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

2006 ◽  
Vol 68 (3) ◽  
pp. 505-514 ◽  
Author(s):  
Howard S. Hock ◽  
Annemie Ploeger
Keyword(s):  
Pattern Formation ◽  
Motion Pattern ◽  
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.

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.

Memory Processes, Aging, Cognitive Decline, and Neurodegenerative Diseases

2006 ◽  
Vol 11 (4) ◽  
pp. 304-311 ◽  
Author(s):  
Lars-Göran Nilsson
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Decline ◽  
Neurodegenerative Disease ◽  
Genetic Markers ◽  
Brain Activity ◽  
Memory Performance ◽  
Modeling And Simulations ◽  
Aging And Health ◽  
Explained Variance ◽  
Different Levels

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.

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