Visible and near-infrared multispectral analysis of rocks at Meridiani Planum, Mars, by the Mars Exploration Rover Opportunity

Multispectral measurements in the visible and near infrared of rocks at Meridiani Planum by the Mars Exploration Rover Opportunity's Pancam are described. The Pancam multispectral data show that the outcrops of the Burns formation consist of two main spectral units which in stretched 673, 535, 432 nm color composites appear buff- and purple-colored. These units are referred to as the HFS and LFS spectral units based on higher and lower values of 482 to 535 nm slope. Spectral characteristics are consistent with the LFS outcrop consisting of less oxidized, and the HFS outcrop consisting of more oxidized, iron-bearing minerals. The LFS surfaces are not as common and appear, primarily, at the distal ends of outcrop layers and on steep, more massive surfaces, locations that are subject to greater eolian erosion. Consequently, the HFS surfaces are interpreted as a weathering rind. Further inherent spectral differences between layers and between different outcrop map units, both untouched and patches abraded by the rover's Rock Abrasion Tool, are also described. Comparisons of the spectral parameters of the Meridiani outcrop with a set of laboratory reflectance measurements of Fe^(3+)–bearing minerals show that the field of outcrop measurements plots near the fields of hematite, ferrihydrite, poorly crystalline goethite, and schwertmannite. Rind and fracture fill materials, observed intermittently at outcrop exposures, are intermediate in their spectral character between both the HFS and LFS spectral classes and other, less oxidized, surface materials (basaltic sands, spherules, and cobbles)

Exploration of Victoria Crater by the Mars Rover Opportunity

The Mars rover Opportunity has explored Victoria crater, a ~750-meter eroded impact crater formed in sulfate-rich sedimentary rocks. Impact-related stratigraphy is preserved in the crater walls, and meteoritic debris is present near the crater rim. The size of hematite-rich concretions decreases up-section, documenting variation in the intensity of groundwater processes. Layering in the crater walls preserves evidence of ancient wind-blown dunes. Compositional variations with depth mimic those ~6 kilometers to the north and demonstrate that water-induced alteration at Meridiani Planum was regional in scope

The astrobiology primer: An outline of general knowledge - Version 1, 2006

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Exploration of Victoria Crater by the Mars Rover Opportunity

The Mars rover Opportunity has explored Victoria crater, a ~750-meter eroded impact crater formed in sulfate-rich sedimentary rocks. Impact-related stratigraphy is preserved in the crater walls, and meteoritic debris is present near the crater rim. The size of hematite-rich concretions decreases up-section, documenting variation in the intensity of groundwater processes. Layering in the crater walls preserves evidence of ancient wind-blown dunes. Compositional variations with depth mimic those ~6 kilometers to the north and demonstrate that water-induced alteration at Meridiani Planum was regional in scope.Organismic and Evolutionary Biolog

Hematite Spherules at Meridiani: Results from MI, Mini-TES, and Pancam

We report on observations of hematite-bearing spherules at Meridiani Planum made using the Microscopic Imager (MI), Mini-Thermal Emission Spectrometer (Mini-TES), and Panoramic Camera (Pancam) instruments on the Mars Exploration Rover Opportunity. Spherules were observed on soil surfaces and in outcrop rocks, both on undisturbed surfaces and in abraded surfaces ground using the Rock Abrasion Tool (RAT). Spherule size and shape change little along the 850 m eastward traverse from Eagle Crater to Endurance Crater, but spherules decrease and then slightly increase in size along the 6 km traverse from Endurance south to Victoria Crater. Local populations range from submillimeters to several millimeters in diameter. An additional small diameter (100 micro m) size population is possible. An increase in irregular shapes is found near Victoria Crater. This, combined with the size decrease south of Endurance, suggests either a changing depositional environment, or variation in the duration and timing of diagenetic events. The dominant smaller size population observed early in the mission in aeolian areas and ripple crests is observed as the primary size population in abraded outcrop farther south. This suggests that successively younger beds are exposed at the surface along the southward traverse. Stratigraphically higher units removed by erosion could be recorded by the present surface lag deposit. Coordinated systematic observations are used to determine optical and infrared hematite indices of the surface soils in Pancam and Mini-TES. In spite of the systematic variation seen in MI, both Pancam and Mini-TES indices are highly variable based on the local surface, and neither show systematic trends south of Endurance. The lack of a 390 cm^(-1) feature in Mini-TES spectra suggests concentric or radial interior structure within the spherules at scales too fine for MI to observe. Mini-TES does not detect any silicate component in the spherules. A bound water component in soils or in exchange with the atmosphere is observed. These spherules have been previously interpreted as concretions formed within what were once water-saturated, diagenetically altered "dirty evaporate'' sandstone sediments. Our observations support this interpretation; however, no single terrestrial analog provides a model that can account for all attributes of the spherules on Mars.Organismic and Evolutionary Biolog

