Search results for "mars"

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

2010

[1] 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 Mossbauer (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 …

Bounce Rock-A shergottite-like basalt encountered at Meridiani Planum, Mars

2011

Additional co-authors: Thanasis ECONOMOU, Steven P. GOREVAN, Brian C. HAHN, Gostar KLINGELHOFER, Timothy J. McCOY, Harry Y. McSWEEN Jr, Douglas W. MING, Richard V. MORRIS, Daniel S. RODIONOV, Steven W. SQUYRES, Heinrich WANKE, Shawn P. WRIGHT, Michael B. WYATT, Albert S. YEN

Fe Mossbauer spectroscopy as a tool in astrobiology

2006

The element Fe and Fe-bearing minerals occur ubiquitously throughout the field of astrobiology. Cycling between the various oxidation states of Fe provides a source of energy available for life. Banded iron formations may record the rise of oxygenic photosynthesis. The distribution of Fe between Fe-bearing minerals and its oxidation states can help to characterize and understand ancient environments with respect to the suitability for life by constraining the primary rock type and the redox conditions under which it crystallized, the extent of alteration and weathering, the type of alteration and weathering products, and the processes and environmental conditions for alteration and weatheri…

Spectral, mineralogical, and geochemical variations across Home Plate, Gusev Crater, Mars indicate high and low temperature alteration

2009

Over the last ~3 years in Gusev Crater, Mars, the Spirit rover observed coherent variations in color, mineralogy, and geochemistry across Home Plate, an ~80 m-diameter outcrop of basaltic tephra. Observations of Home Plate from orbit and from the summit of Husband Hill reveal clear differences in visible/near-infrared (VNIR) colors between its eastern and western regions that are consistent with mineralogical compositions indicated by Mössbauer spectrometer (MB) and by Miniature Thermal Emission Spectrometer (Mini-TES). Pyroxene and magnetite dominate the east side, while olivine, nanophase Fe oxide (npOx) and glass are more abundant on the western side. Alpha Particle X-Ray Spectromet…

The Spirit Rover's Athena science investigation at Gusev Crater, Mars.

2004

The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. Gusev is hypothesized to be the site of a former lake, but no clear evidence for lacustrine sedimentation has been found to date. Instead, the dominant lithology is basalt, and the dominant geologic processes are impact events and eolian transport. Many rocks exhibit coatings and other characteristics that may be evidence for minor aqueous alteration. Any lacustrine sediments that may exist at this location within Gusev apparently have been buried by lavas that have undergone subsequent impact disruption.

Distribution patterns, floristic structure and habitat requirements of the alpine river plant community Stuckenietum amblyphyllae ass. nova (Potamete…

2012

This paper discusses the floristic structure, distribution and habitat requirements of a new aquatic syntaxon, <em>Stuckenietum a</em><em>m</em><em>b</em><em>l</em><em>y</em><em>p</em><em>h</em><em>ylla</em><em>e </em>ass. nova. Patches of the <em>Stuckenietum amblyphyllae </em>association occur in the Pamir Alai Mountains in Middle Asia (Tajikistan). The biotope of this community represent high mountain rivers and ponds at the bottom of glacial river valleys situ- ated at elevations between 1900 and 3800 m. Patches of the <em>Stuckenietum amblyphyllae </em>ass…

Distribution, floristic structure and habitat requirements of the riparian forest community Populetum talassicae ass. nova in the Central Pamir-Alai …

2013

This paper discusses the floristic structure, distribution and habitat requirements of a new forest syntaxon, <em>Populetum talassicae </em>ass. nova. The potential range of the <em>Populetum talassicae </em>association comprises the central Pamir-Alai and Tian-Shan Mountains in Middle Asia. The biotope of this community comprises high mountain river valleys and shore zones of mountain lakes situ- ated at elevations between 2200 and 2750 m. Phytocoenoses of the <em>Populetum talassicae </em>association are characterized by a clear predominance in the tree layer of a characteristic species of the association ‒ <em>Populus talassica</em>. Shrubs…

Avian brood parasitism in a Mediterranean region. hosts and habitat preferences of Common Cuckoos Cuculus canorus

2009

Capsule Cuckoos in Italy support the ‘host preference’ hypothesis. Aims To identify the species parasitized in a Mediterranean area, in Italy; to quantify the frequency of parasitism on each host species; and to determine whether some species and/or habitat types are parasitized more than expected from a homogeneous distribution. Methods Nest records dating from 1865 were compiled from literature, nest card programmes, and personal communication with ornithologists working in the region. Comparisons of parasitism frequencies were made among and within habitats for all cuckoo hosts. Results The most frequently parasitized hosts were Great Reed Warbler, European Robin, Marsh Warbler, Redstart…

Influencia del género sobre el proceso de desarrollo del síndrome de quemarse por el trabajo (Burnout) en profesionales de enfermería

2002

The purpose of this study was to analyze if gender differences establish significant differences in the levels and process of the burnout syndrome. Results indicate that the men (N = 72) perceive significantly more despersonalization that t he women (N = 258). In the sample of men p ersonal accomplishment was not a significant antecedent of despersonalization, while in the sample of women emotional exhaustion was not a significant antecedent of inclination to be absent. As a c onclusion it i s recommended that managers of personnel i n h ealth sector should take into consideration the gender differences in the intervention on the burnout syndrome.

Valencia.

Relleu representat per cotes d'altitud. - Marges dividits per quadrícula alfanumèrica. - Data aproximada