Ages and abundances in large-scale stellar disks of nearby S0 galaxies

By undertaking deep long-slit spectroscopy with the focal reducer SCORPIO of the Russian 6m telescope, we studied stellar population properties and their variation with radius in 15 nearby S0 galaxies sampling a wide range of luminosities and environments. For the large-scale stellar disks of S0s, we have measured SSP-equivalent metallicities ranging from the solar one down to [Z/H]=-0.4 - -0.7, rather high magnesium-to-iron ratios, [Mg/Fe] > +0.2, and mostly old SSP-equivalent ages. Nine of 15 (60%) galaxies have large-scale stellar disks older than 10 Gyr, and among those we find all the galaxies which reside in denser environments. The isolated galaxies may have intermediate-age stellar disks which are 7-9 Gyr old. Only two galaxies of our sample, NGC 4111 and NGC 7332, reveal SSP-equivalent ages of their disks of 2-3 Gyrs. Just these two young disks appear to be thin, while the other, older disks have scale heights typical for thick stellar disks. The stellar populations in the bulges at radii of 0.5r_eff are on the contrary more metal-rich than the solar metallicity, with the ages homogeneously distributed between 2 and 15 Gyr, being almost always younger than the disks. We conclude that S0 galaxies could not form in groups at z=0.4 as is thought now; a new scenario of the general evolution of disk galaxies is proposed instead.Comment: Accepted to the MNRA

Enabling and promoting walking rehabilitation by paired associative stimulation after incomplete paraplegia : a case report

Introduction: Paired associative stimulation (PAS) is a combination of transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS) and induces plastic changes in the human corticospinal tract. We have previously shown that PAS consisting of TMS pulses given at 100% of stimulator output and high-frequency PNS is beneficial for motor rehabilitation of patients with a chronic incomplete spinal cord injury (SCI). The therapeutic possibilities of this PAS variant for walking rehabilitation of paraplegic patients are unexplored. Case presentation: A 47-year old man with traumatic incomplete paraplegia (AIS D, neurological level T7) received PAS to his left leg for 3 months at 12 months post injury (PAS1) and for an additional 3 months at 24 months post injury (PAS2). The right leg had normal AIS scores and was not stimulated. Before PAS, the patient was nonambulatory, could not stand without weight support, and was consequently not eligible for conventional walking rehabilitation. After PAS1, the patient could stand for 1.5 min and take 13 steps (24 steps in follow up) on parallel bars without weight support and was enrolled into conventional walking rehabilitation. He achieved independent walking ability with a rollator. During PAS2, walking distance increased 2.4 times faster than during the preceding year. The left leg AIS score and spinal cord independence measure mobility subscore increased. No adverse effects were detected. Discussion: This is the first report of PAS with a high-frequency peripheral component that enabled and promoted walking rehabilitation. Together with previous reports on this technique, this result encourages further research into its therapeutic potential and mechanism. © 2020, The Author(s).Peer reviewe

Validity of abundances derived from spaxel spectra of the MaNGA survey

We measured the emission lines in the spaxel spectra of MaNGA galaxies in order to determine the abundance distributions therein. It has been suggested that the strength of the low-ionization lines, R_2, N_2, and S_2 may be increased (relative to Balmer lines) in (some) spaxel spectra of the MaNGA survey due to a contribution of the radiation of the diffuse ionized gas. Consequently, the abundances derived from the spaxel spectra through strong-line methods may suffer from large errors. We examined this expectation by comparing the behaviour of the line intensities and the abundances estimated through different calibrations for slit spectra of HII regions in nearby galaxies, for fibre spectra from the SDSS, and for spaxel spectra of the MaNGA survey. We found that the S_2 strength is increased significantly in the fibre and spaxel spectra. The mean enhancement changes with metallicity and can be as large as a factor of 2. The mean distortion of R_2 and N_2 is less than a factor of 1.3. This suggests that Kaufmann et al.'s demarcation line between AGNs and HII regions in the BPT diagram is a useful criterion to reject spectra with significantly distorted strengths of the N_2 and R_2 lines. We find that the three-dimensional R calibration, which uses the N_2 and R_2 lines, produces reliable abundances in the MaNGA galaxies. The one-dimensional N2 calibration produces either reliable or wrong abundances depending on whether excitation and N/O abundance ratio in the target region (spaxel) are close to or differ from those parameters in the calibrating points located close to the calibration relation. We then determined abundance distributions within the optical radii in the discs of 47 MaNGA galaxies. The optical radii of the galaxies were estimated from the surface brightness profiles constructed based on the MaNGA observations.Comment: 19 pages, 15 figures, accepted for publication in A&

Gravitational potential of a homogeneous circular torus: new approach

The integral expression for gravitational potential of a homogeneous circular torus composed of infinitely thin rings is obtained. Approximate expressions for torus potential in the outer and inner regions are found. In the outer region a torus potential is shown to be approximately equal to that of an infinitely thin ring of the same mass; it is valid up to the surface of the torus. It is shown in a first approximation, that the inner potential of the torus (inside a torus body) is a quadratic function of coordinates. The method of sewing together the inner and outer potentials is proposed. This method provided a continuous approximate solution for the potential and its derivatives, working throughout the region.Comment: 10 pages, 9 figures, 1 table; some misprints in formulae were correcte

Restoration of hand function with long-term paired associative stimulation after chronic incomplete tetraplegia: a case study

INTRODUCTION: This case study explores the gains in hand function in an individual with a chronic spinal cord injury (SCI). The intervention was long-term paired associative simulation (PAS). We aimed to provide PAS until full recovery of hand muscle strength occurred, or until improvements ceased. CASE PRESENTATION: A 46-year-old man with traumatic C7 AIS B tetraplegia was administered PAS three times per week. After 24 weeks, PAS was combined with concomitant motor training of the remaining weak hand muscles. Outcome measures included the manual muscle test (MMT), motor-evoked potentials (MEPs), F-responses, hand functional tests, and the spinal cord independence measure (SCIM). DISCUSSION: After 47 weeks of PAS the subject had improved self-care and indoor mobility and was able to perform complex motor tasks (SCIM score improved from 40 to 56). His left hand regained maximum MMT score (total 75; increase of score from baseline condition 19); the effect remained stable in the 32-week follow up. In the right-hand muscles, MMT scores of 4-5 were observed in follow up (total 71; increase from baseline 48). Improved values were also observed in other outcomes. This is the first demonstration of long-term PAS restoring muscle strength corresponding to MMT scores of 4-5 in an individual with chronic SCI. The effect persisted for several months, indicating that PAS induces stable plastic changes in the corticospinal pathway.Peer reviewe

Myasthenia Gravis Diagnosis with Surface-enhanced Raman Spectroscopy

Modern medicine aims to diagnose diseases at early stages which constitutes a relevant task of biomedical research. The present investigation focuses on myasthenia, a disease that takes the third place in terms of frequency worldwide, has complex symptoms and is difficult to treat. It is early diagnostics that allows for providing competent medical assistance and, sometimes, curing the patient. To detect the cause of the disease, the Raman spectroscopy was used to study blood serum samples covered with quartz glass with gold clusters embedded. The Raman cross-section has been amplified with the gold nanoparticles which made it possible to detect Botulotoxin-A in blood serum of patients suffering from myastheni