A bathymetric sidescan sonar system

The design and construction of a bathymetric sidescan sonar system capable of operation over a 39 degree vertical sector is described. Field tests conducted at a dam site indicate that the completed system does not function as required. This is due to errors in the sonar depth measurement which are caused by reverberation resulting from the multiple scattering of sound from the dam floor. Recommendations are made so that future systems will be less susceptible to this interference source

Use of a Static Magnetic Field in Measuring the Thermal Conductivity of a Levitated Molten Droplet

Numerical models are used to analyze the complex behaviour of magnetically levitated droplets in the context of determining their thermophysical properties. We focus on a novel method reported in Tsukada et al. [4] which uses periodic laser heating to determine the thermal conductivity of an electromagnetically levitated droplet in the presence of a static DC field to suppress convection. The results obtained from the spectral-collocation based free surface code SPHINX and the commercial package COMSOL independently confirm and extend previous findings in [4]. By including the effects of turbulence and movement of the free surface SPHINX can predict the behaviour of the droplet in dynamic regimes with and without the DC magnetic field. COMSOL is used to investigate arbitrary amplitude axial translational oscillations when the spherical droplet is displaced off its equilibrium. The results demonstrate that relatively small amplitude oscillations could cause significant variation in Joule heating and redistribution of the temperature. The effect of translational oscillations on the lumped circuit inductance is analysed. When a fixed voltage drive is applied across the terminals of the levitation coil, this effect will cause the coil current to change and a correction is needed to the electromagnetic force acting on the droplet

Anxiety’s ambiguity: an investigation into the meaning of anxiety in existentialist philosophy and literature

The dissertation has two primary aims: 1) To investigate the significance and role of anxiety in the work of existentialist writers; 2) To synthesize a unified account of its meaning within this tradition. There are seven substantial chapters, the first concerning the divergence between clinical anxiety and the existential version using the fear-anxiety distinction as a foil. Existential anxiety is Thai defined in terms of anxiety A (before the world as contingent), anxiety B (before the self as free), and urangst (an unappropriable disquiet caused by the incommensurability of anxieties A and B). Chapter 2 concerns Kierkegaard's The Concept of Anxiety. His emphasis on choice, guilt and ambiguity lay the foundations for existentialism, but the suggestion that anxiety can be overcome in faith distances him from later existentialists. Chapter 3 reads Heidegger as secularizing Kierkegaard's ideas. Here we find the origins of the anxiety A/B structure, but I find that his attempt to define an 'authentic' comportment which embraces these two sources fails. In Chapter 4 Sartre's anxiety before the 'nothingness' of a self responsible for creating values is discussed and found wanting. However, his ideas on bad faith and authenticity seem to be more alive to the ambiguity of existence that anxiety reveals. The relation between anxiety and death is a primary concern of Chapter 5 (on Tillich). I contend that death is important (though not in the way Tillich thinks it is), but that otherwise he underplays urangst and die dynamism required in an authoitic response to anxiety. The complexities of this process are further explored in Chapter 6 with respect to Rorty's version of 'irony'; and in the final chapter where two novels (Conrad's Heart of Darkness and Camus' The Fall) are read as demonstrating the subjective dynamics of authenticity in terms of the anxiety structure that has been developed

Ligand-dependent opening of the multiple AMPA receptor conductance states: a concerted model

Modulation of the properties of AMPA receptors at the post-synaptic membrane is one of the main suggested mechanisms behind synaptic plasticity in the central nervous system of vertebrates. Electrophysiological recordings of single channels stimulated with agonists showed that both recombinant and native AMPA receptors visit multiple conductance states in an agonist concentration dependent manner. We propose an allosteric model of the multiple conductance states based on concerted conformational transitions of the four subunits, as an iris diaphragm. Our model predicts that the thermodynamic behaviour of the conductance states upon full and partial agonist stimulations can be described with increased affinity of receptors as they progress to higher conductance states. The model also predicts existence of AMPA receptors in non-liganded conductive substates. However, spontaneous openings probability decreases with increasing conductances. Finally, we predict that the large conductance states are stabilized within the rise phase of a whole-cell EPSC in glutamatergic hippocampal neurons. Our model provides a mechanistic link between ligand concentration and conductance states that can explain thermodynamic and kinetic features of AMPA receptor gating.Comment: 4 figures, models available on demand. They will be published by BioModels Database upon publication of the articl

Monitoring in a grid cluster

The monitoring of a grid cluster (or of any piece of reasonably scaled IT infrastructure) is a key element in the robust and consistent running of that site. There are several factors which are important to the selection of a useful monitoring framework, which include ease of use, reliability, data input and output. It is critical that data can be drawn from different instrumentation packages and collected in the framework to allow for a uniform view of the running of a site. It is also very useful to allow different views and transformations of this data to allow its manipulation for different purposes, perhaps unknown at the initial time of installation. In this context, we present the findings of an investigation of the Graphite monitoring framework and its use at the ScotGrid Glasgow site. In particular, we examine the messaging system used by the framework and means to extract data from different tools, including the existing framework Ganglia which is in use at many sites, in addition to adapting and parsing data streams from external monitoring frameworks and websites

Characterization of Mmp37p, a \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e Mitochondrial Matrix Protein with a Role in Mitochondrial Protein Import

