scholarly journals Linking dynamical perceptual decisions at different levels of description in motion pattern formation: Computational simulations

2006 ◽  
Vol 68 (3) ◽  
pp. 515-533 ◽  
Author(s):  
David F. Nichols ◽  
Howard S. Hock ◽  
Gregor Schöner
Keyword(s):  
Pattern Formation ◽  
Motion Pattern ◽  
Computational Simulations ◽  
Different Levels

Compartments, wingless and engrailed: patterning the ventral epidermis of Drosophila embryos

Development ◽  
1996 ◽  
Vol 122 (12) ◽  
pp. 4095-4103 ◽  
Author(s):  
P.A. Lawrence ◽  
B. Sanson ◽  
J.P. Vincent
Keyword(s):  
Pattern Formation ◽  
Wing Disc ◽  
High Concentration ◽  
Good Region ◽  
Steep Slopes ◽  
Cuticular Structures ◽  
Different Levels ◽  
Promote Cell Death ◽  
Drosophila Embryos

Recent experiments on the wing disc of Drosophila have shown that cells at the interface between the anterior and posterior compartments drive pattern formation by becoming the source of a morphogen. Here we ask whether this model applies to the ventral embryonic epidermis. First, we show that interfaces between posterior (engrailed ON) and anterior (engrailed OFF) cells are required for pattern formation. Second, we provide evidence that Wingless could play the role of the morphogen, at least within part of the segmental pattern. We looked at the cuticular structures that develop after different levels of uniform Wingless activity are added back to unsegmented embryos (wingless- engrailed-). Because it is rich in landmarks, the T1 segment is a good region to analyse. There, we find that the cuticle formed depends on the amount of added Wingless activity. For example, a high concentration of Wingless gives the cuticle elements normally found near the top of the presumed gradient. Unsegmented embryos are much shorter than wild type. If Wingless activity is added in stripes, the embryos are longer than if it is added uniformly. We suggest that the Wingless gradient landscape affects the size of the embryo, so that steep slopes would allow cells to survive and divide, while an even distribution of morphogen would promote cell death. Supporting the hypothesis that Wingless acts as a morphogen, we find that these stripes affect, at a distance, the type of cuticle formed and the planar polarity of the cells.

Consideration of Environmentally Assisted Fatigue in Austenitic Stainless Steel — Applicability and Comparison of Existing Numerical Procedures

2013 ◽  
Author(s):  
Sven H. Reese ◽  
Johannes Seichter ◽  
Dietmar Klucke
Keyword(s):  
Level Of Detail ◽  
Correction Factors ◽  
Computational Simulations ◽  
Simplified Approach ◽  
Integrated Method ◽  
Levels Of Detail ◽  
Different Levels ◽  
Calculation Procedures ◽  
Real Plant ◽  
Plant Components

Consideration of environmentally assisted fatigue (EAF) is in discussion internationally. In German KTA Rules the effect is taken into account by means of so called attention thresholds. While the laboratory phenomena themselves are being accepted widely, numerical calculation procedures are revised continuously and transition from laboratory to real plant components is not clarified yet. Since NUREG/CR-6909, formulas for calculating the Fen factors have been modified several times. For example in ANL-LWRS47-2011 a new set of formulas was published and slightly revised by ANL in 2012. Various calculation procedures like the strain-integrated method and simplified approach have been published while each approach yields to different results. Beyond this, additional topics like weld factors or plasticity correction factors have to be taken into account. Calculation procedures depending on the level of detail and in the description of loads are yielding to significant variations in the results. Respecting these topics in context of different levels of detail in computational simulations, numerical cumulative usage factor (CUF) evaluation results are likely to differ, depending on the assumptions made. On the basis of a practical example, methods and approaches will be discussed and recommendations in terms of avoiding over-conservatism and misinterpretation will be presented.

scholarly journals A model of self-organized motion pattern formation

2010 ◽  
Vol 1 (3) ◽  
pp. 371-371
Author(s):  
H. S. Hock ◽  
C. L. Park ◽  
G. Schoner
Keyword(s):  
Pattern Formation ◽  
Motion Pattern ◽  
Self Organized

scholarly journals Linking levels in motion pattern formation through dynamical coupling: evidence from psychophysics and simulations

2010 ◽  
Vol 3 (9) ◽  
pp. 278-278
Author(s):  
D. F Nichols ◽  
H. S Hock ◽  
A. Ploeger ◽  
G. Schoner
Keyword(s):  
Pattern Formation ◽  
Motion Pattern ◽  
Dynamical Coupling

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

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