Are Nemiana Palij and Beltanelliformis Menner (Beltanelloides (Sokolov)) synonyms or different genera?

2021 ◽  
pp. 213-220
Author(s):  
Volodymyr Paliy ◽  
Volodymyr Grytsenko ◽  
Sergiy Mosyakin
Keyword(s):  
Biochemical Evidence ◽  
Good Preservation ◽  
Clastic Rocks ◽  
Geological Age ◽  
Characteristic Features ◽  
Facial Differences ◽  
New Phase ◽  
Ancient Remains ◽  
Shape And Size ◽  
Organic Remains

During recent decades, the issue of the nature of Ediacaran cyclic imprints, including the widely distributed in Podillia (southwestern Ukraine) Nemiana simplex Palij, 1976, and the less common Beltanelliformis brunsae Menner, 1974 (Beltanelloides sorichevae (Sokolov), 1965) has been actively debated. Several new and similar forms were discovered in other regions of the Globe. The disk-like outlines were considered to be sufficient characters to synonymize several earlier recognized genera and species. The main additional features used to distinguish cyclic genera included such features as the shape and sculpture of surfaces, facial differences, and geological age. Novel palaeobiochemical studies of these ancient remains opened a new phase of discussions on the possible identities of the organisms that formed these fossil structures. Sometimes the remains are covered with thin brown films providing biochemical evidence for the cyanobacterial nature of some structures, for example Beltanelliformis brunsae. However, these films are found only in clayey or carbonate environments (rocks). For Nemiana Palij, characteristic features are clustered communities and budding. In contrast, Beltanelliformis brunsae formed taphonomic communities of closely arranged disks almost identical in their shape and size. Nemiana simplex structures are confined to clastic rocks (mostly thin-grained sandstones or siltstone), which are not suitable for good preservation of imprints and organic remains of ancient animals, cyanobacteria, algae, and plants. Considering these and some additional considerations, synonimization of Nemiana та Beltanelliformis, as well as some other Ediacaran fossil structures differing in their morphology, is at best premature.

Where is the Anthropocene? IR in a new geological epoch

2020 ◽  
Vol 96 (1) ◽  
pp. 211-224 ◽  
Author(s):  
Dahlia Simangan
Keyword(s):  
International Relations ◽  
Human Experience ◽  
Natural Sciences ◽  
Ecological Security ◽  
Historical Injustice ◽  
Security Issues ◽  
Geological Age ◽  
New Phase ◽  
Theoretical Foundations

Abstract Several disciplines outside the natural sciences, including International Relations (IR), have engaged with the Anthropocene discourse in order to theorize their relevance and translate their practical value in this new phase of the Earth's history. Some IR scholars have called for a post-humanist IR, planet politics, a cosmopolitan view, and ecological security, among other approaches, to recalibrate the theoretical foundations of the discipline, making it more attuned to the realities of the Anthropocene. Existing discussions, however, tend to universalize human experience and gravitate towards western ontologies and epistemologies of living in the Anthropocene. Within this burgeoning scholarship, how is the IR discipline engaging with the Anthropocene discourse? Although the Anthropocene has become a new theoretical landscape for the conceptual broadening of conventional IR subjects, this review reveals the need for sustained discussion that highlights the differentiated human experiences in the Anthropocene. The existing IR publications on the Anthropocene locates the non-spatial narratives of vulnerability and historical injustice, the non-modernist understanding of nature, the agency of the vulnerable, and the amplification of security issues in the Anthropocene. It is in amplifying these narratives that the IR discipline can broaden and diversify the discourse on the Anthropocene and, therefore, affirm its relevance in this new geological age.

scholarly journals Experimental study of shear deformation of the medium formed by the massif of ribbed grains

2021 ◽  
Vol 43 (2) ◽  
pp. 178-188
Author(s):  
S.V. Mykulyak ◽  
V.O. Polyakovskyi ◽  
S.I. Skurativskyi
Keyword(s):  
Stress State ◽  
Shear Deformation ◽  
Granular Media ◽  
External Action ◽  
Characteristic Size ◽  
Long Range Correlations ◽  
Deformation Properties ◽  
Self Organized Criticality ◽  
Characteristic Features ◽  
Shape And Size

