Embryonic axis orientation in the mouse and its correlation with blastocyst relationships to the uterus

Development ◽  
1985 ◽  
Vol 89 (1) ◽  
pp. 15-35
Author(s):  
L. J. Smith

Each of the three primary axes of the primitive streak (6¾ days p.c.) to C-shaped (9½ days) stage mouse embryo has a specific relationship to the uterine horn axes. By a retrograde analysis of younger sectioned embryos it has been possible to construct an axis fate map for the implanting 4¼-day blastocyst and to show how its implantation in one or the other of two specific orientations to the ends and walls of the horn leads to these embryo-horn relationships. The implanting blastocyst axis fate map can be related to an axis fate map of the attached blastocyst (Smith, 1980) since these too are in one or the other of two orientations to the ends and walls of the horn. It is suggested that the asymmetries of the attached and implanting blastocysts that allowed the distinctive attachment and implantation orientations to be recognized, are the initial expressions of a three-dimensional system of positional information that is present in the attached blastocyst.

1996 ◽  
Vol 74 (1-2) ◽  
pp. 4-9
Author(s):  
M. R. M. Witwit

The energy levels of a three-dimensional system are calculated for the rational potentials,[Formula: see text]using the inner-product technique over a wide range of values of the perturbation parameters (λ, g) and for various eigenstates. The numerical results for some special cases agree with those of previous workers where available.


1976 ◽  
Vol 15 (2) ◽  
pp. 197-222
Author(s):  
R. J. Hartman

This paper uses the general solution of the linearized initial-value problem for an unbounded, exponentially-stratified, perfectly-conducting Couette flow in the presence of a uniform magnetic field to study the development of localized wave-type perturbations to the basic flow. The two-dimensional problem is shown to be stable for all hydrodynamic Richardson numbers JH, positive and negative, and wave packets in this flow are shown to approach, asymptotically, a level in the fluid (the ‘isolation level’) which is a smooth, continuous, function of JH that is well defined for JH < 0 as well as JH > 0. This system exhibits a rich complement of wave phenomena and a variety of mechanisms for the transport of mean flow kinetic and potential energy, via linear wave processes, between widely-separated regions of fluid; this in addition to the usual mechanisms for the absorption of the initial wave energy itself. The appropriate three-dimensional system is discussed, and the role of nonlinearities on the development of localized disturbances is considered.


Author(s):  
Malena I. Español ◽  
Dmitry Golovaty ◽  
J. Patrick Wilber

In this paper, we derive a continuum variational model for a two-dimensional deformable lattice of atoms interacting with a two-dimensional rigid lattice. The starting point is a discrete atomistic model for the two lattices which are assumed to have slightly different lattice parameters and, possibly, a small relative rotation. This is a prototypical example of a three-dimensional system consisting of a graphene sheet suspended over a substrate. We use a discrete-to-continuum procedure to obtain the continuum model which recovers both qualitatively and quantitatively the behaviour observed in the corresponding discrete model. The continuum model predicts that the deformable lattice develops a network of domain walls characterized by large shearing, stretching and bending deformation that accommodates the misalignment and/or mismatch between the deformable and rigid lattices. Two integer-valued parameters, which can be identified with the components of a Burgers vector, describe the mismatch between the lattices and determine the geometry and the details of the deformation associated with the domain walls.


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