Infinite charge mobility in muscovite at 300K

Evidence is presented for infinite charge mobility in natural crystals of muscovite mica at room temperature. Muscovite has a basic layered structure containing a flat monatomic sheet of potassium sandwiched between mirror silicate layers. It is an excellent electrical insulator. Studies of defects in muscovite crystals indicated that positive charge could propagate over great distances along atomic chains in the potassium sheets in absence of an applied electric potential. The charge moved in association with anharmonic lattice excitations that moved at about sonic speed and created by nuclear recoil of the radioactive isotope K40. This was verified by measuring currents passing through crystals when irradiated with energetic alpha particles at room temperature. The charge propagated more than 1000 times the range of the alpha particles of average energy and 250 times the range of channelling particles of maximum energy. The range is limited only by size of the crystal.Comment: 6 pages, 8 figure

Hyperconductivity in fluorphlogopite at 300 K and 1.1 T

We report on studies of hyperconductivity in which electric charge moves in a solid in the absence of an applied electric field. This is indicative of a non-Ohmic mechanism. Our results are consistent with charge being carried ballistically by mobile nonlinear lattice excitations called quodons moving along close-packed atomic chains in the cation layers of some silicates. The finding that quodons can trap and carry a charge was first found by the authors in muscovite (Russell F. M. et al., EPL, 120 (2017) 46001), which previously was not possible. In this paper we have also found hyperconductivity in lepidolite, phlogopite and synthetic fluorphlogopite but not in biotite or quartz. We have found that a current continues to flow for many seconds after the creation of quodons is stopped, indicating they have long flight-paths. This shows that quodons are decoupled from phonons, must experience elastic reflection at boundaries and are not stopped by inevitable dislocations or other minor defects. We have also found that quodons can anneal defects caused by mechanical working of crystal faces. The current carried by quodons is unaffected by a magnetic field of 1.1 T.Ministerio de Ciencia e Innovación, PRX18/00360Ministerio de Economía y competitividad, FIS2015-65998- C2-2-PJunta de Andalucía, 2017/FQM-28

3-D SPH simulations of colliding winds in eta Carinae

We study colliding winds in the superluminous binary eta Carinae by performing three-dimensional, Smoothed Particle Hydrodynamics (SPH) simulations. For simplicity, we assume both winds to be isothermal. We also assume that wind particles coast without any net external forces. We find that the lower density, faster wind from the secondary carves out a spiral cavity in the higher density, slower wind from the primary. Because of the phase-dependent orbital motion, the cavity is very thin on the periastron side, whereas it occupies a large volume on the apastron side. The model X-ray light curve using the simulated density structure fits very well with the observed light curve for a viewing angle of i=54 degrees and phi=36 degrees, where i is the inclination angle and phi is the azimuth from apastron.Comment: 6 pages, 3 figures, To be published in Proceedings of IAU Symposium 250: Massive Stars as Cosmic Engines, held in Kauai, Hawaii, USA, Dec 2007, edited by F. Bresolin, P.A. Crowther & J. Puls (Cambridge University Press

On the charge of quodons

Muscovite mica is a mineral in which the tracks of charged swift particles, from radioactivity or cosmic rays, can be recorded and made visible by decoration with the mineral magnetite. Also, the tracks of quasi-one-dimensional lattice excitations, called quodons, moving along close-packed directions can be recorded. Most quodon tracks evolve from nuclear recoils following decay of the radioactive isotope 40K in mica. The recording process is charge sensitive: moving positive charge precipitates black magnetite and moving negative charge leads to clear epidote. Computer modeling of lattice excitations suggest that breathers or solitons can trap a charge. Most of the decays of 40K leave behind a charge, about 90% of them positive. So the evolution of most quodons from nuclear recoil events occurs in the presence of a charge. The possible energies and mechanisms of charge transmission in the lattice are analyzed. The outcome of 40K decay can be Ca++, Ar0, Ar+ and Ar++. These ions not only have different recoil energy and charge, but also different electron levels and ionization potentials. The first collision of the primary recoiling ion can be inelastic with the transfer of charge to the secondary ion K+. We analyze the possible results taking into account charge, energy and momentum conservation and considering the possible ionization states of the K atoms, which can be intrinsic localized modes, solitons, kinks or crowdions, travelling charge states and combinations of them

Reliability of a Shuttle reaction timer

Reaction, movement, and task times refer to the times needed to initially respond to a stimulus, make the specific movement, and complete the entire task. This study evaluated the reliability of a simple reaction timer designed to mimic a Space Shuttle task (turning on an overhead switch)

Ballistic charge transport by mobile nonlinear excitations

The developments in hyperconductivity, the loss-free transmission of electric charge at room temperature and above, due to the ballistic transport of electric charge in crystals with quasi-layered structure, are reported. The electric charge is carried by quodons, a type of mobile nonlinear intrinsic localized mode of lattice excitation observed as fossil tracks in layered silicates and recently by laboratory experiments. Here, ballistic means moving with minimal scattering or interaction with phonons. A test for hyperconductivity in solid materials is developed. It is based on the unique effect of short-term continuation of transport of charge, by total internal reflection, after creation of quodons has ceased. This effect is called the slow-quodon-decay effect or SQD effect. So far, only layered silicates have been shown to exhibit hyperconductivity. New evidence is presented for hyperconductivity in chrysotile, a nonlayered silicate material with new results. Being a fibrous material, it is more flexible than the sheet mica phyllosilicates. It is found that quodons can also be created and carry charge in very different materials, such as polymers, but without showing hyperconductivity, because of the very short range and lifetime of quodons in those materials.Ministerio de Ciencia, Innovación y Universidades PID2019-109175GB-C2

An ancient spliceosomal intron in the ribosomal protein L7a gene (Rpl7a) of Giardia lamblia

BACKGROUND: Only one spliceosomal-type intron has previously been identified in the unicellular eukaryotic parasite, Giardia lamblia (a diplomonad). This intron is only 35 nucleotides in length and is unusual in possessing a non-canonical 5' intron boundary sequence, CT, instead of GT. RESULTS: We have identified a second spliceosomal-type intron in G. lamblia, in the ribosomal protein L7a gene (Rpl7a), that possesses a canonical GT 5' intron boundary sequence. A comparison of the two known Giardia intron sequences revealed extensive nucleotide identity at both the 5' and 3' intron boundaries, similar to the conserved sequence motifs recently identified at the boundaries of spliceosomal-type introns in Trichomonas vaginalis (a parabasalid). Based on these observations, we searched the partial G. lamblia genome sequence for these conserved features and identified a third spliceosomal intron, in an unassigned open reading frame. Our comprehensive analysis of the Rpl7a intron in other eukaryotic taxa demonstrates that it is evolutionarily conserved and is an ancient eukaryotic intron. CONCLUSION: An analysis of the phylogenetic distribution and properties of the Rpl7a intron suggests its utility as a phylogenetic marker to evaluate particular eukaryotic groupings. Additionally, analysis of the G. lamblia introns has provided further insight into some of the conserved and unique features possessed by the recently identified spliceosomal introns in related organisms such as T. vaginalis and Carpediemonas membranifera