Molecular clock analyses estimate that crown-group animals began diversifying hundreds of millions of years before the start of the Cambrian period. However, the fossil record has not yielded unequivocal evidence for animals during this interval. Some of the most promising candidates for Precambrian animals occur in the Weng'an biota of South China, including a suite of tubular fossils assigned...

The author has published equations for predicting the air borne sound transmission of double leaf cavity walls due to the structure borne sound transmission across the air cavity via (possibly resilient) line connections, but has never published the full derivation of these equations. The author also derived equations for the case when the connections are rigid point connections but has never u...

The packing problem of long thin filaments that are injected into confined spaces is of fundamental interest for physicists and biologists alike. How linear threads pack and coil is well known only for the ideal case of rigid containers, though. Here, we force long elastic rods into flexible spatial confinement borne by an elastic shell to examine under which conditions recently acquired knowle...

There are various bubble cavitation phenomena in daily production and life, near-wall is the most common one. This paper studies dynamics between a rigid wall an elastic wall, by changing distance two walls initial position of bubble, several different collapse patterns obtained. Then, we discuss changes migration distance, gravity, maximum radius during cavitation. Finally, numerical simulatio...

Certain unresolved ambiguities surround pressure determinations for incompressible flows, both Navier-Stokes and magnetohydrodynamic. For uniform-density fluids with standard Newtonian viscous terms, taking the divergence of the equation of motion leaves a Poisson equation for the pressure to be solved. But Poisson equations require boundary conditions. For the case of rectangular periodic boun...

BACKGROUND AND PURPOSE Wall shear stress (WSS) and pressure are important factors in the development of cerebral aneurysms. We aimed to develop a computational fluid dynamics simulator for flow in the complete circle of Willis to study the impact of variations in vessel radii and bifurcation angles on WSS and pressure on vessel walls. METHODS Blood flow was modeled with Navier-Stokes equation...

Polarized one- and two-dimensional infrared spectra were obtained from the epidermis of onion (Allium cepa) under hydrated and mechanically stressed conditions. By Fourier-transform infrared microspectroscopy, the orientation of macromolecules in single cell walls was determined. Cellulose and pectin exhibited little orientation in native epidermal cell walls, but when a mechanical stress was p...

This paper aims to provide support for the view that individual concepts are basic to natural language semantics. First, the use of constant individual concepts allows us to maintain Kripke’s view of proper names as nondescriptional rigid designators in the face of problems created by so-called “empty names.” And second, the distinction between constant and variable individual concepts can func...

We give a partial positive answer to a conjecture of Tyurin ([28]). Indeed we prove that on a general quintic hypersurface of P every arithmetically Cohen–Macaulay rank 2 vector bundle is infinitesimally rigid.

What happens to the entropy increase principle as the Universe evolve to form the bigcrunch singularity? What happens to the uncertainity relations along the process of gravitational collapses? What is the quantum mechanical description of a Radon atom in a rigid box when the distance of consecutive nodes and antinodes of ψ is equal to or less than the diameter of the atom? What is the position...