First-passage-time statistics of a Brownian particle driven by an arbitrary unidimensional potential with a superimposed exponential time-dependent drift

In one-dimensional systems, the dynamics of a Brownian particle are governed by the force derived from a potential as well as by diffusion properties. In this work, we obtain the first-passage-time statistics of a Brownian particle driven by an arbitrary potential with an exponential temporally decaying superimposed field up to a prescribed threshold. The general system analyzed here describes the sub-threshold signal integration of integrate-and-fire neuron models, of any kind, supplemented by an adaptation-like current, whereas the first-passage-time corresponds to the declaration of a spike. Following our previous studies, we base our analysis on the backward Fokker Planck equation and study the survival probability and the first-passage-time density function in the space of the initial condition. By proposing a series solution we obtain a system of recurrence equations, which given the specific structure of the exponential time-dependent drift, easily admit a simpler Laplace representation. Naturally, the present general derivation agrees with the explicit solution we found previously for the Wiener process in (2012 JPhysA 45 185001). However, to demonstrate the generality of the approach, we further explicitly evaluate the first-passage-time statistics of the underlying Ornstein Uhlenbeck process. To test the validity of the series solution, we extensively compare theoretical expressions with the data obtained from numerical simulations in different regimes. As shown, agreement is precise whenever the series is truncated at an appropriate order. Beyond the fact that both the Wiener and Ornstein Uhlenbeck processes have a direct interpretation in the context of neuronal models, given their ubiquity in different fields, our present results will be of interest in other settings where an additive state-independent temporal relaxation process is being developed as the particle diffuses.Comment: 22 pages (20 pages in the journal version), 3 figures, published in J. Phys.

Banking in Brazil: Structure, Performance, Drivers, and Policy Implications

he objective of this paper is to analyze the industry structure of banking services in Brazil in order to shed light on financial performance and its drivers at a disaggregated level. The study illustrates how differences across market segments -- which tend to be averaged out in aggregate analysis -- need to be taken into account when analyzing performance and designing public policy for the banking sector. In particular, retail banking is found to be less sensitive to price competition and to exhibit considerably higher returns than corporate banking. The authors identify and discuss the factors underlying revenues, costs, and risks in each market segment, and conclude with policy implications.Brazil; banking; competition; industry structure; performance

Estrategias retóricas para la escritura autobiográfica en la historia de las Indias de Fray Bartolomé de las casas

Lo autobiográfico en la Historia de las Indias no debe ser comprendido como una muestra más de la incontrolable subjetividad del obispo de Chiapa porque la autoescritura estuvo regulada por la historiografía. En una historia diferente el dominico asumió un papel protagónico-ejemplar. La propia presentación siguió el modelo de la confesión y proyectó dos facetas de la actuación del obispo: el justo y la del elegido. Para acreditar su biografismo usó varios recursos como señalar sus atributos morales y crear un efecto de distancia entre narrador y personaje

Ricardo Palma ethos in its tradiciones

The role of the ethos of the writer in the likelihood of a literary form called ‘tradition’, where you play with data from written sources and oral tradition, invented in the nineteenth century by the Peruvian Ricardo Palma to generate social consensus is analyzed about the identity of his nascent country.Se analiza el papel que juega el ethos del escritor en la verosimilitud de una forma literaria denominada ‘tradición’ —donde se juega con datos de fuentes escritas y de tradición oral—, inventada en el siglo XIX por el peruano Ricardo Palma para generar consensos sociales en torno a la identidad de su naciente patria

Fray Bartolomé de las Casas, historiador profeta

El artículo aborda, desde una perspectiva retórica, el discurso profético de fray Bartolomé de las Casas en la Historia de las India

El bestiario medieval en las crónicas de Indias (siglos XV y XVI)

El artículo estudia la forma en que está presente el Bestiario medieval, Bestiarum vocabulum , en las crónicas de indias hasta fines del siglo xvi . a partir de un corpus inte- grado por cinco crónicas se concluyó que el Bestiario no fue un modelo a seguir en el tratamiento de la fauna ni una fuente. sin embargo, se advierte un cuadro de similitudes que derivan de la convergencia en una tradición zoológica, pues tanto los bestiarios como las crónicas participan de una vasta y añeja red de vasos comunicantes diseminada incluso más allá de los libros

El Extremo Oriente y la condición del indio en el siglo XVI

This article seeks to verify that during the process of historical concretion of the New World and its inhabitants during the XVI century, differentiation from the nations and inhabitants of East Asia played an important role. Although the idea of the Asian condition of America, the Fourth Part of the World, was soon abandoned, the newly discovered world continued to be interpreted from the perspective of some elements that characterized the East Indies. In this sense, that region continued to be a cultural, geographical and historical reference pattern for the America

La fiesta patronal de Xico, Veracruz.Tradición oral y festividad

Se describen algunos aspectos dela fiesta patronal en Santa María Magdalena enXico, Veracruz, particularmente los elementosculturales indígenas incorporados a la culturafestiva xiqueña bajo los términos de «tradiciónoral». Además de constatar su presencia deestos elementos culturales, se observa que sevan ocultando cada vez más, incluso puedepensarse que su transformación apunta envarios casos hacia su pérdida u olvido. Eltrabajo estuvo enfocado de manera particularal arco floral y al mito-narración de Juan delMonte y a las vivencias de identidad quegenera los relatos sobre la imagen de SantaMaría Magdalena