Many mitochondrial proteins are encoded by nuclear genes and after translation in the cytoplasm are imported via translocases in the outer and inner membranes, the TOM and TIM complexes, respectively. Here, we report the characterization of the mitochondrial protein, Mmp37p (YGR046w) and demonstrate its involvement in the process of protein import into mitochondria. Haploid cells deleted of MMP37 are viable but display a temperature-sensitive growth phenotype and are inviable in the absence of mitochondrial DNA. Mmp37p is located in the mitochondrial matrix where it is peripherally associated with the inner membrane. We show that Mmp37p has a role in the translocation of proteins across the mitochondrial inner membrane via the TIM23-PAM complex and further demonstrate that substrates containing a tightly folded domain in close proximity to their mitochondrial targeting sequences display a particular dependency on Mmp37p for mitochondrial import. Prior unfolding of the preprotein, or extension of the region between the targeting signal and the tightly folded domain, relieves their dependency for Mmp37p. Furthermore, evidence is presented to show that Mmp37 may affect the assembly state of the TIM23 complex. On the basis of these findings, we hypothesize that the presence of Mmp37p enhances the early stages of the TIM23 matrix import pathway to ensure engagement of incoming preproteins with the mtHsp70p/PAM complex, a step that is necessary to drive the unfolding and complete translocation of the preprotein into the matrix

A voyage to Arcturus: a model for automated management of a WLCG Tier-2 facility

With the current trend towards "On Demand Computing" in big data environments it is crucial that the deployment of services and resources becomes increasingly automated. Deployment based on cloud platforms is available for large scale data centre environments but these solutions can be too complex and heavyweight for smaller, resource constrained WLCG Tier-2 sites. Along with a greater desire for bespoke monitoring and collection of Grid related metrics, a more lightweight and modular approach is desired. In this paper we present a model for a lightweight automated framework which can be use to build WLCG grid sites, based on "off the shelf" software components. As part of the research into an automation framework the use of both IPMI and SNMP for physical device management will be included, as well as the use of SNMP as a monitoring/data sampling layer such that more comprehensive decision making can take place and potentially be automated. This could lead to reduced down times and better performance as services are recognised to be in a non-functional state by autonomous systems

Anti-Patents

Conventional wisdom has long perceived the patent and tort systems as separate legal entities, each tasked with a starkly different mission. Patent law rewards novel ideas; tort law deters harmful conduct. Against this backdrop, this Essay uncovers the opposing effects of patent and tort law on innovation, introducing the injurer-innovator problem. Patent law incentivizes injurers --often uniquely positioned to make technological breakthroughs--by allowing them to profit from licensing their inventions to competitors. Yet tort law, by imposing liability for failures to invest in care, forces injurers to incur the cost of implementing their own innovations. When the cost of self-implementation exceeds the revenues that may be reaped from patenting new technologies, injurers are better off refraining from developing socially desirable inventions. The injurer-innovator problem remarkably persists under both negligence and strict liability regimes, and in the face of different victim types. Multiple real-world examples demonstrate the extent and pervasiveness of this phenomenon. To realign the incentives provided by the patent and tort systems, this Essay proposes a new legal construct: anti-patents. While a standard patent grants an inventor the exclusive right to use its invention, an anti-patent creates the converse exclusivity regime: the inventor, and only the inventor, is not required to use the invention. Importantly, anti-patents retain the existing patent protection, allowing injurer-innovators to charge monopolistic prices from competitors but simultaneously eliminating the obstacle created by tort law. An injurer-innovator who owns an anti-patent will enjoy immunity from the heightened standard of care to which the rest of the industry would now be subject. The Essay further shows that the anti-patent mechanism not only succeeds at harmonizing patent and tort law toward the advancement of technological progress but also outperforms alternative schemes employed to stimulate innovation (i.e., prizes, grants, and tax benefits). Finally, it ties the logic that underlies anti-patents to existing doctrines designated to elicit the disclosure of private information

Usability engineering for code-based multi-factor authentication

The increase in the use of online banking and other alternative banking channels has led to improved flexibility for customers but also an increase in the amount of fraud across these channels. The industry recommendation for banks and other financial institutions is to use multi-factor customer authentication to reduce the risk of identity theft and fraud for those choosing to use such banking channels. There are few multi-factor authentication solutions available for banks to use that offer a convenient security procedure across all banking channels. The CodeSure card presented in this research is such a device offering a convenient, multi-channel, two-factor code-based security solution based on the ubiquitous Chip-and-PIN bank card. In order for the CodeSure card to find acceptance as a usable security solution, it must be shown to be easy to use and it must also be easy for customers to understand what they are being asked to do, and how they can achieve it. This need for a usability study forms the basis of the research reported here. The CodeSure card is also shown to play a role in combating identity theft. With the growing popularity of online channels, this research also looks at the threat of phishing and malware, and awareness of users about these threats. Many banks have ceased the use of email as a means to communicate with their customers as a result of the phishing threat, and an investigation into using the CodeSure card's reverse (sender) authentication mode is explored as a potential solution in regaining trust in the email channel and reintroducing it as a means for the bank to communicate with its customers. In the 8 experiments presented in this study the CodeSure card was rated acceptably high in terms of mean usability. Overall, the research reported here is offered in support of the thesis that a usable security solution predicated on code-based multi-factor authentication will result in tangible improvements to actual security levels in banking and eCommerce services, and that the CodeSure card as described here can form the basis of such a usable security solution