The Cauchy 5 Small, Low-Volume Lunar Shield Volcano:Evidence for Volatile Exsolution-Eruption Patterns and Type 1/Type 2 Hybrid Irregular Mare Patch Formation

The lunar shield volcano Cauchy 5, sitting at the low diameter‐height‐volume end of the population, is the only known example containing two different types of Irregular Mare Patches (IMPs) in very close association: (1) the pit crater interior Type 1 IMP composed of bleb‐like mounds surrounded by a hummocky and blocky floor unit and (2) Type 2 IMPs, small, often optically immature pits less than ~5 m deep, located on the generally block‐deficient shield flanks. A four‐phase lunar magma ascent/eruption model predicts that during a relatively brief eruption, low magma rise rates maximize volatile exsolution in lava filling the pit crater. Bubble‐rich magmas overtop the pit crater and form extremely vesicular flows on the shield flanks. Exposure of the flanking flows to vacuum produces a fragmental layer of exploded glassy bubble walls. Subsequent second boiling upon cooling of the flanking flow interiors releases additional volatiles which migrate and collect, forming magmatic foams and gas pockets. As magma rise rates slow, trapped gas and magmatic foam build up below the cooling pit crater floor. Magmatic foams are extruded to form Type 1 IMP deposits. Type 2 IMPs on the flanks are interpreted to be due primarily to subsequent impacts causing collapse of the flow surface layer into the extremely vesicle‐ and void‐rich flow interior. Anomalously young pit crater floor/shield flank crater retention ages compared with surrounding maria ages may be due to effects of Cauchy 5 substrate characteristics (extreme micro‐ and macroporosity, foamy nature, and glassy auto‐regolith) on superposed crater formation and retention

Hidden symmetries for thermodynamics and emergence of relativity

Erik Verlinde recently proposed an idea about the thermodynamic origin of gravity. Though this is a beautiful idea which may resolve many long standing problems in the theories of gravity, it also raises many other problems. In this article I will comment on some of the problems of Verlinde's proposal with special emphasis on the thermodynamical origin of the principle of relativity. It is found that there is a large group of hidden symmetries of thermodynamics which contains the Poincare group of the spacetime for which space is emergent. This explains the thermodynamic origin of the principle of relativity.Comment: V1: 4 pages, comments/criticisms welcomed; V2: references added; V3: typos and minor corrections? V4? substantial changes in Section 3 and other parts mad

Lunar Irregular Mare Patches:Classification, Characteristics, Geologic Settings, Updated Catalog, Origin, and Outstanding Questions

One of the most mysterious lunar features discovered during the Apollo era was Ina, a ~2 × 3-km depression composed of bleb-like mounds surrounded by hummocky and blocky terrains. Subsequent studies identified dozens of similar features in lunar maria, describing them as Irregular Mare Patches (IMPs). Due to the unusual and complex characteristics of IMPs, their specific formation mechanism is debated. To improve our understanding of the nature and origin of IMPs, we undertook an updated search and geological characterization of all IMPs and established a classification approach encompassing the full spectrum of IMPs. We present an updated catalog of 91 IMPs and survey the detailed characteristics of each IMP. We find that the majority of IMPs occur in maria emplaced over three billion years ago, contemporaneous with the peak period of global lunar volcanism. We utilized geologic context information and characteristics to establish two classification schemes for lunar IMPs: (1) geologic context: IMPs are categorized into (a) small shield volcano summit pit floor and flank, (b) linear/sinuous rille interior and adjacent exterior, and (c) typical maria; (2) characteristics: IMPs are classified into (a) “mound + floor” and (b) “pit only” types. We showed the range of characteristics of lunar IMPs was consistent with the waning-stage magmatic foam formation and extrusion scenario in different environments. Our updated catalog and classification raise several outstanding questions concerning the nature and origin of lunar IMPs. Assessing these questions will improve our knowledge of lunar thermal and geologic evolution. ©2020. American Geophysical Union. All Rights Reserved

Mare Domes in Mare Tranquillitatis:Identification, Characterization, and Implications for Their Origin

Mare domes, small shield volcanoes typically <∼30 km diameter, are part of the spectrum of lunar volcanic features that characterize extrusive basalt deposits. We used new spacecraft data to document these in Mare Tranquillitatis, among the oldest maria and the site commonly interpreted as an ancient degraded non-mascon impact basin. We found 283 known and suspected mare domes, with the majority (n = 229) concentrated on a broad, ∼450 km circular topographic rise in eastern Mare Tranquillitatis. The domes (median diameter 5.6 km, height 68 m, volume 0.7 km3) contain summit pits (74%; median diameter 0.8 km), and exhibit minor compositional variability between domes and surrounding flows, suggesting that domes both supply and are embayed by these flows. Based on their characteristics and associations, we interpret the small shield volcanoes to have been built from individual low-volume (<∼10–100 km3), low volatile content, short duration, cooling-limited eruptions. The ∼450 km broad volcanic rise is ∼920 m high (volume ∼1.6 × 105 km3) and is interpreted to be built from multiple occurrences of small shield eruptions, a shield plains volcanism style. This implies a shallow mantle source region capable of supplying distributed dike-emplacement and eruption events over an area of 1.75 × 105 km2 early in mare volcanism history (∼3.7 Ga). The difference between Mare Tranquillitatis and younger mare-filled mascon basins is attributed to the more ancient thermal state and crustal structure of the viscously relaxed Tranquillitatis basin, and a shallower broad magma source region present in earlier lunar thermal history

