Searching for Fast Optical Transients using VERITAS Cherenkov Telescopes

Astronomical transients are intrinsically interesting things to study. Fast optical transients (microsecond timescale) are a largely unexplored field of optical astronomy mainly due to the fact that large optical telescopes are oversubscribed. Furthermore, most optical observations use instruments with integration times on the order of seconds and are thus unable to resolve fast transients. Current-generation atmospheric Cherenkov gamma-ray telescopes, however, have huge collecting areas (e.g., VERITAS, which consists of four 12-m telescopes), larger than any existing optical telescopes, and time is typically available for such studies without interfering with gamma-ray observations. The following outlines the benefits of using a Cherenkov telescope to detect optical transients and the implementation of the VERITAS Transient Detector (TRenDy), a dedicated multi-channel photometer based on field-programmable gate arrays. Data are presented demonstrating the ability of TRenDy to detect transient events such as a star passing through its field of view and the optical light curve of a pulsar

Power Protection Analysis for a Ten Bus System

Each power system built in the industry requires a protection plan. Undetected faults in a power system can contribute to hazardous conditions, overheating of power devices, low or high system voltages, unbalanced conditions, and blackouts. This senior project is the design of a protection plan for a power system using the software Electric Transient Analyzer Program (ETAP). With ten buses, five transformers, two generators, two motors, and six transmission lines, there are many possibilities for a fault to occur. The Load flow and fault analysis are studied before the system is protected. All components of the system are protected using methods such as differential and overcurrent protection. Without a proper power protection plan, any disturbance within the network has a chance of rendering the network inoperable. This project illustrates the protection styles and techniques used by professional engineers in the field of power

Route Choice from Local Information: Comparing Theories of Movement and Intelligibility

Intelligibility, the extent to which non-local structure can be inferred from local properties, is examined using new methods based on angular segment analysis, demonstrating that such a property is consistent with exosomatic navigation. In many urban networks, effective movement is possible without knowledge of the broader structure, or memory, using information conveyed to a navigator only by the angles of each intersection. Results suggest that this is not due to a particular optimisation of the grid unique to cities, as has been suggested, but can result in many possible networks, including random ones. A relationship between intelligibility and predictability of movement, implied in previous literature, is shown not always to hold. Additional methodological and theoretical contributions are made in proposing a novel measure of immediate angular intelligibility, and in demonstrating equivalences between this and traditional axial line intelligibility, and between a number of other methods proposed to predict movement in the literature

Calcium dependence of Eugenol tolerance and toxicity in Saccharomyces cerevisiae

Eugenol is a plant-derived phenolic compound which has recognised therapeutical potential as an antifungal agent. However little is known of either its fungicidal activity or the mechanisms employed by fungi to tolerate eugenol toxicity. A better exploitation of eugenol as a therapeutic agent will therefore depend on addressing this knowledge gap. Eugenol initiates increases in cytosolic Ca2+ in Saccharomyces cerevisiae which is partly dependent on the plasma membrane calcium channel, Cch1p. However, it is unclear whether a toxic cytosolic Ca2+elevation mediates the fungicidal activity of eugenol. In the present study, no significant difference in yeast survival was observed following transient eugenol treatment in the presence or absence of extracellular Ca2+. Furthermore, using yeast expressing apoaequorin to report cytosolic Ca2+ and a range of eugenol derivatives, antifungal activity did not appear to be coupled to Ca2+ influx or cytosolic Ca2+ elevation. Taken together, these results suggest that eugenol toxicity is not dependent on a toxic influx of Ca2+. In contrast, careful control of extracellular Ca2+ (using EGTA or BAPTA) revealed that tolerance of yeast to eugenol depended on Ca2+ influx via Cch1p. These findings expose significant differences between the antifungal activity of eugenol and that of azoles, amiodarone and carvacrol. This study highlights the potential to use eugenol in combination with other antifungal agents that exhibit differing modes of action as antifungal agents to combat drug resistant infections

Additively manufactured versus conventionally pressed cranioplasty implants: An accuracy comparison

This article compared the accuracy of producing patient-specific cranioplasty implants using four different approaches. Benchmark geometry was designed to represent a cranium and a defect added simulating a craniectomy. An ‘ideal’ contour reconstruction was calculated and compared against reconstructions resulting from the four approaches –‘conventional’, ‘semi-digital’, ‘digital – non-automated’ and ‘digital – semi-automated’. The ‘conventional’ approach relied on hand carving a reconstruction, turning this into a press tool, and pressing titanium sheet. This approach is common in the UK National Health Service. The ‘semi-digital’ approach removed the hand-carving element. Both of the ‘digital’ approaches utilised additive manufacturing to produce the end-use implant. The geometries were designed using a non-specialised computer-aided design software and a semi-automated cranioplasty implant-specific computer-aided design software. It was found that all plates were clinically acceptable and that the digitally designed and additive manufacturing plates were as accurate as the conventional implants. There were no significant differences between the additive manufacturing plates designed using non-specialised computer-aided design software and those designed using the semi-automated tool. The semi-automated software and additive manufacturing production process were capable of producing cranioplasty implants of similar accuracy to multi-purpose software and additive manufacturing, and both were more accurate than handmade implants. The difference was not of clinical significance, demonstrating that the accuracy of additive manufacturing cranioplasty implants meets current best practice

Exosomatic Route Choice in Navigation: Evidence from video game player data

We investigate the extent to which navigation may be performed using exosomatic cues directly viewed in the environment, as opposed to relying on memory of a map or mental representation. Using trajectory data from a virtual navigation game app, Sea Hero Quest, we analyse the moment to moment route choices of 200 participants, and compare these against the expected routes based on several spatial variables measured from current isovists. Observations suggest that there is substantial evidence that for most participants navigation in a novel environment is indeed largely based on direct exosomatic information, and is based specifically on the space actually viewed, as opposed to that inferred by the shape of occluding edges. We also find evidence that strategies differ between individuals, in that the better navigators will deviate more from the exosomatic method, and rely more on their own memory and internal knowledge of the environment