Mineralogical-geochemical features of magnetite occurrences in serpentinites of the Kalkan area (Main Uralian fault zone, South Urals)

Chemical and mineralogical composition of magnetite occurrences from serpentinites of the Kalkan melange area of the Main Uralian Fault zone (South Urals) are studied. Abundant Cu minerals including native copper, Cu sulfdes (covellite, bornite, minerals of the chalcocite-digenite series), chlorides (nantokite), Cu carbonates and Cu silicates are found in magnetite ores. Magnetite also contains abundant inclusions of cobaltpentlandite, rare Ag and Bi sulfdes, heazlewoodite and awaruite. All magnetite occurrences host relicts of chromites, the composition of which (moderate to high Cr / (Cr + Al) values) indicates a strong depletion of a peridotite protolith, which formed in the upper mantle below a forearc basin. A two-stage formation model of magnetite occurrences is suggested. At an early stage, the disseminated magnetite with inclusions of Cu-Fe-Co sulfdes formed under the infuence of metalliferous fuids in serpentinized ultramafc rocks at the bottom of the oceanic basin. During collision, serpentinites were tectonized with the formation of small bodies of massive magnetite ores and Cu, Ag and Bi sulfdes and native minerals.

A depletion of ammonia and water by storms in the deep atmosphere of Jupiter

<p>Microwave observations by the Juno spacecraft have shown that, contrary to expectations, the concentration of ammonia is still variable down to pressures of tens of bars in Jupiter. While mid-latitudes show a strong depletion, the equatorial zone of Jupiter has an abundance of ammonia that is high and nearly uniform with depth. In parallel, Juno determined that the Equatorial Zone is peculiar for its absence of lightning, which is otherwise prevalent most everywhere else on the planet. We show that a model accounting for the presence of small-scale convection and water storms originating in Jupiter’s deep atmosphere accounts for the observations. At mid-latitudes, where thunderstorms powered by water condensation are present, ice particles may be lofted high in the atmosphere, in particular into a region located at pressures between 1.1 and 1.5 bar and temperatures between 173K and 188K, where ammonia vapor can dissolve into water ice to form a low-temperature liquid phase containing about 1/3 ammonia and 2/3 water. We estimate that, following the process creating hailstorms on Earth, this liquid phase enhances the growth of hail-like particles that we call ‘mushballs’. Their growth and fall over many scale heights can effectively deplete ammonia, and consequently, water to great depths in Jupiter’s atmosphere. In the Equatorial Zone, the absence of thunderstorms shows that this process is not occurring, implying that small-scale convection can maintain a near homogeneity of this region. We predict that water, which sinks along with ammonia, should also be depleted down to pressures of tens of bars. Except during storms, Jupiter's deep atmosphere should be stabilized by the mean molecular weight gradient created by the increase in abundance of ammonia and water with depth.  This new vision of the mechanisms at play, which are both deep and latitude-dependent, has consequences for our understanding of Jupiter’s deep interior and of giant-planet atmospheres in general.</p>

PVT and Pressure Analysis in Third pay Reservoir of Zubair Oilfield Southern Iraq

In this paper the pressure drop and PVT data that used in the model to describe the behavior ofreservoir fluids of 3rd pay reservoir of Zubair field is explained. The wells in Hammar-Shuaiba area showhigh Gas Oil Ratio, exceeding 1,000 scf/stb. This is bad sign and that mean reservoir pressure is reducedramatically and gas will produced , finally the energy that use to push the oil from reservoir to thesurface will decrease. Eleven samples have been collected and analyzed from all 3rd pay reservoirs overthe years, seven samples in Hammar –Shuaiba area. The PVT data resulted to be scattered, being notpossible to define any acceptable conclusion about their trend versus depths, taking also into account thatthey are not referred to the same temperature. The main difference between the old and new PVT is theBubble Point pressure at reservoir conditions, which increases from 2646 psi to 2760 psi. Historicalpressure behavior shows that water Injection is beneficial to maintain stable pressure trend. Pressureanalysis shows a strong depletion start from 2013 in various zones of Hammar Shuaiba domes.

