Seasonal thermal habitat use and bathymetric distribution of burbot in Tanada and Copper Lakes, Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2016Burbot Lota lota are a cold water, benthic, primarily piscivorous species that inhabits lakes and rivers throughout their Holarctic distribution. Habitat requirements for Burbot are still poorly understood, in part due to the disregard this species has received in fisheries management plans. From June 2009 through September 2011, I investigated the seasonal movements and bathymetric distribution of Burbot in Tanada and Copper lakes, Alaska, using archival tags programmed to record water depth and temperature. One hundred and forty Burbot (70 in each lake) were surgically implanted with archival tags, and 1 year later fish were recaptured to retrieve the archived data (Tanada Lake: 15 fish; Copper Lake: 9 fish). During the ice-out period in spring (mid-May through June), Burbot initiated a migration to the littoral zone (mean depth = 10.72 m; mean internal temperature = 9.4°C). In the summer months (July and August) when lakes were stratified and photoperiod was nearly constant, Burbot occupied the thermocline (mean depth = 7.28 m; mean internal temperature = 12.1°C). During fall months prior to the ice-up period (September and October), occupancy depth shifted to the profundal zone (mean depth = 22.09 m; mean internal temperature = 6.3°C). Under the ice, Burbot remained in the profundal zone and a putative spawning period was observed during February and March when Burbot from both lakes migrated from the profundal zone to ≤ 5 m in depth (mean internal temperature = 2.1°C). Throughout the year Burbot displayed a pattern of diel vertical movements with activity levels peaking during crepuscular hours. However, during the summer when photoperiod was nearly constant, Burbot were relatively sedentary, with only 22% of depth records indicating movement (changes in depth ≥ 1 m). Results from this study indicate that photoperiod and water temperature were highly correlated with seasonal depth occupancy and activity levels in Burbot

Microstability analysis of pellet fuelled discharges in MAST

Reactor grade plasmas are likely to be fuelled by pellet injection. This technique transiently perturbs the profiles, driving the density profile hollow and flattening the edge temperature profile. After the pellet perturbation, the density and temperature profiles relax towards their quasi-steady-state shape. Microinstabilities influence plasma confinement and will play a role in determining the evolution of the profiles in pellet fuelled plasmas. In this paper we present the microstability analysis of pellet fuelled H-mode MAST plasmas. Taking advantage of the unique capabilities of the MAST Thomson scattering system and the possibility of synchronizing the eight lasers with the pellet injection, we were able to measure the evolution of the post-pellet electron density and temperature profiles with high temporal and spatial resolution. These profiles, together with ion temperature profiles measured using a charge exchange diagnostic, were used to produce equilibria suitable for microstability analysis of the equilibrium changes induced by pellet injection. This analysis, carried out using the local gyrokinetic code GS2, reveals that the microstability properties are extremely sensitive to the rapid and large transient excursions of the density and temperature profiles, which also change collisionality and beta e significantly in the region most strongly affected by the pellet ablation.Comment: 21 pages, 10 figures. This is an author-created, un-copyedited version of an article submitted for publication in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Characterisation of the L-mode Scrape Off Layer in MAST: decay lengths

This work presents a detailed characterisation of the MAST Scrape Off Layer in L-mode. Scans in line averaged density, plasma current and toroidal magnetic field were performed. A comprehensive and integrated study of the SOL was allowed by the use of a wide range of diagnostics. In agreement with previous results, an increase of the line averaged density induced a broadening of the midplane density profile.Comment: 30 pages, 11 figure

Efficient Behavior of Small-World Networks

We introduce the concept of efficiency of a network, measuring how efficiently it exchanges information. By using this simple measure small-world networks are seen as systems that are both globally and locally efficient. This allows to give a clear physical meaning to the concept of small-world, and also to perform a precise quantitative a nalysis of both weighted and unweighted networks. We study neural networks and man-made communication and transportation systems and we show that the underlying general principle of their construction is in fact a small-world principle of high efficiency.Comment: 1 figure, 2 tables. Revised version. Accepted for publication in Phys. Rev. Let

