SPECTRAL CLASSIFICATION OF ARCHAEAL AND BACTERIAL GENOMES

2002 ◽  
Vol 10 (03) ◽  
pp. 233-241 ◽  
Author(s):  
SU-LONG NYEO ◽  
I-CHING YANG ◽  
CHI-HAO WU
Keyword(s):  
Dna Sequences ◽  
Power Spectra ◽  
Helical Structure ◽  
Spectral Classification ◽  
Bacterial Genomes ◽  
Denaturation Temperature ◽  
Noncoding Sequences ◽  
Double Helical Structure ◽  
Complete Genomes

The power spectra of the nucleotides in the coding and noncoding sequences of the complete genomes of twenty-two archaea and bacteria are obtained. According to the intensities at the periodicity of 3 bp in the spectra, it is observed that the genomic sequences may be classified into three types. Moreover, the spectra generally have a small but broad peak in the 10–11 bp periodicities. For the archaea, the peak is seen to locate preferably at about 10 bp periodicity, while for the bacteria, it tends to locate at about 11 bp. These features suggest that the DNA sequences of archaea generally have a tighter double helical structure than those of bacteria in order to cope with harsh environmental conditions. Besides, among the archaea, A. Pernixi K1 is found to have the largest periodicity of about 11 bp, but has a comparatively high CG content in its genome and hence a high denaturation temperature.

Note on the spectral classification of carbon stars in the photographic infrared region

1966 ◽  
Vol 24 ◽  
pp. 21-23
Author(s):  
Y. Fujita
Keyword(s):  
Infrared Region ◽  
Spectral Classification ◽  
Carbon Stars

We have investigated the spectrograms (dispersion: 8Å/mm) in the photographic infrared region fromλ7500 toλ9000 of some carbon stars obtained by the coudé spectrograph of the 74-inch reflector attached to the Okayama Astrophysical Observatory. The names of the stars investigated are listed in Table 1.

Ultraviolet Spectral Classification of O and B Stars in the Large Magellanic Cloud

1999 ◽  
Vol 117 (6) ◽  
pp. 2856-2867 ◽  
Author(s):  
Margaret M. Smith Neubig ◽  
Frederick C. Bruhweiler
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Spectral Classification ◽  
B Stars

Discovery of New Genera Challenges the Subtribal Classification of Tok-Tok Beetles (Coleoptera: Tenebrionidae: Sepidiini)

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Olivia M Gearner ◽  
Marcin J Kamiński ◽  
Kojun Kanda ◽  
Kali Swichtenberg ◽  
Aaron D Smith
Keyword(s):  
Dna Sequences ◽  
Species Group ◽  
Phylogenetic Placement ◽  
Darkling Beetles ◽  
Species Groups ◽  
Taxonomic Groups ◽  
Inference Methods ◽  
A New Species ◽  
Coleoptera Tenebrionidae

Abstract Sepidiini is a speciose tribe of desert-inhabiting darkling beetles, which contains a number of poorly defined taxonomic groups and is in need of revision at all taxonomic levels. In this study, two previously unrecognized lineages were discovered, based on morphological traits, among the extremely speciose genera Psammodes Kirby, 1819 (164 species and subspecies) and Ocnodes Fåhraeus, 1870 (144 species and subspecies), namely the Psammodes spinosus species-group and Ocnodes humeralis species-group. In order to test their phylogenetic placement, a phylogeny of the tribe was reconstructed based on analyses of DNA sequences from six nonoverlapping genetic loci (CAD, wg, COI JP, COI BC, COII, and 28S) using Bayesian and maximum likelihood inference methods. The aforementioned, morphologically defined, species-groups were recovered as distinct and well-supported lineages within Molurina + Phanerotomeina and are interpreted as independent genera, respectively, Tibiocnodes Gearner & Kamiński gen. nov. and Tuberocnodes Gearner & Kamiński gen. nov. A new species, Tuberocnodes synhimboides Gearner & Kamiński sp. nov., is also described. Furthermore, as the recovered phylogenetic placement of Tibiocnodes and Tuberocnodes undermines the monophyly of Molurina and Phanerotomeina, an analysis of the available diagnostic characters for those subtribes is also performed. As a consequence, Phanerotomeina is considered as a synonym of the newly redefined Molurina sens. nov. Finally, spectrograms of vibrations produced by substrate tapping of two Molurina species, Toktokkus vialis (Burchell, 1822) and T. synhimboides, are presented.

