International Actors and Internal Conflicts

Surveys the recent literature relating to conflict and mediation activities, and presents a range of options available to states, international organizations, regional organizations, and NGOs seeking to mediate internal conflicts

A Quantitative Steinitz Theorem for Plane Triangulations

We give a new proof of Steinitz's classical theorem in the case of plane triangulations, which allows us to obtain a new general bound on the grid size of the simplicial polytope realizing a given triangulation, subexponential in a number of special cases. Formally, we prove that every plane triangulation $G$ with $n$ vertices can be embedded in $\mathbb{R}^2$ in such a way that it is the vertical projection of a convex polyhedral surface. We show that the vertices of this surface may be placed in a $4n^3 \times 8n^5 \times \zeta(n)$ integer grid, where $\zeta(n) \leq (500 n^8)^{\tau(G)}$ and $\tau(G)$ denotes the shedding diameter of $G$, a quantity defined in the paper.Comment: 25 pages, 6 postscript figure

Supporting children with genetic syndromes in the classroom: the example of 22q deletion syndrome

An increasing number of children are likely to have a known genetic cause for their special educational needs. One such genetic condition is 22q11.2 deletion syndrome (22qDS), a genetic syndrome associated with early speech and language difficulties, global and specific cognitive impairments, difficulties with attention and difficulties with social-emotional functioning. In this article the learning and behavioural strengths and needs of this genetic syndrome are described along with recommendations for classroom-based interventions. Suggested recommendations in the learning and emotional-behavioural domains for the syndrome draw on a number of approaches that have been found to be useful for children with a range of conditions including ADHD, ASD and dyscalculia. While teachers cannot be expected to know about all potential genetic causes for special educational needs, knowing that a genetic condition is likely to be associated with a pattern of relative cognitive and behavioural strengths and needs is important

On the Potential of Large Ring Lasers

We describe a new ring laser with area A = 833 m^2 and update performance statistics for several such machines. Anandan & Chaio 1982 judged ring lasers inferior to matter interferometers as possible detectors of gravitational waves. However, we note that geophysically interesting results have been obtained from large ring lasers and that there is still a lot of room for improvements.Comment: accepted optics communication

How many nn-vertex triangulations does the 33-sphere have?

It is known that the $3$-sphere has at most $2^{O(n^2 \log n)}$ combinatorially distinct triangulations with $n$ vertices. Here we construct at least $2^{\Omega(n^2)}$ such triangulations.Comment: 9 pages, 1 figur

Peroxy radical detection by chemical amplification (PERCA)

Important reactions of atmospheric free radicals are the chain oxidation of NO and CO. Thus: H2O + NO yields OH + NO2; OH + CO yields H + CO2; H + O2 + M yields HO2 + M. In most models, the need to know the free radical concentration could also be described as the need to know the rate of the above oxidation chain in the atmosphere. It is the total rate of this chain (also carried by RO2 and RO) which was measured using the PERCA. The PERCA is thus essentially a RO sub X meter. The PERCA works by adding excess CO (10%) and NO (5ppm) to a stream of air and measuring the NO2 produced after 3s of reaction time. Since other processes produce NO2, the chain reaction is modulated by switching the CO for N2. The chain length is limited by the reaction OH + NO yields HONO and is modeled to be somewhat over 1000. Measured chain lengths agree with the modeled numbers

Performance-Based Pay for Teachers

CRS ReportCRSTeachersPerformancePay01.pdf: 10899 downloads, before Oct. 1, 2020

Generalized Legendre transformations and symmetries of the WDVV equations

The Witten-Dijkgraaf-Verlinde-Verlinde (or WDVV) equations, as one would expect from an integrable system, has many symmetries, both continuous and discrete. One class - the so-called Legendre transformations - were introduced by Dubrovin. They are a discrete set of symmetries between the stronger concept of a Frobenius manifold, and are generated by certain flat vector fields. In this paper this construction is generalized to the case where the vector field (called here the Legendre field) is non-flat but satisfies a certain set of defining equations. One application of this more general theory is to generate the induced symmetry between almost-dual Frobenius manifolds whose underlying Frobenius manifolds are related by a Legendre transformation. This also provides a map between rational and trigonometric solutions of the WDVV equations.Comment: 23 page