The approach to the study of the seismically active zone as an open system that is in a state of self-organized criticality is becoming increasingly used in modern research. The models used in this approach should reflect the most characteristic features of such media: discreteness, nonequilibrium, nonlinear and nonlocal nature of interactions. In this paper, the medium is modeled by a granular massif with ribbed grains. Three different massifs are used in the research. Within one massif, all grains are identical, while grains from different massifs differ in shape (cubic or irregular ribbed) and characteristic size. A number of experiments of shear deformation of such granular massifs were carried out in order to study the influence of the shape and size of grains on the statistical charac-teristics of the process. The influence of the stress state on the deformation properties of these media was also studied. The experiments proved the qualitative similarity of the behavior of different granular media. Obtained experimentally force jumps, represen-ting the reaction of the granular medium to shear deformation, obey the distributions in the form of power dependencies. However, the magnitudes of the forces arising in the massifs depend on the grain shape and size as well as the stress state in the massifs. The experiments with shear deformation of the granular media under the external action of small impulse stresses have shown that such action causes a smoother, devoid of sharp jumps, deformation. External perturbations shift the distribution of the force jumps towards smaller values, leaving their exponents unchanged. The analysis of experimental results using nonadditive statistical mechanics confirmed the presence of long-range correlations in the massif of ribbed granules during its shear deformation.

Ultrathin frozen sections of yeast without aldehyde prefixation

1978 ◽  
Vol 36 (2) ◽  
pp. 58-59
Author(s):  
K. J. Böhm ◽  
a. E. Unger
Keyword(s):  
Aqueous Solutions ◽  
Biological Material ◽  
Yeast Cells ◽  
Frozen Sections ◽  
Good Preservation ◽  
Ultrathin Frozen Sections

During the last years it was shown that also by means of cryo-ultra-microtomy a good preservation of substructural details of biological material was possible. However the specimen generally was prefixed in these cases with aldehydes.Preparing ultrathin frozen sections of chemically non-prefixed material commonly was linked up to considerable technical and manual expense and the results were not always satisfying. Furthermore, it seems to be impossible to carry out cytochemical investigations by means of treating sections of unfixed biological material with aqueous solutions.We therefore tried to overcome these difficulties by preparing yeast cells (S. cerevisiae) in the following manner:

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

Ultrastructural modification of cellular interactions in cancer tumor

1978 ◽  
Vol 36 (2) ◽  
pp. 318-319
Author(s):  
N. P. Dmitrieva
Keyword(s):  
Cancer Cells ◽  
Human Thyroid ◽  
Adjacent Cell ◽  
Main Role ◽  
Cellular Interactions ◽  
Electron Microscopic ◽  
Cancer Tumor ◽  
Normal Human ◽  
Characteristic Features

One of the most characteristic features of cancer cells is their ability to metastasia. It is suggested that the modifications of the structure and properties of cancer cells surfaces play the main role in this process. The present work was aimed at finding out what ultrastructural features apear in tumor in vivo which removal of individual cancer cells from the cell population can provide. For this purpose the cellular interactions in the normal human thyroid and cancer tumor of this gland electron microscopic were studied. The tissues were fixed in osmium tetroxide and were embedded in Araldite-Epon.In normal human thyroid the most common type of intercellular contacts was represented by simple junction formed by the parallelalignment of adjacent cell membranees leaving in between an intermembranes space 15-20 nm filled with electronlucid material (Fig. 1a). Sometimes in the basal part of cells dilatations of the intercellular space 40-50 nm wide were found (Fig. 1a). Here the cell surfaces may form single short microvilli.

Electron microscopy of niobium and tantalum hydrides

1978 ◽  
Vol 36 (1) ◽  
pp. 644-645
Author(s):  
T. Schober
Keyword(s):  
Electron Microscopy ◽  
Heat Storage ◽  
Measurement Techniques ◽  
Metal Hydrides ◽  
Detailed Understanding ◽  
Storage Devices ◽  
Unit Cells ◽  
Endothermic Reactions ◽  
Hydrogen Reactions ◽  
New Phase

Nb, Ta and V are prototype substances for the study of the endothermic reactions of H with metals. Such metal-hydrogen reactions have gained increased importance due to the application of metal-hydrides in hydrogen- und heat storage devices. Electron microscopy and diffraction were demonstrated to be excellent methods in the study of hydride morphologies and structures (1). - Figures 1 and 2 show the NbH and TaH phase diagrams (2,3,4). EM techniques have contributed substantially to the elucidation of the structures and domain configurations of phases β, ζ and ε (1,4). Precision length measurement techniques of distances in reciprocal space (5) recently led to a detailed understanding of the distortions of the unit cells of phases ζ and ε (4). In the same work (4) the existence of the new phase η was shown. It is stable near -68 °C. The sequence of transitions is thus below 70 %.

Development of 200kV ultrahigh-resolution analytical electron microscope

1989 ◽  
Vol 47 ◽  
pp. 108-109
Author(s):  
T. Kaneyama ◽  
M. Naruse ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
Electron Microscope ◽  
Optical Constants ◽  
Materials Science ◽  
Objective Lens ◽  
The Finite Element Method ◽  
Ultrahigh Resolution ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Characteristic Features ◽  
Better Than

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.

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