scholarly journals A modern scleractinian coral with a two-component calcite–aragonite skeleton

2020 ◽  
pp. 202013316
Author(s):  
Jarosław Stolarski ◽  
Ismael Coronado ◽  
Jack G. Murphy ◽  
Marcelo V. Kitahara ◽  
Katarzyna Janiszewska ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Southern Ocean ◽  
Phylogenetic Relationship ◽  
Fossil Record ◽  
Scleractinian Coral ◽  
Scleractinian Corals ◽  
Marine Organisms ◽  
Close Phylogenetic Relationship ◽  
Two Component ◽  
Selection Of

One of the most conserved traits in the evolution of biomineralizing organisms is the taxon-specific selection of skeletal minerals. All modern scleractinian corals are thought to produce skeletons exclusively of the calcium-carbonate polymorph aragonite. Despite strong fluctuations in ocean chemistry (notably the Mg/Ca ratio), this feature is believed to be conserved throughout the coral fossil record, spanning more than 240 million years. Only one example, the Cretaceous scleractinian coral Coelosmilia (ca. 70 to 65 Ma), is thought to have produced a calcitic skeleton. Here, we report that the modern asymbiotic scleractinian coral Paraconotrochus antarcticus living in the Southern Ocean forms a two-component carbonate skeleton, with an inner structure made of high-Mg calcite and an outer structure composed of aragonite. P. antarcticus and Cretaceous Coelosmilia skeletons share a unique microstructure indicating a close phylogenetic relationship, consistent with the early divergence of P. antarcticus within the Vacatina (i.e., Robusta) clade, estimated to have occurred in the Mesozoic (ca. 116 Mya). Scleractinian corals thus join the group of marine organisms capable of forming bimineralic structures, which requires a highly controlled biomineralization mechanism; this capability dates back at least 100 My. Due to its relatively prolonged isolation, the Southern Ocean stands out as a repository for extant marine organisms with ancient traits.

Competition of Verb Aspects and Its Resolution as a Creative Act (Based on the Material of Aspects Variants in the Texts by F. M. Dostoevsky)

2020 ◽  
Vol 81 (2) ◽  
pp. 56-63
Author(s):  
S. A. Karpukhin
Keyword(s):  
Traditional Method ◽  
Contextual Analysis ◽  
Verb Aspect ◽  
Component Theory ◽  
Two Component ◽  
Artistic Interpretation ◽  
New Perspective ◽  
First Time ◽  
Selection Of ◽  
Aspectual Meaning

The article considers the competition of verbal aspects from a new perspective. Instead of employing the traditional method of demonstrating this phenomenon — an empirical replacement of the aspect of a verb in a phrase with the opposite — the author examines Dostoevsky’s choice between the variants found in different manuscripts of the same text. For the first time, based on a two-component theory of the semantic invariant of a verb type, the aspectual meaning of the selection of a verb aspect is revealed and, as a result of contextual analysis, an artistic interpretation of the selected type is proposed.

CHROMOSOME PAIRING IN TWO INTERSPECIFIC HYBRIDS OF TRIFOLIUM

1970 ◽  
Vol 12 (4) ◽  
pp. 790-794 ◽  
Author(s):  
Chi-Chang Chen ◽  
Pryce B. Gibson
Keyword(s):  
Phylogenetic Relationship ◽  
Chromosome Pairing ◽  
Trifolium Repens ◽  
Interspecific Hybrids ◽  
Triploid Hybrid ◽  
Close Phylogenetic Relationship ◽  
Metaphase I

Both Trifolium repens (2n = 32) and T. nigrescens (2n = 16) formed bivalents during meiosis. However, their triploid hybrid showed an average of 4.27 trivalents per microsporocyte at metaphase I. The frequency of trivalents in the hybrid between T. nigrescens and autotetraploid T. occidentale (2n = 32) was 5.69. The data are interpreted to indicate: (1) a possible autotetraploid origin of T. repens; and (2) a close phylogenetic relationship among T. repens, T. nigrescens and T. occidentale.

Three new species of Sectonema Thorne, 1930 (Dorylaimida: Aporcelaimidae) from Vietnam

Nematology ◽  
2016 ◽  
Vol 18 (5) ◽  
pp. 517-536 ◽  
Author(s):  
Sergio Álvarez-Ortega ◽  
Thi Anh Duong Nguyen ◽  
Joaquín Abolafia ◽  
Thi Thanh Tam Vu ◽  
Michael Bonkowski ◽  
...  
Keyword(s):  
New Species ◽  
Phylogenetic Relationship ◽  
Ventral Side ◽  
Molecular Data ◽  
Evolutionary Tree ◽  
Neck Length ◽  
Natural Habitats ◽  
Line Drawings ◽  
Close Phylogenetic Relationship ◽  
Three New Species

