Tracing the evolutionary stage of Bok globules: CCS and NH3

Abstract Determining the mechanism by which high-mass stars are formed is essential for our understanding of the energy budget and chemical evolution of galaxies. By using the New IRAM KIDs Array 2 (NIKA2) camera on the Institut de Radio Astronomie Millimétrique (IRAM) 30-m telescope, we have conducted high-sensitivity and large-scale mapping of a fraction of the Galactic plane in order to search for signatures of the transition between the high- and low-mass star-forming modes. Here, we present the first results from the Galactic Star Formation with NIKA2 (GASTON) project, a Large Programme at the IRAM 30-m telescope which is mapping ≈2 deg2 of the inner Galactic plane (GP), centred on ℓ = 23${_{.}^{\circ}}$9, b = 0${_{.}^{\circ}}$05, as well as targets in Taurus and Ophiuchus in 1.15 and 2.00 mm continuum wavebands. In this paper we present the first of the GASTON GP data taken, and present initial science results. We conduct an extraction of structures from the 1.15 mm maps using a dendrogram analysis and, by comparison to the compact source catalogues from Herschel survey data, we identify a population of 321 previously-undetected clumps. Approximately 80 per cent of these new clumps are 70 μm-quiet, and may be considered as starless candidates. We find that this new population of clumps are less massive and cooler, on average, than clumps that have already been identified. Further, by classifying the full sample of clumps based upon their infrared-bright fraction – an indicator of evolutionary stage – we find evidence for clump mass growth, supporting models of clump-fed high-mass star formation.

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Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

ISME Communications ◽

10.1038/s43705-021-00041-z ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Yue Xing ◽

Xiaoxi Kang ◽

Siwei Zhang ◽

Yujie Men

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Selective Pressure ◽

Fold Increase ◽

Streptomycin Resistance ◽

Evolutionary Stage ◽

Fitness Costs ◽

Evolutionary Trajectories ◽

K 12 ◽

Late Stages

AbstractTo explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5–6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

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Anatomie, histologie et affinités de l'appareil séricigène des Hersilia Sav. et Aud. (Araneae: Hersiliidae)

Canadian Journal of Zoology ◽

10.1139/z84-017 ◽

1984 ◽

Vol 62 (1) ◽

pp. 97-106 ◽

Cited By ~ 2

Author(s):

Jacqueline Kovoor

Keyword(s):

Type A ◽

The Other ◽

Secretory Cells ◽

Evolutionary Stage ◽

Type B ◽

Outer Coat ◽

Silk Glands ◽

Single Protein

Although hersiliid spiders do not spin any webs, their silk glands, which belong to six types, are large and complex. Two groups of ampullate glands, one opening on the anterior spinnerets and the other on the median spinnerets, secrete two proteins each. About 180 pyriform glands are clearly bipartite. Over 200 type A aciniform glands opening on the median and posterior spinnerets are made up of three categories of secretory cells. Silk from these glands consists of two proteins (core and outer coat) joined together by an intermediary layer of acidic glycoprotein. All the 160 type B aciniform glands opening on the posterior spinnerets secrete a single protein. Fifty tubuliform glands opening on the median and posterior spinnerets produce two proteins, one of which is coloured. As in Urocteinae, long posterior spinnerets and large, numerous aciniform and tubuliform glands are correlated with swathing of prey and egg-cocoon construction. In Lycosidae and Agelenidae, the ampullate glands show the same number and distribution according to the spinnerets. However, anatomical and histochemical features of hersiliid aciniform and ampullate glands are close to those of some Araneoidea. Apart from peculiar characteristics, silk glands of Hersilia might represent an intermediate evolutionary stage towards Araneoidea.

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Aminoacyl-tRNA Synthetases, the Genetic Code, and the Evolutionary Process

Microbiology and Molecular Biology Reviews ◽

10.1128/mmbr.64.1.202-236.2000 ◽

2000 ◽

Vol 64 (1) ◽

pp. 202-236 ◽

Cited By ~ 447

Author(s):

Carl R. Woese ◽

Gary J. Olsen ◽

Michael Ibba ◽

Dieter Söll

Keyword(s):

