Non-relativistic bound states in a moving thermal bath

We study the propagation of non-relativistic bound states moving at constant velocity across a homogeneous thermal bath and we develop the effective field theory which is relevant in various dynamical regimes. We consider values of the velocity of the bound state ranging from moderate to highly relativistic and temperatures at all relevant scales smaller than the mass of the particles that form the bound state. In particular, we consider two distinct temperature regimes, corresponding to temperatures smaller or higher than the typical momentum transfer in the bound state. For temperatures smaller or of the order of the typical momentum transfer, we restrict our analysis to the simplest system, a hydrogen-like atom. We build the effective theory for this system first considering moderate values of the velocity and then the relativistic case. For large values of the velocity of the bound state, the separation of scales is such that the corresponding effective theory resembles the soft collinear effective theory (SCET). For temperatures larger than the typical momentum transfer we also consider muonic hydrogen propagating in a plasma which contains photons and massless electrons and positrons, so that the system resembles very much heavy quarkonium in a thermal medium of deconfined quarks and gluons. We study the behavior of the real and imaginary part of the static two-body potential, for various velocities of the bound state, in the hard thermal loop approximation. We find that Landau damping ceases to be the relevant mechanism for dissociation from a certain "critical" velocity on in favor of screening. Our results are relevant for understanding how the properties of heavy quarkonia states produced in the initial fusion of partons in the relativistic collision of heavy ions are affected by the presence of an equilibrated quark-gluon plasma.Comment: 25 pages, 4 figures. Minor corrections, reference added. Closely matches version to be published in Physical Review

Properties of bio-based gum Arabic/clay aerogels

Lightweight bio-based aerogels from sustainable gum Arabic (GA) and sodium montmorillonite (Na+-MMT) clay were prepared by means of a simple freeze-drying process. GA/clay aerogels showed high porosity (87.9%–94.9%) of mainly open type and the mechanical properties were improved by the clay. When 40% of clay was added to pure GA, the specific modulus and the absorbed energy of resultant aerogels increased by 1.6 and 4.2 times respectively. On the other hand, the exponent value for modulus in the power-law model for cellular materials increased from 1.95 to 3.28 due to the more anisotropic structures induced by the presence of the clay. In terms of thermal stability and flame retardancy, clay content played a dominant role. With 50% of clay loading, the initial decomposition temperature increased by nearly 16 °C and the peak of heat release rate was 3-fold reduced.Peer ReviewedPostprint (author's final draft

Mapping Access to Fresh Produce, Fish and Shellfish at a Local Level Using a Mixed - Method Community Food Assessment Approach: A Case Study - St. Helena Island, South Carolina

This report is a summary of a community food assessment (CFA) conducted over the course of five field survey trips to St. Helena Island, South Carolina, from December 2011 to July 2013. The goal of this CFA was to understand community characteristics related to the distribution and consumption of fresh produce, fish and shellfish. The method used for this CFA is composed of three parts, (1) spatial analysis using Geographic Information System (GIS) data (2) a community food assessment survey focused on where residents obtain their food and (3) ethnographic interviews with local growers, subsistence farmers and consumers. Applying this mixed-method approach, we uncovered an intricate informal network of subsistence farmers who supply the local food system with fresh produce, shellfish and fish products. Initial fieldwork findings indicate that during harvest, fresh produce, fish and shellfish are regularly dispersed, free of charge, throughout the community by familial and neighbor-to-neighbor sharing relationships. Additional food is shared for low or no cost via informal access points such as front-yard produce stands, county food pantries, and distribution at local places of worship. Of those surveyed on the island, (N=50) 75 percent report having either direct or indirect access to fresh produce, fish and shellfish through this informal network. These preliminary findings suggest that rural communities with limited transportation access to supermarkets may actually have substantially more access to fresh fruits, vegetables and other culturally significant foods than previously determined by conventional quantitative \u27formal\u27 food desert detection methodologies

Transferencia tecnológica, ¿Qué podemos aprender de la experiencia internacional?

