The formation and evolution of the Martian mantle: a Martian meteorite perspective

Revealing the internal composition and evolution of the terrestrial planets is crucial to understanding planetary evolution in the Solar System and beyond. Mars is a perfect source of this information, since its mantle was not homogenized after the earliest phases of planetary differentiation. However, the interior evolution and composition of Mars is still unknown. Martian meteorites are the only rock samples from Mars that are available on Earth. The aim of this research is to obtain new insights about Martian mantle formation and its evolution from the perspective of the Martian meteorites. In particular, this work is divided into three interdisciplinary investigations in order to obtain new constraints on our knowledge about the Martian mantle. Firstly, the Tissint Martian meteorite was investigated since it is the meteorite that is most representative of the Martian mantle. This meteorite was analysed with the objective of obtaining information about the thermal state and convective activity in the Mars’ mantle. Major- and trace-element data for Tissint olivine and pyroxene were reported, and these data were used to provide new insights into the dynamics of the Tissint magma chamber, as well as the dynamics and temperature of Martian mantle at the time of Tissint crystallisation. Secondly, the potential for chemical tracing of the different Martian mantle sources was investigated by analysing rhenium-osmium and sulphur isotope compositions in five of the ten known nakhlite lava flows (Nakhla, Lafayette, MIL 090032, Yamato 000593, and Yamato 000749). In addition, these findings were used to suggest a plausible scenario to account for nakhlite magma origins. These findings were also utilised to discuss the implications of this work for fingerprinting the processes responsible for setting Martian mantle compositions during late-stage crystallization of a Martian magma ocean. Thirdly, the abundance of the volatile element chlorine in the Martian mantle was calculated by analysing amphibole and apatite phases in the two shergottites Tissint and Zagami. After finding that these phases record magmatic conditions of the Martian interior, the partition coefficients between chlorine and the parent melt were used to estimate the chlorine abundance of the shergottite magma source. In sum, the importance of the combined new findings are presented to explore their implications for our understanding of Mars’ formation and evolution and, more generally, the evolution of terrestrial planets

INSIGHTS INTO THE RELATIONSHIP BETWEEN MIXING DURATION AND VOLCANIC EXPLOSIVITY INDEX (VEI): PACAYA AND FUEGO VOLCANOES, GUATEMALA

This study investigates whether the timing of magma mixing phenomena could be related to explosivity and style of volcanic activity. Lava flow and tephra samples, derived from observed, energetically-diverse eruptions, from Pacaya and Fuego volcanoes (Guatemala), were studied, the Volcanic Explosivity Index (VEI) was used as an indicator of eruption intensity. Polarized light microscopy and Scanning Electron Microscopy (SEM) techniques were used for textural and geochemical measurements. Results are interpreted as evolution of mixing through changes in textures of plagioclase and olivine crystals. These suggest that boxy-cellular plagioclase (high frequency in VEI 0 samples) is associated with brief mixing residence time prior to the eruption, while sieve and spongy textures in plagioclase (high frequency in VEI 1-2 samples) reflect heating by recharge events with a hotter melt, and reflect longer time in the magma chamber prior to the eruption. CSD data lead to a model to explain the increase in explosivity. Crystal size distributions with a significative step that derive from a single mixing event correlates with low intensity eruptions (VEI 0-1) because convection is hindered by the dissolution of the microcrysts, while multiple or prolonged events of mixing gives a more linear curve resulting in a high content of phenocrysts that make convection difficult, increasing the explosive potential (VEI 2). Besides, CSDs analysis show how the residence time in the shallow magma chamber increase from VEI 0 to VEI 2 samples. As a result, this study could assert that the number of mixing events that determine the final CSDs shape, and the magma mixing-to-eruption duration is proportional to the explosivity of the volcanic event

The one-hour post-load plasma glucose predicts progression to prediabetes in a multiethnic cohort of obese youths

One-hour post-load hyperglycemia has been proposed as an independent predictor of type 2 diabetes in adults. We examined whether 1-hour plasma glucose (1hPG) during an oral glucose tolerance test (OGTT) can predict changes in the glucose tolerance status in a multiethnic cohort of youths with normal glucose tolerance (NGT)

