The Elusive Origin of Mercury

The MESSENGER mission sought to discover what physical processes determined Mercury's high metal to silicate ratio. Instead, the mission has discovered multiple anomalous characteristics about our innermost planet. The lack of FeO and the reduced oxidation state of Mercury's crust and mantle are more extreme than nearly all other known materials in the solar system. In contrast, moderately volatile elements are present in abundances comparable to the other terrestrial planets. No single process during Mercury's formation is able to explain all of these observations. Here, we review the current ideas for the origin of Mercury's unique features. Gaps in understanding the innermost regions of the solar nebula limit testing different hypotheses. Even so, all proposed models are incomplete and need further development in order to unravel Mercury's remaining secrets.Comment: To appear in "Mercury: The View after MESSENGER" edited by Solomon, Nittler & Anderson (www.cambridge.org/9781107154452). This version is free to view and download for personal use only. Not for re-distribution, re-sale or use in derivative works. 37 pages, 5 figure

Identification of weeds from the cabbage family (Brassicaceae) found in the agrocenoses of the Russian Federation

Members of the Brassicaceae family are of great significance as weeds and invasive plants; they are one of the leading families of the alien fraction in the segetal floras of various regions of Russia. Among the cruciferous weeds growing over Russia, there are many species that are wild relatives to cultivated plants. Some cultivated species grow outside of their cultivation areas as ruderal and segetal plants. Among the cruciferous plants growing in Russia, 28 species out of 19 genera are regulated as harmful organisms in 33 different countries. Most of the species from this list are widespread weeds in Russia.To establish the presence of Brassicaceae species in Russian agrocenoses, we analyzed published sources, herbarium materials stored in the Russian leading herbaria, and materials collected by the authors during field explorations in 2017–2022 in 19 subject entities of the Russian Federation.  Identification of cruciferous plants is often a rather difficult task, so the goal of this work was to develop a convenient identification key that would make in possible to identify weeds of this family found in Russian agrocenoses.  Most of the available keys are designed for fruit-bearing specimens of cruciferous plants. For phytosanitary purposes, it is important to identify plants prior to their fruiting period. Therefore, we additionally used the characters of flowering plants (including their vegetative organs) enabling us to identify cruciferous plants at the flowering stage. Based on such features, a table was made, which included all weedy species of Brassicaceae found in agrocenoses within Russia (83 species in total). On the basis of this table, an identification key was produced for the identification of genera and some species of weedy cruciferous plants. Afterwards, fractional species-specific keys were made for the genera containing species controllable in importing countries

Optimization of Robustness of Complex Networks

Networks with a given degree distribution may be very resilient to one type of failure or attack but not to another. The goal of this work is to determine network design guidelines which maximize the robustness of networks to both random failure and intentional attack while keeping the cost of the network (which we take to be the average number of links per node) constant. We find optimal parameters for: (i) scale free networks having degree distributions with a single power-law regime, (ii) networks having degree distributions with two power-law regimes, and (iii) networks described by degree distributions containing two peaks. Of these various kinds of distributions we find that the optimal network design is one in which all but one of the nodes have the same degree, $k_1$ (close to the average number of links per node), and one node is of very large degree, $k_2 \sim N^{2/3}$, where $N$ is the number of nodes in the network.Comment: Accepted for publication in European Physical Journal

Computational Repurposing of Mitoxantrone-Related Structures against Monkeypox Virus : A Molecular Docking and 3D Pharmacophore Study

Acknowledgments: A sincere thanks to P.S. Oberoi (I.C.A.R, N.D.R.I., India) and Rishi Vachaspathy Astakala (Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, UK) for their constructive suggestions. Additionally, thank Nidhan Singh Oberoi and Albrn Care, India. Funding: B.F.M. acknowledges national funds from the Portuguese FCT—Fundação para a Ciência e a Tecnologia, I.P., within the projects UIDB/04564/2020 and UIDP/04564/2020.Peer reviewedPublisher PD

Lack of Evidence of In-Situ Decay of Aluminum-26 in a FeO-Poor Ferromagnesian Crystalline Silicate Particle, Pyxie, from Comet Wild 2

One of the important discoveries from the Stardust mission is the observation of crystalline silicate particles that resemble Ca, Al-rich inclusions (CAIs) and chondrules in carbonaceous chondrites], which suggests radial transport of high temperature solids from the inner to the outer solar nebula regions and capture by accreting cometary objects. The Al-Mg isotope analyses of CAI-like and type II chondrule-like particles revealed no excess of Mg-26 derived from in-situ decay of Al-26 (Tau)(sub 1/2) = 0.705Myr; ), suggesting late formation of these particles. However, the number of Wild 2 particles analyzed for Al-Mg isotopes is still limited (n = 3). In order to better understand the timing of the formation of Wild 2 particles and possible radial transport in the protoplanetary disk, we performed SIMS (Secondary Ion Mass Spectrometer) Al-Mg isotope analyses of plagioclase in a FeO-poor ferromagnesian Wild 2 particle, which is the most abundant type among crystalline Wild 2 particles