Genetic Code ◽

Phylogenetic Trees ◽

Genetic Material ◽

Evolutionary Process ◽

Group Iv ◽

Evolutionary Relationships ◽

Evolutionary Stage ◽

Trna Synthetases ◽

Aminoacyl Trna Synthetases ◽

The Individual

SUMMARY The aminoacyl-tRNA synthetases (AARSs) and their relationship to the genetic code are examined from the evolutionary perspective. Despite a loose correlation between codon assignments and AARS evolutionary relationships, the code is far too highly structured to have been ordered merely through the evolutionary wanderings of these enzymes. Nevertheless, the AARSs are very informative about the evolutionary process. Examination of the phylogenetic trees for each of the AARSs reveals the following. (i) Their evolutionary relationships mostly conform to established organismal phylogeny: a strong distinction exists between bacterial- and archaeal-type AARSs. (ii) Although the evolutionary profiles of the individual AARSs might be expected to be similar in general respects, they are not. It is argued that these differences in profiles reflect the stages in the evolutionary process when the taxonomic distributions of the individual AARSs became fixed, not the nature of the individual enzymes. (iii) Horizontal transfer of AARS genes between Bacteria and Archaea is asymmetric: transfer of archaeal AARSs to the Bacteria is more prevalent than the reverse, which is seen only for the “gemini group.” (iv) The most far-ranging transfers of AARS genes have tended to occur in the distant evolutionary past, before or during formation of the primary organismal domains. These findings are also used to refine the theory that at the evolutionary stage represented by the root of the universal phylogenetic tree, cells were far more primitive than their modern counterparts and thus exchanged genetic material in far less restricted ways, in effect evolving in a communal sense.

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ANALYSIS OF THE STRUCTURAL DYNAMICS OF THE DIGITAL ECONOMY IN TODAY'S REALITIES

Scientific Journal ECONOMIC SYSTEMS ◽

10.29030/2309-2076-2021-14-1-40-47 ◽

2021 ◽

Vol 14 (1) ◽

pp. 40-47

Author(s):

Tatуana Ivanovna LOMACHENKO ◽

Keyword(s):

Structural Dynamics ◽

Digital Technology ◽

Business Strategy ◽

Production Management ◽

Production Efficiency ◽

Business Processes ◽

Business Environment ◽

Digital Economy ◽

Digital Transformation ◽

Evolutionary Stage

Nowadays, there is no consensus that digitalization is a threat to business security or an opportunity to comprehensively manage the entire chain of business processes in real time, taking into account incoming data from all assets. However, political and economic instability, demand volatility, and competition are all a set of global challenges that digital transformation has responded to. In industry, the competitive advantage has become not the ownership of the enterprise, the firm, but access to digital technology, on which the efficiency of work with specific resources depends. The processes of forming individual business segments related to production management based on modern digital technology have already been launched and most companies are focused on this direction. The article reveals the features of the evolutionary stage of digital economy development, presents the relationship of this process with the formation of the conceptual framework from the theoretical foundations, substantiated in the 1990s by foreign and domestic scientists to modern approaches in the interpretation of digital economy definitions. The article proposes the structural dynamics of the digital economy in today's realities, revealing internal problems, opportunities for economic growth, maturity and readiness of the state to new ways of doing business in the digital economy and digital transformation, to form the country's national strategy. In addition, the conditions under which digital transformation opens up new opportunities for the business environment, the public sector and society as a whole are presented. Changes in business strategy, organizational forms, business process capabilities, new approaches in working with clients, competitive advantages, increase in profit sources are analyzed. As a result, the efficiency of the whole system increases, which allows to reach a fundamentally new level of production efficiency in a short time.

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Allometric heterochrony in the Pliocene-Pleistocene planktic foraminiferal clade Globoconella

Paleobiology ◽

10.1017/s0094837300011143 ◽

1994 ◽

Vol 20 (1) ◽

pp. 66-84 ◽

Cited By ~ 21

Author(s):

Kuo-Yen Wei

Keyword(s):

Opposite Direction ◽

Morphological Evolution ◽

Evolutionary Stage ◽

Allometric Growth ◽

Displacement Mode ◽

Ancestral Lineage ◽

Wide Range ◽

Allometric Analysis ◽

Acceleration Mode ◽

Evolutionary Stasis

Allometric analysis of the size-shape relationships in the Pliocene-Pleistocene planktic foraminiferal Globorotalia (Globoconella) puncticulata-inflata plexus reveals several heterochronic modes underlying the morphological evolution of the clade. The ancestral lineage, G. puncticulata, is a peramorphocline, showing a pre-displacement mode of heterochrony between 3.5 Ma and 3.0 Ma and an acceleration mode from 3.0 to 2.7 Ma. A different peramorphosis process, isometric giantism (hypermorphosis), in the ontogeny of the ancestral stocks of Globoconella occurred at about 3.5 Ma and gave rise to the G. inflata lineage. The descendant lineage, G. inflata, appears to have adopted a paedomorphosis trend by delaying the onset of the neanic stage in ontogeny during the period of 3.5 to 2.35 Ma, resulting in a series of transposition allometries. During the interval of 2.4 to 1.73 Ma, the allometries shifted to the opposite direction, signifying a pre-displacement trend. Evolutionary stasis marks the evolution during 1.73 to 0.25 Ma. Neoteny concluded the final evolutionary stage of the G. inflata lineage during the latest Quaternary (0.26 to 0.05 Ma). The enormous plasticity and fluctuations in morphology of G. inflata are attributed to the highly positive allometric growth during the ontogeny and the wide-range transposing allometries in the phyletic history. The major changes in heterochronic mode coincide with paleoceanographic events, suggesting that the morphological evolution in the Globoconella clade has been modulated by changes in paleoceanographic conditions.

