On Length Spectra of Lattices

The aim of this thesis is to study Schmutz Schaller\u27s conjecture that in dimensions 2 to 8 the lattices with the best sphere packings have maximal lengths. This means that the distinct norms which occur in these lattices are greater than those of any other lattice in the same dimension with the same covolume. Although the statement holds asymptotically we explicitly present a counter-example. However, it seems that there is nothing but this exception

“Real” Places in Marguerite Duras’s Wartime Paris

In the four autobiographical narratives in Marguerite Duras’s La Douleur (1985) The War (1994), over one hundred proper place names appear. While these place names all refer to real places, the relationship between these signifiers and their actual geographical referents is mediated, first by their signifieds—the reader’s mental constructs of the places mentioned—and further by their appearance in a text that necessarily creates its own, non-material world. Yet this essay argues that in this uncharacteristically realist text Duras works hard to create the illusion that the Paris there is in fact Occupied Paris, the real city in which she lived out the experiences recounted in her text. She does this, in large part, by indicating the location of each scene with meticulous precision, thus grounding the stories, quite literally, in a geographically and historically situated reality. While many of these sites are among the best-known, and literal, lieux de mémoire ‘sites of memory’ of the Paris of the Second World War, the mention of more obscure places might appear gratuitous. Yet it is precisely in their gratuity, that such details become essential elements of the forceful effet de réel ‘reality effect’ created in the text

Técnicas para el análisis y visualización de interacciones en ambientes virtuales

Foros asíncronos, listas de correo electrónico, y salas de chat crean ambientes de interacción virtual en los cuales puede ser difícil detectar problemas de comunicación entre los participantes. Quien quiera enseñar por medio de un ambiente en línea, se encuentra con que los actuales sistemas de gestión de aprendizajes no proveen mucha información respecto de la estructura de comunicación del grupo, nivel de participación, y otras características estructurales de la interacción que se da en este medio. En este trabajo, se exploró el uso de metodología de análisis de redes sociales (ARS) y visualizaciones en espacios en línea. Se muestra de qué modo se pueden crear objetos visuales que representan las intangibles interacciones en línea y se analizó la utilidad de esas imágenes como dispositivos para reconocimiento de patrones. Se examinó la validez de las técnicas de ARS y visualizaciones como herramientas para que instructores de cursos en línea e investigadores evalúen participación e interacción en foros de discusión. Este estudio mostró que las métricas ARS y la visualización de interacciones son herramientas útiles y potencialmente efectivas para analizar patrones de interacción en línea.Asynchronous forums, e-mail lists, and chat rooms create virtuaql environments where it may not be easy to detect communication problemas among the participants. Anyone who wants to teach through an online environment finds that current learning management systems do not provide enough information about the communication structure of the group, level of participation, and other structural characteristics of the interactions that happen in this environment. In this work, the use of social network analisis methods (SNA) and visualizations for online environments had been explored. The procedures to create the visual objects that represent intangible online interactions are shown and the usefulness of these images as devices for data pattern recognition is analized. The validity of SNA techniques and visualizations as tools for instructors of online courses and researchers to evaluate participation and interaction in discussion forums was examined. This study showed that SNA metrics and the visualization of interactions are useful and potentially effective tools to analize online interaction patterns

Assessing Causation in Breast Implant Litigation: The Role of Science Panels

In two recent cases, federal judges appointed panels of scientific experts to help assess conflicting scientific testimony regarding causation of systemic injuries by silicone gel breast implants. This article will describe the circumstances that gave rise to the appointments, the procedures followed in making the appointments and reporting to the courts, and the reactions of the participants in the proceedings