Observations of OJ 287 from the Geodetic VLBI Archive of the Washington Correlator

We present 27 geodetic VLBI maps of OJ 287 obtained from the archive of the Washington correlator. The observations presented here were made between 1990 October and 1996 December. During this period a sequence of six superluminal components has been identified. We measured the proper motion of these components to be approximately 0.5 mas/yr, which is about twice as high as that seen in previous VLBI observations. These results imply a higher component ejection rate than previously observed, in good agreement with the observed occurrences of radio outbursts. We have examined a possible connection between VLBI components and optical flares in the framework of a binary black hole system.Comment: 9 pages, 5 included figures, emulateapj.sty, accepted to The Astrophysical Journa

Phase Diagram of β′\beta'-(BEDT-TTF)2_2ICl2_2 under High Pressure Based on the First-Principles Electronic Structure

We present a theoretical study on the superconductivity of $\beta'$-(BEDT-TTF)$_2$ICl$_2$ at $T_{\rm c}=$14.2 K under a high hydrostatic pressure recently found, which is the highest among organic superconductors. In the present work, we study an effective model using the fluctuation-exchange (FLEX) approximation based on the results of first-principles calculation. In the obtained phase diagram, the superconductivity with $d_{xy}$-like symmetry is realized next to the antiferromagnetic phase, as a result of the one-dimensional to two-dimensional crossover driven by the pressure.Comment: 4 pages, 3 figures. accepted for publication in J. Phys. Soc. Jpn. errors correcte

The Na+ Channel Inactivation Gate Is a Molecular Complex: A Novel Role of the COOH-terminal Domain

Electrical activity in nerve, skeletal muscle, and heart requires finely tuned activity of voltage-gated Na+ channels that open and then enter a nonconducting inactivated state upon depolarization. Inactivation occurs when the gate, the cytoplasmic loop linking domains III and IV of the α subunit, occludes the open pore. Subtle destabilization of inactivation by mutation is causally associated with diverse human disease. Here we show for the first time that the inactivation gate is a molecular complex consisting of the III-IV loop and the COOH terminus (C-T), which is necessary to stabilize the closed gate and minimize channel reopening. When this interaction is disrupted by mutation, inactivation is destabilized allowing a small, but important, fraction of channels to reopen, conduct inward current, and delay cellular repolarization. Thus, our results demonstrate for the first time that physiologically crucial stabilization of inactivation of the Na+ channel requires complex interactions of intracellular structures and indicate a novel structural role of the C-T domain in this process

Near-Shore Aggregation Mechanism of Electrolyte Decomposition Products to Explain Solid Electrolyte Interphase Formation

To get insight of the formation mechanism of solid electrolyte interphase (SEI) film in Lithium-ion battery (LIB), we examine a probable scenario, referred to as “surface growth mechanism,” for electrolyte involving ethylene carbonate (EC) solvent and vinylene carbonate (VC) additive by using density functional theory (DFT). We first extracted stable SEI film components (SFCs) for the EC/VC electrolyte and constructed probable SFC aggregates via DFT molecular dynamics. We then examined their solubility in the EC solution, their adhesion to a model graphite electrode, and the electronic properties. The results showed that the SFC aggregates are characterized by “unstable adhesion” to the graphite surface and “high electronic insulation” against the EC solution. These characteristics preclude explaining SEI growth up to a typical thickness of several tens of nanometers based on the surface growth mechanism. With the present results, we propose “near-shore aggregation” mechanism, where the SFCs formed at the electrode surface desorb into the near-shore region and form aggregates. The SFC aggregates coalesce and come into contact with the electrode to complete the SEI formation. The present model provides a novel perspective for the long-standing problem of SEI formation

Deterioration of perennial sea ice in the Beaufort Gyre from 2003 to 2012 and its impact on the oceanic freshwater cycle

© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 1271-1305, doi:10.1002/2013JC008999.Time series of ice draft from 2003 to 2012 from moored sonar data are used to investigate variability and describe the reduction of the perennial sea ice cover in the Beaufort Gyre (BG), culminating in the extreme minimum in 2012. Negative trends in median ice drafts and most ice fractions are observed, while open water and thinnest ice fractions (<0.3 m) have increased, attesting to the ablation or removal of the older sea ice from the BG over the 9 year period. Monthly anomalies indicate a shift occurred toward thinner ice after 2007, in which the thicker ice evident at the northern stations was reduced. Differences in the ice characteristics between all of the stations also diminished, so that the ice cover throughout the region became statistically homogenous. The moored data are used in a relationship with satellite radiometer data to estimate ice volume changes throughout the BG. Summer solid fresh water content decreased drastically in consecutive years from 730 km3 in 2006 to 570 km3 in 2007, and to 240 km3 in 2008. After a short rebound, solid fresh water fell below 220 km3 in 2012. Meanwhile, hydrographic data indicate that liquid fresh water in the BG in summer increased 5410 km3 from 2003 to 2010 and decreased at least 210 km3 by 2012. The reduction of both solid and liquid fresh water components indicates a net export of approximately 320 km3 of fresh water from the region occurred between 2010 and 2012, suggesting that the anticyclonic atmosphere-ocean circulation has weakened.Support for Krishfield, Proshutinsky, and Timmermans, partial financial support of logistics, hydrographic observations on the board of Canadian icebreaker, and full financial coverage of all mooring instrumentation was provided by the National Science Foundation (under grants OPP-0230184, OPP-0424864, ARC-0722694, ARC-0806306, ARC- 0856531, ARC-1107277, and ARC- 1203720), and Woods Hole Oceanographic Institution internal funding. Funding for Tateyama was provided by the International Arctic Research Center – Japan Aerospace Exploration Agency (IJIS) Arctic project, and for Williams, Carmack, and McLaughlin by Fisheries and Oceans Canada

Observations of BL Lacertae from the Geodetic VLBI Archive of the Washington Correlator

We present maps of BL Lac obtained from geodetic VLBI data from the archive of the Washington correlator. The observations were made from 1996 March to 1996 November, with periods from one experiment to another as short as 1 month. The dominant structure of the maps is given by a superluminal component (C2) moving predominantly at position angle ~190°. At the later epochs a new superluminal component (C3) emerges from the core and moves along a trajectory at a higher position angle (200°). We also include maps from observations made in 1995 June and August showing the main component (C2) in the early stages of its evolution, as well as an older component (C1). The position angle of the component C1 is nearly the same as that of the new component C3. The component C2 shows indications of nonradial motion, which is discussed in terms of a helically distorted jet. The best fit was obtained for a half-opening angle of the jet of 2.6d and an angle of the helical axis to the line of sight of 17°

Observations of OJ 287 from the Geodetic-VLBI Archive of the Washington Correlator

We present 27 geodetic VLBI maps of OJ 287 obtained from the archive of the Washington correlator. The observations presented here were made between 1990 October and 1996 December. During this period a sequence of six superluminal components has been identified. We measured the proper motion of these components to be approximately 0.5 mas yr-1, which is about twice as high as that seen in previous VLBI observations. These results imply a higher component ejection rate than previously observed, in good agreement with the observed occurrences of radio outbursts. We have examined a possible connection between VLBI components and optical flares in the framework of a binary black hole system

Helical motion and the origin of QPO in blazar-type sources

Recent observations and analysis of blazar sources provide strong evidence for (i) the presence of significant periodicities in their lightcurves and (ii) the occurrence of helical trajectories in their radio jets. In scenarios, where the periodicity is caused by differential Doppler boosting effects along a helical jet path, both of these facts may be naturally tied together. Here we discuss four possible driving mechanisms for the occurrence of helical trajectories: orbital motion in a binary system, Newtonian-driven jet precession, internal jet rotation and motion along a global helical magnetic field. We point out that for non-ballistic helical motion the observed period may appear strongly shortened due to classical travel time effects. Finally, the possible relevance of the above mentioned driving mechanisms is discussed for Mkn~501, OJ 287 and AO 0235+16.Comment: 6 pages, 1 figure; presented at the 5th Microquasar Workshop, Beijing, June 2004. Accepted for publication in the Chinese Journal of Astronomy and Astrophysic

Atmospheric gamma-ray observation with the BETS detectorfor calibrating atmospheric neutrino flux calculations

We observed atmospheric gamma-rays around 10 GeV at balloon altitudes (15~25 km) and at a mountain (2770 m a.s.l). The observed results were compared with Monte Carlo calculations to find that an interaction model (Lund Fritiof1.6) used in an old neutrino flux calculation was not good enough for describing the observed values. In stead, we found that two other nuclear interaction models, Lund Fritiof7.02 and dpmjet3.03, gave much better agreement with the observations. Our data will serve for examining nuclear interaction models and for deriving a reliable absolute atmospheric neutrino flux in the GeV region.We observed atmospheric gamma-rays around 10 GeV at balloon altitudes (15~25 km) and at a mountain (2770 m a.s.l). The observed results were compared with Monte Carlo calculations to find that an interaction model (Lund Fritiof1.6) used in an old neutrino flux calculation was not good enough for describing the observed values. In stead, we found that two other nuclear interaction models, Lund Fritiof7.02 and dpmjet3.03, gave much better agreement with the observations. Our data will serve for examining nuclear interaction models and for deriving a reliable absolute atmospheric neutrino flux in the GeV region