Kleinian groups and the complex of curves

We examine the internal geometry of a Kleinian surface group and its relations to the asymptotic geometry of its ends, using the combinatorial structure of the complex of curves on the surface. Our main results give necessary conditions for the Kleinian group to have `bounded geometry' (lower bounds on injectivity radius) in terms of a sequence of coefficients (subsurface projections) computed using the ending invariants of the group and the complex of curves. These results are directly analogous to those obtained in the case of punctured-torus surface groups. In that setting the ending invariants are points in the closed unit disk and the coefficients are closely related to classical continued-fraction coefficients. The estimates obtained play an essential role in the solution of Thurston's ending lamination conjecture in that case.Comment: 32 pages. Published copy, also available at http://www.maths.warwick.ac.uk/gt/GTVol4/paper3.abs.htm

Reading the Illegible

Editing this special issue of Amodern was done, one could say, under the influence, in a reader-to-reader relationship with Craig Dworkin’s 2003 monographic study of “a tradition of poetic illegibility.” [1] Having read for over a decade now under the influence of his poetry and critical work, I borrowed the title from Dworkin’s book. What is more, in keeping with his impetus as projected there and extended in his most recent collection of essays, No Medium, I called for contributions that could think through the inter-relatedness of two things in an ambitious manner: the pressure put on the poetic imagination (for better and worse) by limit-cases of il/legibility; and technical and conceptual innovations in reading practices that have somehow shifted the horizonal divide-lines between the legible and illegible via a relationship to academic research. [2

Who is taking responsibility for that text?

This paper will outline my understanding of the constitutive problematics that figure a context for so-called Conceptual Writing, with a focus on the politics of how and why such writers write. I will begin by transposing two propositions from the discourse of literary theory: Michel Foucault's concept of the "Author function" (1969) and Rachel Malik's concept of the "horizons of the publishable" (2004). Conjoining them in an age of born-digital textualities, I will propose the concept of "publishing as praxis" as a lever to help us speculate on how so-called Conceptual Writing over-works an interpellated identity of the writer-as-consumer and consciously inverts the traditional compositional logic of production then reproduction. So leveraged, I will conclude by showing how even trans-disciplinary acts of Conceptual Writing work onto the inside of literature (as an institution plus its criticisms) by re-phrasing its central epistemological question of authoriality

Solution of the symmetric eigenproblem AX=lambda BX by delayed division

Delayed division is an iterative method for solving the linear eigenvalue problem AX = lambda BX for a limited number of small eigenvalues and their corresponding eigenvectors. The distinctive feature of the method is the reduction of the problem to an approximate triangular form by systematically dropping quadratic terms in the eigenvalue lambda. The report describes the pivoting strategy in the reduction and the method for preserving symmetry in submatrices at each reduction step. Along with the approximate triangular reduction, the report extends some techniques used in the method of inverse subspace iteration. Examples are included for problems of varying complexity

Introduction

Introduction for Resilient Pedagogy

Architecture of Engagement: Autonomy-Supportive Leadership for Instructional Improvement

This multiple paper dissertation addresses the importance of improving student success in online higher education programs by providing support for instructors. The autonomy-supportive structures to improve instructional practice are explained through three main domains, including instructional development, instructional design, and instructional practice. The first paper addresses instructional leadership with the theoretical foundations and practical considerations necessary for instructional leaders. Recommendations are made to use microcredentials or digital badges to scaffold programming using self-determination theory. The second paper addresses the importance of instructional design in improving instructional practice including the intentionality involved in implementing a gamification strategy to improve online student motivation. The third paper addresses instructional practice with a mixed-method sequential explanatory case study. Using the community of inquiry framework, this paper explains intentional course design, course facilitation, and student perceptions of the digital powerups strategy. The conclusion considers implications for practice and the need for instructional leaders to scaffold an architecture of engagement to support instructors and improve student success

Remediation Of A Clay Contaminated With Petroleum Hydrocarbons Using Soil Reagent Mixing

Soil reagent mixing (SRM) is a remediation technique whereby powder or slurried reagents are delivered and mixed in-situ or ex-situ with contaminated soils or sediments by augers or other types of soil mixers. This paper summarises the work carried out for a laboratory treatability study of SRM on clayey soil samples contaminated with petroleum hydrocarbon compounds from a petrol filling station site in Kent, UK. The study examined the effects of mixing binder reagents on the total soil and leachate concentrations of hydrocarbons. Quicklime, hydrated lime and ordinary Portland cement, in a number of different formulations, were used in the study. Furthermore, the addition of gypsum to some reagent formulations was evaluated in an attempt to improve the strength of the binder/soil mix. Temperature and evolution of volatiles were monitored during the mixing of soils with the reagents. The mixing of soil with binder reagents resulted in changes in physical and physico-chemical properties of the clay, and in significant decreases in total soils and leachate concentrations of petroleum hydrocarbon compounds. The mechanisms responsible for the decreases in concentrations were examined. Significant increases in the remoulded strength of the clay were observed upon addition of certain binder formulations

Ionising radiation exposure from medical imaging – A review of Patient's (un) awareness

Introduction: Medical imaging is the main source of artificial radiation exposure. Evidence, however, suggests that patients are poorly informed about radiation exposure when attending diagnostic scans. This review provides an overview of published literature with a focus on nuclear medicine patients on the level of awareness of radiation exposure from diagnostic imaging. Methods: A review of available literature on awareness, knowledge and perception of ionising radiation in medical imaging was conducted. Articles that met the inclusion criteria were subjected to critical appraisal using the Mixed Methods Appraisal Tool. Results: 140 articles identified and screened for eligibility, 24 critically assessed and 4 studies included in synthesis. All studies demonstrated that patients were generally lacking awareness about radiation exposure and highlighted a lack of communication between healthcare professionals and patients with respect to radiation exposure. Conclusion: Studies demonstrate a need to better inform patients about their radiation exposure, and further studies focusing on nuclear medicine patients are particularly warranted. Implications for practice: Adequate and accurate information is crucial to ensure the principle of informed consent is present

A Note on Real Tunneling Geometries

In the Hartle-Hawking ``no boundary'' approach to quantum cosmology, a real tunneling geometry is a configuration that represents a transition from a compact Riemannian spacetime to a Lorentzian universe. I complete an earlier proof that in three spacetime dimensions, such a transition is ``probable,'' in the sense that the required Riemannian geometry yields a genuine maximum of the semiclassical wave function.Comment: 5 page

Reconstructing the global topology of the universe from the cosmic microwave background

If the universe is multiply-connected and sufficiently small, then the last scattering surface wraps around the universe and intersects itself. Each circle of intersection appears as two distinct circles on the microwave sky. The present article shows how to use the matched circles to explicitly reconstruct the global topology of space.Comment: 6 pages, 2 figures, IOP format. To be published in the proceedings of the Cleveland Cosmology and Topology Workshop 17-19 Oct 1997. Submitted to Class. Quant. Gra