Left ventricular false tendons: echocardiographic characteristics in the Polish population

Background: False tendon (FT) is described in a wide range (40% to 62%) of the examined hearts depending on age and additional heart abnormalities. On echocardiography, the range is even wider (1.6–78%), depending on study design and inclusion criteria. Ultrasonographic characteristics of left ventricular FTs in the Polish population are not well known. Materials and methods: Echocardiographic examinations of 1,679 consecutive patients were evaluated. All cases were classified according to American Society of Echocardiography Committee of Nomenclature and Standards Document on Identification of the Segments of the Heart Muscle. Results: In our study, fibrous structures in the lumen of the left ventricle were detected in 100 (6%) subjects of the study group. The age of the subjects ranged from 16 to 87 years (mean age 47.9), 50 were males and 50 were females. In 94% of the subjects, FT was a single structure. No patient had clinically evident arrhythmia. Conclusions: In the Polish population, FT can be identified in all age groups, and the prevalence is similar to that reported in the literature

High-temperature performance of ferritic steels in fireside corrosion regimes: temperature and deposits

The paper reports high temperature resistance of ferritic steels in fireside corrosion regime in terms of temperature and deposits aggressiveness. Four candidate power plant steels: 15Mo3, T22, T23 and T91 were exposed under simulated air-fired combustion environment for 1000 h. The tests were conducted at 600, 650 and 700 °C according to deposit-recoat test method. Post-exposed samples were examined via dimensional metrology (the main route to quantify metal loss), and mass change data were recorded to perform the study of kinetic behavior at elevated temperatures. Microstructural investigations using ESEM-EDX were performed in order to investigate corrosion degradation and thickness of the scales. The ranking of the steels from most to the least damage was 15Mo3 > T22 > T23 > T91 in all three temperatures. The highest rate of corrosion in all temperatures occurred under the screening deposit

Angular diameters, fluxes and extinction of compact planetary nebulae: further evidence for steeper extinction towards the Bulge

We present values for angular diameter, flux and extinction for 70 Galactic planetary nebulae observed using narrow band filters. Angular diameters are derived using constant emissivity shell and photoionization line emission models. The mean of the results from these two models are presented as our best estimate. Contour plots of 36 fully resolved objects are included and the low intensity contours often reveal an elliptical structure that is not always apparent from FWHM measurements. Flux densities are determined, and for both H-alpha and O[III] there is little evidence of any systematic differences between observed and catalogued values. Observed H-alpha extinction values are determined using observed H-alpha and catalogued radio fluxes. H-alpha extinction values are also derived from catalogued H-alpha and H-beta flux values by means of an Rv dependent extinction law. Rv is then calculated in terms of observed extinction values and catalogued H-alpha and H-beta flux values. Comparing observed and catalogue extinction values for a subset of Bulge objects, observed values tend to be lower than catalogue values calculated with Rv = 3.1. For the same subset we calculate = 2.0, confirming that toward the Bulge interstellar extinction is steeper than Rv = 3.1. For the inner Galaxy a relation with the higher supernova rate is suggested, and that the low-density warm ionized medium is the site of the anomalous extinction. Lowvalues of extinction are also derived using dust models with a turnover radius of 0.08 microns.Comment: Accepted by MNRAS. 17 pages, 9 figures (including 36 contour plots of PNe), 5 Tables (including 2 large tables of angular diameters, fluxes and extinction

Chemical Abundances of Planetary Nebulae in the Sagittarius Dwarf Elliptical Galaxy

Spectrophotometry and imaging of the two planetary nebulae He2-436 and Wray16-423, recently discovered to be in the Sagittarius dwarf elliptical galaxy, are presented. Wray16-423 is a high excitation planetary nebula (PN) with a hot central star. In contrast He2-436 is a high density PN with a cooler central star and evidence of local dust, the extinction exceeding that for Wray16-423 by E(B-V)=0.28. The extinction to Wray16-423, (E(B-V)=0.14), is consistent with the extinction to the Sagittarius (Sgr) Dwarf. Both PN show Wolf-Rayet features in their spectra, although the lines are weak in Wray16-423. Images in [O III] and H-alpha+[N II], although affected by poor seeing, yield a diameter of 1.2'' for Wray16-423 after deconvolution; He~2-436 was unresolved. He2-436 has a luminosity about twice that of Wray16-423 and its size and high density suggest a younger PN. In order to reconcile the differing luminosity and nebular properties of the two PN with similar age progenitor stars, it is suggested that they are on He burning tracks The abundance pattern is very similar in both nebulae and shows an oxygen depletion of -0.4 dex with respect to the mean O abundance of Galactic PN and [O/H] = -0.6. The Sgr PN progenitor stars are representative of the higher metallicity tail of the Sgr population. The pattern of abundance depletion is similar to that in the only other PN in a dwarf galaxy companion of the Milky Way, that in Fornax, for which new spectra are presented. However the abundances are larger than for Galactic halo PN suggesting a later formation age. The O abundance of the Sgr galaxy deduced from its PN, shows similarities with that of dwarf ellipticals around M31, suggesting that this galaxy was a dwarf elliptical before its interaction with the Milky Way.Comment: 24 pages, Latex (aas2pp4.sty) including 5 postscript figures. To appear in Ap

Bright Planetary Nebulae and their Progenitors in Galaxies Without Star Formation

