| 1. |
- Ming, D.W., et al.
(författare)
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Volatile and organic compositions of sedimentary rocks in Yellowknife Bay, Gale Crater, Mars
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 343:6169
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Tidskriftsartikel (refereegranskat)abstract
- H2O, CO2, SO2, O2, H2, H2S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. H2O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, and amorphous materials. Thermal decomposition of carbonates and combustion of organic materials are candidate sources for the CO2. Concurrent evolution of O2 and chlorinated hydrocarbons suggests the presence of oxychlorine phase(s). Sulfides are likely sources for sulfur-bearing species. Higher abundances of chlorinated hydrocarbons in the mudstone compared with Rocknest windblown materials previously analyzed by Curiosity suggest that indigenous martian or meteoritic organic carbon sources may be preserved in the mudstone; however, the carbon source for the chlorinated hydrocarbons is not definitively of martian origin.
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| 2. |
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| 3. |
- McLennan, S.M., et al.
(författare)
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Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 343:6169
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Tidskriftsartikel (refereegranskat)abstract
- Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine–rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.
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| 4. |
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| 5. |
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| 6. |
- Vaniman, D.T., et al.
(författare)
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Mineralogy of a mudstone at Yellowknife Bay, Gale Crater, Mars
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 343:6169
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Tidskriftsartikel (refereegranskat)abstract
- Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, iron sulfides, amorphous material, and trioctahedral smectites. The John Klein smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. The Cumberland smectite has basal spacing at both ~13.2 and ~10 angstroms. The larger spacing suggests a partially chloritized interlayer or interlayer magnesium or calcium facilitating H2O retention. Basaltic minerals in the mudstone are similar to those in nearby eolian deposits. However, the mudstone has far less Fe-forsterite, possibly lost with formation of smectite plus magnetite. Late Noachian/Early Hesperian or younger age indicates that clay mineral formation on Mars extended beyond Noachian time.
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| 7. |
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| 8. |
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| 9. |
- Ross, I L, et al.
(författare)
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Increased Cardiovascular Risk in South African Patients with Addison's Disease.
- 2013
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Ingår i: Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et métabolisme. - : Georg Thieme Verlag KG. - 1439-4286. ; 45:12, s. 905-10
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Tidskriftsartikel (refereegranskat)abstract
- Patients with Addison's disease (AD) are believed to be at risk for cardiovascular disease (CVD). South Africa, like the rest of the developing world is experiencing an increase in CVD and patients with AD may be at double the risk of their peers. We wished to explore AD patients' CVD risk factors. A cross-sectional nationwide study in South Africa of patients with AD was conducted. A cohort of 147 patients with AD and 147 healthy control subjects were matched by age, gender, ethnicity, and BMI as far as was possible. Lipoproteins and highly-sensitive C-reactive-protein (hs-CRP) were the main outcome measures. AD patients had significantly higher triglycerides; (p=0.001), lower HDLC (p<0.001), higher hs-CRP (p<0.001), and more small dense LDL; (p=0.002) than controls. Nonesterified fatty acids were lower in patients (p<0.001). Approximately 65% [95% confidence interval (CI 55.6-72.4%)] had hypercholesterolaemia, 75% (CI 64.8-81.2%) had low HDLC, and 75% (CI 68.0-84.1%) had a higher LDLC. Thirteen percent of AD patients had diabetes mellitus, but none of the risk factors differed from the nondiabetics. Only HDLC correlated positively with daily hydrocortisone dose (r=0.32; p=0.005). In conclusion dyslipidaemia is common in South African AD patients; CVD risk assessment and intervention are probably warranted in the management of these patients.
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