The Crystallographic Modeling of C60 Orientations in a Cubic Lattice

1994 ◽  
Vol 359 ◽  
Author(s):  
Veniamin Sh. Shekhtman ◽  
Ruben A. Dilanyan ◽  
Oksana G. Rybchenko
Keyword(s):  
Main Axis ◽  
Cubic Lattice ◽  
Orientational Glass ◽  
Orientational Ordering ◽  
Different Levels

ABSTRACTThe symmetry conditions which rule the matching of a fulleren molecule's main axis in a translational lattice are considered. The full set of orientational states for the structure of fullerene are obtained. The different levels of correlations between symmetry axes of icosahedral molecule and cubic lattice are considered. This result used for analysis of orientational ordering models, including modulation structure and discrete orientational glass.

Etude cinétique de quelques événements lies à une levée de dominance apicale par décapitation ou ablation de l'axe principal à différents niveaux chez la Tomate, Lycopersicum esculentum

1980 ◽  
Vol 58 (2) ◽  
pp. 281-294
Author(s):  
Kim Anh Ha Ngoc
Keyword(s):  
Apical Dominance ◽  
Main Axis ◽  
Main Stem ◽  
Axillary Buds ◽  
Axillary Bud ◽  
Lycopersicum Esculentum ◽  
Tomato Plants ◽  
Different Levels

In intact tomato plants, axillary buds are completely inhibited by the main apex. A release from apical dominance is obtained by decapitation or excision of the main axis at different levels. These excisions lead to a wave of mitotic reactivation along the main stem which progresses in the basipetal way and is followed by an activation of axillary bud in the acropetal direction, from the base to the axillary bud apex. After release from apical dominance, axillary buds don't react equally. There is a basipetal gradient of their capacity of outgrowth. In the younger subapical axillary buds, mitotic reactivation is the first step observed (after 3 h); the cellular elongation occurs after 3–6 h, and foliar organogenesis begins only after 24 h. The basal axillary buds are reactivated much later. Adult leaves don't play any role on their axiliaries: the total defoliation of the plant does not lead to the outgrowth of all the axillary or cotyledonary buds.

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.

Implications of Person Fluctuation for the Stability and Validity of Test Scores

Methodology ◽  
2006 ◽  
Vol 2 (4) ◽  
pp. 142-148 ◽  
Author(s):  
Pere J. Ferrando
Keyword(s):  
Item Response ◽  
Test Scores ◽  
Temporal Stability ◽  
Person Fit ◽  
Item Parameters ◽  
Individual Trait ◽  
The Stability ◽  
The Individual ◽  
Different Levels ◽  
Fluctuation Model

In the IRT person-fluctuation model, the individual trait levels fluctuate within a single test administration whereas the items have fixed locations. This article studies the relations between the person and item parameters of this model and two central properties of item and test scores: temporal stability and external validity. For temporal stability, formulas are derived for predicting and interpreting item response changes in a test-retest situation on the basis of the individual fluctuations. As for validity, formulas are derived for obtaining disattenuated estimates and for predicting changes in validity in groups with different levels of fluctuation. These latter formulas are related to previous research in the person-fit domain. The results obtained and the relations discussed are illustrated with an empirical example.

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