The association of the roof rat (Rattus rattus) with the Himalayan blackberry (Rubus discolor) and Algerian ivy (Hedera canariensis) in California

The roof rat (Rattus rattus) utilizes Algerian ivy and the Himalayan blackberry for food and cover, often living Independent of man. Algerian ivy is the most popular ornamental and ground cover plant in California and is used extensively for landscaping, particularly in southern California. The Himalayan blackberry, inhabited by feral roof rats, grows abundantly in northern California along inland creeks and in pastureland of the Sacramento Valley and in the foothills of the Sierra Nevada. Rats construct platform nests on or within the dense layer of canes that accumulate within the thickets. Information on distribution and recommendations for the control of the roof rat within the blackberry habitat are presented. A potential human plague threat exists where rodent cohabitants of the berry thickets may become involved in epizootics

Determination of activation volumes of reversal in perpendicular media

We discuss a method for the determination of activation volumes of reversal in perpendicular media. This method does not require correction for the self-demagnetizing field normally associated with these media. This is achieved by performing time dependence measurements at a constant level of magnetization. From the difference in time taken for the magnetization to decay to a fixed value at two fields-separated by a small increment DeltaH, the activation volume can be determined. We report data for both CoCrPt alloy films and a multilayer film, typical of those materials under consideration for use as perpendicular media. We find activation volumes that are consistent with the hysteresis curves of the materials. The activation volume scales qualitatively with the exchange coupling. The alloy films have significantly lower activation volumes, implying that they would be capable of supporting a higher data density

Magnetization reversal in AFC media

In this paper, we report on a study of magnetization reversal processes in antiferromagnetically coupled media. We describe the reversal in terms of the reversible and irreversible susceptibility that has been measured for the CoCrPtB system of fixed-recording layer thickness and variable-stabilization layer thickness. We rind that very thin stabilization layers do not couple strongly to the recording layer, and that for Mrt greater than 0.11 memu/cm(2), some of the change in magnetization becomes irreversible

Activation volumes in CoPtCr-SiO2 perpendicular recording media

CoPtCr-SiO2 perpendicular recording media with varying levels of SiO2 were examined by two different methods to determine the activation volume. The first is based on the sweep-rate dependence of the remanence coercivity using Sharrock's equation. The second is based on the measurement of the fluctuation field from time-dependence data, determined using a magneto-optical Kerr effect (MOKE) magnetometer. The values of V-act measured at the coercivity for both methods are almost the same, with the fluctuation field and activation volumes increasing with the SiO2 content. The difference between V-act and the grain volume measured directly from bright-field TEM images decreases as the SiO2 content increases due to the reduction of intergranular exchange coupling. The experimental results indicate that values of V-act obtained from single- and double-layered media are consistent. It was also found that the coercivity and normalized hysteresis loop slope at coercivity varied with SiO2 content, with the coercivity peaking at 8 at % SiO2 (nearly 26 vol% SiO2)

Time dependence in perpendicular media with a soft underlayer

In this paper we describe measurements of magnetic viscosity or time dependence in magnetic thin films suitable for use as perpendicular recording media. Generally, such effects cannot be measured using conventional magnetometry techniques due to the presence of a thin (0.1 mum) soft underlayer (SUL) in the media necessary to focus the head field. To achieve our results we have developed an ultrastable MOKE magnetometer, the construction of which is described. This has enabled us to measure nominally identical films with and without the presence of the SUL. We find that the presence of the SUL narrows the energy barrier distribution in the perpendicular film increasing the nucleation field (H-n), reducing the coercivity (H-c) and results in an increase in the squareness of the loop. This in turn results in an increase in the magnitude of the viscosity in the region of the H-c but that the range of fields over which the viscosity occurs is reduced

Thermal performance: the politics of environmental management in architecture

How do architects address the ambiguity of practice, being on the one hand tasked with making buildings that perform well in terms of energy use and environmental strategy, and on the other facilitating the production of capital, through their service to ensuring that the performance of the occupants (efficiency, productivity and wellbeing) is satisfied? In this PhD by practice, I use the theoretical concept of ‘the performative’ through both the written thesis and project to interrogate the various ways in which thermal management becomes entangled with management processes. The context is specific: the workplace at a moment of convergence between smart technology with architecture; where notionally, agency is given over to autonomous environmental systems to do the right thing, and work environments that are embedded in performative-linguistic company cultures that urge their occupants to ‘do the right thing’. In other words – where machines do things with fans and boilers, and humans do things with emails, meetings, performance reviews and corporate culture. I invoke Lucy Schuman’s question ‘who is doing what to whom?’ to draw attention to the way that actions are elicited from employees through discursive and constitute organisational practices. At a point where new-build non-domestic buildings, which are specifically designed to perform environmentally well, are failing to do so- I invoke Isabelle Stengers’ ethical proposition ‘what are we busy doing?’ to ask whether architects’ actions are fundamentally compromised by this entanglement. I propose a strategy for architects to address their practice in relation to these propositions, and trace the actions as they migrate through discursive fields – sustainability, organisational management, theories of motivation, workplace politics, technological innovation, activism and resistance. The narrative of the written thesis is asynchronous, and is interconnected with the project in multiple ways, it is structured in such a way so as to introduce strategies of encountering the various discursive fields which form the context of study. The project work, on the other hand, immerses the reader directly within these fields. The database that reveals the multiple realms that embed the concepts of power, economics, desire, love, productivity and war into the architectural concerns for comfort and energy use; while the performance video places two subjects constituted by management, whose passions are put to work and situate them within a discursive environment latent with the full cultural significance of its metaphors in the workplace of the knowledge economy. The first part of the written component of the thesis opens up discussions about performance and action – which are generally applicable for the discourse of environmental performance, as mediated by the occupant and the use of technology, within the contemporary workplace. I move into the second part of the written thesis, which places the context specifically within the conceptual domain of thermal management, elaborates on the implications of taking a performance oriented approach to ‘heat’, and reveals how performance and the domain of heat converge on issues of productivity, subjectivity, and wellbeing. The two actors who perform in the video can only continuously improve their performance, every action can be subverted or appropriated, presenting the urgency for my conclusion in the written thesis, that as we, in architecture, are expected to also act entrepreneurially – the question is not how we do so subversively, or as a mode of critique. We should instead pay attention to Stengers’ and Suchman’s questions, and paying attention to what is brought about, and for whom, and focus our work on care for precarious, exhausted and hyper-active subjectivities that are produced through these actions

Visual Narratives: Storytelling in the Digital Age

This research will identify the components of visual narratives in 2D and 3D animated films and their relation to elements in literature and other earlier forms of storytelling. Over the course of 150 years animation has evolved from phenakistoscopes and flips books to full length feature films. Today, stories need not be grounded by realities in order to be told visually, as in theater. Specialized artists and programmers can create and modify every aspect of environments and characters in order to convey a story most effectively. However, the act of transforming an idea into computer data and later to a visual narrative that will move audiences is extremely complex and involves more psychology than one would expect of a cartoon. Animating artists must understand how the elements of art, particularly shape and color, draw out specific emotional responses from viewers; much like an author must know the precise adjective to guide their readers through their tale. By delving into the specifics of these elements, this research seeks to broaden the understanding and appreciation of visual narratives in animated film as a significant form of modern storytelling