118 research outputs found

    Subspecialty preferences among Neurologists of the future.

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    INTRODUCTION: In the era of neurological subspecialization, most neurologists will have a field of specialist interest. The aim of this cross-sectional multi-national study was to identify the key areas of interest among trainees or junior specialists, assess the potential influence of an interest in research, and consider the results in light of population needs. METHODS: A total of 300 residents and junior neurologists who received a bursary to attend the European Academy of Neurology conference were invited to participate in this study. Demographic and work-related characteristics, as well as main subspecialty of choice were examined via an anonymous electronic questionnaire. Participants holding a higher degree (PhD/MD) or working in research posts were considered research oriented. RESULTS: In total, 191 Neurologists in training or junior specialists responded (response rate 63.7%). Full data were available for 187 participants (59.4% females). The study sample had a mean age of 30.5±3.4 years (range 25 - 45). The most popular subspecialty was movement disorders (18.2%), followed by multiple sclerosis (11.2%) and epilepsy (10.2%). This did not differ significantly between the participants who were or were not research-oriented. CONCLUSIONS: There is a potential mismatch between the interests of trainees, and the future needs of the populations they serve, which it is important to identify for workforce planning

    Moessbauer Mineralogy on the Moon: The Lunar Regolith

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    A first-order requirement for spacecraft missions that land on solid planetary objects is instrumentation for mineralogical analyses. For purposes of providing diagnostic information about naturally-occurring materials, the element iron is particularly important because it is abundant and multivalent. Knowledge of the oxidation state of iron and its distribution among iron-bearing mineralogies tightly constrains the types of materials present and provides information about formation and modification (weathering) processes. Because Moessbauer spectroscopy is sensitive to both the valence of iron and its local chemical environment, the technique is unique in providing information about both the relative abundance of iron-bearing phases and oxidation state of the iron. The Moessbauer mineralogy of lunar regolith samples (primarily soils from the Apollo 16 and 17 missions to the Moon) were measured in the laboratory to demonstrate the strength of the technique for in situ mineralogical exploration of the Moon. The regolith samples were modeled as mixtures of five iron-bearing phases: olivine, pyroxene, glass, ilmenite, and metal. Based on differences in relative proportions of iron associated with these phases, volcanic ash regolith can be distinguished from impact-derived regolith, impact-derived soils of different geologic affinity (e.g., highlands, maria) can be distinguished on the basis of their constituent minerals, and soil maturity can be estimated. The total resonant absorption area of the Moessbauer spectrum can be used to estimate total FeO concentrations

    Chemostratigraphy and Fe Mineralogy of the Victoria Crater Duck Bay Section: Opportunity APXS and Moessbauer Results

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    Meridiani Planum is a vast plain of approximately horizontally bedded sedimentary rocks composed of mixed and reworked basaltic and evaporitic sands containing secondary, diagenetic minerals [e.g., 1-5]. Because bedding planes are subparallel to topography, investigation of contiguous stratigraphy requires examining exposures in impact craters. Early in the mission (sols 130-317), Opportunity was commanded to do detailed study of exposed outcrops in Endurance crater, including the contiguous Karatepe section at the point of ingress. Just over 1000 sols later and roughly 7 km to the south, the rover is being commanded to do a similar study of the Duck Bay section of Victoria crater. Here we report on the preliminary results from the Alpha Particle X-ray Spectrometer (APXS) and Moessbauer instruments

    Marquette Island: A Distinct Mafic Lithology Discovered by Opportunity

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    While rolling over the Meridiani Planum sedimentary terrane, the rover Opportunity has occasionally discovered large, > 10 cm erratics. Most of these have proven to be meteorites [1], but one - Bounce Rock - is a martian basaltic rock similar in composition to the meteorite EETA79001 lithology B [2]. Presently, Opportunity is intensively investigating an --30 cm tall rock named Marquette Island that may be a distinct type of martian mafic lithology. We report the results of its continuing investigation using the Microscopic Imager (MI); Mossbauer Spectrometer (MB) and Alpha Particle X-ray Spectrometer (APXS). A companion abstract discusses the results of Panoramic Camera (Pancam) imaging of the rock [3]

    Santorini, Another Meteorite on Mars and Third of a Kind

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    The Mars Exploration Rover (MER) Opportunity has been studying Meridiani Planum for five years. On sol 1634 of its mission, Opportunity left Victoria crater after investigating it for approximately 682 sols [1] and is now on a journey towards Endeavour, a 24 km diameter crater about 12 km southeast of Victoria. A priority along the way is the investigation of cobbles, which in the jargon of the MER science team denotes any loose rock fragment larger than a couple of centimeters. Cobbles investigated thus far are of diverse origin [2] and provide the only means to investigate material other than the ubiquitous sulfate-rich outcrop, basaltic sand or hematiterich spherules dubbed blueberries. Some of these cobbles are meteorites [3]. Meteorites on Mars are not just a curiosity that make Mars a more Earth-like planet. Metallic iron in meteorites, for example, may be used as a more sensitive tracer for volatile surface interactions compared to igneous minerals [4]. Between sols 1713 and 1749, including the period of Mars solar conjunction, Opportunity investigated a cobble informally named Santorini. Its chemical and mineralogical composition is very similar to Barberton and Santa Catarina, two cobbles that were identified as meteorites and which are probably related to each other [3]. Santorini was investigated with the rover s Panoramic Camera (Pancam), Microscopic Imager (MI), Alpha-Particle X-ray Spectrometer (APXS) and Moessbauer (MB) spectrometer. The miniature Thermal Emission Spectrometer (mini-TES) was not operational at the time. The Rock Abrasion Tool (RAT) could not be used to brush off potential dust coatings because of unfavorable geometry

