We report the first detection in space of the single deuterated isotopologue of methylcyanoacetylene, CH2DC3N. A total of fifteen rotational transitions, with J = 8-12 and Ka = 0 and 1, were ...identified for this species in TMC-1 in the 31.0-50.4 GHz range using the Yebes 40m radio telescope. The observed frequencies were used to derive for the first time the spectroscopic parameters of this deuterated isotopologue. We derive a column density of (8.0 ± 0.4) × 1010 cm-2. The abundance ratio between CH3C3N and CH2DC3N is ∼22. We also theoretically computed the principal spectroscopic constants of 13C isotopologues of CH3C3N and CH3C4H and those of the deuterated isotopologues of CH3C4H for which we could expect a similar degree of deuteration enhancement. However, we have not detected either CH2DC4H nor CH3C4D nor any 13C isotopologue. The different observed deuterium ratios in TMC-1 are reasonably accounted for by a gas phase chemical model where the low temperature conditions favor deuteron transfer through reactions with H2D+.
The list of potential, possible or probable predatory scholarly open access (OA) publishers compiled by Jeffrey Beall was examined to determine the effect of their inclusion upon authors, and a ...possible bias against OA journals. Manually collected data from the publication archives of a sample of 250 journals from Beall publishers reveals a strong tendency towards a decline in their article output during 2012–2020. A comparison of the subset of 506 Beall journals indexed in Scopus with a benchmark set of other OA journals in Scopus with similar characteristics shows that Beall journals reveal as a group a strong decline in citation impact over the years, and reached an impact level far below that of their benchmarks. The Beall list of publishers was found to be heterogeneous in terms of bibliometric indicators but to be clearly differentiated from OA journals not included in the list. The same bibliometric comparison against comparable non‐OA journals reveal similar, but less marked, differences in citation and publication growth.
ABSTRACT
We report here the first detection in the interstellar medium of the cyanomidyl radical (HNCN). Using the Yebes 40m and the IRAM 30m telescopes, we have targeted the doublets of the N = 2–1, ...4–3, 5–4, 6–5, and 7–6 transitions of HNCN towards the molecular cloud G+0.693-0.027. We have detected three unblended lines of HNCN, these are the N = 6–5 doublet and one line of the N = 4–3 transition. Additionally, we present one line of the N = 5–4 transition partially blended with emission from other species. The local thermodynamic equilibrium best fit to the data gives a molecular abundance of (0.91 ± 0.05) × 10−10 with respect to H2. The relatively low abundance of this species in G+0.693-0.027 and its high reactivity suggest that HNCN is possibly produced by gas-phase chemistry. Our work shows that this highly reactive molecule is present in interstellar space, and thus it represents a plausible precursor of larger prebiotic molecules with the nitrogen–carbon–nitrogen backbone such as cyanamide (NH2CN), carbodiimide (HNCNH), and formamidine (NH2CHNH).
Using Scopus data, we construct a global map of science based on aggregated journal–journal citations from 1996–2012 (N of journals = 20,554). This base map enables users to overlay downloads from ...Scopus interactively. Using a single year (e.g., 2012), results can be compared with mappings based on the Journal Citation Reports at the Web of Science (N = 10,936). The Scopus maps are more detailed at both the local and global levels because of their greater coverage, including, for example, the arts and humanities. The base maps can be interactively overlaid with journal distributions in sets downloaded from Scopus, for example, for the purpose of portfolio analysis. Rao‐Stirling diversity can be used as a measure of interdisciplinarity in the sets under study. Maps at the global and the local level, however, can be very different because of the different levels of aggregation involved. Two journals, for example, can both belong to the humanities in the global map, but participate in different specialty structures locally. The base map and interactive tools are available online (with instructions) at http://www.leydesdorff.net/scopus_ovl.
We present the first detection of HCNS (thiofulminic acid) in space with the QUIJOTE line survey in the direction of TMC-1. We performed a complete study of the isomers of CHNS and CHNO, including ...NCO and NCS. The derived column densities for HCNS, HNCS, and HSCN are (9.0 ± 0.5) × 10
9
, (3.2 ± 0.1) × 10
11
, and (8.3 ± 0.4) × 10
11
cm
−2
, respectively. The HNCS/HSCN abundance ratio is 0.38. The abundance ratios HNCO/HNCS, HCNO/HCNS, HOCN/HSCN, and NCO/NCS are 34 ± 4, 8.3 ± 0.7, 0.18 ± 0.03, and 0.78 ± 0.07, respectively. These ratios cannot be correctly reproduced by our gas-phase chemical models, which suggests that formation paths for these species are missing, and/or that the adopted dissociative recombination rates for their protonated precursors have to be revised. The isotopologues H
15
NCO, DNCO, HN
13
CO, DCNO, H
34
SCN, and DSCN have also been detected with the ultrasensitive QUIJOTE line survey.
Abstract
The high brightness temperatures, Tb ≳ 1013 K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. Refractive scattering by the ...interstellar medium may affect such measurements. We quantify the scattering properties and the sub-mas scale source parameters for the quasar B0529+483. Using RadioAstron correlated flux density measurements at 1.7, 4.8, and 22 GHz on projected baselines up to 240 000 km we find two characteristic angular scales in the quasar core, about 100 and 10 μas. Some indications of scattering substructure are found. Very high brightness temperatures, Tb ≥ 1013 K, are estimated at 4.8 and 22 GHz even taking into account the refractive scattering. Our findings suggest a clear dominance of the particle energy density over the magnetic field energy density in the core of this quasar.
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