The Arabidopsis NOT4A E3 ligase coordinates PGR3 expression to regulate chloroplast protein translation

Chloroplast function requires the coordinated action of nuclear- and chloroplast-derived proteins, including several hundred nuclear-encoded pentatricopeptide repeat (PPR) proteins that regulate plastid mRNA metabolism. Despite their large number and importance, regulatory mechanisms controlling PPR expression are poorly understood. Here we show that the Arabidopsis NOT4A ubiquitin-ligase positively regulates PROTON GRADIENT 3 (PGR3), a PPR protein required for translating 30S ribosome subunits and several thylakoid-localised photosynthetic components within chloroplasts. Loss of NOT4A function leads to a strong depletion of plastid ribosomes, which reduces mRNA translation and negatively impacts photosynthetic capacity, causing pale-yellow and slow-growth phenotypes. Quantitative transcriptome and proteome analyses reveal that these defects are due to a lack of PGR3 expression in not4a, and we show that normal plastid function is restored through transgenic PGR3 expression. Our work identifies NOT4A as crucial for ensuring robust photosynthetic function during development and stress-response, through modulating PGR3 levels to coordinate chloroplast protein synthesis.

Pyroclastic rocks from Kanchanaburi and Uthai Thani Province, Inthanon Zone, Western Thailand

<p>A series of pyroclastic rocks are mapped as a Silurian-Devonian unit in the Kanchanaburi-Uthai Thani area, Western Thailand, which belongs to the Inthanon Zone. These pyroclastic rocks were discovered and described for the first time in 1977 and mentioned in the 1:250,000 Suphanburi geologic map sheet and report. Since then these rocks were poorly investigated and their formation and geotectonic setting is unclear. As a result, we report petrographic, geochemical and geochronological data of these pyroclastic rocks. Petrographically, the pyroclastic rocks can be described as a meta-quartz-K-feldspar crystal tuff, a meta-quartz crystal tuff, and a meta-lithic tuff. They are made up of mm sized clasts in a finely grained matrix. The clasts consist of potassium feldspar, rounded quartz, embayed quartz, trachytic and metasedimentary rock clasts embedded in a highly altered devitrified fine-ash matrix containing sericite.</p><p>The whole-rock composition shows enrichments in SiO<sub>2</sub> and K<sub>2</sub>O and a strong depletion in CaO and Na<sub>2</sub>O which is related to late alteration of the volcanoclastic rocks. Based on the immobile element classification plot of Pearce 1996, the tuffs can be classified as trachyandesite, trachyte, dacite and rhyolite. Their chondrite-normalized REE patterns display light REE enrichment with nearly flat heavy REE and a negative Eu anomaly, typical for calcalkaline volcanic rocks. Most samples fall in the volcanic arc granites field in the granite discrimination diagrams of Pearce 1984.</p><p>Zircons extracted from the tuffs will be used to constrain their crystallization age by U-Pb LA-MCICPMS dating. This allows us to constrain the age of formation and to place this in context with the closure of the Paleotethys.</p>

Pebble drift and planetesimal formation in protoplanetary discs with embedded planets

Nearly axisymmetric gaps and rings are commonly observed in protoplanetary discs. The leading theory regarding the origin of these patterns is that they are due to dust trapping at the edges of gas gaps induced by the gravitational torques from embedded planets. If the concentration of solids at the gap edges becomes high enough, it could potentially result in planetesimal formation by the streaming instability. We tested this hypothesis by performing global 1D simulations of dust evolution and planetesimal formation in a protoplanetary disc that is perturbed by multiple planets. We explore different combinations of particle sizes, disc parameters, and planetary masses, and we find that planetesimals form in all of these cases. We also compare the spatial distribution of pebbles from our simulations with protoplanetary disc observations. Planets larger than one pebble isolation mass catch drifting pebbles efficiently at the edge of their gas gaps, and depending on the efficiency of planetesimal formation at the gap edges, the protoplanetary disc transforms within a few 100 000 yr to either a transition disc with a large inner hole devoid of dust or to a disc with narrow bright rings. For simulations with planetary masses lower than the pebble isolation mass, the outcome is a disc with a series of weak ring patterns but there is no strong depletion between the rings. By lowering the pebble size artificially to a 100 micrometer-sized “silt”, we find that regions between planets get depleted of their pebble mass on a longer time-scale of up to 0.5 million years. These simulations also produce fewer planetesimals than in the nominal model with millimeter-sized particles and always have at least two rings of pebbles that are still visible after 1 Myr.

Geochemical features of Malyutka ore-bearing massif rocks, Khudolaz complex, South Urals: evidence of hydrothermal reprecipitation of siderophile and chalcophile elements

Hydrothermal processes play an important role in the reprecipitation of ore elements, but it is difficult to characterize their qualitative and quantitative parameters for large objects. The compact homogeneous internal structure of the ultramafic massif Malyutka of the Khudolaz differentiated complex provides a good opportunity to characterize the features of the hydrothermal reprecipitation of mobile elements in it. The geochemical features of barren and ore-bearing variously altered rocks of the Malyutka massif have been studied using the methods of X-ray fluorescence (XRF) and mass spectrometry with inductively coupled plasma (ICP MS) analyzes. The results show a strong depletion of ores by siderophile (Ni, Co) and chalcophile (S, Cu, As, Se, Cd, Bi, Pb and many others) elements under hydrothermal influence, which is consistent with the postmagmatic dissolution and replacement of sulfide minerals not only by secondary sulfides, but also silicates. Leaching led to a reprecipitation of these elements, mainly to dispersion, both inside the intrusion and outside it. Most lithophile macro- and microelements have not reprecipitated significantly in hydrothermal conditions.