3-manifolds which are spacelike slices of flat spacetimes

We continue work initiated in a 1990 preprint of Mess giving a geometric parameterization of the moduli space of classical solutions to Einstein's equations in 2+1 dimensions with cosmological constant 0 or -1 (the case +1 has been worked out in the interim by the present author). In this paper we make a first step toward the 3+1-dimensional case by determining exactly which closed 3-manifolds M^3 arise as spacelike slices of flat spacetimes, and by finding all possible holonomy homomorphisms pi_1(M^3) to ISO(3,1).Comment: 10 page

(G)hosting television: Ghostwatch and its medium

This article’s subject is Ghostwatch (BBC, 1992), a drama broadcast on Halloween night of 1992 which adopted the rhetoric of live non-fiction programming, and attracted controversy and ultimately censure from the Broadcasting Standards Council. In what follows, we argue that Ghostwatch must be understood as a televisually-specific artwork and artefact. We discuss the programme’s ludic relationship with some key features of television during what Ellis (2000) has termed its era of ‘availability’, principally liveness, mass simultaneous viewing, and the flow of the television super-text. We trace the programme’s television-specific historicity whilst acknowledging its allusions and debts to other media (most notably film and radio). We explore the sophisticated ways in which Ghostwatch’s visual grammar and vocabulary and deployment of ‘broadcast talk’ (Scannell 1991) variously ape, comment upon and subvert the rhetoric of factual programming, and the ends to which these strategies are put. We hope that these arguments collectively demonstrate the aesthetic and historical significance of Ghostwatch and identify its relationship to its medium and that medium’s history. We offer the programme as an historically-reflexive artefact, and as an exemplary instance of the work of art in television’s age of broadcasting, liveness and co-presence

The human factor in an effective structure management system

This paper demonstrates that while an effective structure monitoring system benefits strongly from the integration of modern technologies, human experience and oversight remain the essential component. The myriad of technologies available for structure monitoring and management are improving at a great rate. These technologies provide analysis and oversight at levels which historically have been uneconomical or unachievable. A single instance of the DamWatch application is providing real-time, always-on monitoring of 12,000 dam structures for 3,000 users in the United States (Caldwell, Scannell, & Herbert, 2014). Automated systems can tirelessly monitor data feeds, rapidly perform complex calculations and dispatch notifications. However, this paper argues that the impacts of this growing role for technology, while powerful, is still superseded by the impacts of the human input in structure management systems. An optimal structure management system should be designed with this in mind. This includes ensuring data is complete and accurate, easily accessible and understandable for users. User contribution and involvement in structure management systems should not be limited by an individual’s computer literacy. Users should be trained and supported to ensure they are able to react to and leverage data provided by information systems. Clearly defined protocols allow individuals to make informed decisions and organizations to respond promptly to developing situations. To assess these arguments we will examine a number of case studies. These case studies will focus on hydrologic events which affected bridge and dam structures in the care of multiple, unrelated managing authorities. By exploring the incidents, the responses and the eventual outcomes, we will weigh the role of human data in the effective management of structures exposed to the natural environment

A Mandated Minimum Competency Testing Program and Its Impact on Learning Disabled Students: Curricular Validity and Comparative Performances

This research was published by the KU Center for Research on Learning, formerly known as the University of Kansas Institute for Research in Learning Disabilities.In this study, LD specialists, regular class teachers, and parents of LD students judged that the objectives of the Kansas Minimum Competency Specifications prescribed for nonhandicapped students were applicable to LD students. In addition, the Kansas Minimal Competency Test was administered to LD students under standard and oral conditions. Results showed that they did not perform as well as their nonhandicapped peers at any of the five grade levels. The test was then administered under two modified conditions. Learning disabled students' performance on some objectives at every grade level was not improved by either administering items orally or administering the test one grade level above that designated for nonhandicapped students

Notes on a paper of Mess

These notes are a companion to the article "Lorentz spacetimes of constant curvature" by Geoffrey Mess, which was first written in 1990 but never published. Mess' paper will appear together with these notes in a forthcoming issue of Geometriae Dedicata.Comment: 26 page