The topology of deformation spaces of Kleinian groups

Let M be a compact, hyperbolizable 3-manifold with nonempty incompressible boundary and let AH(\pi_1(M)) denote the space of (conjugacy classes of) discrete faithful representations of \pi_1(M) into PSL 2 (C). The components of the interior MP(\pi_1(M)) of AH(\pi_1(M)) (as a subset of the appropriate representation variety) are enumerated by the space A(M) of marked homeomorphism types of oriented, compact, irreducible 3-manifolds homotopy equivalent to M. In this paper, we give a topological enumeration of the components of the closure of MP(\pi_1(M)) and hence a conjectural topological enumeration of the components of AH(\pi_1(M)). We do so by characterizing exactly which changes of marked homeomorphism type can occur in the algebraic limit of a sequence of isomorphic freely indecomposable Kleinian groups. We use this enumeration to exhibit manifolds M for which AH(\pi_1(M)) has infinitely many components.Comment: 49 pages, published versio

Piloting Multimodal Learning Analytics using Mobile Mixed Reality in Health Education

© 2019 IEEE. Mobile mixed reality has been shown to increase higher achievement and lower cognitive load within spatial disciplines. However, traditional methods of assessment restrict examiners ability to holistically assess spatial understanding. Multimodal learning analytics seeks to investigate how combinations of data types such as spatial data and traditional assessment can be combined to better understand both the learner and learning environment. This paper explores the pedagogical possibilities of a smartphone enabled mixed reality multimodal learning analytics case study for health education, focused on learning the anatomy of the heart. The context for this study is the first loop of a design based research study exploring the acquisition and retention of knowledge by piloting the proposed system with practicing health experts. Outcomes from the pilot study showed engagement and enthusiasm of the method among the experts, but also demonstrated problems to overcome in the pedagogical method before deployment with learners

Waltzing peakons and compacton pairs in a cross-coupled Camassa-Holm equation

We consider singular solutions of a system of two cross-coupled Camassa-Holm (CCCH) equations. This CCCH system admits peakon solutions, but it is not in the two-component CH integrable hierarchy. The system is a pair of coupled Hamiltonian partial differential equations for two types of solutions on the real line, each of which separately possesses exp(-|x|) peakon solutions with a discontinuity in the first derivative at the peak. However, there are no self-interactions, so each of the two types of peakon solutions moves only under the induced velocity of the other type. We analyse the `waltzing' solution behaviour of the cases with a single bound peakon pair (a peakon couple), as well as the over-taking collisions of peakon couples and the antisymmetric case of the head-on collision of a peakon couple and a peakon anti-couple. We then present numerical solutions of these collisions, which are inelastic because the waltzing peakon couples each possess an internal degree of freedom corresponding to their `tempo' -- that is, the period at which the two peakons of opposite type in the couple cycle around each other in phase space. Finally, we discuss compacton couple solutions of the cross-coupled Euler-Poincar\'e (CCEP) equations and illustrate the same types of collisions as for peakon couples, with triangular and parabolic compacton couples. We finish with a number of outstanding questions and challenges remaining for understanding couple dynamics of the CCCH and CCEP equations

The Square Root Depth Wave Equations

We introduce a set of coupled equations for multilayer water waves that removes the ill-posedness of the multilayer Green-Naghdi (MGN) equations in the presence of shear. The new well-posed equations are Hamiltonian and in the absence of imposed background shear they retain the same travelling wave solutions as MGN. We call the new model the Square Root Depth equations, from the modified form of their kinetic energy of vertical motion. Our numerical results show how the Square Root Depth equations model the effects of multilayer wave propagation and interaction, with and without shear.Comment: 10 pages, 5 figure

Automated Software Testing in the DoD: Current Practices and Opportunities for Improvement

The concept of automating the testing of software-intensive systems has been around for decades, but the practice of automating testing is scarce in many industries, especially in the government defense sector. A one-year project initiated by the Office of the Secretary of Defense (OSD), Scientific Test and Analysis Techniques Center of Excellence (STAT COE) and sponsored by Navy OPNAV N94 set out to: study the degree to which the Department of Defense (DoD) has adopted automated software testing (AST); share the best software practices used by industry; and develop and distribute an AST implementation guide intended for program management and novice DoD software test automators. The Current State of Automated Software Testing in the Department of Defense, AST Practices and Pitfalls Guide, and the AST Implementation Guide are available at www.afit.edu/stat

