Spine surgery is a matter of interest of several specialities. The development of new instrumentations brought a number of new operative techniques. Minimally invasive surgery, endoscopy, offers superior results, but first disapontiments appear as well. What to operate, when and how? A schematic presentation of pathology, operative procedures and indications are presented.

This study tests the hypotheses that the birefringent calcite and stereom structure of the brittlestar (Ophiuroidea, Echinodermata) endoskeleton polarizes light and that certain brittlestars respond to polarized light. The first hypothesis was tested in Ophioderma brevispinum by examining ossicles from freshly killed specimens under polarized light. This analysis revealed that the lateral arm s...

We demonstrate a novel strong law of large numbers for branching processes, with a simple proof via measure-theoretic manipulations and spine theory. Roughly speaking, any sequence of events that eventually occurs almost surely for the spine entails the almost sure convergence of a certain sum over particles in the population.

Why do neurons have dendritic spines? This question-the heart of what Yuste calls "the spine problem"-presupposes that why-questions of this sort have scientific answers: that empirical findings can favor or count against claims about why neurons have spines. Here we show how such questions can receive empirical answers. We construe such why-questions as questions about how spines make a differ...

We establish a calculus for branched spines of 3-manifolds by means of branched Matveev-Piergallini moves and branched bubblemoves. We briefly indicate some of its possible applications in the study and definition of State-Sum Quantum Invariants.

The reaction between the flexible ligand (1,4-bis(pyridine-2-yl-methanethio)benzene) and Ag+ produces two novel coordination polymers with macrocyclic cages or pockets contained within their backbones, depending upon the ratio of starting materials.

The vertebral column of the Atlantic white-sided dolphin, Lagenorhynchus acutus, reflects the radical reorganization of the cetacean column for locomotion in water. Both posterior thoracic and anterior caudal vertebrae have been ‘‘lumbarized,’’ and discontinuities occur within the caudal series at the synclinal point and fluke base. Morphology changes subtly as body size increases. Neural proce...

The vertebral column is a conserved anatomical structure that defines the vertebrate phylum. The periodic or segmental pattern of the vertebral column is established early in development when the vertebral precursors, the somites, are rhythmically produced from presomitic mesoderm (PSM). This rhythmic activity is controlled by a segmentation clock that is associated with the periodic transcript...