7,424 research outputs found
Large N reduction on a twisted torus
We consider SU(N) lattice gauge theory at infinite N defined on a torus with
a CP invariant twist. Massless fermions are incorporated in an elegant way,
while keeping them quenched. We present some numerical results which suggest
that twisting can make numerical simulations of planar QCD more efficient.Comment: 14 pages, 2 figures, 1 tabl
Numerical solution of open string field theory in Schnabl gauge
Using traditional Virasoro level-truncation computations, we evaluate
the open bosonic string field theory action up to level . Extremizing
this level-truncated potential, we construct a numerical solution for tachyon
condensation in Schnabl gauge. We find that the energy associated to the
numerical solution overshoots the expected value at level .
Extrapolating the level-truncation data for to estimate the vacuum
energies for , we predict that the energy reaches a minimum value at , and then turns back to approach asymptotically as . Furthermore, we analyze the tachyon vacuum expectation value (vev),
for which by extrapolating its corresponding level-truncation data, we predict
that the tachyon vev reaches a minimum value at , and then turns
back to approach the expected analytical result as .Comment: 37 pages, 9 figures, some typos correcte
Convex drawings of the complete graph: topology meets geometry
In this work, we introduce and develop a theory of convex drawings of the
complete graph in the sphere. A drawing of is convex if, for
every 3-cycle of , there is a closed disc bounded by
such that, for any two vertices with and both in
, the entire edge is also contained in .
As one application of this perspective, we consider drawings containing a
non-convex that has restrictions on its extensions to drawings of .
For each such drawing, we use convexity to produce a new drawing with fewer
crossings. This is the first example of local considerations providing
sufficient conditions for suboptimality. In particular, we do not compare the
number of crossings {with the number of crossings in} any known drawings. This
result sheds light on Aichholzer's computer proof (personal communication)
showing that, for , every optimal drawing of is convex.
Convex drawings are characterized by excluding two of the five drawings of
. Two refinements of convex drawings are h-convex and f-convex drawings.
The latter have been shown by Aichholzer et al (Deciding monotonicity of good
drawings of the complete graph, Proc.~XVI Spanish Meeting on Computational
Geometry (EGC 2015), 2015) and, independently, the authors of the current
article (Levi's Lemma, pseudolinear drawings of , and empty triangles,
\rbr{J. Graph Theory DOI: 10.1002/jgt.22167)}, to be equivalent to pseudolinear
drawings. Also, h-convex drawings are equivalent to pseudospherical drawings as
demonstrated recently by Arroyo et al (Extending drawings of complete graphs
into arrangements of pseudocircles, submitted)
A new Viola (Violaceae) from the Argentinian Andes
Viola beati, a hitherto unknown species of V. sect. Andinium (Violaceae) is described and illustrated. It is an inconspicuous, diminutive, perennial forb currently known from only one locality in NW Argentina. We draw attention to its morphology, ecology, rarity and endemism. The differences between V. beati and its apparently only close relative, V. singularis J. M. Watson & A. R. Flores, are defined
Large reduction with the Twisted Eguchi-Kawai model
We examine the breaking of symmetry recently reported for the Twisted
Eguchi-Kawai model (TEK). We analyse the origin of this behaviour and propose
simple modifications of twist and lattice action that could avoid the problem.
Our results show no sign of symmetry breaking and allow us to obtain values of
the large infinite volume string tension in agreement with extrapolations
from results based upon straightforward methods.Comment: latex file 14 pages, 4 figure
Banking concentration, information asymmetries and credit rationing: The Argentinean case
This paper highlights the importance of the information efficiency in the banking sector as a way to ensure his correct operation as financial intermediary and the correct functioning of the economy in general. The problems of information in the banks distort their relation with the financing demand and especially with the sector of the SMEs, what really means an important obstacle for the smooth operation of any market system. The analysis is centred in the relative size of the financial institutions, the generation of different types of information and the way how it affects the sector of the SMEs. By means of empirical evidence we will show how the greater size of the banks has influence on the creation of information systems that are not well adapted for some segments of the demand or even they do not generate information at all
Geminiviral protein Rep interferes in PCNA sumoylation
Rep is a multifunctional protein essential for replication of geminivirus that interferes with the sumoylation of a key protein in the DNA replication, PCNA (Proliferating Cell Nuclear Antigen). It is known that Rep is capable of interacting with a plethora of plant proteins, including PCNA. Despite the biological significance remains unknown, it’s thought that this interaction should play a key role for generating new copies of the virus genome. Therefore, in order to characterize this interaction, we study which lysines are sumoylated in tomato PCNA (SlPCNA). Considering conservation, location and presence of sumoylation domain criteria, we have identified some candidate lysines and studied how its mutation affects this protein sumoylation in Escherichia coli assays. Finally, we plan to confirm and characterize the Rep interference on SlPCNA sumoylation and determine if this interference occurs in planta.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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