Treatment of secondary hyperparathyroidism in kidney disease: what we know and do not know about use of calcimimetics and vitamin D analogs

There is a growing understanding of the pathophysiology of secondary hyperparathyroidism (SHPT) and a recent emergence of new agents for SHPT treatment in patients with advanced kidney disease. At the same time, appreciation that mineral metabolic derangements promote vascular calcification and contribute to excess mortality, along with recognition of potentially important “non-classical” actions of vitamin D, have prompted the nephrology community to reexamine the use of various SHPT treatments, such as activated vitamin D sterols, phosphate binders, and calcimimetics. In this review, the evidence for treatment of SHPT with calcimimetics and vitamin D analogs is evaluated, with particular consideration given to recent clinical trials that have reported encouraging findings with cinacalcet use. Additionally, several controversies in the pathogenesis and treatment of SHPT are explored. The proposition that calcitriol deficiency is a true pathological state is challenged, the relative importance of the vitamin D receptor and the calcium sensing receptor in parathyroid gland function is summarized, and the potential relevance of non-classical actions of vitamin D for patients with advanced renal disease is examined. Taken collectively, the balance of evidence now supports a treatment paradigm in which calcimimetics are the most appropriate primary treatment for SHPT in the majority of end stage renal disease patients, but which nevertheless acknowledges an important role for modest doses of activated vitamin D sterols

Is Cheap Talk Effective at Eliminating Hypothetical Bias in a Provision Point Mechanism?

Significant difference between response to real and hypothetical valuation questions is often referred to as hypothetical bias. Some economists have had success with using “cheap talk” (which entails reading a script that explicitly highlights the hypothetical bias problem before participants make any decisions) as a means of generating unbiased responses in a referendum format. In this article, we test the robustness of cheap talk using a voluntary contribution mechanism with a provision point over a wide range of possible payment amounts. Our results confirm the existence of hypothetical bias, and suggest that cheap talk may eliminate hypothetical bias, but only for respondents facing higher payments

A3: Hydrogeology of the Former Chlor-Alkali Facility Superfund Site and Downstream Bed Sediment Mercury Contamination in the Androscoggin River, Berlin, New Hampshire

Guidebook for field trips in Western Maine and Northern New Hampshire: New England Intercollegiate Geological Conference, p. 61-80

The Children Who Ran For Congress and the School Up On The Hill: An Oral-Institutional History of Capitol Page School, 1926-1983

Although the corpus of work on Congressional history is impressive, there is one aspect of life inside the Capitol that has been neglected for over 200 years. Young messenger boys, or Pages, have worked for Congress since its early sessions but have never received much attention. This dissertation traces the evolution of Capitol Page School and by doing so, also follows the evolution of the larger Page system. The purpose of the study is to find out what the historical record can reveal about the history of Capitol Page School. Once that story is told, conclusions can be drawn about things like institutional inertia in Congress, preserving tradition, unusual childhood occupations and informal civic education, among others. Using both a documents review and an oral history approach allowed for a rich description of the evolution of Capitol Page School. Chapter Two reports on Page culture before 1926, concentrating on the relationships between Members of Congress and the boys, and how Pages formed their own culture and community as adjuncts of the Congress. Chapter Three examines the social conditions that were present in the 1920s which forced the formation of a school specifically for Pages inside the Capitol, run as a private enterprise by an individual teacher, and the subsequent attempts to continue the school. Chapter Four describes how Senator Harold Burton intervened to improve conditions at Capitol Page School, and also includes a previously unknown cache of information and behind-the-scenes maneuvering. Chapter Five explains the physical move of the school and then traces the substantial legislation that Congress failed to pass in order to give Pages an official residence to live in, and describes the precarious nature of the school. Chapter Six gives special attention to three noteworthy subcultures within the Page system: girls, African-Americans and Supreme Court Pages, and describes how each group began and received special consideration. Chapter Seven reports on how Capitol Page School was forced to dissolve in the early 1980s and how two new schools were formed to replace it. Chapter Eight discusses what can be learned from the historical record