the 21 cm line emission of H i in 37 targeted fields at intermediate Galactic latitude.
[en] Complete text of publication follows. A global marine magnetic data set was created by Quesnel et al. (2009). The GEODAS DVD Version 5.0.10, which is available from the U. S. National Geophysical Data Center, was used as the data source of this data set. Magnetic anomalies were recalculated using a comprehensive main and external field model CM4 (Sabaka et al., 2004), then were cleaned by careful check and removal of spurious data, and finally a line leveling method was applied to reduce data misfits among various cruises. The data set consists of about 20 million records collected by about 2400 cruises from 1953 to 2003. Some more marine magnetic data were added to the GEODAS in 2008. They were collected by about 180 survey cruises mainly of Australia, New Zealand and Japan. Additionally, we also obtained marine magnetic data near the Spanish coast. There are about 3 million records in these new data. We recalculated magnetic anomalies for the new records and cleaned them in the same way as the old data set. As for the line leveling, we modified the method slightly. When we created the old data set, we treated all the cruises equally in the line leveling method. Although the method was satisfactory, in order to further reduce the RMS crossover difference (COD) of the whole data set, it is particularly important to reduce the CODs of cruises with large RMS CODs. Approximately 60 cruises have RMS CODs > 200 nT, while about 140 cruises have RMS CODs > 150 nT. We first tried to minimize the CODs of these cruises, either by adjusting data to reduce the data offsets with the other cruise data or by removing data near the points with large CODs. Then, we applied the line leveling method to all the cruises. We will show more details on the revised data set and the results of line leveling.