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Nitrogen and hydrogen fractionation in high-mass star-forming cores from observations of HCN and HNC

Astronomy and Astrophysics ◽

10.1051/0004-6361/201730576 ◽

2018 ◽

Vol 609 ◽

pp. A129 ◽

Cited By ~ 12

Author(s):

L. Colzi ◽

F. Fontani ◽

P. Caselli ◽

C. Ceccarelli ◽

P. Hily-Blant ◽

...

Keyword(s):

Solar System ◽

Solar Nebula ◽

Rotational Transition ◽

High Mass ◽

Evolutionary Stage ◽

Mass Star ◽

Stellar Cluster ◽

Star Forming ◽

Star Forming Regions ◽

Dense Cores

The ratio between the two stable isotopes of nitrogen, 14N and 15N, is well measured in the terrestrial atmosphere (~272), and for the pre-solar nebula (~441, deduced from the solar wind). Interestingly, some pristine solar system materials show enrichments in 15N with respect to the pre-solar nebula value. However, it is not yet clear if and how these enrichments are linked to the past chemical history because we have only a limited number of measurements in dense star-forming regions. In this respect, dense cores, which are believed to be the precursors of clusters and also contain intermediate- and high-mass stars, are important targets because the solar system was probably born within a rich stellar cluster, and such clusters are formed in high-mass star-forming regions. The number of observations in such high-mass dense cores has remained limited so far. In this work, we show the results of IRAM-30 m observations of the J = 1−0 rotational transition of the molecules HCN and HNC and their 15N-bearing counterparts towards 27 intermediate- and high-mass dense cores that are divided almost equally into three evolutionary categories: high-mass starless cores, high-mass protostellar objects, and ultra-compact Hii regions. We have also observed the DNC(2–1) rotational transition in order to search for a relation between the isotopic ratios D/H and 14N/15N. We derive average 14N/15N ratios of 359 ± 16 in HCN and of 438 ± 21 in HNC, with a dispersion of about 150–200. We find no trend of the 14N/15N ratio with evolutionary stage. This result agrees with what has been found for N2H+ and its isotopologues in the same sources, although the 14N/15N ratios from N2H+ show a higher dispersion than in HCN/HNC, and on average, their uncertainties are larger as well. Moreover, we have found no correlation between D/H and 14N/15N in HNC. These findings indicate that (1) the chemical evolution does not seem to play a role in the fractionation of nitrogen, and that (2) the fractionation of hydrogen and nitrogen in these objects is not related.

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On the Evolutionary Stage of the Interacting Binary AU Mon

Publications of the Astronomical Society of the Pacific ◽

10.1086/678457 ◽

2014 ◽

Vol 126 (943) ◽

pp. 821-826 ◽

Cited By ~ 5

Author(s):

R. E. Mennickent

Keyword(s):

Evolutionary Stage

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The magnetic field in the dense photodissociation region of DR 21

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3898 ◽

2020 ◽

Author(s):

Atanu Koley ◽

Nirupam Roy ◽

Karl M Menten ◽

Arshia M Jacob ◽

Thushara G S Pillai ◽

...

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Zeeman Effect ◽

Zeeman Splitting ◽

Weak Field ◽

Field Energy ◽

Evolutionary Stage ◽

Maser Emission ◽

The Magnetic Field ◽

Photodissociation Region

Abstract Measuring interstellar magnetic fields is extremely important for understanding their role in different evolutionary stages of interstellar clouds and of star formation. However, detecting the weak field is observationally challenging. We present measurements of the Zeeman effect in the 1665 and 1667 MHz (18 cm) lines of the hydroxyl radical (OH) lines toward the dense photodissociation region (PDR) associated with the compact H ii region DR 21 (Main). From the OH 18 cm absorption, observed with the Karl G. Jansky Very Large Array, we find that the line of sight magnetic field in this region is ∼0.13 mG. The same transitions in maser emission toward the neighbouring DR 21(OH) and W 75S-FR1 regions also exhibit the Zeeman splitting. Along with the OH data, we use [C ii] 158 μm line and hydrogen radio recombination line data to constrain the physical conditions and the kinematics of the region. We find the OH column density to be ∼3.6 × 1016(Tex/25 K) cm−2, and that the 1665 and 1667 MHz absorption lines are originating from the gas where OH and C+ are co-existing in the PDR. Under reasonable assumptions, we find the measured magnetic field strength for the PDR to be lower than the value expected from the commonly discussed density–magnetic field relation while the field strength values estimated from the maser emission are roughly consistent with the same. Finally, we compare the magnetic field energy density with the overall energetics of DR 21’s PDR and find that, in its current evolutionary stage, the magnetic field is not dynamically important.

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