An investigation into the ground-living spider communities of Hamsterley forest

A study was made of the ground-living spider communities of a commercial forest, using sites at various stages of the management cycle to represent different stages of succession. Clear-felling resulted in an increase in the abundance of large polyphagous cursorial hunters associated with open habitats, and a corresponding reduction in the numbers of small web-building litter species, with a more limited prey range, which characterised the later stages of succession. The most important factor in this change appeared to be the removal of the canopy, resulting in a modification of microclimatic conditions, and degradation of the litter layer. In the first nine years after clear-felling, there were clear and relatively rapid changes in community structure associated with successional age. The observed changes were considered to be mainly due to the increasing vegetation density in this period, which provided both particular structures and a more favourable microclimate for certain species. Associated changes were also found in species richness, abundance, diversity and eveness, which increased during this period. These attributes decreased into late succession, though the pattern was less clear for species abundance, and the oldest sites were less species rich, diverse and even than those of early succession. In late succession, the rate of community change slowed, the most mature sites being very similar in terms of their communities. In general, the differences that did exist were not related to the position of the site on the successional gradient. It was considered that these differences were not due to a single factor, but rather reflected the importance of different factors at each site

Planetary Praxes and Sustainable Universities

What is sustainability in Higher Education (HE)? How should it be represented? Who gets to decide? This thesis offers a response to a particular technocratic and teleological way of thinking about sustainability in Higher Education, which has a series of high profile advocates in theory and policy. In contrast, my study explores two particular sustainability projects (Energy Management Project and Local Food) at a large Canadian suburban university campus. Using a grounded theory/situational analysis approach, I represent these two projects as dynamically bound praxes (shaped by a series of actors and imaginaries). Results: given the historical exigency and contention surrounding sustainability since the mid-90s, a multiplicity of actors in the Keele campus, both semiotic and material, have moved into positions to transform its demarcated boundaries therein. As I have begun to map these movements, I suggest this work be continued by future researchers in a position to do so

Examining Ecosystems and Infrastructure Perspectives of Platforms: The Case of Small Tourism Service Providers in Indonesia and Rwanda

Digital platforms are significantly affecting how firms and individuals undertake economic exchange. With their global expansion, exploring the implications of platforms for those who sell goods or provide services in the global south is an important agenda for determining their value. Yet, we argue that existing frameworks only provide a partial understanding of activities and relations. In this paper, we examine platforms through an analysis of two theoretical perspectives. Established ecosystems perspectives focus on platform governance, centralizing the activities of the ‘platform owner’. Such perspectives allow an analysis of platform strategy but can underplay the ways platform sellers and service providers engage with platforms. Infrastructure perspectives, in contrast, approach platforms as large and complex systems, which we argue allows for better analysis of the practices and agency of such actors. An analysis of small tourism service providers in Indonesian and Rwandan tourism supports the discussion of these two perspectives. Findings highlight the growth of global platforms, but service providers face challenges in using them effectively. Infrastructure perspectives highlight risks that service providers face in being pulled into adverse relationships as platforms become ubiquitous. As platforms expand, their complexity leads to challenges in engagement, but with potential for learning and collaboration

Role Preference: Are Handheld Computers an Educational or Personal Technology?

As an educational delivery platform, current handheld computer technology provides a low-cost, networked, small-form factor appliance with sufficient machine resources to support instruction, learning, assessment, and collaboration. Yet, except in the fields of medicine and law, handheld adoption for collegiate classroom use has been minimal. This study presents the results of an empirical investigation of users and non-users of handheld technology in higher education. Faculty and student personal technology preferences, handheld usage practices, and experience profiles are presented. Results confirm handhelds are peripheral to most collegiate instruction with usage confined primarily to performing personal information management. When handhelds are used for education, they function as a portable extension of the personal computer. Implications for educational practice are presented

Development of Preventive Measures to Reduce Mortalities for Holding Live Wild-caught Flounder in Recirculating Aquaculture Systems