Two Years at Meridiani Planum: Results from the Opportunity Rover

The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling ∼8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict “hopper crystals” that might reflect the formation of halite, thick weathering rinds on rock surfaces, resistant fracture fills, and networks of polygonal fractures likely caused by dehydration of sulfate salts. Chemical variations with depth show that the siliciclastic fraction of outcrop rock has undergone substantial chemical alteration from a precursor basaltic composition. Observations from microscopic to orbital scales indicate that ancient Meridiani once had abundant acidic groundwater, arid and oxidizing surface conditions, and occasional liquid flow on the surface

Nursing’s role in tuberculosis control: a discussion from the perspective of equity El rol de la enfermería em el control de la tuberculosis: uma discusión desde la perspectiva de la equidad O papel da enfermagem no controle da tuberculose: uma discussão sob a perspectiva da equidade

This paper aims to analyze nurses’ role in tuberculosis control from the perspective of equity in the context of Latin American countries. Tuberculosis is frequently associated with poverty, but many other determinants play an important role in its prevalence. Latin American countries fight against the presence of this illness and nursing professionals play a protagonist role in TB control, proposing comprehensive interventions in different spheres - individuals, families and society. The focus of nursing intervention ranges from public policy proposals, based on epidemiological research, through the establishment of multi-sector programs, to direct care and client education at the operative level. Different professional nursing institutions can play a decisive role in this problem’ integral approach, both in national and international scopes. This requires the establishment of educative, social, technical and politically integrated support networks.<br>El objetivo del presente artículo es analizar el rol de la enfermera en el control de la tuberculosis desde la perspectiva de la equidad, en el ámbito de los países latinoamericanos. La tuberculosis está asociada frecuentemente con la pobreza, pero muchos otros determinantes juegan un rol importante en su prevalencia. Los países latinoamericanos luchan contra la presencia de esta enfermedad y la enfermería juega un rol protagónico en el control de este problema planteando intervenciones integrales en diferentes esferas del individuo, de la familia y de la sociedad. La intervención de enfermería se extiende desde el planteamiento de políticas públicas, basadas en estudios de base epidemiológica, mediante la implementación de programas multisectoriales, hasta la atención directa y la educación de los usuarios en el plan operativo. Las diferentes instituciones profesionales de enfermería pueden desarrollar un papel decisivo en el abordaje integral del problema, no sólo en el ámbito nacional sino también en el internacional, para esto se requiere establecer redes de apoyo con integración educativa, social, técnica y política.<br>O objetivo do presente artigo foi analisar o papel do profissional da enfermagem no controle da tuberculose, sob a perspectiva da equidade, no âmbito dos países da América Latina. A tuberculose está frequentemente associada à pobreza, mas muitos outros determinantes contribuem de modo importante para sua prevalência. Os países sul-americanos lutam contra essa enfermidade e a enfermagem possui papel de protagonista no controle desse problema, reivindicando intervenções integrais, voltadas para as diferentes esferas: individual, familiar e social. A intervenção da enfermagem é enfocada desde o desenho das políticas públicas, com base em estudos epidemiológicos, mediante a implementação de programas multissetoriais, até a assistência direta e a educação dos usuários no plano operativo. Diferentes instituições profissionais da enfermagem podem desenvolver atuação decisiva para a abordagem integral do problema, no âmbito nacional e internacional, devendo, para isso, estabelecer redes de apoio integradas às dimensões educativas, social, técnica e política

