Numerical Algorithm for Detecting Ion Diffusion Regions in the Geomagnetic Tail with Applications to MMS Tail Season May 1 -- September 30, 2017

We present a numerical algorithm aimed at identifying ion diffusion regions (IDRs) in the geomagnetic tail, and test its applicability. We use 5 criteria applied in three stages. (i) Correlated reversals (within 90 s) of Vx and Bz (at least 2 nT about zero; GSM coordinates); (ii) Detection of Hall electric and magnetic field signatures; and (iii) strong (>10 mV/m) electric fields. While no criterion alone is necessary and sufficient, the approach does provide a robust, if conservative, list of IDRs. We use data from the Magnetospheric Multiscale Mission (MMS) spacecraft during a 5-month period (May 1 to September 30, 2017) of near-tail orbits during the declining phase of the solar cycle. We find 148 events satisfying step 1, 37 satisfying steps 1 and 2, and 17 satisfying all three, of which 12 are confirmed as IDRs. All IDRs were within the X-range [-24, -15] RE mainly on the dusk sector and the majority occurred during traversals of a tailward-moving X-line. 11 of 12 IDRs were on the dusk-side despite approximately equal residence time in both the pre- and post-midnight sectors (56.5% dusk vs 43.5% dawn). MMS could identify signatures of 4 quadrants of the Hall B-structure in 3 events and 3 quadrants in 7 of the remaining 12 confirmed IDRs identified. The events we report commonly display Vx reversals greater than 400 km/s in magnitude, normal magnetic field reversals often >10 nT in magnitude, maximum DC |E| which are often well in excess of the threshold for stage 3. Our results are then compared with the set of IDRs identified by visual examination from Cluster in the years 2000-2005.Comment: In Submission at JGR:Space Physic

Unilateral choanal atresia

Choanal atresia was first described by Otto in 1830 (Otto A., 1830). This condition is a rare one. Polson et al. (1943) found that in the period 1829-1945, only five hundred cases had been reported. A report on a case of unilateral choanal atresia is presented. The etiology, diagnosis and treatment of the condition are also discussed. The patient, a sixteen year old girl, presented at St. Luke's Hospital Malta with foul smelling discharge from the right side of the nose. As regards etiology, most of the cases are congenital, only very few being caused by syphilis, diphtheria, trauma or tuberculosis. All bilateral choanal atresia cases need emergency operation and removal of the obstruction and insertion of Aechersen's cannulae, to restore patency of the nasal airway, while unilateral cases need no urgent treatment.peer-reviewe

Kilohertz QPOs in Neutron Star Binaries modeled as Keplerian Oscillations in a Rotating Frame of Reference

Since the discovery of kHz quasi-periodic oscillations (QPO) in neutron star binaries, the difference between peak frequencies of two modes in the upper part of the spectrum, i.e. Delta (omega)=omega_h-omega_K has been studied extensively. The idea that the difference Delta(omega) is constant and (as a beat frequency) is related to the rotational frequency of the neutron star has been tested previously. The observed decrease of Delta(omega) when omega_h and omega_k increase has weakened the beat frequency interpretation. We put forward a different paradigm: a Keplerian oscillator under the influence of the Coriolis force. For such an oscillator, omega_h and the assumed Keplerian frequency omega_k hold an upper hybrid frequency relation: omega^2_h-omega^2_K=4*Omega^2, where Omega is the rotational frequency of the star's magnetosphere near the equatorial plane. For three sources (Sco X-1, 4U 1608-52 and 4U 1702-429), we demonstrate that the solid body rotation Omega=Omega_0=const. is a good first order approximation. Within the second order approximation, the slow variation of Omega as a function of omega_K reveals the structure of the magnetospheric differential rotation. For Sco X-1, the QPO have frequencies approximately 45 and 90 Hz which we interpret as the 1st and 2nd harmonics of the lower branch of the Keplerian oscillations for the rotator with vector Omega not aligned with the normal of the disk: omega_L/2 pi=(Omega/pi)(omega_K/omega_h)sin(delta) where delta is the angle between vector Omega and the vector normal to the disk.Comment: 13 pages, 3 figures, accepted for publications in ApJ Letter

2,9,16,23-Tetra­kis(1-methyl­eth­yl)-5,6,11,12,13,14,19,20,25,26,27,28-dodecadehydro­tetra­benzo[a,e,k,o]cyclo­eicosene1

The title compound, C48H40, is a tetra­isopropyl-substituted polyannulenoenyne. The unsubstituted polyannulenoenyne, C36H16 (CSD: RICVEE; CAS: 186494-87-1), has quasi-D 2 (222) symmetry, as determined by least-squares fit (excluding H atoms) to a model optimized in D 2 symmetry by mol­ecular mechanics (r.m.s. deviation = 0.239 Å). The least-squares fits of 36 common C atoms of the title compound (at 90 K) to the parent (at 295 K) and to the optimized model show r.m.s. deviations of 0.419 and 0.426 Å, respectively

Reply to comment by H. Hasegawa on "Evolution of Kelvin-Helmholtz activity on the dusk flank magnetopause"

We demonstrate, on experimental grounds, that the justifications for the comment by Hasegawa [2009], hereinafter H09, on work done by Foullon et al. [2008], hereinafter F08, are not well founded

4-Formyl-2-nitrophenyl 3-nitro-2-methylbenzoate

In the title formyl nitro aryl benzoate derivative, CH NO, the benzene rings form a dihedral angle of 4.96(3)°. The mean plane of the central ester group, C-O-C-(=O)-C (r.m.s. deviation = 0.0484Å), is twisted away from the formyl nitro aryl and benzoate rings by 46.61(5) and 49.93(5)°, respectively. In the crystal, the molecules are packed forming C-H⋯O interactions in chains which propagate along [010]. Edge-fused R 3(15) rings are generated along this direction