scholarly journals UV Spectral Classification of B Stars

1985 ◽  
Vol 111 ◽  
pp. 411-413
Author(s):  
Janet Rountree ◽  
George Sonneborn ◽  
Robert J. Panek
Keyword(s):  
Classification System ◽  
Classification Criteria ◽  
High Dispersion ◽  
Spectral Classification ◽  
Early Type ◽  
B Stars ◽  
Dimensional Classification ◽  
Early Type Stars ◽  
Comprehensive Classification

Previous studies of ultraviolet spectral classification have been insufficient to establish a comprehensive classification system for ultraviolet spectra of early-type stars because of inadequate spectral resolution. We have initiated a new study of ultraviolet spectral classification of B stars using high-dispersion IUE archival data. High-dispersion SWP spectra of MK standards and other B stars are retrieved from the IUE archives and numerically degraded to a uniform resolution of 0.25 or 0.50 Å. The spectra (in the form of plots or photowrites) are then visually examined with the aim of setting up a two-dimensional classification matrix. We follow the method used to create the MK classification system for visual spectra. The purpose of this work is to examine the applicability of the MK system (and in particular, the set of standard stars) in the ultraviolet, and to establish classification criteria in this spectral region.

scholarly journals A New Revision of the HDEC (Henry Draper Extension Charts) Catalog

2016 ◽  
Vol 25 (1) ◽  
Author(s):  
N. Ashimbaeva ◽  
V. Sementsov
Keyword(s):  
Binary Systems ◽  
Measurement Model ◽  
Spectral Classification ◽  
Multiple Systems ◽  
Cross Matching

AbstractA new version of the HDEC (Henry Draper Extension Charts) catalog is presented. The catalog includes 88,548 entries, more than 3500 of which (components of binary systems) were earlier corrupted by an algorithmic error (1579 multiple systems were revealed). Spectral classification of these objects has been corrected manually using the CDS data. We also corrected some mistakes of the catalog detected by the measurement model and cross-matching with other CDS catalogs, and, in some cases, by the authors of the catalog and through collaboration of the HDEC users.

scholarly journals Living supramolecular polymerization of fluorinated cyclohexanes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Oleksandr Shyshov ◽  
Shyamkumar Vadakket Haridas ◽  
Luca Pesce ◽  
Haoyuan Qi ◽  
Andrea Gardin ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Self Assembly ◽  
Materials Science ◽  
Helical Structure ◽  
The Self ◽  
Supramolecular Polymers ◽  
Aliphatic Compound ◽  
Double Helical Structure ◽  
Key Driver ◽  
Supramolecular Polymerization

AbstractThe development of powerful methods for living covalent polymerization has been a key driver of progress in organic materials science. While there have been remarkable reports on living supramolecular polymerization recently, the scope of monomers is still narrow and a simple solution to the problem is elusive. Here we report a minimalistic molecular platform for living supramolecular polymerization that is based on the unique structure of all-cis 1,2,3,4,5,6-hexafluorocyclohexane, the most polar aliphatic compound reported to date. We use this large dipole moment (6.2 Debye) not only to thermodynamically drive the self-assembly of supramolecular polymers, but also to generate kinetically trapped monomeric states. Upon addition of well-defined seeds, we observed that the dormant monomers engage in a kinetically controlled supramolecular polymerization. The obtained nanofibers have an unusual double helical structure and their length can be controlled by the ratio between seeds and monomers. The successful preparation of supramolecular block copolymers demonstrates the versatility of the approach.

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