9,755 research outputs found
QUASI FROBENIUS LIE ALGEBRAS CONSTRUCTION OF N=4 SUPERCONFORMAL FIELD THEORIES
Manin triple construction of N=4 superconformal field theories is considered.
The correspondence between quasi Frobenius finite-dimensional Lie algebras and
N=4 superconformal field theories is established.Comment: 20 pages, PLAINTE
Cycles are strongly Ramsey-unsaturated
We call a graph H Ramsey-unsaturated if there is an edge in the complement of
H such that the Ramsey number r(H) of H does not change upon adding it to H.
This notion was introduced by Balister, Lehel and Schelp who also proved that
cycles (except for ) are Ramsey-unsaturated, and conjectured that,
moreover, one may add any chord without changing the Ramsey number of the cycle
, unless n is even and adding the chord creates an odd cycle.
We prove this conjecture for large cycles by showing a stronger statement: If
a graph H is obtained by adding a linear number of chords to a cycle ,
then , as long as the maximum degree of H is bounded, H is either
bipartite (for even n) or almost bipartite (for odd n), and n is large.
This motivates us to call cycles strongly Ramsey-unsaturated. Our proof uses
the regularity method
Resolving the structure of TiBe
There has been considerable controversy regarding the structure of
TiBe, which is variously reported as hexagonal and tetragonal. Lattice
dynamics simulations based on density functional theory show the tetragonal
phase space group to be more stable over all temperatures, while the
hexagonal phase exhibits an imaginary phonon mode, which, if followed, would
lead to the cell adopting the tetragonal structure. We then report the
predicted ground state elastic constants and temperature dependence of the bulk
modulus and thermal expansion for the tetragonal phase.Comment: In press at Acta Crystallographica B. Supplementary material appende
Differential effect of denervation on free radical scavenging enzymes in slow and fast muscle of rat
To determine the effect of denervation on the free radical scavenging systems in relation to the mitochondrial oxidative metabolism in the slow twitch soleus and fast twitch extensor digitorum longus (EDL) muscles, the sciatic nerve of the rat was crushed in the mid-thigh region and the muscle tissue levels of 5 enzymes were studied 2 and 5 weeks following crush. Radioimmunoassays were utilized for the selective measurement of cuprozinc (cytosolic) and mangano (mitochondrial) superoxide dismutases. These data represent the first systematic report of free radical scavening systems in slow and fast muscles in response to denervation. Selective modification of cuprozinc and manganosuperoxide dismutases and differential regulation of GSH-peroxidase was demonstrated in slow and fast muscle
The introduction of new interventional procedures in the British National Health Service : A qualitative study
Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.Peer reviewedPostprin
The ''motion silencing'' illusion results from global motion and crowding
Suchow and Alvarez (2011) recently devised a striking illusion, where objects changing in color, luminance, size, or shape appear to stop changing when they move. They refer to the illusion as ''motion silencing of awareness to visual change.'' Here we present evidence that the illusion results from two perceptual processes: global motion and crowding. We adapted Suchow and Alvarez's stimulus to three concentric rings of dots, a central ring of ''target dots'' flanked on either side by similarly moving flanker dots. Subjects had to identify in which of two presentations the target dots were continuously changing (sinusoidally) in size, as distinct from the other interval in which size was constant. The results show: (a) Motion silencing depends on target speed, with a threshold around 0.2 rotations per second (corresponding to about 108/s linear motion). (b) Silencing depends on both target-flanker spacing and eccentricity, with critical spacing about half eccentricity, consistent with Bouma's law. (c) The critical spacing was independent of stimulus size, again consistent with Bouma's law. (d) Critical spacing depended strongly on contrast polarity. All results imply that the ''motion silencing'' illusion may result from crowding
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