A Helmholtzian operator and electromagnetic-nuclear field

submitted by: cloudmichael
A Helmholtzian operator is a linear second order partial differential operator, typically in four independant variables; a generalization of the d'Alembertian operator where it's additional constant vanishes. When the time-independant version (in three independent (space) variables acting on a function or vector vanishes, the resulting equation is called the Helmholtz's equation. In four dimensions this equation is referred to as the Klein-Gordon equation (with imaginary constant) . The...

The d'Alembertian and Maxwell's equations

submitted by: cloudmichael
The d'Alembertian is a linear second order differential operator, typically in four independant variables. The time-independant version (in three independent (space) variables is called the Laplacian operator. When it's action on a function or vector vanishes, the resulting equation is called the wave equation (or Laplace's equation). When it's action is identified with a non-zero function (or vector function) the resulting equation is called Poisson's equation. This equation is fundamental...

Probing the spindle matrix

submitted by: JCB
A microtubule-independent network of proteins called the spindle matrix is involved in assembling mitotic and meiotic spindles, but whether the matrix makes a mechanical contribution to spindle shape is unclear. Gatlin et al. manipulate spindles with microneedles to directly probe the mechanical properties of the spindle matrix. This biosights episode presents the paper by Gatlin et al. from the February 22, 2010 issue of The Journal of Cell Biology, and includes an interview with lead...