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High‐resolution 2D and 3D data remotely acquired by SuperCam's Remote Micro‐Imager and Mastcam‐Z aboard the Perseverance rover enabled us to characterize the stratigraphic architecture and sedimentary record of the Kodiak butte, an isolated remnant of the western delta fan of Jezero crater. Using these data, we build up on previous interpretations of the butte interpreted as a prograding Gilbert‐type deltaic series. We characterize three individual stratigraphic Units 0 to 2 on the eastern and northern faces of the butte. Each Unit displays the same vertical succession of prodeltaic/lacustrine bottomsets, delta slope toesets and foresets, and fluvially influenced topsets of a deltaic plain with a braided river pattern, shown by 11 individual sedimentary facies. We infer that these individual Units record the formation of three distinct deltaic mouth bars successively across time and space. For the first time on another planet than Earth, we are able to construct a precise sequence stratigraphic framework to highlight lake‐level fluctuations at the time the Kodiak butte was emplaced, during the latest stages of deltaic activity. We identify four hydrogeological cycles indicated by alternating rises and falls of the lake‐level on the order of 5–10 m. These were most probably linked to climatic events and variations controlling lake water inputs in probable relation to an astronomical control. Plain Language Summary: Kodiak butte is an isolated remnant of the main western sedimentary fan of Jezero crater. It displays the characteristic structures of a Gilbert‐type delta, a structure that shows deposition of fluvial material into a standing body of water, here interpreted to be a lake within Jezero crater. 11 individual sedimentary facies (textures, grain‐sizes, and structures) of the rocks exposed at Kodiak suggest that the depositional environments ranged from the fluvial plain to a steep subaqueous slope and into the bottom of the shallow Jezero lake. Our observations further show that Kodiak butte is organized into three distinct stratigraphic Units (0–2), each displaying the same vertical succession of bottomsets, toesets, foresets and topsets. This architecture is interpreted as reflecting three distinct deltaic packages, formed consecutively and not at the same time. Using these facies and stratigraphic architecture data, we are able for the first time on another planet than Earth, to precisely construct a sequence stratigraphic framework for the formation of Kodiak. This framework illustrates with unprecedented precision successive episodes of rises and falls of the paleo‐lake‐level (in the order of 5–10 m) involved in the construction and evolution of the western Jezero delta. Key Points: New observations on the Kodiak delta remnant were carried out to characterize its detailed facies and stratigraphic architectureThree deltaic mouth bars are identified showing 4D succession of depositional settings ranging from deltaic plain to slope to shallow lakeThe first ever sequence stratigraphic framework on Mars shows four cycles of alternating rises and falls of the lake‐level within 5–10 m [ABSTRACT FROM AUTHOR]

The Atacama Desert, on the western margin of the Central Andes, hosts some of the world's largest porphyry copper deposits (PCDs). Despite a hyperarid climate, many of these PCDs have undergone secondary "supergene" enrichment, whereby copper has been concentrated via groundwater-driven leaching and reprecipitation, yielding supergene profiles containing valuable records of weathering and landscape evolution. We combine hematite (U-Th-Sm)/He geochronology and oxygen isotope analysis to compare the weathering histories of two Andean PCDs and test the relative importance of climate and tectonics in controlling both enrichment and water table movement. At Cerro Colorado, in the Precordillera, hematite precipitation records prolonged weathering from ~31 to ~2 Ma, tracking water table descent following aridity-induced canyon incision from the late Miocene onward. By contrast, hematite at Spence, within the Central Depression, is mostly younger than ~10.5 Ma, suggesting exhumation ended much later. A heavy oxygen isotopic signature for Spence hematite suggests that upwelling formation water has been an important source of groundwater, accounting for a high modern water table despite persistent hyperaridity, whereas isotopically light hematite at Cerro Colorado formed in the presence of meteoric water. Compared with published paleo-environmental and sedimentological records, our data show that weathering can persist beneath appreciable post-exhumation cover, under hyperarid conditions unconducive to enrichment. The susceptibility of each deposit to aridity-induced water table descent, canyon incision and deep weathering has been controlled by recharge characteristics and morphotectonic setting. Erosional exhumation, rather than aridity-induced water table decay, appears to be more important for the development of supergene enrichment. [ABSTRACT FROM AUTHOR]

We built a collector to filter interplanetary dust particles (IDPs) larger than 5 μm from the clean air at the Amundsen Scott South Pole station. Our sampling strategy used long duration, continuous dry filtering of near‐surface air in place of short duration, high‐speed impact collection on flags flown in the stratosphere. We filtered ~107 m3 of clean Antarctic air through 20 cm diameter, 3 µm filters coupled to a suction blower of modest power consumption (5–6 kW). Our collector ran continuously for 2 years and yielded 41 filters for analyses. Based on stratospheric concentrations, we predicted that each month's collection would provide 300–900 IDPs for analysis. We identified 19 extraterrestrial (ET) particles on the 66 cm2 of filter examined, which represented ~0.5% of the exposed filter surfaces. The 11 ET particles larger than 5 µm yield about a fifth of the expected flux based on >5 µm stratospheric ET particle flux. Of the 19 ET particles identified, four were chondritic porous IDPs, seven were FeNiS beads, two were FeNi grains, and six were chondritic material with FeNiS components. Most were <10 µm in diameter and none were cluster particles. Additionally, a carbon‐rich candidate particle was found to have a small 15N isotopic enrichment, supporting an ET origin. Many other candidate grains, including chondritic glasses and C‐rich particles with Mg and Si and FeS grains, require further analysis to determine if they are ET. The vast majority of exposed filter surfaces remain to be examined. [ABSTRACT FROM AUTHOR]

