Discrete Dynamical Systems: A Brief Survey

Dynamical system is a mathematical formalization for any fixed rule that is described in time dependent fashion. The time can be measured by either of the number systems - integers, real numbers, complex numbers. A discrete dynamical system is a dynamical system whose state evolves over a state space in discrete time steps according to a fixed rule. This brief survey paper is concerned with the part of the work done by José Sousa Ramos [2] and some of his research students. We present the general theory of discrete dynamical systems and present results from applications to geometry, graph theory and synchronization

Instanton Corrected Non-Supersymmetric Attractors

We discuss non-supersymmetric attractors with an instanton correction in Type IIA string theory compactified on a Calabi-Yau three-fold at large volume. For a stable non-supersymmetric black hole, the attractor point must minimize the effective black hole potential. We study the supersymmetric as well as non-supersymmetric attractors for the D0-D4 system with instanton corrections. We show that in simple models, like the STU model, the flat directions of the mass matrix can be lifted by a suitable choice of the instanton parameters.Comment: Minor modifications, Corrected typos, 38 pages, 1 figur

Particle Learning and Smoothing

Particle learning (PL) provides state filtering, sequential parameter learning and smoothing in a general class of state space models. Our approach extends existing particle methods by incorporating the estimation of static parameters via a fully-adapted filter that utilizes conditional sufficient statistics for parameters and/or states as particles. State smoothing in the presence of parameter uncertainty is also solved as a by-product of PL. In a number of examples, we show that PL outperforms existing particle filtering alternatives and proves to be a competitor to MCMC.Comment: Published in at http://dx.doi.org/10.1214/10-STS325 the Statistical Science (http://www.imstat.org/sts/) by the Institute of Mathematical Statistics (http://www.imstat.org

The world-sheet corrections to dyons in the Heterotic theory

All the linear alpha-prime corrections, however excluding the gravitational Chern-Simons correction, are studied in the toroidally compactified critical Heterotic string theory. These corrections are computed to the entropy for a BPS static spherical four dimensional dyonic black hole which represents a wrapped fundamental string carrying arbitrary winding and momentum charges along one cycle in the presence of KK-monopole and H-monopole charges associated to another cycle. It is verified that after the inclusion of the gravitational Chern-Simons corrections [hep-th/0608182], all the linear alpha-prime corrections to the entropy for the supersymmetric dyon can be reproduced by the inclusion of only the Gauss-Bonnet Lagrangian to the supergravity approximation of the induced Lagrangian.Comment: JHEP style, 17 Pages; v2: a typo corrected ; v3: The coupling of the gravitational Chern-Simons terms to the three form field strength taken into account. The conclusion correcte

Partition functions and elliptic genera from supergravity

We develop the spacetime aspects of the computation of partition functions for string/M-theory on AdS(3) xM. Subleading corrections to the semi-classical result are included systematically, laying the groundwork for comparison with CFT partition functions via the AdS(3)/CFT(2) correspondence. This leads to a better understanding of the "Farey tail" expansion of Dijkgraaf et. al. from the point of view of bulk physics. Besides clarifying various issues, we also extend the analysis to the N=2 setting with higher derivative effects included.Comment: 34 page

Aceleração do ganho genético para produtividade e outras características chaves para a competitividade da cultura de arroz irrigado.

São discutidas as características chaves visadas pelo melhoramento genético para uma maior competitividade agronômica e comercial do arroz: Produtividade, Alta capacidade de perfilhamento. Resistência ao acamamento das plantas. Resistência à toxidez por excesso de ferro no solo. Tolerância à herbicidas para controle de arroz vermelho e adaptação ao sistema de cultivo de arroz pré-germinado. Resistência à brusone. Tolerância aos estresse de temperatura baixa nas fases de germinação, emergência e vegetativa e vigor inicial de plântulas; Tolerância aos estresses de temperatura alta na fase reprodutiva; Qualidade de grãos.Palestra