Transverse tectonic structural elements across Himalayan mountain front, eastern Arunachal Himalaya, India: Implication of superposed landform development on analysis of neotectonics

Geomorphology ◽  
2017 ◽  
Vol 282 ◽  
pp. 176-194 ◽  
Author(s):  
S.S. Bhakuni ◽  
Khayingshing Luirei ◽  
Girish Ch. Kothyari ◽  
Watinaro Imsong
Keyword(s):  
Structural Elements ◽  
Mountain Front ◽  
Himalayan Mountain ◽  
Landform Development ◽  
Arunachal Himalaya

Stability of the gravel-sand transition of the Ganga Plains recorded in Siwalik stratigraphy; implications for extreme floods

2020 ◽  
Author(s):  
Laura Quick ◽  
Hugh Sinclair ◽  
Mikael Attal ◽  
Rajiv Sinha ◽  
Rohtash Kumar
Keyword(s):  
Depositional Environments ◽  
Gangetic Plain ◽  
Extreme Floods ◽  
Close Proximity ◽  
Mountain Front ◽  
Himalayan Mountain ◽  
Siwalik Group ◽  
Indo Gangetic Plain ◽  
Stable Feature

<p>Many rivers of the Indo-Gangetic Plain are prone to abrupt switching of channel courses causing devastating floods over some of the world’s poorest and most densely populated regions. Recent work has identified the gravel-sand transition as an avulsion node for the channels; notably the avulsion of the Kosi River in 2008 occurred in close proximity to its gravel-sand transition. The gravel-sand transition is a geomorphic feature observed within all major mountain-fed, and smaller foothill-fed Himalayan rivers ranging from 10 to 20 km downstream from the mountain front. It is characterised by an abrupt downstream reduction in grain size from gravel to sand and is often associated with a break in channel gradient, which suggests it is a relatively stable feature over the last few thousands of years.</p><p>However, new subsurface data from the Kosi mega-fan in eastern Nepal reveals 10-20 Ka gravels located ~50 km downstream from the current gravel-sand transition. The implication is that this key geomorphic boundary can periodically prograde considerably further into the Ganga Plains. A greater long-term (>10<sup>6</sup> yrs) understanding of the controls on the gravel-sand transition is achieved by studying the stratigraphic record of the Miocene Siwalik Group, which is exhumed as a series of thrusted fault blocks at the Himalayan mountain front. The Siwalik succession is divided into three lithofacies units that coarsens upwards from siltstones and sandstones to coarse conglomerates. The units are termed the Lower, Middle and Upper Siwaliks respectively and reflect the current depositional environments found on the Ganga Plains. <br>The gravel-sand transition is recorded as the contact between the Middle and Upper Siwaliks. Significant gravel pulses have been identified directly below the Middle to Upper Siwalik contact and suggests that the gravel-sand transition is indeed mobile and can episodically prograde far into the plains. Sedimentological characteristics of the gravel pulses and sediment entrainment calculations suggest that extreme events (e.g. enhanced monsoon, earthquakes and GLOFS) can force gravel far into the Ganga Plains, impacting the position the gravel-sand transition. These episodes of distant gravel progradation must represent extreme floods from which the sedimentological system must take many years to recover. Such events are beyond the historic timescales of human narrative, and hence have not been recognised as a risk to the populations of the plains.</p>

Structural phenomena in the growth of carbon nanotubes

1993 ◽  
Vol 51 ◽  
pp. 750-751
Author(s):  
Jun Jiao
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Carbonaceous Material ◽  
Cluster Growth ◽  
Structural Elements ◽  
Rich Variety ◽  
Different Shapes ◽  
Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

Designing TIMP (tissue inhibitor of metalloproteinases) variants that are selective metalloproteinase inhibitors

2003 ◽  
Vol 70 ◽  
pp. 201-212 ◽  
Author(s):  
Hideaki Nagase ◽  
Keith Brew
Keyword(s):  
Three Dimensional ◽  
Therapeutic Interventions ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Structural Basis ◽  
Structural Elements ◽  
Ridge Structure ◽  
Extracellular Matrix Components ◽  
Metalloproteinase Inhibitors ◽  
The Matrix ◽  
A Disintegrin And Metalloproteinase

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs), enzymes that play central roles in the degradation of extracellular matrix components. The balance between MMPs and TIMPs is important in the maintenance of tissues, and its disruption affects tissue homoeostasis. Four related TIMPs (TIMP-1 to TIMP-4) can each form a complex with MMPs in a 1:1 stoichiometry with high affinity, but their inhibitory activities towards different MMPs are not particularly selective. The three-dimensional structures of TIMP-MMP complexes reveal that TIMPs have an extended ridge structure that slots into the active site of MMPs. Mutation of three separate residues in the ridge, at positions 2, 4 and 68 in the amino acid sequence of the N-terminal inhibitory domain of TIMP-1 (N-TIMP-1), separately and in combination has produced N-TIMP-1 variants with higher binding affinity and specificity for individual MMPs. TIMP-3 is unique in that it inhibits not only MMPs, but also several ADAM (a disintegrin and metalloproteinase) and ADAMTS (ADAM with thrombospondin motifs) metalloproteinases. Inhibition of the latter groups of metalloproteinases, as exemplified with ADAMTS-4 (aggrecanase 1), requires additional structural elements in TIMP-3 that have not yet been identified. Knowledge of the structural basis of the inhibitory action of TIMPs will facilitate the design of selective TIMP variants for investigating the biological roles of specific MMPs and for developing therapeutic interventions for MMP-associated diseases.

Formation Of An Estimate For A State Contract With A Firm Price In The Construction Sector

2020 ◽  
pp. 47-57
Keyword(s):  
Construction Projects ◽  
Cost Of Capital ◽  
Federal Budget ◽  
The State ◽  
Structural Elements ◽  
Construction Sector ◽  
Construction Process ◽  
Practical Application ◽  
Stage Of Development ◽  
Capital Construction

The issues of determining the estimated cost of capital construction projects with the involvement of Federal budget funds at the stage of development of project documentation, during verification of the accuracy of determining the estimated cost and the initial (maximum) contract price are considered. On the basis of the assessment of amendments to urban planning legislation for the purpose of implementing a state contract by the contractor ( based on the results of competitive procedures or without competitive procedures by decision of state authorities), the procedure for forming the estimate as part of a state (municipal) contract, the price of which is firm, is presented. For the purpose of mutual settlements between the customer and the contractor for the work performed, the formation of primary accounting documentation, as well as for checking the work performed by regulatory authorities, an example of drawing up an estimate of the state (municipal) contract on the basis of grouping costs according to structural elements and complexes of work is given. The result of the research conducted was the development of regulations and the formation of criteria for their practical application by state bodies, institutions, organizations and other participants in the investment-construction process, as well as recipients of budget funds, who perform the functions of the state (municipal) customer, developer and technical customer.

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