Irreducible Modules for the Lie Algebra of Divergence Zero Vector Fields on a Torus

This paper investigates the irreducibility of certain representations for the Lie algebra of divergence zero vector fields on a torus. In "Irreducible Representations of the Lie-Algebra of the Diffeomorphisms of a d-Dimensional Torus," S. Eswara Rao constructs modules for the Lie algebra of polynomial vector fields on a d-dimensional torus, and determines the conditions for irreducibility. The current paper considers the restriction of these modules to the subalgebra of divergence zero vector fields. It is shown here that Rao's results transfer to similar irreducibility conditions for the Lie algebra of divergence zero vector fields.Comment: 13 page

Re-envisioning access for the digital preservation community: challenges, opportunities and recommendations

Digital material is not new and has been preserved for a couple of decades now. With a growing digital preservation community, and a growing number of practitioners identifying as doing something digital, there is an understanding that this material is here to stay. More and more institutions are publishing digital strategies or creating networks focusing on digital material. However, when looking at this in practice there seems to be a disconnect between what is being stated within these networks and strategies and what is being made accessible to the public. This thesis will explore this disconnect by first understanding how the digital preservation community has been providing access to this material and how they are envisioning it in the future. This exploration surfaces both a) how digital material can no longer be seen as separate from the infrastructure that ensures its materiality and b) how the provision of access is not just a technological question, but also a social, legal and ethical one. This thesis will also seek to explore the ways in which those who identify as digital preservation practitioners articulate their role and responsibilities. It will do so by drawing on relevant literature and gaining perspectives from practitioners and other relevant participants through in-depth interviews. Building from this exploration, this thesis will offer recommendations for how this practice can move forward in negotiating the provision of access to digital material in the online public space of the internet. This research is part of a collaborative project with The National Archives, UK where a number of the ideas encountered during this work were explored in practice. Some of these results have helped shape the recommendations given in the final chapters of this thesis

Advanced protective coating for superalloys

Superior oxidation protection for nickel-base alloys at temperatures up to 1367 K was obtained with cobalt-base alloy coating. Coating had 25 Cr, 14 Al, and 0.5 Y weight percent composition. Coating was applied by electron beam vapor deposition to thickness of 76 to 127 microns

Una reflexión metodológica, ontológica y epistemológica del trabajo de campo en una práctica espiritista posmoderna

This article has three parts. First, we present the voices of some authors who have been characterized by their treatment of spirituality, either because they are more inclined to the ontological turn and empathy with the research subject, an eminently spiritual subject, or because they emphasize their preference for positivist approach. Secondly, a case study by the author is analyzed. It is the one carried out in the Círculos de Ánima [Circles of Anima] of an association originally from Barcelona and that has spread throughout Latin America. We intend to involve the reader in the tensions entailed in participant observation in a spiritualistic practice and which are revealed before and from academic and research practice. Finally, the dilemma between ‘flow’ and ‘control’ as the way to enter into New Age spirituality, as well as the oscillation between belief and disbelief along the investigation, are exposed.Este artículo tiene tres partes. En primer lugar presentamos las voces de algunos autores que se han caracterizado por su tratamiento de la espiritualidad, bien sea porque son más proclives al giro ontológico y a la empatía con el sujeto de investigación, un sujeto eminentemente espiritual, bien porque destacan su preferencia por la aproximación positivista. En segundo lugar se analiza un estudio de caso de la autora. Es el realizado en los Círculos de Ánima de una asociación originaria de Barcelona y que se ha extendido por Iberoamérica. Pretendemos hacer partícipe al lector de las tensiones que implica la observación participante en una práctica espiritista y que se revelan ante y desde la práctica académica e investigadora. Finalmente, se expone la disyuntiva entre ‘flujo’ y ‘control’ como el camino para entrar en la espiritualidad neoeriana, y la oscilación entre la creencia y la descreencia mientras dura la investigación

Assessing Two-Mode Semantic Network Story Representations Using a False Memory Paradigm

This paper describes a novel method of representing semantic networks of stories (and other text) as a two-mode graph. This method has some advantages over traditional one-mode semantic networks, but has the potential drawback (shared with n-gram text networks) that it contains paths that are not present in the text. An empirical study was devised using a false memory paradigm to determine whether these induced paths are remembered as being true of a set of stories. Results indicate that participants report false memories consistent with the induced paths. Implications for further research and two-mode semantic representations are discussed