Variations in the 6.2 μ\mum emission profile in starburst-dominated galaxies: a signature of polycyclic aromatic nitrogen heterocycles (PANHs)?

Analyses of the polycyclic aromatic hydrocarbon (PAH) feature profiles, especially the 6.2 $\mu$m feature, could indicate the presence of nitrogen incorporated in their aromatic rings. In this work, 155 predominantly starburst-dominated galaxies (including HII regions and Seyferts, for example), extracted from the Spitzer/IRS ATLAS project (Hern\'an-Caballero & Hatziminaoglou 2011), have their 6.2 $\mu$m profiles fitted allowing their separation into the Peeters' A, B and C classes (Peeters et al. 2002). 67% of these galaxies were classified as class A, 31% were as class B and 2% as class C. Currently class A sources, corresponding to a central wavelength near 6.22 $\mu$m, seem only to be explained by polycyclic aromatic nitrogen heterocycles (PANH, Hudgins et al. 2005), whereas class B may represent a mix between PAHs and PANHs emissions or different PANH structures or ionization states. Therefore, these spectra suggest a significant presence of PANHs in the interstellar medium (ISM) of these galaxies that could be related to their starburst-dominated emission. These results also suggest that PANHs constitute another reservoir of nitrogen in the Universe, in addition to the nitrogen in the gas phase and ices of the ISM

Comment on "Ab initio calculations of the lattice parameter and elastic stiffness coefficients of bcc Fe with solutes" Comp. Mat. Sci. v.126 pp.503-513 (2017)

In a recent paper, the authors propose to separately calculate the volumetric and chemical contributions to the elastic stiffness coefficients of systems containing solutes, as it is "computationally more efficient". We show that this is not the case and further that their methodology and hence their results are incorrect. There is no short cut for performing the desired calculations, if done rigorously, as we show in our 2012 work

The Golden Brain (the Praesidium of the Russian Academy of Sciences) (Photograph, with permission, by Nataliya Sadovskaya)

<p>The Golden Brain (the Praesidium of the Russian Academy of Sciences) (Photograph, with permission, by Nataliya Sadovskaya)</p

Papers Published in <i>Nature</i> and <i>Science</i> by Researchers with the 15 Most Common Russian Surnames (Ivanov[a], Kuznetsov[a], Smirnov[a], Etc)

<p>The number of all papers in which at least one coauthor has a name from this list is shown by the solid line, and the number of such papers that list at least one address inside the Soviet Union or Russia is shown by the broken line. Whereas before 1992 nearly 100% of ethnic Russians doing toplevel science resided inside the Soviet Union and Russia (hardly surprising!), by now, this number has dropped to below 25%.</p

Papers Published in <i>Nature</i> and <i>Science</i> in Which at Least One of the Coauthors Lists an Address inside the Soviet Union or Russia

<p>The actual number of such papers is shown by the solid line. Their “effective number,” into which each paper contributes with the coefficient equal to the fraction of addresses inside the Soviet Union or Russia from all the listed addresses, is shown by the broken line. In recent years, the contribution of ethnic Russians to high-quality research increased, but their work is mostly performed outside Russia.</p

Additional file 1: of Sugar Lego: gene composition of bacterial carbohydrate metabolism genomic loci

Bacterial genomes. 665 studied bacterial genomes, specified by species and strain name and taxonomy data available from GenBank [19]. (XLS 81 kb

Covariance matrix of strength vectors for constitutive-exon ASSs (<i>M</i>. <i>musculus</i>).

<p>Notations are the same as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0144388#pone.0144388.g002" target="_blank">Fig 2</a>. Positions (-12, -7) demonstrating the characteristic periodic pattern are marked by the black rectangle. (A) Original DSS sequences. (B) Artificial DSS sequences with the same dinucleotide content as the original sequences in positions (-12, -7) (see main text).</p

Relative strength changes ω for different positions of ASSs, in their evolution between the dog-human-mouse common ancestor and each of these species.

<p>Relative strength changes ω for different positions of ASSs, in their evolution between the dog-human-mouse common ancestor and each of these species.</p

Dinucleotide frequencies within the region of periodic correlations (positions (-12, -7)) of PPT.

<p>Observed/expected ratio of dinucleotide frequencies within PPT (positions (-12, -7)) and within adjacent intron. Dinucleotides are ordered by the observed/expected ratio within PPT, from low to high. The expected values were obtained based on mononucleotide content. The significance of the difference between observed/expected ratio within PPTs and within adjacent introns are indicated: * 0.01 < p ≤ 0.05; ** 0.001 < p ≤ 0.01; *** p ≤ 0.001; ns p > 0.05.</p

Relative strength changes ω for different positions of DSSs, in their evolution between the dog-human-mouse common ancestor and each of these species.

<p>Relative strength changes ω for different positions of DSSs, in their evolution between the dog-human-mouse common ancestor and each of these species.</p