scholarly journals Backward stochastic dynamics with a subdifferential operator and non-local parabolic variational inequalities

2018 ◽  
Vol 128 (2) ◽  
pp. 644-688 ◽  
Author(s):  
Alain Bensoussan ◽  
Yiqun Li ◽  
Sheung Chi Phillip Yam
Keyword(s):  
Variational Inequalities ◽  
Stochastic Dynamics ◽  
Subdifferential Operator ◽  
Non Local

scholarly journals First passage time on pattern formation in a non-local Fisher population dynamics

Open Physics ◽  
2013 ◽  
Vol 11 (12) ◽  
Author(s):  
Miguel Fuentes ◽  
Manuel Cáceres
Keyword(s):  
Stochastic Dynamics ◽  
First Passage Time ◽  
Mode Selection ◽  
Passage Time ◽  
Unstable State ◽  
Perturbation Approach ◽  
Stochastic Field ◽  
Small Noise ◽  
Theoretical Predictions ◽  
Non Local

AbstractWe use stochastic dynamics to develop the patterned attractor of a non-local extended system. This is done analytically using the stochastic path perturbation approach scheme, where a theory of perturbation in the small noise parameter is introduced to analyze the random escape of the stochastic field from the unstable state. Emphasis is placed on the specific mode selection that these types of systems exhibit. Concerning the stochastic propagation of the front we have carried out Monte Carlo simulations which coincide with our theoretical predictions.

Fast closure of long loops at the initiation of the folding transition of globular proteins studied by time-resolved FRET-based methods

2014 ◽  
Vol 10 (4) ◽  
Author(s):  
Tomer Orevi ◽  
Gil Rahamim ◽  
Sivan Shemesh ◽  
Eldad Ben Ishay ◽  
Dan Amir ◽  
...  
Keyword(s):  
Stochastic Dynamics ◽  
Sequence Data ◽  
Random Search ◽  
Excitation Energy Transfer ◽  
Globular Proteins ◽  
Conformational Space ◽  
Resonance Excitation ◽  
Time Resolved ◽  
Non Local

AbstractThe protein folding problem would be considered “solved” when it will be possible to “read genes”, i.e., to predict the native fold of proteins, their dynamics, and the mechanism of fast folding based solely on sequence data. The long-term goal should be the creation of an algorithm that would simulate the stepwise mechanism of folding, which constrains the conformational space and in which random search for stable interactions is possible. Here, we focus attention on the initial phases of the folding transition starting with the compact disordered collapsed ensemble, in search of the initial sub-domain structural biases that direct the otherwise stochastic dynamics of the backbone. Our studies are designed to test the “loop hypothesis”, which suggests that fast closure of long loop structures by non-local interactions between clusters of mainly non-polar residues is an essential conformational step at the initiation of the folding transition of globular proteins. We developed and applied experimental methods based on time-resolved resonance excitation energy transfer (trFRET) measurements combined with fast mixing methods and studied the initial phases of the folding of

scholarly journals Preconditioning for Allen–Cahn variational inequalities with non-local constraints

2012 ◽  
Vol 231 (16) ◽  
pp. 5406-5420 ◽  
Author(s):  
Luise Blank ◽  
Lavinia Sarbu ◽  
Martin Stoll
Keyword(s):  
Variational Inequalities ◽  
Local Constraints ◽  
Non Local

Toward High-Resolution Low-Voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 218-219
Author(s):  
Zhifeng Shao
Keyword(s):  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Operating Voltage ◽  
Probe Radius ◽  
Non Local ◽  
Electron Microscopes ◽  
Image Position ◽  
Scanning Electron Microscopes

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as

Chromatic aberration and low-voltage SEM

1987 ◽  
Vol 45 ◽  
pp. 546-547
Author(s):  
Zhifeng Shao ◽  
A.V. Crewe
Keyword(s):  
Electron Energy ◽  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Primary Electron ◽  
Probe Size ◽  
Non Local ◽  
Optical Treatment ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

For scanning electron microscopes, it is plausible that by lowering the primary electron energy, one can decrease the volume of interaction and improve resolution. As shown by Crewe /1/, at V0 =5kV a 10Å resolution (including non-local effects) is possible. To achieve this, we would need a probe size about 5Å. However, at low voltages, the chromatic aberration becomes the major concern even for field emission sources. In this case, δV/V = 0.1 V/5kV = 2x10-5. As a rough estimate, it has been shown that /2/ the chromatic aberration δC should be less than ⅓ of δ0 the probe size determined by diffraction and spherical aberration in order to neglect its effect. But this did not take into account the distribution of electron energy. We will show that by using a wave optical treatment, the tolerance on the chromatic aberration is much larger than we expected.

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