    Visible and near-infrared multispectral analysis of geochemically measured rock fragments at the Opportunity landing site in Meridiani Planum

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    We have used visible and near‐infrared Panoramic Camera (Pancam) spectral data acquired by the Opportunity rover to analyze 15 rock fragments at the Meridiani Planum landing site. These spectral results were then compared to geochemistry measurements made by the in situ instruments Mössbauer (MB) and Alpha Particle X‐ray Spectrometer (APXS) to determine the feasibility of mineralogic characterization from Pancam data. Our results suggest that dust and alteration rinds coat many rock fragments, which limits our ability to adequately measure the mineralogy of some rocks from Pancam spectra relative to the different field of view and penetration depths of MB and APXS. Viewing and lighting geometry, along with sampling size, also complicate the spectral characterization of the rocks. Rock fragments with the same geochemistry of sulfate‐rich outcrops have similar spectra, although the sulfate‐rich composition cannot be ascertained based upon Pancam spectra alone. FeNi meteorites have spectral characteristics, particularly ferric oxide coatings, that generally differentiate them from other rocks at the landing site. Stony meteorites and impact fragments with unknown compositions have a diverse range of spectral properties and are not well constrained nor diagnostic in Pancam data. Bounce Rock, with its unique basalt composition, is easily differentiated in the Pancam data from all other rock types at Meridiani Planum. Our Pancam analyses of small pebbles adjacent to these 15 rock fragments suggests that other rock types may exist at the landing site but have not yet been geochemically measured

    Mars Exploration Rover APXS Results from Matijevic Hill

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    Correlation analysis of APXS results on the eastern slope rocks indicate that the Matijevic Hill rocks are overall compositionally distinct from the Shoemaker Formation rocks [6]. Compared to the Shoemaker impactites, Matijevic Hill rocks are higher in Al, Si, and Ni, and lower in Ti, Fe, and Zn. No significant variation is evident in the APXS analyses that indicate the presence of a smectite or other phyllosilicate, as opposed to basaltic rocks. However, APXS data cannot in themselves rule out phyllosilicates. If indeed this material contains smectite, as seen from orbit, it implies that the rock has been isochemically altered to create the phyllosilicate content. The Cl content of the Cape York rocks is relatively high, and whereas the S/Cl ratio in the Burns Formation is 4x higher than in soil, in the Cape York rocks it is lower than in soil. These trends indicate that the alteration processes and types of aqueous salt loads were different between Cape York and Meridiani. In addition, significant deviations from the Martian Mn/Fe ratio are observed in Whitewater Lake coatings and the altered Grasford/Deadwood rocks (Fig. 3). These variations indicate that the redox/pH conditions during alteration of the Shoemaker Formation rocks and the Matijevic Hill rocks were similar, but that the Deadwood/Grasberg unit may have undergone alteration under different conditions, possibly at a later time. The Matijevic Hill outcrops appear to share a common genetic origin. It is not yet clear whether both the Shoemaker impactites and Matijevic Hill rocks are related to the formation of Endeavour Crater, or whether the Matijevic Hill suite represents a prior episode of Martian impact or volcanism. Opportunity continues to investigate both hypotheses

    Mauna Kea, Hawaii as an Analogue Site for Future Planetary Resource Exploration: Results from the 2010 ILSO-ISRU Field-Testing Campaign

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    Within the framework of the International Lunar Surface Operation - In-Situ Resource Utilization Analogue Test held on January 27 - February 11, 2010 on the Mauna Kea volcano in Hawaii, a number of scientific instrument teams collaborated to characterize the field site and test instrument capabilities outside laboratory environments. In this paper, we provide a geological setting for this new field-test site, a description of the instruments that were tested during the 2010 ILSO-ISRU field campaign, and a short discussion for each instrument about the validity and use of the results obtained during the test. These results will form a catalogue that may serve as reference for future test campaigns. In this paper we provide a description and regional geological setting for a new field analogue test site for lunar resource exploration, and discuss results obtained from the 2010 ILSO-ISRU field campaign as a reference for future field-testing at this site. The following instruments were tested: a multispectral microscopic imager, MMI, a Mossbauer spectrometer, an evolved gas analyzer, VAPoR, and an oxygen and volatile extractor called RESOLVE. Preliminary results show that the sediments change from dry, organic-poor, poorly-sorted volcaniclastic sand on the surface, containing basalt, iron oxides and clays, to more water- and organic-rich, fine grained, well-sorted volcaniclastic sand, primarily consisting of iron oxides and depleted of basalt and clays. Furthermore, drilling experiments showed a very close correlation between drilling on the Moon and drilling at the test site. The ILSO-ISRU test site was an ideal location for testing strategies for in situ resource exploration at the lunar or martian surface
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