We present chemical abundances for planetary nebulae in M32, NGC 185, and NGC 205 based upon spectroscopy obtained at the Canada-France-Hawaii Telescope using the Multi-Object Spectrograph. From these and similar data compiled from the literature for other Local Group galaxies, we consider the origin and evolution of the stellar progenitors of bright planetary nebulae in galaxies where star formation ceased long ago. The ratio of neon to oxygen abundances in bright planetary nebulae is either identical to that measured in the interstellar medium of star-forming dwarf galaxies or at most changed by a few percent, indicating that neither abundance is significantly altered as a result of the evolution of their stellar progenitors. Several planetary nebulae appear to have dredged up oxygen, but these are the exception, not the rule. The progenitors of bright planetary nebulae typically enhance their original helium abundances by less than 50%. In contrast, nitrogen enhancements can reach factors of 100. However, nitrogen often shows little or no enhancement, suggesting that nitrogen enrichment is a random process. The helium, oxygen, and neon abundances argue that the typical bright planetary nebulae in all of the galaxies considered here are the progeny of stars with initial masses of approximately 1.5 Msun or less, based upon the nucleosynthesis predictions of current theoretical models. These models, however, are unable to explain the nitrogen enrichment or its scatter. Similar conclusions hold for the bright planetary nebulae in galaxies with ongoing star formation. Thus, though composition varies significantly, there is unity in the sense that the progenitors of typical bright planetary nebulae appear to have undergone similar physical processes. (Abridged)Comment: accepted for publication in the Astrophysical Journa

Critical Race Theory and Education: racism and anti-racism in educational theory and praxis

What is Critical Race Theory (CRT) and what does it offer educational researchers and practitioners outside the US? This paper addresses these questions by examining the recent history of antiracist research and policy in the UK. In particular, the paper argues that conventional forms of antiracism have proven unable to keep pace with the development of increasingly racist and exclusionary education polices that operate beneath a veneer of professed tolerance and diversity. In particular, contemporary antiracism lacks clear statements of principle and theory that risk reinventing the wheel with each new study; it is increasingly reduced to a meaningless slogan; and it risks appropriation within a reformist “can do” perspective dominated by the de-politicized and managerialist language of school effectiveness and improvement. In contrast, CRT offers a genuinely radical and coherent set of approaches that could revitalize critical research in education across a range of inquiries, not only in self-consciously "multicultural" studies. The paper reviews the developing terrain of CRT in education, identifying its key defining elements and the conceptual tools that characterise the work. CRT in education is a fast changing and incomplete project but it can no longer be ignored by the academy beyond North America

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.

[This corrects the article DOI: 10.1186/s13054-016-1208-6.]

Particle-γ Spectroscopy of the (p,d-γ)\u3csup\u3e155\u3c/sup\u3eGd Reaction: Neutron Single-quasiparticle States at N=91

A segmented Si telescope and HPGe array is used to study the 156Gd(p,d-γ)155Gd direct reaction by d-γ and d-γ-γ coincidence measurements using 25-MeV protons. The present investigation is the first time that this N = 91 nucleus and the N = 90 region—which is known for a rapid change from vibrational to rotational character, several low-lying 0+ states in the even-even nuclei, and large Coriolis (ΔΩ = 1) plus ΔN = 2 mixing in the even-odd nuclei—have been studied by particle-γ coincidence following a direct reaction with light ions. Gamma-ray energies and branches, excitation energies, angular distributions, and cross sections are measured for states directly populated in the (p,d) reaction. A new low-energy doublet state at 592.46 keV (previously associated with the K = 0⊗3−/2 [521] bandhead) and several new γ-ray transitions (particularly for states with excitation energies \u3e1 MeV) are presented. Most notably, the previous v 7+/2[404] systematics at and around the N = 90 transition region are brought into question and reassigned as ν 5+/2[402]. This reassignment makes the ν 1+/2[400], ν 3+/2[402], and ν 5+/2[402] orbitals, which originate from the 3s1/2, 2d3/2, and 2d5/2 spherical states, respectively, responsible for the three largest cross sections to positive-parity states in the (p,d)155Gd direct reaction. These three steeply upsloping orbitals undergo ΔN = 2 mixing with their N = 6 orbital partners, which are oppositely sloped with respect to deformation. The presence of these steeply sloped and crossing orbitals near the Fermi surface could weaken the monopole pairing strength and increase the quadrupole pairing strength of neighboring even-even nuclei, which would bring ν 2p-2h 0+ states below 2Δ. Indeed, this could account for a large number of the low-lying 0+ states populated in the (p,t)154Gd direct reaction

The Acceleration of the Nebular Shells in Planetary Nebulae in the Milky Way Bulge

We present a systematic study of line widths in the [\ion{O}{3}]$\lambda$5007 and H$\alpha$ lines for a sample of 86 planetary nebulae in the Milky Way bulge based upon spectroscopy obtained at the \facility{Observatorio Astron\'omico Nacional in the Sierra San Pedro M\'artir (OAN-SPM)} using the Manchester Echelle Spectrograph. The planetary nebulae were selected with the intention of simulating samples of bright extragalactic planetary nebulae. We separate the planetary nebulae into two samples containing cooler and hotter central stars, defined by the absence or presence, respectively, of the \ion{He}{2} $\lambda$6560 line in the H$\alpha$ spectra. This division separates samples of younger and more evolved planetary nebulae. The sample of planetary nebulae with hotter central stars has systematically larger line widths, larger radii, lower electron densities, and lower H$\beta$ luminosities. The distributions of these parameters in the two samples all differ at significance levels exceeding 99%. These differences are all in agreement with the expectations from hydrodynamical models, but for the first time confirmed for a homogeneous and statistically significant sample of galactic planetary nebulae. We interpret these differences as evidence for the acceleration of the nebular shells during the early evolution of these intrinsically bright planetary nebulae. As is the case for planetary nebulae in the Magellanic Clouds, the acceleration of the nebular shells appears to be the direct result of the evolution of the central stars.Comment: accepted for publication in Astrophysical Journa