Model and theoretical seismicity

1967 ◽  
Vol 57 (3) ◽  
pp. 341-371 ◽  
Author(s):  
R. Burridge ◽  
L. Knopoff
Keyword(s):  
Numerical Model ◽  
Potential Energy ◽  
Main Sequence ◽  
Magnitude Scale ◽  
Laboratory Model ◽  
Earthquake Mechanism

abstract A laboratory and a numerical model have been constructed to explore the role of friction along a fault as a factor in the earthquake mechanism. The laboratory model demonstrates that small shocks are necessary to the loading of potential energy into the focal structure; a large part, but not all, of the stored potential energy is later released in a major shock, at the end of a period of loading energy into the system. By the introduction of viscosity into the numerical model, aftershocks take place following a major shock. Both models have features which describe the statistics of shocks in the main sequence, the statistics of aftershocks and the energy-magnitude scale, among others.

The Main Sequence of Human Optokinetic Afternystagmus (OKAN)

2009 ◽  
Vol 101 (6) ◽  
pp. 2889-2897 ◽  
Author(s):  
Andre Kaminiarz ◽  
Kerstin Königs ◽  
Frank Bremmer
Keyword(s):  
Neural Networks ◽  
Eye Movements ◽  
Main Sequence ◽  
Critical Role ◽  
Saccade Target ◽  
Control Mechanisms ◽  
Visually Guided ◽  
Background Characteristics ◽  
Optokinetic Afternystagmus

Different types of fast eye movements, including saccades and fast phases of optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN), are coded by only partially overlapping neural networks. This is a likely cause for the differences that have been reported for the dynamic parameters of fast eye movements. The dependence of two of these parameters—peak velocity and duration—on saccadic amplitude has been termed “main sequence.” The main sequence of OKAN fast phases has not yet been analyzed. These eye movements are unique in that they are generated by purely subcortical control mechanisms and that they occur in complete darkness. In this study, we recorded fast phases of OKAN and OKN as well as visually guided and spontaneous saccades under identical background conditions because background characteristics have been reported to influence the main sequence of saccades. Our data clearly show that fast phases of OKAN and OKN differ with respect to their main sequence. OKAN fast phases were characterized by their lower peak velocities and longer durations compared with those of OKN fast phases. Furthermore we found that the main sequence of spontaneous saccades depends heavily on background characteristics, with saccades in darkness being slower and lasting longer. On the contrary, the main sequence of visually guided saccades depended on background characteristics only very slightly. This implies that the existence of a visual saccade target largely cancels out the effect of background luminance. Our data underline the critical role of environmental conditions (light vs. darkness), behavioral tasks (e.g., spontaneous vs. visually guided), and the underlying neural networks for the exact spatiotemporal characteristics of fast eye movements.

scholarly journals Extended main sequence turnoffs in open clusters as seen by Gaia – I. NGC 2818 and the role of stellar rotation

2018 ◽  
Vol 480 (3) ◽  
pp. 3739-3746 ◽  
Author(s):  
N Bastian ◽  
S Kamann ◽  
I Cabrera-Ziri ◽  
C Georgy ◽  
S Ekström ◽  
...  
Keyword(s):  
Main Sequence ◽  
Open Clusters ◽  
Stellar Rotation

scholarly journals Spatially Broad Observations of Internal Waves in the Upper Ocean at the Hawaiian Ridge

2006 ◽  
Vol 36 (6) ◽  
pp. 1085-1103 ◽  
Author(s):  
Joseph P. Martin ◽  
Daniel L. Rudnick ◽  
Robert Pinkel
Keyword(s):  
Numerical Model ◽  
Energy Density ◽  
Potential Energy ◽  
Internal Waves ◽  
Upper Ocean ◽  
Mean Square ◽  
The South ◽  
South Side ◽  
Topographic Slope ◽  
Hawaiian Ridge

Abstract The density and current structure at the Hawaiian Ridge was observed using SeaSoar and Doppler sonar during a survey extending from Oahu to Brooks Banks. Across- and along-ridge changes in internal wave statistics in the upper ocean within 200 km of the ridge are investigated. Internal waves with trough-to-crest amplitude as large as 60 m and horizontal wavelength of about 50 km are observed repeatedly in across-ridge sections of potential density. Within 150 km of the ridge, kinetic and potential energy density exceed open-ocean values with maxima about 10 times Garrett–Munk levels. In the Kauai Channel (KC), the kinetic energy density is largest along an M2 internal tide ray. The ray originates at the northern edge of the ridge peak at a large across-ridge change in topographic slope and terminates at the ocean surface about 30–40 km south of the ridge peak. Kinetic and potential energy density are larger on the south side of the ridge at KC, the side with larger topographic slope. Energy density is also larger on the south side of the ridge at KC in numerical model results and on the side of steeper topographic slope in analytical model results. Along the ridge, the largest observed values of mean-square shear and mean-square slope of isopycnal depth are collocated with the largest energy density in numerical model results. Mean-square shear and mean-square slope increase with decreasing bottom depth and with increasing M2 barotropic tidal forcing.

