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Abstract We present laboratory rotational spectroscopy of five isomers of cyanoindene (2-, 4-, 5-, 6-, and 7-cyanoindene) using a cavity Fourier transform microwave spectrometer operating between 6 and 40 GHz. Based on these measurements, we report the detection of 2-cyanoindene (1H-indene-2-carbonitrile; 2- C 9 H 7 CN ) in GOTHAM line survey observations of the dark molecular cloud TMC-1 using the Green Bank Telescope at centimeter wavelengths. Using a combination of Markov Chain Monte Carlo, spectral stacking, and matched filtering techniques, we find evidence for the presence of this molecule at the 6.3 σ level. This provides the first direct observation of the ratio of a cyano-substituted polycyclic aromatic hydrocarbon to its pure hydrocarbon counterpart, in this case indene, in the same source. We discuss the possible formation chemistry of this species, including why we have only detected one of the isomers in TMC-1. We then examine the overall hydrocarbon:CN-substituted ratio across this and other simpler species, as well as compare to those ratios predicted by astrochemical models. We conclude that while astrochemical models are not yet sufficiently accurate to reproduce absolute abundances of these species, they do a good job at predicting the ratios of hydrocarbon:CN-substituted species, further solidifying -CN tagged species as excellent proxies for their fully symmetric counterparts.
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Evidence does not support the conclusion that Hexarthra intermedia (Rotifera, Monogononta, Flosculariaceae) causes mortality in Bosmina longirostris (Cladocera, Diplostraca, Branchiopoda)
Based on observations of preserved samples, Jaramillo-Londoño & Pinto-Coelho (2010) describe a putative ecological relationship between the rotifer Hexarthra intermedia and the cladoceran Bosmina longirostris as a fusion of parasitism and interference competition. They argue that H. intermedia enter the filtering chamber of B. longirostris allowing the rotifer to exploit food collected by Bosmina, while simultaneously receiving protection from predators. In addition, they surmise that the result of this interaction can lead to death of Bosmina. We posit two simpler explanations for their observations. (1) Presence of H. intermedia in the cladoceran’s filtering chamber is an artifact of the collection methods. (2) Statistical correlations between the population levels of these two species simply means that the environment was suitable for their growth. Thus until additional evidence corroborates their findings, the simpler explanations should prevail.
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- PAR ID:
- 10214759
- Date Published:
- Journal Name:
- Limnética
- Volume:
- 38
- Issue:
- 1
- ISSN:
- 0213-8409
- Page Range / eLocation ID:
- 147-157
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.23818/limn.38.16
