Ribbon-type presynaptic active zones are a hallmark of excitatory retinal synapses, and the ribbon organelle is thought to serve as the organizing point of the presynaptic active zone. Imaging of exocytosis from isolated retinal neurons, however, has revealed ectopic release (i.e., release away from ribbons) in significant quantities. Here, we demonstrate in an in vitro mouse retinal slice prep...

We prove that a crossing change along a double point circle on a 2-knot is realized by ribbon-moves for a knotted torus obtained from the 2-knot by attaching a 1-handle. It follows that any 2-knots for which the crossing change is an unknotting operation, such as ribbon 2-knots and twistspun knots, have trivial Khovanov-Jacobsson number. A surface-knot or -link is a closed surface embedded in 4...

as a part of a major ecological study of hanna wetland, semirum region, isfahan province, parasitic infestation of 3 native and one introduced fish species were investigated. a total of 120 fish specimens were collected by both cast net and a series of gillnets between fall and winter 2007, and spring and summer 2008. some of the observed parasites are reported for the first time as new host re...

Vermiculture is the culture of earthworms. The goal is to continually increase the number of worms in order to obtain a sustainable harvest. The worms are either used to expand a vermicomposting operation or sold to customers who use them for the same or other purposes. Vermicomposting is the process by which worms are used to convert organic materials (usually wastes) into a humus-like materia...

This paper explores the effect of impeller design on the chaotic mixing in a helical ribbon mixer. Numerical simulations using the Smoothed Particle Hydrodynamics (SPH) method are used to solve for the fluid flow around the moving impellor. The mixing flow is visualised by extracting the hyperbolic Lagrangian Coherent Structures (LCS) of the flow from the Finite-Time Lyapunov Exponent (FTLE) fi...

W. H. Tutte’s 1947 paper on a ring generated by graphs satisfying a contraction-deletion relation is extended to ribbon graphs. This ring of ribbon graphs is a polynomial ring on an infinite set of one-vertex ribbon graphs. Acknowledgements: The LSU Research Experience for Undergraduates Program is supported by a National Science Foundation grant, DMS-0648064. Page 16 RHIT Undergrad. Math. J., ...

A ribbon is a double structure on P. The geometry of a ribbon is closely related to that of a smooth curve. In this note we consider linear series on ribbons. Our main result is an explicit determinantal description for the locus W r 2n of degree 2n line bundles with at least (r +1)-dimensional sections on a ribbon. We also discuss some results of Clifford and Brill-Noether type.

A closed duplex DNA molecule relaxed and containing nucleosomes has a different linking number from the same molecule relaxed and without nucleosomes. What does this say about the structure of the nucleosome? A mathematical study of this question is made, representing the DNA molecule by a ribbon. It is shown that the linking number of a closed ribbon can be decomposed into the linking number o...

CASE REPORT A 58 year old woman attended the emergency department with a one month history of right upper abdominal pain, vomiting, and fever. Her physical examination revealed tenderness in the right upper quadrant. Laboratory test results at presentation revealed mildly increased liver enzymes aspartate transaminase:353 U/l, alanine transaminase:218 U/l, γ-glutamyltransferase:110 U/l, alkalin...