Three new species of the genus Sectonema collected from natural habitats in Vietnam are studied, described and illustrated, including line drawings, LM and/or SEM pictures. Sectonema birrucephalum sp. n. is characterised by its 2.73-4.35 mm long body, lip region 18-20 μm broad and offset by deep constriction, odontostyle 10.0-11.5 μm long on its ventral side, 659-989 μm long neck, pharyngeal expansion occupying 63-68% of total neck length, uterus a simple tube, 221-277 μm long, pars refringens vaginae present, V = 54-56, tail short (31-43 μm, c = 85-111, c′ = 0.6-0.8) and rounded, spicules 72-75 μm long, and four or five irregularly spaced ventromedian supplements beyond the range of the spicules. Sectonema buccociliatum sp. n. is distinguished by its 2.00-2.46 mm long body, lip region offset by constriction, 19-20 μm broad and bearing perioral cilia-like structures, odontostyle 13-14 μm long at its ventral side, 530-625 μm long neck, pharyngeal expansion occupying 62-69% of total neck length, uterus a simple tube, 116-152 μm long, pars refringens vaginae present, V = 56-62, tail short (23-31 μm, c = 72-104, c′ = 0.6-0.8) and rounded, spicules 56-68 μm long, and 3-5 spaced and weakly developed ventromedian supplements beyond the range of the spicules. Sectonema ciliatum sp. n. is characterised by its 2.79-3.13 mm long body, lip region offset by constriction, 21-22 μm broad and bearing perioral cilia-like structures, odontostyle 14-15 μm long at its ventral side, 699-722 μm long neck, pharyngeal expansion occupying 60% of total neck length, uterus a simple tube, 201-244 μm long, pars refringens vaginae present, V = 52-53, tail short (33-35 μm, c = 82-92, c′ = 0.6-0.7) and rounded, spicules 70-72 μm long, and three or four spaced and weakly developed ventromedian supplements beyond the range of the spicules. Molecular data obtained for S. ciliatum sp. n. and the derived evolutionary tree show a close phylogenetic relationship with other species of the genus.

Analysing sport data with clusters of opposite preferences

2018 ◽  
Vol 18 (5-6) ◽  
pp. 505-524 ◽  
Author(s):  
Rosaria Simone ◽  
Maria Iannario
Keyword(s):  
Sport Participation ◽  
Sport Activity ◽  
Discrete Models ◽  
Component Mixture ◽  
Rating Data ◽  
Self Evaluation ◽  
Specific Policy ◽  
Two Component ◽  
Competing Models ◽  
Selection Of

In the analysis of questionnaire-based evaluation of sport preferences, measurements of sport participation, opinions on social implications such as resurgence of racism, violence in stadiums and doping, the need arises to establish connections among motivations, subjects’ characteristics and responses. In this setting, the article deals with a selection of statistical models suitable to analyse sport rating data in which clusters of opposite responses are observed. Specifically, a two-component mixture of inverse hypergeometric (MIHG) distributions will be introduced and tested against competing models in order to yield a multifold interpretation of results. The ultimate comparative analysis will consider discrete models with a specific focus on those accounting for both uncertainty and feeling of self-evaluation in presence of inflation at the extreme categories. After a brief review of the methods, the proposal will be discussed both on ranking and rating data on the basis of two surveys on sport preferences and on measurements of sport activity: the identification of clusters of respondents with opposite choices will be investigated also in terms of covariates by comparing fitting performances of the selected models. The conclusions and insights offered by the study can be exploited to design plans of action for some specific policy or marketing strategy.

Statoblast morphology and systematics of the freshwater bryozoan Hyalinella orbisperma (Kellicott, 1882)

1992 ◽  
Vol 70 (8) ◽  
pp. 1536-1540 ◽  
Author(s):  
Anthony Ricciardi ◽  
Timothy S. Wood
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phylogenetic Relationship ◽  
Georgian Bay ◽  
Close Phylogenetic Relationship ◽  
First Time ◽  
Scanning Electron

The freshwater bryozoan Hyalinella orbisperma (Ectoprocta: Phylactolaemata), previously known only from Michigan, is added to the list of Canadian fauna from a specimen collected at Georgian Bay, Ontario. Floatoblasts match the appearance of those described from Michigan. The sessoblast of this species is recorded and illustrated for the first time. The case for other species with sessoblasts in the genus Hyalinella is extremely weak. Scanning electron microscopy of the floatoblast and sessoblast reveals a raised reticulation with interstitial tubercles covering the capsule periblast, suggesting a close phylogenetic relationship with certain Plumatella species. It is proposed that H. orbisperma be reassigned to the genus Plumatella.

scholarly journals A survey of HK, HPt, and RR domains and their organization in two-component systems and phosphorelays proteins of organisms with fully sequenced genomes