Multi-technique comparison of atherogenic and MCD NASH models highlights changes in sphingolipid metabolism

Lipotoxicity is a key player in the pathogenesis of nonalcoholic steatohepatitis (NASH), a progressive subtype of nonalcoholic fatty liver disease (NAFLD). In the present study, we combine histological, transcriptional and lipidomic approaches to dissociate common and specific alterations induced by two classical dietary NASH models (atherogenic (ATH) and methionine/choline deficient (MCD) diet) in C57BL/6J male mice. Despite a similar degree of steatosis, MCD-fed mice showed more pronounced liver damage and a worsened pro-inflammatory and pro-fibrogenic environment than ATH-fed mice. Regarding lipid metabolism, the ATH diet triggered hepatic counter regulatory mechanisms, while the MCD diet worsened liver lipid accumulation by a concomitant increase in lipid import and reduction in lipid export. Liver lipidomics revealed sphingolipid enrichment in both NASH models that was accompanied by an upregulation of the ceramide biosynthesis pathway and a significant rise in dihydroceramide levels. In contrast, the phospholipid composition was not substantially altered by the ATH diet, whereas the livers of MCD-fed mice presented a reduced phosphatidylcholine to phosphatidylethanolamine (PC/PE) ratio and a strong depletion in phospholipids containing the sum of 34–36 carbons in their fatty acid chains. Therefore, the assessment of liver damage at the histological and transcriptional level combined with a lipidomic analysis reveals sphingolipids as shared mediators in liver lipotoxicity and pathogenesis of NASH.

Identification of Factors Linked to Higher Water-Deficit Stress Tolerance in Amaranthus hypochondriacus Compared to Other Grain Amaranths and A. hybridus, Their Shared Ancestor

Water deficit stress (WDS)-tolerance in grain amaranths (Amaranthus hypochondriacus, A. cruentus and A. caudatus), and A. hybridus, their presumed shared ancestor, was examined. A. hypochondriacus was the most WDS-tolerant species, a trait that correlated with an enhanced osmotic adjustment (OA), a stronger expression of abscisic acid (ABA) marker genes and a more robust sugar starvation response (SSR). Superior OA was supported by higher basal hexose (Hex) levels and high Hex/sucrose (Suc) ratios in A. hypochondriacus roots, which were further increased during WDS. This coincided with increased invertase, amylase and sucrose synthase activities and a strong depletion of the starch reserves in leaves and roots. The OA was complemented by the higher accumulation of proline, raffinose, and other probable raffinose-family oligosaccharides of unknown structure in leaves and/or roots. The latter coincided with a stronger expression of Galactinol synthase 1 and Raffinose synthase in leaves. Increased SnRK1 activity and expression levels of the class II AhTPS9 and AhTPS11 trehalose phosphate synthase genes, recognized as part of the SSR network in Arabidopsis, were induced in roots of stressed A. hypochondriacus. It is concluded that these physiological modifications improved WDS in A. hypochondriacus by raising its water use efficiency.

Gas phase Elemental abundances in Molecular cloudS (GEMS)

GEMS is an IRAM 30 m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud Taurus molecular cloud (TMC) 1. Extensive millimeter observations have been carried out with the IRAM 30 m telescope (3 and 2 mm) and the 40 m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO+, HCN, CS, SO, HCS+, and N2H+ in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from AV ~ 3 to ~20 mag. Two phases with differentiated chemistry can be distinguished: (i) the translucent envelope with molecular hydrogen densities of 1−5 × 103 cm−3; and (ii) the dense phase, located at AV > 10 mag, with molecular hydrogen densities >104 cm−3. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C+/C/CO transition zone (AV ~ 3 mag) where C/H ~ 8 × 10−5 and C/O ~ 0.8−1, until the beginning of the dense phase at AV ~ 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate an S∕H ~ (0.4−2.2) × 10−6, an abundance ~7–40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S∕H ~ 8 × 10−8). Based on our chemical modeling, we constrain the value of ζH2 to ~(0.5–1.8) × 10−16 s−1 in the translucent cloud.