Over 8 years later, though, Opportunity would discover a completely different type of spherule at the Endeavour Crater that were likely older and not as iron-heavy as the original "blueberries" the rover found in its early days.
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" Nevertheless, Burt said, his team's impact spherule hypothesis "explains their spherical shape, their strict size maximum (caused by their suspension in a turbulent gas), their very wide and uniform distribution, and their unusual bluish, shiny appearance and mineralogy.
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In another 2005 paper authored by the same team, this one appearing in Nature, the scientists suggested that the pebbles were an unusual type of impact spherule, formed by the complex tumbling interactions between iron flakes and the sticky, acidic, and salty steam and dust clouds produced by major meteorite impacts on the iron-rich Red Planet.
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Immunity to coccidioidomycosis induced in mice by purified spherule, arthrospore, and mycelial vaccines.
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There, they develop into a thick- walled spherule filled with endospores that cause a pyogenic (pus-causing) inflammation.
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Acidic water rich in iron then dissolve the calcite leaving behind the iron rich (hematite) spherule. This leads to the conclusion that the blueberries may have formed early in Mars’s history when the atmosphere was more dense by the same process.
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Recent works, however, have found that impacts from this inner asteroid belt would be insufficient to explain the formation of ancient impact spherule beds and the lunar basins, and that the asteroid belt was probably not the source of the Late Heavy Bombardment.
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The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Underlying the thin soil layer, are flat-lying sedimentary rocks. These rocks are finely laminated, are rich in sulfur, and contain abundant sulfate salts.S. Squyres, et al.
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Malhmoodite is a creamy-white mineral with a silky luster. It exhibits a 3 on the Mohs hardness scale. The spherules of Malhmoodite are made up of thin, flat, radiating, optically homogeneous crystals and seem to form in a parallel extinction and positive elongation. The cores of the spherules appear to be loose material, making up about one-third to one-half of the radius of the spherule.
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However, the core seems to show higher amounts of Si than the rest of the spherule by using X-ray spectra. The fibers of the mineral are soft and the density could not be directly measured. It was instead calculated using the unit-cell content of four formula units and determined to be 2.877 g/cm3. In the crystal structure work of Malhmoodite, it was found that there was a common [Zr(PO4)2]2- layer.
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Researchers have also criticized the conclusions of various studies for incorrect age-dating of the sediments, contamination by modern carbon, inconsistent hypothesis that made it difficult to predict the type and size of bolide, lack of proper identification of lonsdaleite, confusing an extraterrestrial impact with other causes such as fire, and for inconsistent use of the carbon spherule "proxy". Naturally occurring lonsdaleite has also been identified in non-bolide diamond placer deposits in the Sakha Republic.
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The continuation of the bombardment is predicted to generate basin-forming impacts on the Earth and Chicxulub- sized craters on the Earth and Moon. Impact craters on the Moon and impact spherule beds found on the Earth dated to this period are consistent with these predictions. The E-belt model predicts a remnant population will remain on Hungaria-like orbits. The initial population of E-belt asteroids was calculated based on the population of potential basin-forming impactors remaining among the Hungaria asteroids.
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In December 2018, CCMV replication was fully reconstituted in Saccharomyces cerevisiae, a type of yeast. In this experiment, it was found that protein 1a was the only viral factor needed to induce invagination of the endoplasmic reticulum and begin the replication process. The 2a polymerase was found to be recruited by protein 1a after the formation of the replication spherule. One limitation was realized for the replication of CCMV in S. cerevisiae, and this was due to the lack of RNA-3 replication.
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At the base of the Rove Formation, between the Rove and the underlying Gunflint Iron Formation, there is a lateral layer of shocked quartz and feldspar grains found within accretionary lapilli, accreted grain clusters and spherule masses. These pieces of debris indicate that the layer contains hypervelocity impact ejecta. Zircon geochronologic data shows that this layer formed 1878 to 1836 million years ago; the Sudbury Impact event occurred . Because of the closeness in dating and the nearness of the crater, the Sudbury Impact event is the likely source for the ejecta; these are the oldest ejecta linked to a specific event on Earth.
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All classes possess a type of phagocytic amebocyte, which engulf invading particles and infected cells, aggregate or clot, and may be involved in cytotoxicity. These cells are usually larger and granular, and are suggested to be a main line of defense against potential pathogens. Depending on the class, echinoderms may have spherule cells (for cytotoxicity, inflammation, and anti-bacterial activity), vibratile cells (for coelomic fluid movement and clotting), and crystal cells (potential osmoregulatory cells in sea cucumbers),. The coelomocytes also secrete Anti-Microbial Peptides (AMPs) against bacteria, and have a set of lectins and complement proteins as part of an innate immune system that is still being characterized.
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Typically, key beds were created as the result of either instantaneous events or (geologically speaking) very short episodes of the widespread deposition of a specific types of sediment. As the result, key beds often can be used for both mapping and correlating sedimentary rocks and dating them. Volcanic ash beds (tonsteins and bentonite beds) and impact spherule beds, and specific megaturbidites are types of key beds created by instantaneous events. The widespread accumulation of distinctive sediments over a geologically short period of time have created key beds in the form of peat beds, coal beds, shell beds, marine bands, black shales in cyclothems, and oil shales.
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Crater counts using topographic data from the Lunar Reconnaissance Orbiter find an excess of small craters relative to large impact-basins when compared to the size distribution of the asteroid belt. However, if the E-belt was the product of collisions among a small number of large asteroids, it may have had a size distribution that differed from that of the asteroid belt with a larger fraction of small bodies. A recent work has found that the bombardment originating from the inner band of asteroids would yield only two lunar basins and would be insufficient to explain ancient impact spherule beds. It suggests instead that debris from a massive impact was the source, noting that this would better match the size distribution of impact craters.
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The JPL team found many fragmented blueberries and suggested the fracturing occurred after spherule formation. They believe the fracturing either be from meteoric impacts, or the “same process” that “fractured the outcrop.” However, the team note this would not explain the presence of the smallest hematite spherules detected. The smallest are close to perfectly spherical and therefore cannot be explained by fracturing or erosion. NASA’s JPL also found that blueberries uncovered by the Rock Abrasion Tool aboard Opportunity were about 4 mm (0.16 inches) semi-major axis length at Eagle Crater and Endurance crater, about 2.2mm (0.087 inches) at Vostok, and about 3.0 mm (0.12 inches) at Naturaliste (crater). Those found in “the plains” were smaller (1-2mm or 0.04-0.08 inches) than those of Eagle and Endurance craters.
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