Stratigraphy and sedimentology of a dry to wet eolian depositional system, Burns formation, Meridiani Planum, Mars

Outcrop exposures of sedimentary rocks at the Opportunity landing site (Meridiani Planum) form a set of genetically related strata defined here informally as the Burns formation. This formation call be subdivided into lower, middle, and upper units which, respectively, represent eolian dune, eolian sand sheer, and mixed eolian sand sheet and interdune facies associations. Collectively, these three units are at least 7 m thick and define a "wetting-upward" Succession which records a progressive increase in the influence of groundwater and, ultimately, surface water in controlling primary depositional processes.The Burns lower unit is interpreted as a dry dune field (though grain composition indicates an evaporitic source), whose preserved record of large-scale cross-bedded sandstones indicates either superimposed bedforms of variable size or reactivation of lee-side slip faces by episodic (possibly seasonal) changes in wind direction. The boundary between the lower and middle units is a significant eolian deflation surface. This surface is interpreted to record eolian erosion down to the capillary fringe of the water table, where increased resistance to wind-induced erosion was promoted by increased sediment cohesiveness in the capillary fringe. The overlying Burns middle unit is characterized by fine-scale planar-laminated to low-angle-stratified sandstones. These sandstones accumulated during lateral migration of eolian impact ripples over the flat to gently undulating sand sheet surface. In terrestrial settings, sand sheets may form ail intermediate environment between dune fields and interdune or playa surfaces. The contact between the middle and upper units of the Burns formation is interpreted as a diagenetic front, where recrystallization in the phreatic or capillary zones may have occurred, The upper unit of the Burns formation contains a mixture of sand sheet facies and interdune facies. Interdune facies include wavy bedding, irregular lamination with convolute bedding and possible small tepee or salt-ridge structures, and cm-scale festoon cross-lamination indicative of shallow subaqueous flows marked by current velocities of a few tens of cm/s. Most likely, these currents were gravity-driven, possibly unchannelized flows resulting from the flooding of interdune/playa surfaces. However, evidence for lacustrine sedimentation, including mudstones or in situ bottom-growth evaporites, has not been observed so far at Eagle and Endurance craters.Mineralogical and elemental data indicate that the eolian sandstones of the lower and middle units, as well as the subaqueous and eolian deposits of the Burns upper unit, were derived from an evaporitic source. This indirectly points to a temporally equivalent playa where lacustrine evaporites or ground-water-generated efflorescent crusts were deflated to provide a source of sand-sized particles that were entrained to form eolian dunes and sand sheets. This process is responsible for the development of sulfate eolianites at White Sands, New Mexico, and could have provided a prolific flux of sulfate sediment at Meridiani. Though evidence for surface water in the Burns formation is mostly limited to the upper unit, the associated sulfate eolianites provide strong evidence for the critical role of groundwater in controlling sediment production and stratigraphic architecture throughout the formation. (c) 2005 Elsevier B.V. All rights reserved.</p

Two years at Meridiani Planum: Results from the opportunity rover

The Mars Exploration Rover Opportunity has spent more than 2 years exploring Meridiani Planum, traveling b <8 kilometers and detecting features that reveal ancient environmental conditions. These include well-developed festoon (trough) cross-lamination formed in flowing liquid water, strata with smaller and more abundant hematite-rich concretions than those seen previously, possible relict "hopper crystals" that might reflect the formation of halite, thick weathering rinds on rock surfaces, resistant fracture fills, and networks of polygonal fractures likely caused by dehydration of sulfate salts. Chemical variations with depth show that the siliciclastic fraction of outcrop rock has undergone substantial chemical alteration from a precursor basaltic composition. Observations from microscopic to orbital scales indicate that ancient Meridiani once had abundant acidic groundwater, arid and oxidizing surface conditions, and occasional liquid flow on the surface