Quantum East model: localization, non-thermal eigenstates and slow dynamics

We study in detail the properties of the quantum East model, an interacting quantum spin chain inspired by simple kinetically-constrained models of classical glasses. Through a combination of analytics, exact diagonalization and tensor-network methods we show the existence of a transition, from a fast to a slow thermalization regime, which manifests itself throughout the spectrum. On the slow side, by exploiting the localization of the ground state and the form of the Hamiltonian, we explicitly construct a large (exponential in size) number of non-thermal states which become exact finite-energy-density eigenstates in the large-size limit, as expected for a true phase transition. A ``super-spin'' generalization allows us to find a further large class of area-law states proved to display very slow relaxation. These states retain memory of their initial conditions for extremely long times. Our numerical analysis reveals that the localization properties are not limited to the ground state and that} many eigenstates have large overlap with product states and can be approximated well by matrix product states at arbitrary energy densities. The mechanism that induces localization to the ground state, and hence the non-thermal behavior of the system, can be extended to a wide range of models including a number of simple spin chains. We discuss implications of our results for slow thermalization and non-ergodicity more generally in disorder-free systems with constraints and we give numerical evidence that these results may be extended to two dimensional systems.Comment: 21 pages, 16 figure

Biotechnological Potential and Safety Evaluation of Dextran- and Riboflavin-Producing Weisella cibaria Strains for Gluten-Free Baking

Gluten consumption causes several immunological and non-immunological intolerances in susceptible individuals. In this study, the dextran-producing Weissella cibaria BAL3C-5 and its derivative, the riboflavin-overproducing strain BAL3C-5 C120T, together with a commercial bakery yeast, were used to ferment gluten-free (GF)-doughs obtained from corn and rice flours at two different concentrations and supplemented with either quinoa, buckwheat, or chickpea to obtain laboratory-scale GF bread. The levels of dextran, riboflavin, and total flavins were determined in the fermented and breads. Both strains grew in fermented doughs and contributed dextran, especially to those made with corn plus quinoa (~1 g/100 g). The highest riboflavin (350–150 µg/100 g) and total flavin (2.3–1.75 mg/100 g) levels were observed with BAL3C-5 C120T, though some differences were detected between the various doughs or breads, suggesting an impact of the type of flour used. The safety assessment confirmed the lack of pathogenic factors in the bacterial strains, such as hemolysin and gelatinase activity, as well as the genetic determinants for biogenic amine production. Some intrinsic resistance to antibiotics, including vancomycin and kanamycin, was found. These results indicated the microbiological safety of both W. cibaria strains and indicated their potential application in baking to produce GF bread.This research was funded in Spain by the Spanish Ministry of Science and Innovation (grant RTI2018-097114-B-I00), by the Basque Government (grants IT1662-22 and PIBA_2020_1_0032) and by CSIC (grant 2022AEP028). This research was funded in Italy by the Italian Ministry of University and Research Project PE0000003 P.R. is the beneficiary of a grant by the University of Milan in the framework of “Linea 2—A. 2022”

Comparison of Intralesional Hyaluronic Acid vs. Verapamil for the Treatment of Acute Phase Peyronie's Disease: A Prospective, Open-Label Non-Randomized Clinical Study

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HDV can constrain HBV genetic evolution in hbsag: Implications for the identification of innovative pharmacological targets

Chronic HBV + HDV infection is associated with greater risk of liver fibrosis, earlier hepatic decompensation, and liver cirrhosis hepatocellular carcinoma compared to HBV mono-infection. However, to-date no direct anti-HDV drugs are available in clinical practice. Here, we identified conserved and variable regions in HBsAg and HDAg domains in HBV + HDV infection, a critical finding for the design of innovative therapeutic agents. The extent of amino-acid variability was measured by Shannon-Entropy (Sn) in HBsAg genotype-D sequences from 31 HBV + HDV infected and 62 HBV mono-infected patients (comparable for demographics and virological-parameters), and in 47 HDAg genotype-1 sequences. Positions with Sn = 0 were defined as conserved. The percentage of conserved HBsAg-positions was significantly higher in HBV + HDV infection than HBV mono-infection (p = 0.001). Results were confirmed after stratification for HBeAg-status and patients’ age. A Sn = 0 at specific positions in the C-terminus HBsAg were correlated with higher HDV-RNA, suggesting that conservation of these positions can preserve HDV-fitness. Conversely, HDAg was characterized by a lower percentage of conserved-residues than HBsAg (p < 0.001), indicating higher functional plasticity. Furthermore, specific HDAg-mutations were significantly correlated with higher HDV-RNA, suggesting a role in conferring HDV replicative-advantage. Among HDAg-domains, only the virus-assembly signal exhibited a high genetic conservation (75% of conserved-residues). In conclusion, HDV can constrain HBsAg genetic evolution to preserve its fitness. The identification of conserved regions in HDAg poses the basis for designing innovative targets against HDV-infection