2015 ◽  
Author(s):  
Baldiri Salvado ◽  
Ester Vilaprinyo ◽  
Albert Sorribas ◽  
Rui Alves
Keyword(s):  
Response Regulator ◽  
Signal Transmission ◽  
Pr Proteins ◽  
Component Systems ◽  
Two Component ◽  
Domains Of Life ◽  
Two Component Systems ◽  
Operon Organization ◽  
The Individual ◽  
Selection Of

Two Component Systems and Phosphorelays (TCS/PR) are environmental signal transduction cascades in prokaryotes and, less frequently, in eukaryotes. The internal domain organization of proteins and the topology of TCS/PR cascades play an important role in shaping the responses of the circuits. It is thus important to maintain updated censuses of TCS/PR proteins in order to identify the various topologies used by nature and enable a systematic study of the dynamics associated with those topologies. To create such a census, we analyzed the proteomes of 7609 organisms from all domains of life with fully sequenced and annotated genomes. To begin, we survey each proteome searching for proteins containing domains that are associated with internal signal transmission within TCS/PR: Histidine Kinase (HK), Response Regulator (RR) and Histidine Phosphotranfer (HPt) domains, and analyze how these domains are arranged in the individual proteins. Then, we find all types of operon organization and calculate how much more likely are proteins that contain TCS/PR domains to be coded by neighboring genes than one would expect from the genome background of each organism. Finally, we analyze if the fusion of domains into single TCS/PR proteins is more frequently observed than one might expect from the background of each proteome. We find 50 alternative ways in which the HK, HPt, and RR domains are observed to organize into single proteins. In prokaryotes, TCS/PR coding genes tend to be clustered in operons. 90% of all proteins identified in this study contain just one of the three domains, while 8% of the remaining proteins combine one copy of an HK, a RR, and/or an HPt domain. In eukaryotes, 25% of all TCS/PR proteins have more than one domain. These results might have implications for how signals are internally transmitted within TCS/PR cascades. These implications could explain the selection of the various designs in alternative circumstances.

scholarly journals Dynamics of the concept CANADA in English-Canadian poetic texts of the 18th–21st centuries

2019 ◽  
Keyword(s):  
Structural Components ◽  
Canadian History ◽  
Component Structure ◽  
Cognitive Characteristics ◽  
Two Component ◽  
Poetic Texts ◽  
English Canadian ◽  
Historical Periods ◽  
Cultural Features ◽  
Selection Of

The article deals with the trends of historical dynamics of linguistic and cognitive characteristics of the concept Canada in English-Canadian poetic texts of the 18th–21st centuries. This research deploys a complex semantic and cognitive analysis of its lexical-semantic nominative means of poetic texts. As a result specific features of national, cultural and author’s knowledge encoded in the poetic texts are identified and classified. The lexical nominative means of the concept Canada are viewed in terms of two groups of nominative means: direct and figurative. All the nominations are classified according to several criteria. Direct and figurative nominative means of the concept Canada variously characterize physical, geographical, territorial, demographic, social, political, historical, and cultural features of the Canadian state. The variability in priority of thematic nomination groups of the concept Canada in different historical periods of the statehood formation reveals the influence of the extralingual factors on the authors’ selection of nominative means of the concept Canada. The concept Canada combines the features of both a literary, cultural and a toponymic concept. It has been modeled as a complex two-component structure that includes a sensory-notional and a figurative component. Historically conditioned transformations of the structural components of the concept Canada is interpreted in terms of its invariant and diachronically variable linguistic and cognitive characteristics. During three periods of Canadian history, the transformations of the structural components of the concept Canada reveal themselves as either the hierarchic shifts of the literary concepts-slots in the sensory-notional component or as the variability of the set of conceptual metaphors in its figurative component.

Coral microatolls and a probable Middle Ordovician example

1990 ◽  
Vol 64 (1) ◽  
pp. 39-43 ◽  
Author(s):  
David R. Kobluk ◽  
Iqbal Noor
Keyword(s):  
Coral Reefs ◽  
Fossil Record ◽  
Scleractinian Coral ◽  
Regional Scale ◽  
Southern Ontario ◽  
Middle Ordovician ◽  
Reef Environments ◽  
Maximum Water ◽  
Water Depths ◽  
Tabulate Corals

A disk-shaped massive colony of Tetradium, from the Middle Ordovician Bobcaygeon Formation in southern Ontario, displays features of a coral microatoll. This is the first pre-Holocene coral microatoll yet described, indicating that some tabulate corals in level-bottom communities were growing as microatolls as do many modern colonial skeleton-secreting organisms.The microatoll therefore is not strictly a Quaternary or even Cenozoic phenomenon, but has a fossil record that may span most of the Phanerozoic. This indicates that the special conditions necessary for microatoll growth have existed outside of reef environments, and were present before the advent of scleractinian coral reefs. It may be possible to use ancient microatolls to estimate absolute water depths at low tide, thereby providing a means for estimating maximum water depths on a local and regional scale.

Sign in / Sign up

Export Citation Format

Share Document