Los procesos de transferencia tecnológica, son fundamentales en la consolidación de la innovación, entendiendo este último concepto como “la conversión de ideas en productos, procesos o servicios que tienen éxito en el mercado” (Jacob et al, 2001). Es por esto que la definición, desarrollo e implementación de estructuras e instrumentos adecuados que apoyen la transferencia de conocimiento y tecnología hacia la industria, en conjunto con condiciones del entorno económico y social, son claves en el crecimiento y desarrollo de los países o regiones en particular.Los procesos de transferencia tecnológica, son fundamentales en la consolidación de la innovación, entendiendo este último concepto como “la conversión de ideas en productos, procesos o servicios que tienen éxito en el mercado” (Jacob et al, 2001). Es por esto que la definición, desarrollo e implementación de estructuras e instrumentos adecuados que apoyen la transferencia de conocimiento y tecnología hacia la industria, en conjunto con condiciones del entorno económico y social, son claves en el crecimiento y desarrollo de los países o regiones en particular.Los procesos de transferencia tecnológica, son fundamentales en la consolidación de la innovación, entendiendo este último concepto como “la conversión de ideas en productos, procesos o servicios que tienen éxito en el mercado” (Jacob et al, 2001). Es por esto que la definición, desarrollo e implementación de estructuras e instrumentos adecuados que apoyen la transferencia de conocimiento y tecnología hacia la industria, en conjunto con condiciones del entorno económico y social, son claves en el crecimiento y desarrollo de los países o regiones en particular

¿Una Macama jerezana? Jerez y la difusión de las "Macamas" al -Hariri en al-Andalus

Se ofrece una concisa panoramica sobre la difusion de las "Macamas" en Jerez, ciudad que acogió una escuela de transmision de las mismas y que produjo varios comentarios de esa obra

La Industria Cultural y la crítica educativa en América Latina: una perspectiva histórica

El presente artículo tiene como objetivo examinar a tres autores que desde sus propios campos disciplinarios académicos aportaron para el desarrollo de un saber educativo en América latina en los temas de cultura, comunicación y educación. Para ello y en su un primer momento, se entregará una reflexión histórica sobre la importancia que ha jugado la Industria Cultural en América Latina a partir de los aportes académico de Andrés Bello, cuyo accionar intelectual estuvo enfocado a cohesionar la unidad nacional de los recientes estados latinoamericanos del siglo XIX. Será a través del lenguaje escrito y oral, proveniente de la llamada cultura ilustrada, y con el apoyo de los medios de comunicación de la época en que el proyecto bellista se convertirá en la primera estrategia comunicativa y educativa que buscó plasmar las nuevas y variadas dimensiones de la naciente Cultura Sudamericana. De igual manera, y en el mismo sentido, revisaremos las posiciones de los escritores y periodistas José Martí y Rubén Darío, quienes se ven confrontados con una Modernidad que comienza a reemplazar a la Cultura Ilustrada por la Cultura de Masas. Sus poemas y escritos en los periódicos de la época instalaron por vez primera, una impronta académica ligada a la crítica y la educación como es el cuestionamiento a la industria cultural y sus narrativas mediáticas que opera a fines del siglo XIX desde los diversos medios de comunicación. Finalmente, se analizará cómo surge la crítica comunicativa en Latinoamérica frente a los procesos de dominación, que no solo provienen desde lo económico, sino también, desde las llamadas industrias culturales que emergen con mucha fuerza a mediados del siglo XX. Dichos medios de comunicación proyectan los procesos culturales como un producto mercantil, diluyendo con esta acción comunicativa y mediática, las auténticas dimensiones de la cultura.The purpose of this article is to study three authors from different academic fields who have contributed to the development of educational knowledge systems in Latin America in the areas of culture, media communication, and education. In order to do so, I will first explore a historical study about the importance of the Cultural Industry in Latin America, based on academic contributions by Andres Bello, who focused intellectually to give cohesion to national unity in the recently-established XIX century Latin American states. Enlightened culture emerges from its written and spoken language, and with support of the media at the time, the “bellista project” would become the first media communication and educational strategy aimed at capturing the new and varied dimensions of a nascent South American Culture. Similarly and in the same vein, I will look into the stance of writers and journalists, José Martí and Rubén Darío, who had to face Modernity as it began to replace the Enlightenment for a Culture for the Masses. Their poems and writings in newspapers back then, established an academic standpoint, for the first time, linked to media analysis and education, such as questioning the cultural industry and media narratives that were operating towards the end of the XIX century, in different media outlets. Finally, I examine how media analysis in Latin America emerged in the face of processes of domination that came not only from the economic but the so called cultural industries that surfaced with so much power in the mid-twentieth century. These media outlets show cultural processes as a marketable product while diluting the true real dimensions of culture