6,306 research outputs found
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 with vertices can
be embedded in 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 integer grid, where and denotes the shedding diameter of , 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
How many -vertex triangulations does the -sphere have?
It is known that the -sphere has at most
combinatorially distinct triangulations with vertices. Here we construct at
least such triangulations.Comment: 9 pages, 1 figur
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
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
Recommended from our members
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
- …