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- Cousin, A., et al.
(författare)
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Compositions of coarse and fine particles in martian soils at gale: A window into the production of soils
- 2015
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 249, s. 22-42
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Tidskriftsartikel (refereegranskat)abstract
- The ChemCam instrument onboard the Curiosity rover provides for the first time an opportunity to study martian soils at a sub-millimeter resolution. In this work, we analyzed 24 soil targets probed by ChemCam during the first 250 sols on Mars. Using the depth profile capability of the ChemCam LIBS (Laser-Induced Breakdown Spectroscopy) technique, we found that 45% of the soils contained coarse grains (>500 μm). Three distinct clusters have been detected: Cluster 1 shows a low SiO2 content; Cluster 2 corresponds to coarse grains with a felsic composition, whereas Cluster 3 presents a typical basaltic composition. Coarse grains from Cluster 2 have been mostly observed exposed in the vicinity of the landing site, whereas coarse grains from Clusters 1 and 3 have been detected mostly buried, and were found all along the rover traverse. The possible origin of these coarse grains was investigated. Felsic (Cluster 2) coarse grains have the same origin as the felsic rocks encountered near the landing site, whereas the origin of the coarse grains from Clusters 1 and 3 seems to be more global. Fine-grained soils (particle size < laser beam diameter which is between 300 and 500 μm) show a homogeneous composition all along the traverse, different from the composition of the rocks encountered at Gale. Although they contain a certain amount of hydrated amorphous component depleted in SiO2, possibly present as a surface coating, their overall chemical homogeneity and their close-to-basaltic composition suggest limited, or isochemical alteration, and a limited interaction with liquid water. Fine particles and coarse grains from Cluster 1 have a similar composition, and the former could derive from weathering of the latter. Overall martian soils have a bulk composition between that of fine particles and coarse grains. This work shows that the ChemCam instrument provides a means to study the variability of soil composition at a scale not achievable by bulk chemical analyses.
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- Bidartondo, Martin, et al.
(författare)
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Preserving accuracy in GenBank
- 2008
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Ingår i: Science. ; 319:5870
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Stålberg, Peter, et al.
(författare)
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Minimally invasive parathyroidectomy and thyroidectomy : current concepts
- 2007
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Ingår i: The Surgeon. - 1479-666X. ; 5:5, s. 301-308
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Forskningsöversikt (refereegranskat)abstract
- The introduction of various techniques for minimally invasive parathyroidectomy (MIP) and minimally invasive thyroid surgery (MITS) have changed both the conceptual and surgical approach to parathyroid disease and single thyroid nodules. Perceived advantages of minimally invasive surgery both among clinicians and patients, have been a major factor in the development of new surgical techniques, as well as refinement in preoperative localisation techniques. Worldwide the number of patients being operated on using MIP or MITS has steadily increased. At some major centres as many as 70% of patients with primary hyperparathyroidism have their operation using MIP. In this review we discuss the underlying pathology and investigative procedures, as well as the various techniques used, all of which now have excellent outcomes at a minimal cost and with minimal complications. Based on our own experience we recommend the use of a lateral focused mini-incision for both MIP and MIT since they both use standard equipment and standard dissection techniques familiar to all experienced endocrine surgeons.
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