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

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&

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

Thermodynamics of Two - Band Superconductors: The Case of MgB2_{2}

Thermodynamic properties of the multiband superconductor MgB$_{2}$ have often been described using a simple sum of the standard BCS expressions corresponding to $\sigma$- and $\pi$-bands. Although, it is \textit{a priori} not clear if this approach is working always adequately, in particular in cases of strong interband scattering. Here we compare the often used approach of a sum of two independent bands using BCS-like $\alpha$-model expressions for the specific heat, entropy and free energy to the solution of the full Eliashberg equations. The superconducting energy gaps, the free energy, the entropy and the heat capacity for varying interband scattering rates are calculated within the framework of two-band Eliashberg theory. We obtain good agreement between the phenomenological two-band $\alpha$-model with the Eliashberg results, which delivers for the first time the theoretical verification to use the $\alpha$-model as a useful tool for a reliable analysis of heat capacity data. For the thermodynamic potential and the entropy we demonstrate that only the sum over the contributions of the two bands has physical meaning.Comment: 27 pages, 10 figures, 1 table, submitted to Phys. Rev.

Theory of the Optical Conductivity in the Cuprate Superconductors

We present a study of the normal state optical conductivity in the cuprate superconductors using the nearly antiferromagnetic Fermi liquid (NAFL) description of the magnetic interaction between their planar quasiparticles. We find that the highly anisotropic scattering rate in different regions of the Brillouin zone, both as a function of frequency and temperature, a benchmark of NAFL theory, leads to an average relaxation rate of the Marginal Fermi Liquid form for overdoped and optimally doped systems, as well as for underdoped systems at high temperatures. We carry out numerical calculations of the optical conductivity for several compounds for which the input spin fluctuation parameters are known. Our results, which are in agreement with experiment on both overdoped and optimally doped systems, show that NAFL theory explains the anomalous optical behavior found in these cuprate superconductors.Comment: REVTEX file, 8 PostScript figure

Infrared and optical properties of pure and cobalt-doped LuNi_2B_2C

We present optical conductivity data for Lu(Ni$_{1-x}$Co$_x$)$_2$B$_2$C over a wide range of frequencies and temperatures for x=0 and x=0.09. Both materials show evidence of being good Drude metals with the infrared data in reasonable agreement with dc resistivity measurements at low frequencies. An absorption threshold is seen at approximately 700 cm-1. In the cobalt-doped material we see a superconducting gap in the conductivity spectrum with an absorption onset at 24 +/- 2 cm-1 = 3.9$ +/- 0.4 k_BT_c suggestive of weak to moderately strong coupling. The pure material is in the clean limit and no gap can be seen. We discuss the data in terms of the electron-phonon interaction and find that it can be fit below 600 cm-1 with a plasma frequency of 3.3 eV and an electron-phonon coupling constant lambda_{tr}=0.33 using an alpha^{2}F(omega) spectrum fit to the resistivity.Comment: 10 pages with 10 embedded figures, submitted to PR

Електронний підручник як засіб оптимізації післядипломної підготовки спеціалістів охорони здоров’я

Aim. To determine the scientific and methodological approaches to elaboration of electronic textbooks.Materials and methods. The methods of analysis and generalization were used in the study.Results. The study gave a possibility to assess domestic regulatory support for elaboration and implementation of electronic textbooks, define their types, basic characteristics and basic principles of development. The authorial definition of an “electronic textbook” and an algorithm to create electronic textbooks are presented.Conclusions. The algorithm for electronic textbook elaboration created in the study has been used to develop an electronic textbook of the second type “Pharmaceutical and biomedical aspects of medicines” for postgraduate training of healthcare professionals.Цель: определение научно-методических подходов к созданию электронного учебника.Материалы и методы. В работе были использованы методы анализа и обобщения.Результаты исследования. Изучено отечественное нормативное обеспечение создания и внедрения электронных учебников с обозначением их типов, базовых характеристик и основных принципов разработки. Представлены авторское определение понятия «электронный учебник» и алгоритм его создания.Выводы. Отработан алгоритм создания электронного учебника, на основании которого создан электронный учебник второго типа для системы последипломного образования специалистов охраны здоровья «Фармацевтические и медико-биологические аспекты лекарств».Мета: окреслення науково-методичних підходів до створення електронного підручника.Матеріали та методи. У роботі були використані методи аналізу та узагальнення.Результати дослідження. Вивчено вітчизняне нормативне забезпечення створення та упровадження електронних підручників із визначенням їх типів, базових характеристик та основних принципів розробки. Наведено авторське визначення поняття «електронний підручник» та алгоритм його створення.Висновки. Опрацьовано алгоритм створення електронного підручника, на основі якого розроблено електронний підручник другого типу для системи післядипломної освіти фахівців охорони здоров’я «Фармацевтичні та медико-біологічні аспекти ліків»