A substantial high-value market exists for wild-caught live summer flounder (Paralichthys dentatus). An important component of accessing this market is the ability to hold wild-caught flounder in land based recirculating aquaculture systems (RAS). A major constraint to holding summer flounder in land-based RAS is fish mortalities associated with the ectoparasite argulus spp. Very little information exists that provides a live flounder holding facility with FDA approved treatment options to prevent introduction of argulus from wild caught fish into holding systems. The project objective was to test the available FDA approved chemotherapeutics for treatment of ectoparasite infections in summer flounder. To validate treatment efficacy, 8 infected individuals were treated with bath treatments according to maximum recommended doses (250ppm formalin for 60 m; 200 ppm hydrogen peroxide for 30 m; and freshwater for 20 m) and then transferred to separate RAS to monitor for two weeks. Daily observations were made to determine if treatments were lethal to the attached argulus. Following the two week monitoring period, fish from all treatments showed no sign of a reduction in attached argulus. According to the findings of this study, there are currently no FDA approved treatments for argulus infections on summer flounder. It is recommended that a live wild flounder holding facility visually inspect all incoming fish for the presence of argulus and maintain fish in a quarantine system prior to holding in a RAS

GAN Augmentation: Augmenting Training Data using Generative Adversarial Networks

One of the biggest issues facing the use of machine learning in medical imaging is the lack of availability of large, labelled datasets. The annotation of medical images is not only expensive and time consuming but also highly dependent on the availability of expert observers. The limited amount of training data can inhibit the performance of supervised machine learning algorithms which often need very large quantities of data on which to train to avoid overfitting. So far, much effort has been directed at extracting as much information as possible from what data is available. Generative Adversarial Networks (GANs) offer a novel way to unlock additional information from a dataset by generating synthetic samples with the appearance of real images. This paper demonstrates the feasibility of introducing GAN derived synthetic data to the training datasets in two brain segmentation tasks, leading to improvements in Dice Similarity Coefficient (DSC) of between 1 and 5 percentage points under different conditions, with the strongest effects seen fewer than ten training image stacks are available

LEDs to Replace Fluorescent Tubes for Growth of Cultured Algae

Fluorescent bulbs are widely used for algal culture stocks and production in aquaculture operations. Metal halide lamps are also used for production tanks with significant electricity demand and heat production. LED technology promises lower operational costs with less energy waste as heat for equivalent light energy production. Re-tooling algal production facilities with new LED fixtures incurs significant expense that must be recaptured in savings over time. The initial cost, added to concerns over the unknown response of algae to LED light sources may both be factors inhibiting incorporation of this new technology. LED replacement tubes are available to retrofit fluorescent tube fixtures and may offset some conversion costs to replacing light sources. Concerns about the ability of LEDs to provide adequate algae production for hatchery operations led us to run side by side comparison of growth dynamics for four commonly used algae strains using fluorescent light and LED replacement tubes. We also implemented a tunable red and blue LED unit for mass algae production in tanks

Fast gates and steady states: entangling trapped ions

This thesis describes schemes for both a fast two-qubit gate operation and the steady-state preparation of a Bell state with trapped ions. A critical figure of merit for quantum computing with trapped ions is the gate duration relative to the decoherence timescale. We propose a fast gate scheme that off ers improvements in time, fidelity and simplicity of implementation over existing fast gate proposals. Our scheme can operate on both neighbouring and non-neighbouring ions in a long ion crystal. This provides a simpler and faster mechanism than traditional gates for complex quantum computing operations on large numbers of ions. The scheme achieves fidelities well above quantum error correction thresholds around 0.0001, and operates arbitrarily fast given arbitrary laser repetition rates. The production of these ultra-fast pulses is an experimental challenge, and fast gates have not yet been implemented; we present an implementation scheme using pulse splitting to provide a higher repetition rate and the pulse timing freedoms required for the gate scheme. We also analyse the effects of errors in the pulses on the gate operation. We analyse another strategy to generate entanglement using a driven dissipative process. Typically, environmental couplings cause decoherence. However, by combining dissipative dynamics with suitably chosen Hamiltonian evolution, the system can be steered to the desired steady states. Our steady-state scheme prepares a maximally-entangled Bell state with fidelity above 0.99, much higher than for schemes implemented with trapped ions. The driven dissipation continuously pumps the system towards the antisymmetric Bell steady-state, which is dark to the system dynamics and robust to parameter variations. The dominant loss mechanism is anomalous heating of the motional modes, reducing our fidelity by less than 0.01 for current experimental rates. Our scheme jointly addresses the ions and does not use sympathetic cooling. We enhance our scheme by combining the dissipative state preparation with the detection of photons, and obtain a significant fidelity enhancement