Intersections forms and the geometry of lattice Chern-Simons theory

We show that it is possible to formulate Abelian Chern-Simons theory on a lattice as a topological field theory. We discuss the relationship between gauge invariance of the Chern-Simons lattice action and the topological interpretation of the canonical structure. We show that these theories are exactly solvable and have the same degrees of freedom as the analogous continuum theories.Comment: 14 page

The range scheduling aid

The Air Force Space Command schedules telemetry, tracking and control activities across the Air Force Satellite Control network. The Range Scheduling Aid (RSA) is a rapid prototype combining a user-friendly, portable, graphical interface with a sophisticated object-oriented database. The RSA has been a rapid prototyping effort whose purpose is to elucidate and define suitable technology for enhancing the performance of the range schedulers. Designing a system to assist schedulers in their task and using their current techniques as well as enhancements enabled by an electronic environment, has created a continuously developing model that will serve as a standard for future range scheduling systems. The RSA system is easy to use, easily ported between platforms, fast, and provides a set of tools for the scheduler that substantially increases his productivity

The Initial Value Problem For Maximally Non-Local Actions

We study the initial value problem for actions which contain non-trivial functions of integrals of local functions of the dynamical variable. In contrast to many other non-local actions, the classical solution set of these systems is at most discretely enlarged, and may even be restricted, with respect to that of a local theory. We show that the solutions are those of a local theory whose (spacetime constant) parameters vary with the initial value data according to algebraic equations. The various roots of these algebraic equations can be plausibly interpreted in quantum mechanics as different components of a multi-component wave function. It is also possible that the consistency of these algebraic equations imposes constraints upon the initial value data which appear miraculous from the context of a local theory.Comment: 8 pages, LaTeX 2 epsilo

Hard Properties with (Very) Short PCPPs and Their Applications

We show that there exist properties that are maximally hard for testing, while still admitting PCPPs with a proof size very close to linear. Specifically, for every fixed ?, we construct a property P^(?)? {0,1}^n satisfying the following: Any testing algorithm for P^(?) requires ?(n) many queries, and yet P^(?) has a constant query PCPP whose proof size is O(n?log^(?)n), where log^(?) denotes the ? times iterated log function (e.g., log^(2)n = log log n). The best previously known upper bound on the PCPP proof size for a maximally hard to test property was O(n?polylog(n)). As an immediate application, we obtain stronger separations between the standard testing model and both the tolerant testing model and the erasure-resilient testing model: for every fixed ?, we construct a property that has a constant-query tester, but requires ?(n/log^(?)(n)) queries for every tolerant or erasure-resilient tester

A comment on BCC crystalization in higher dimensions

The result that near the melting point three-dimensional crystals have an octahedronic structure is generalized to higher flat non compact dimensions

Cellular internalization of alpha-synuclein aggregates by cell surface heparan sulfate depends on aggregate conformation and cell type.

Amyloid aggregates found in the brain of patients with neurodegenerative diseases, including Alzheimer's and Parkinson's disease, are thought to spread to increasingly larger areas of the brain through a prion-like seeding mechanism. Not much is known about which cell surface receptors may be involved in the cell-to-cell transfer, but proteoglycans are of interest due to their well-known propensity to interact with amyloid aggregates. In this study, we investigated the involvement of plasma membrane-bound heparan and chondroitin sulfate proteoglycans in cellular uptake of aggregates consisting of α-synuclein, a protein forming amyloid aggregates in Parkinson's disease. We show, using a pH-sensitive probe, that internalization of α-synuclein amyloid fibrils in neuroblastoma cells is dependent on heparan sulfate, whereas internalization of smaller non-amyloid oligomers is not. We also show that α-synuclein fibril uptake in an oligodendrocyte-like cell line is equally dependent on heparan sulfate, while astrocyte- and microglia-like cell lines have other means to internalize the fibrils. In addition, we analyzed the interaction between the α-synuclein amyloid fibrils and heparan sulfate and show that overall sulfation of the heparan sulfate chains is more important than sulfation at particular sites along the chains

Effect of Al addition on microstructure of AZ91D

Casting is a net shape or near net shape forming process so work-hardening will not be applicable for improving properties of magnesium cast alloys. Grain refinement, solid-solution strengthening, precipitation hardening and specially designed heat treatment are the techniques used to enhance the properties of these alloys. This research focusses on grain refinement of magnesium alloy AZ91D, which is a widely used commercial cast alloy. Recently, Al-B based master alloys have shown potential in grain refining AZ91D. A comparative study of the grain refinement of AZ91D by addition of 0.02wt%B, 0.04wt%B, 0.1wt%B, 0.5wt%B and 1.0wt%B of A1-5B master alloy and equivalent amount of solute element aluminium is described in this paper. Hardness profile of AZ91D alloyed with boron and aluminium is compared