(E)-N-(3-(5-(3-Acetamidopropyl)-3,6-dioxopiperazin-2-yl)propyl)-5-hydroxy-3-methylpent-2-enamide

Funding The collection of materials was carried out with financial support from the UK Newton Project for UK–Chile Collaboration (JIC CA 586) to Professor Mervyn Bibb, John Inness Centre, Norwich, UK. Acknowledgments The authors would like to thank Albrn Care India, Nidhan Singh Oberoi, and P.S. Oberoi, I.C.A.R-National Dairy Research Institute, India, as well as Aparna Koride for their continued support. They would also like to thank Russell Gray for his support in running the NMR experiments. Data collection was carried out in collaboration with Michael Goodfellow, University of Newcastle, and Juan Asenjo and Barbara Andrews, University of Chile.Peer reviewedPublisher PD

Evolutionary Dynamics on Small-Order Graphs

Abstract. We study the stochastic birth-death model for structured finite populations popularized by Lieberman et al. [Lieberman, E., Hauert, C., Nowak, M.A., 2005. Evolutionary dynamics on graphs. Nature 433, 312-316]. We consider all possible connected undirected graphs of orders three through eight. For each graph, using the Monte Carlo Markov Chain simulations, we determine the fixation probability of a mutant introduced at every possible vertex. We show that the fixation probability depends on the vertex and on the graph. A randomly placed mutant has the highest chances of fixation in a star graph, closely followed by star-like graphs. The fixation probability was lowest for regular and almost regular graphs. We also find that within a fixed graph, the fixation probability of a mutant has a negative correlation with the degree of the starting vertex. 1

Heavy metals, proximate analysis and brine shrimp lethality of vernonia amygdalina and ocimum gratissimum growing in crude oil-rich delta state, nigeria

Funding Information: This research and APC was funded by Schlumberger Faculty for the Future Foundation. The authors acknowledge the financial support of the Schlumberger Faculty for the Future Foundation Scholarship to conduct the present study. The authors also thank Attah Francis Alfred of the Faculty of Pharmaceutical Sciences, University of Ilorin, for arranging raw material for the study. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Peer reviewedPublisher PD

Northwest Africa (NWA) 8785, an EL3 Chondrite with FeO-Rich Matrix

The enstatite (E) chondrites are enigmatic but important for understanding the evolution of the terrestrial planets. They have highly reduced mineral assemblages in which enstatite (near pure in compostion) is the dominant silicate, metal is abundant and contains >2.5 wt. % Si in some EH3s, elements which are generally lithophile in most chondrites occur as sulfide and some E3s contain nitrides and carbides. Notably, stable isotope compositions are similar to the Earth-Moon. Aside from E chondrite clasts in the Kaidun breccia, the enstaite chondrites are dry, lacking evidence of ever having hydrous minerals, distinguishing them from most other chondrite groups and suggesting they formed relatively close to the sun, inside of the snow line. Compared to other chondrite groups, the E3s are also matrix-poor, with EH3s having ~4-12 vol. % and EL3s 5 vol % matrix. Here we present a study of NWA 8785, a remarkable new EL3 chondrite with an FeO-rich, fine-grained matrix. Our goals are to understand E chondrite matrix and the evolution and alteration history of the EL3 parent body

The influence of anesthetics, neurotransmitters and antibiotics on the relaxation processes in lipid membranes

In the proximity of melting transitions of artificial and biological membranes fluctuations in enthalpy, area, volume and concentration are enhanced. This results in domain formation, changes of the elastic constants, changes in permeability and slowing down of relaxation processes. In this study we used pressure perturbation calorimetry to investigate the relaxation time scale after a jump into the melting transition regime of artificial lipid membranes. This time corresponds to the characteristic rate of domain growth. The studies were performed on single-component large unilamellar and multilamellar vesicle systems with and without the addition of small molecules such as general anesthetics, neurotransmitters and antibiotics. These drugs interact with membranes and affect melting points and profiles. In all systems we found that heat capacity and relaxation times are related to each other in a simple manner. The maximum relaxation time depends on the cooperativity of the heat capacity profile and decreases with a broadening of the transition. For this reason the influence of a drug on the time scale of domain formation processes can be understood on the basis of their influence on the heat capacity profile. This allows estimations of the time scale of domain formation processes in biological membranes.Comment: 12 pages, 6 figure