The Master Gauge String

A string background, which is in some precise sense {\em universal} (i.e., incorporating all orders in the Feynman diagram expansion), is proposed to represent pure gauge theories. S-duality at the level of the string metric is considered as well as the vacuum expectation values of 't Hooft and Wilson loops in semiclassical approximation.Comment: LaTeX, 7 pages. Shortened and improve

Non-Critical Confining Strings and the Renormalization Group

String vacua for non critical strings satisfying the requirements of Zig-Zag invariance are constructed. The Liouville mode is shown to play the r\^ole of scale in the Renormalization Group operation. Differences and similarities with the D-brane near horizon approach to non supersymmetric gauge theories are discussed as well.Comment: LaTeX, 19 Pages, one reference adde

A Comment on the Holographic Renormalization Group and the Soft Dilaton Theorem

The equivalence between the holographic renormalization group and the soft dilaton theorem is shown for a class of wrapped metrics solutions of the string beta function equations for the bosonic string.Comment: LaTeX,7 pages. Typos corrected. Minor change

Herramienta para el diseño de elementos estructurales de madera nacional mediante los métodos ASD y LRFD

Proyecto de Graduación (Licenciatura en Ingeniería en Construcción) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería en Construcción, 2010.As a result of this project, we created a tool oriented to this material to this material so important to the sector of construction called timber. This application facilitates the design progress of raw material under LRFD and ASD methods. The application was made in excel 2007 that generates summary sheets that work in turn reports to calculate and distinct for the use of professionals involved with this type of design. During the construction of the tool took into consideration the criteria of professionals involved with the design of wood. In addition to a series of information related to this issue that one way or another were the basis for reaching an appropriate application to reduce delivery times of projects. The completion of the project leads us to recognize the importance of such a tool, to facilitate decision marking involved in this project developed which involve important raw material in the field of construction. All this for the sole purpose of optimizing as much as possible surrounding the timber is sold nationwide.Instituto Tecnológico de Costa Rica. Escuela Ingeniería en Construcción

Uso de las ideas matemáticas y científicas de los Incas, en la enseñanza-aprendizaje de la geometría

Considerando una aproximación Etnomatemática, entendida como el estudio de los procesos matemáticos,símbolos, jergas, mitologías, razonamiento, practicados por grupos culturales identificados; valoramos las posibilidades didácticas que pueden desprenderse del uso de las ideas matemáticas utilizadas en la cultura Inca.El trabajo presenta dos partes. Una valoración del uso de la matemática en la cultura Inca y otra relativa a sugerencias didácticas. Se propone por ejemplo: que los alumnos reconozcan qué conocimientos, patrones, objetos o formas geométricas usaban los incas en sus diversas manifestaciones culturales y tecnológicas. Apartir de estas “tareas" podemos introducir al estudiante en el hermoso mundo de la geometría, haciendo que aprendan de un modo bastante intuitivo y natural

The Renormalization Group Approach to the Confining String

The renormalization group approach towards the string representation of non abelian gauge theories translates, in terms of the string sigma model beta function equations, the renormalization group evolution of the gauge coupling constant and Zamolodchikov`s $c$ function. Tachyon stability, glueball mass gap, renormalization group evolution of the $c$ function and the area law for the Wilson loop are studied for a critical bosonic string vacuum corresponding to a non abelian gauge theory in four dimensional space-time. We prove that the same intrinsic geometry for the string vacuum is universal in some sense, reproducing the Yang-Mills beta function to arbitrary loop order in perturbation theory.Comment: LaTeX, 26 pages. Minor change

Banks, remittances and financial deepening in receiving countries : a model

A remarkable fact of the mushrooming remittances market is the absence of commercial banks as relevant players. Furthermore, remittances have been identified as a potential catalyst for the financial deepening of receiving countries through higher access to banking services by migrants' families. Building upon these features, this paper sets up a two-period financial model of remittances without uncertainty. The formulation acknowledges, on the one hand, the altruism component of remittances sent by migrants to their families and, on the other hand, the dominant position of Money Transfer Operators (MTO's) due to migrants' mistrust to banks, which hinders the access of banks to the market. Altruism compounded with a non-competitive market allows MTO's to set excessively high remittance fees and to attain monopolistic rents. The model shows that banks can challenge this position thanks to their role as providers of remunerated saving and credit, which enables them to overcome the competitive disadvantage derived by migrants' mistrust. Notwithstanding this, the main positive impact of banks' entry is attained through higher competition, not through the provision of financial services. All in all, the entry of banks reduces the fees and increases the level of remittances, allows an optimal consumption smoothing and improves the welfare of migrants and their families, although it also increases the volatility of remittances. [resumen de autor

Brief considerations on business valuation methods

Nowadays, determining the value of a business has gained significant importance in academic and business fields, as the understanding of the value of an organization has become a key tool for the management and marketing of a business. Accordingly, numerous methods have been developed in order to perform these kinds of practices. In this article, the most used and current methods in processes of business evaluation are revised, observing their strengths and weaknesses, with the aim of comparing them and determining that the discounted cash flow methods are the most adequate procedures to perform this type of analysis

Non-Critical Poincar\'e Invariant Bosonic String Backgrounds and Closed String Tachyons

A new family of non critical bosonic string backgrounds in arbitrary space time dimension $D$ and with $ISO(1,D-2)$ Poincar\'e invariance are presented. The metric warping factor and dilaton agree asymptotically with the linear dilaton background. The closed string tachyon equation of motion enjoys, in the linear approximation, an exact solution of ``kink'' type interpolating between different expectation values. A renormalization group flow interpretation ,based on a closed string tachyon potential of type $-T^{2}e^{-T}$, is suggested.Comment: latex, 16 pages, 4 figures, misprints correcte