On the role of fluid infiltration into gravel dunes — Using a 3D numerical model

2016 ◽  
Vol 380 ◽  
pp. 231-244 ◽  
Author(s):  
Gerhard Bartzke ◽  
Lina Podszun ◽  
Katrin Huhn
Keyword(s):  
Numerical Model ◽  
Fluid Infiltration ◽  
3D Numerical Model

scholarly journals Trace fossils associated with Burgess Shale non-biomineralized carapaces: bringing taphonomic and ecological controls into focus

2019 ◽  
Vol 6 (1) ◽  
pp. 172074 ◽  
Author(s):  
M. Gabriela Mángano ◽  
Christopher David Hawkes ◽  
Jean-Bernard Caron
Keyword(s):  
Numerical Model ◽  
Mechanical Stress ◽  
Initial Phase ◽  
Trace Fossils ◽  
Trophic Levels ◽  
Ecological Significance ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
Branching Patterns

The association of trace fossils and non-biomineralized carapaces has been reported from Cambrian Lagerstätten worldwide, but the abundance, ichnodiversity, taphonomy and ecological significance of such associations have yet to be fully investigated. Two main end-member hypotheses are explored based on the study of a relatively wide variety of trace fossils preserved associated to Tuzoia carapaces from the middle Cambrian Burgess Shale in British Columbia. In the ecological Tuzoia garden hypothesis, the bacterially enriched surface of carapaces provides opportunities for intricate ecologic interactions among trophic levels. In the taphonomic shielding hypothesis, the trace fossil–carapace association results from preferential preservation of traces as controlled by compaction independent of any association in life. In an attempt to better understand the role of the carapace as a medium for preservation of trace fossils and to evaluate the effects of mechanical stress related to burial, a numerical model was developed. Results indicate that the carapace can shield underlying sediment from mechanical stress for a finite time, differentially protecting trace fossils during the initial phase of burial and compaction. However, this taphonomic model alone fails to fully explain relatively high-density assemblages displaying a diversity of structures spatially confined within the perimeter of carapaces or branching patterns recording re-visitation.

Exploring the potential energy surfaces of association of NO with aminoacids and related organic functional groups: the role of entropy of association

2007 ◽  
Vol 118 (3) ◽  
pp. 649-663 ◽  
Author(s):  
Rachel Crespo-Otero ◽  
Yoana Pérez-Badell ◽  
Juan Alexander Padrón-García ◽  
Luis Alberto Montero-Cabrera
Keyword(s):  
Potential Energy ◽  
Functional Groups ◽  
Potential Energy Surfaces ◽  
Organic Functional Groups ◽  
Energy Surfaces

The zebrafish as a model for cardiac development and regeneration

2018 ◽  
Author(s):  
Bill Chaudhry ◽  
José Luis de la Pompa ◽  
Nadia Mercader
Keyword(s):  
Heart Development ◽  
Cardiac Development ◽  
Model Organism ◽  
Laboratory Model ◽  
Developmental Studies ◽  
Sequencing Technologies ◽  
Technological Advances ◽  
The Common ◽  
Zebrafish Heart

The zebrafish has become an established laboratory model for developmental studies and is increasingly used to model aspects of human development and disease. However, reviewers and grant funding bodies continue to speculate on the utility of this Himalayan minnow. In this chapter we explain the similarities and differences between the heart from this distantly related vertebrate and the mammalian heart, in order to reveal the common fundamental processes and to prevent misleading extrapolations. We provide an overview of zebrafish including their husbandry, development, peculiarities of their genome, and technological advances, which make them a highly tractable laboratory model for heart development and disease. We discuss the controversies around morphants and mutants, and relate the development and structures of the zebrafish heart to mammalian counterparts. Finally, we give an overview of regeneration in the zebrafish heart and speculate on the role of the model organism in next-generation sequencing technologies.

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