Integrin activation - the importance of a positive feedback

Integrins mediate cell adhesion and are essential receptors for the development and functioning of multicellular organisms. Integrin activation is known to require both ligand and talin binding and to correlate with cluster formation but the activation mechanism and precise roles of these processes are not yet resolved. Here mathematical modeling, with known experimental parameters, is used to show that the binding of a stabilizing factor, such as talin, is alone insufficient to enable ligand-dependent integrin activation for all observed conditions; an additional positive feedback is required.Comment: in press in Bulletin of Mathematical Biolog

Geological Characterization of the Ina Shield Volcano Summit Pit Crater on the Moon:Evidence for Extrusion of Waning-Stage Lava Lake Magmatic Foams and Anomalously Young Crater Retention Ages

Ina, a distinctive ~2 × 3 km D-shaped depression, is composed of unusual bulbous-shaped mounds surrounded by optically immature hummocky/blocky floor units. The crisp appearance, optical immaturity, and low number of superposed impact craters combine to strongly suggest a geologically recent formation for Ina, but the specific formation mechanism remains controversial. We reconfirm that Ina is a summit pit crater/vent on a small shield volcano ~3.5 billion years old. Following detailed characterization, we interpret the range of Ina characteristics to be consistent with a two-component model of origin during the waning stages of summit pit eruption activities. The Ina pit crater floor is interpreted to be dominated by the products of late-stage, low-rise rate magmatic dike emplacement. Magma in the dike underwent significant shallow degassing and vesicle formation, followed by continued degassing below the solidified and highly microvesicular and macrovesicular lava lake crust, resulting in cracking of the crust and extrusion of gas-rich magmatic foams onto the lava lake crust to form the mounds. These unique substrate characteristics (highly porous aerogel-like foam mounds and floor terrains with large vesicles and void space) exert important effects on subsequent impact crater characteristics and populations, influencing (1) optical maturation processes, (2) regolith development, and (3) landscape evolution by modifying the nature and evolution of superposed impact craters and thus producing anomalously young crater retention ages. Accounting for these effects results in a shift of crater size-frequency distribution model ages fro

Mini viral RNAs act as innate immune agonists during influenza virus infection

We thank the High-Throughput Genomics Group at the Wellcome Trust Centre for Human Genetics (funded by Wellcome Trust grant 090532/Z/09/Z) for the generation of adapter-ligated mvRNA sequencing data. This work was supported by the Wellcome Trust grant 098721/Z/12/Z, the joint Wellcome Trust and Royal Society grant 206579/Z/17/Z and a Netherlands Organization for Scientific Research (NWO) grant 825.11.029 to A.J.W.t.V.; EPA Cephalosporin Junior Research Fellowship to D.L.V.B.; support by the Intramural Research Program of NIAID, NIH, to E.d.W.; Research Grants Council of the Hong Kong Special Administrative Region, China, project no. T11-705/14N and a Croucher Senior Research Fellowship to L.L.M.P.; and Medical Research Council (MRC) programme grants MR/K000241/1 and MR/R009945/1 to E.F. and studentship to J.C.L.The molecular processes that determine the outcome of influenza virus infection in humans are multifactorial and involve a complex interplay between host, viral and bacterial factors1. However, it is generally accepted that a strong innate immune dysregulation known as ‘cytokine storm’ contributes to the pathology of infections with the 1918 H1N1 pandemic or the highly pathogenic avian influenza viruses of the H5N1 subtype2,3,4. The RNA sensor retinoic acid-inducible gene I (RIG-I) plays an important role in sensing viral infection and initiating a signalling cascade that leads to interferon expression5. Here, we show that short aberrant RNAs (mini viral RNAs (mvRNAs)), produced by the viral RNA polymerase during the replication of the viral RNA genome, bind to and activate RIG-I and lead to the expression of interferon-β. We find that erroneous polymerase activity, dysregulation of viral RNA replication or the presence of avian-specific amino acids underlie mvRNA generation and cytokine expression in mammalian cells. By deep sequencing RNA samples from the lungs of ferrets infected with influenza viruses, we show that mvRNAs are generated during infection in vivo. We propose that mvRNAs act as the main agonists of RIG-I during influenza virus infection.PostprintPeer reviewe

Quasinormal modes of Schwarzschild black holes in four and higher dimensions

We make a thorough investigation of the asymptotic quasinormal modes of the four and five-dimensional Schwarzschild black hole for scalar, electromagnetic and gravitational perturbations. Our numerical results give full support to all the analytical predictions by Motl and Neitzke, for the leading term. We also compute the first order corrections analytically, by extending to higher dimensions, previous work of Musiri and Siopsis, and find excellent agreement with the numerical results. For generic spacetime dimension number D the first-order corrections go as $\frac{1}{n^{(D-3)/(D-2)}}$. This means that there is a more rapid convergence to the asymptotic value for the five dimensional case than for the four dimensional case, as we also show numerically.Comment: 12 pages, 5 figures, RevTeX4. v2. Typos corrected, references adde

Measurement of the branching fraction for Υ(1S)→τ+τ−\Upsilon (1S) \to \tau^+ \tau^-

We have studied the leptonic decay of the $\Upsilon (1S)$ resonance into tau pairs using the CLEO II detector. A clean sample of tau pair events is identified via events containing two charged particles where exactly one of the particles is an identified electron. We find $B(\Upsilon(1S) \to \tau^+ \tau^-) = (2.61~\pm~0.12~{+0.09\atop{-0.13}})$. The result is consistent with expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS 94/1297, CLEO 94-20 (submitted to Physics Letters B