2,149 research outputs found
Combinatorics of 1-particle irreducible n-point functions via coalgebra in quantum field theory
We give a coalgebra structure on 1-vertex irreducible graphs which is that of
a cocommutative coassociative graded connected coalgebra. We generalize the
coproduct to the algebraic representation of graphs so as to express a bare
1-particle irreducible n-point function in terms of its loop order
contributions. The algebraic representation is so that graphs can be evaluated
as Feynman graphs
Elliptic curves of large rank and small conductor
For r=6,7,...,11 we find an elliptic curve E/Q of rank at least r and the
smallest conductor known, improving on the previous records by factors ranging
from 1.0136 (for r=6) to over 100 (for r=10 and r=11). We describe our search
methods, and tabulate, for each r=5,6,...,11, the five curves of lowest
conductor, and (except for r=11) also the five of lowest absolute discriminant,
that we found.Comment: 16 pages, including tables and one .eps figure; to appear in the
Proceedings of ANTS-6 (June 2004, Burlington, VT). Revised somewhat after
comments by J.Silverman on the previous draft, and again to get the correct
page break
Constructing Elliptic Curves over with Moderate Rank
We give several new constructions for moderate rank elliptic curves over
. In particular we construct infinitely many rational elliptic
surfaces (not in Weierstrass form) of rank 6 over using
polynomials of degree two in . While our method generates linearly
independent points, we are able to show the rank is exactly 6 \emph{without}
having to verify the points are independent. The method generalizes; however,
the higher rank surfaces are not rational, and we need to check that the
constructed points are linearly independent.Comment: 11 page
Suborbifolds and groupoid embeddings
Given the notion of suborbifold of the second author (based on ideas of Borzellino/Brunsden) and the classical correspondence (up to certain equivalences) between (effective) orbifolds via atlases and effective orbifold groupoids, we analyze which groupoid embeddings correspond to suborbifolds and give classes of suborbifolds naturally leading to groupoid embeddings
Wound Healing. Therapeutics
As feridas crónicas representam um problema grave de saúde pública e uma das causas de grande consumo de recursos em saúde. Recentes avanços no conhecimento do mecanismo de cicatrização levaram ao desenvolvimento de novos tratamentos. Definir o papel e eficácia destes novos tratamentos é o próximo passo.
Os autores procuraram neste trabalho abordar algumas terapêuticas, que não terapia compressiva e material de penso, na cicatrização de feridas crónicas
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