Abstract: (U‐Th)/He geochronology and cosmogenic 3He in iron oxides reveal mineral precipitation ages as old as 55 Ma and exposure ages greater than 5 Ma for canga‐cemented plateaus in the Quadrilátero Ferrífero, Brazil, showing that lateritic profiles overlying banded iron‐formation (BIF) landscapes in tropical regions have a long history of surface exposure. The long‐term erosion history obtained from cosmogenic 3He on BIF plateaus confirms that relic surfaces persist in the landscape for millions of years. Combined 3He and (U‐Th)/He dating shows that cangas are preferentially goethite cemented by biogeochemical reactions in the subsurface. Importantly, pebbles of hematite‐magnetite in colluvia or shallow creeks draining the canga‐cemented plateaus record a much longer exposure history than in situ canga blocks, showing that even older duricrusts, now eroded, once blanketed these plateaus. Physically stable but biogeochemically dynamic, cangas armor the landscape by pervasive and recurrent iron cycling and cementation, slowing down the delivery of weathered BIF or friable hematite–magnetite ore to erosion. [ABSTRACT FROM AUTHOR]

Abstract: Following K‐Ar dating of a mudstone and a sandstone, a third sample has been dated by the Curiosity rover exploring Gale Crater. The Mojave 2 mudstone, which contains relatively abundant jarosite, yielded a young K‐Ar bulk age of 2.57 ± 0.39 Ga (1σ precision). A two‐step heating experiment was implemented in an effort to resolve the K‐Ar ages of primary and secondary mineralogical components within the sample. This technique involves measurement of 40Ar released in low‐temperature (500°C) and high‐temperature (930°C) steps, and a model of the potassium distribution within the mineralogical components of the sample. Using this method, the high‐temperature step yields a K‐Ar model age of 4.07 ± 0.63 Ga associated with detrital plagioclase, compatible with the age obtained on the Cumberland mudstone by Curiosity. The low‐temperature step, associated with jarosite mixed with K‐bearing evaporites and/or phyllosilicates, gave a youthful K‐Ar model age of 2.12 ± 0.36 Ga. The interpretation of this result is complicated by the potential for argon loss after mineral formation. Comparison with the results on Cumberland and previously published constraints on argon retentivity of the individual phases likely to be present suggests that the formation age of the secondary materials, correcting for plausible extents of argon loss, is still less than 3 Ga, suggesting post‐3 Ga aqueous processes occurred in the sediments in Gale Crater. Such a result is inconsistent with K‐bearing mineral formation in Gale Lake and instead suggests postdepositional fluid flow at a time after surface fluvial activity on Mars is thought to have largely ceased. [ABSTRACT FROM AUTHOR]

There is acidaemia (low pH), respiratory acidosis (high Paco SB 2 sb ) and metabolic alkalosis (high There is a very severe acidaemia (low pH) with respiratory alkalosis (low Paco SB 2 sb ) and metabolic acidosis (low 15 mmol/L, Na SP + sp 147 mmol/L, K SP + sp 7 mmol/L, Cl SP - sp 95 mmol/L. There is very mild acidaemia (low pH) with respiratory alkalosis (low Paco SB 2 sb ) and metabolic acidosis (low In this case, there are three concomitant disorders: respiratory alkalosis, HAGMA and metabolic alkalosis. [Extracted from the article]

The switching frequency of inductive power transfer may change along with the air gap between two coils due to mutual inductance variation. The mutual inductance is conventionally estimated through experimental measurement or finite element analysis. To simplify this process, a frequency-gap model for series-series compensated inductive power transfer is proposed to calculate the unity-gain frequency based on known air gap and coil geometric parameters. Neumann's formula is applied to compute the mutual inductance of the primary and secondary coils. The experimental results show that the unity-gain frequency can be predicted with varying loads and air gaps (75-250 mm), and a demonstrated unity-gain error of <6%. [ABSTRACT FROM AUTHOR]

Nitric oxide modulates many aspects of PMN function. We investigated the effects of migration across PMEC and PMEC iNOS on PMN apoptosis (Ap) in vitro. PMEC and bone marrow PMN were isolated from iNOS wild type (WT) and knockout (KO) mice. PMN were cultured alone or co-cultured with PMEC monolayers with or without LPS/IFN-γ (LI). The Ap was assessed by microscopic changes, annexin-V (AV) binding by FACS, and caspase-3 activity (C3A). As well, 24 hr after exposure of WT vs KO mice to intratracheal LI, PMN were collected by BAL and Ap assessed. In non-migrated PMN, LI increased AV binding. However, there were no differences between WT and KO PMN. In contrast, Ap by AV binding was significantly greater in PMN post-migration across KO PMEC vs WT PMEC in the presence of LI. Microscopy confirmed these significant differences in PMN Ap. In freshly isolated BAL-PMN, Ap was similar in PMN from WT and KO mice. However, following a further 24 hr incubation, KO BAL-PMN had markedly greater Ap vs WT BAL-PMN (15.2 ± 3.3% vs. 3.0 ± 0.4%, P<0.05). Paradoxically, LI stimulation of PMN decreased C3A by 40-50% in non-migrated PMN and by 80-90% in trans-PMEC migrated PMN, independent of PMN or PMEC iNOS. These data suggest that iNOS expressed in PMEC, but not in PMN, has an important anti-apoptotic effect on PMN during trans-PMEC migration and this effect seems to be caspase-3 independent. [ABSTRACT FROM AUTHOR]