Stellar Populations in the Host Galaxies of Mrk 1014, IRAS 07598+6508, and Mrk 231

We present deep spectroscopic and imaging data of the host galaxies of Mrk 1014, IRAS 07598+6508, and Mrk 231. These objects form part of both the QSO and the ultraluminous infrared galaxy (ULIG) families, and may represent a transition stage in an evolutionary scenario. Our imaging shows that all three objects have highly perturbed hosts with tidal tails and destroyed disks, and appear to be in the final stages of major mergers. The host galaxies of the three objects have spectra typical of E+A galaxies, showing simultaneously features from an old and a young stellar component. We model spectra from different regions of the host galaxies using Bruzual & Charlot spectral synthesis models using two component models including an old underlying population and recent superposed starbursts. Our results indicate a strong connection between interactions and vigorous bursts of star formation in these objects. We propose that the starburst ages found are indicative of young ages for the QSO activity. The young starburst ages found are also consistent with the intermediate position of these objects in the far infrared color-color diagram. (abridged)Comment: 28 pages; uses AASTeX 5.02 and includes 6 eps figures. 9 additional figures in jpeg format. Postscript version including all 15 figures (6264 kb) available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in the October issue of A

A gerbe for the elliptic gamma function

The identities for elliptic gamma functions discovered by A. Varchenko and one of us are generalized to an infinite set of identities for elliptic gamma functions associated to pairs of planes in 3-dimensional space. The language of stacks and gerbes gives a natural framework for a systematic description of these identities and their domain of validity. A triptic curve is the quotient of the complex plane by a subgroup of rank three (it is a stack). Our identities can be summarized by saying that elliptic gamma functions form a meromorphic section of a hermitian holomorphic abelian gerbe over the universal oriented triptic curve.Comment: 54 page

Representation and application of spline-based finite elements

Isogeometric analysis, as a generalization of the finite element method, employs spline methods to achieve the same representation for both geometric modeling and analysis purpose. Being one of possible tool in application to the isogeometric analysis, blending techniques provide strict locality and smoothness between elements. Motivated by these features, this thesis is devoted to the design and implementation of this alternative type of finite elements. This thesis combines topics in geometry, computer science and engineering. The research is mainly focused on the algorithmic aspects of the usage of the spline-based finite elements in the context of developing generalized methods for solving different model problems. The ability for conversion between different representations is significant for the modeling purpose. Methods for conversion between local and global representations are presented

Homotopy theory of higher categories

This is the first draft of a book about higher categories approached by iterating Segal's method, as in Tamsamani's definition of $n$-nerve and Pelissier's thesis. If $M$ is a tractable left proper cartesian model category, we construct a tractable left proper cartesian model structure on the category of $M$-precategories. The procedure can then be iterated, leading to model categories of $(\infty, n)$-categories

Blending techniques in Curve and Surface constructions

Source at https://www.geofo.no/geofoN.html. <p

Blendingsteknikker i kurve- og flatekonstruksjoner

Source at https://www.geofo.no/geofoN.html

The Uses of Writing in Microbusinesses

This study is concerned with the uses of writing in traditional microbusinesses that serve the local community. A review of the literature on workplace literacy suggests that few studies have focussed on businesses of this type. This study seeks to address this gap and contribute to a better understanding of everyday writing in this context. The study is located within the tradition of Literacy Studies and views literacy as a social practice. It also draws on frameworks for the analysis of texts that are compatible with this view. Case studies were undertaken of four microbusinesses, located in a small market town. While these reveal that many writing practices were unique to the individual business they also illustrate how businesses of this type experience similar opportunities and challenges and, in terms of writing, have tended to respond to these in similar ways. This made it possible to identify elements of writing practices that were common across the cases and to explore the ways in which these were reflected in the texts that were produced. Closely embedded in the routines of the workplace activity and shaped by the imperatives of the business, the texts were brief, hurriedly written, often directly onto proformas, and dependent on shared understandings. However, following the trajectories of key texts demonstrated the significant roles these texts played in the running of the businesses, illustrating what it means for a workplace to be ‘textually mediated’ and confirming participants’ assertions that writing was important to the running of the business. The study shows that microbusinesses were less exposed to pressures for change than larger organisations, described in the literature, and this was reflected in their uses of writing. They were however, not immune to wider influences and writing in specific areas of their work was closely controlled by external agencies