Enhancing Perception of Complex Sculptural Forms using Interactive Real-time Ray tracing

This paper looks at experiments into using real-time ray tracing to significantly enhance shape perception of complex three-dimensional digitally created structures. The author is a computational artist whose artistic practice explores the creation of intricate organic three-dimensional forms using simulation of morphogenesis. The generated forms are often extremely detailed, comprising tens of millions of cellular primitives. This often makes depth perception of the resulting structures difficult. His practice has explored various techniques to create presentable artefacts from the data, including high resolution prints, animated videos, stereoscopic installations, 3D printing and virtual reality. The author uses ray tracing techniques to turn the 3D data created from his morphogenetic simulations into visible artefacts. This is typically a time-consuming process, taking from seconds to minutes to create a single frame. The latest generation of graphics processing units offer dedicated hardware to accelerate ray tracing calculations. This potentially allows the generation of ray traced images, including self-shadowed complex structures and multiple levels of transparency, from new viewpoints at frame rates capable of real-time interaction. The author presents the results of his experiments using this technology with the aim of providing significantly enhanced perception of his generated three-dimensional structures by allowing user-initiated interaction to generate novel views, and utilizing depth cues such as stereopsis, depth from motion and defocus blurring. The intention is for these techniques to be usable to present new exhibitable works in a gallery context

Evidence-informed health policy: are we beginning to get there at last

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

An antibody raised against a pathogenic serpin variant induces mutant-like behaviour in the wild-type protein

A monoclonal antibody (mAb) that binds to a transient intermediate may act as a catalyst for the corresponding reaction; here we show this principle can extend on a macro molecular scale to the induction of mutant-like oligomerization in a wild-type protein. Using the common pathogenic E342K (Z) variant of α1-antitrypsin as antigen-whose native state is susceptible to the formation of a proto-oligomeric intermediate-we have produced a mAb (5E3) that increases the rate of oligomerization of the wild-type (M) variant. Employing ELISA, gel shift, thermal stability and FRET time-course experiments, we show that mAb5E3 does not bind to the native state of α1-antitrypsin, but recognizes a cryptic epitope in the vicinity of the post-helix A loop and strand 4C that is revealed upon transition to the polymerization intermediate, and which persists in the ensuing oligomer. This epitope is not shared by loop-inserted monomeric conformations. We show the increased amenity to polymerization by either the pathogenic E342K mutation or the binding of mAb5E3 occurs without affecting the energetic barrier to polymerization. As mAb5E3 also does not alter the relative stability of the monomer to intermediate, it acts in a manner similar to the E342K mutant, by facilitating the conformational interchange between these two states

Adaptive carbon export response to warming in the Sargasso Sea

Ocean ecosystem models predict that warming and increased surface ocean stratification will trigger a series of ecosystem events, reducing the biological export of particulate carbon to the ocean interior. We present a nearly three-decade time series from the open ocean that documents a biological response to ocean warming and nutrient reductions wherein particulate carbon export is maintained, counter to expectations. Carbon export is maintained through a combination of phytoplankton community change to favor cyanobacteria with highcellular carbon-to-phosphorus ratios and enhanced shallow phosphorus recycling leading to increased nutrient use efficiency. These results suggest that surface ocean ecosystems may be more responsive and adapt more rapidly to changes in the hydrographic system than is currently envisioned in earth ecosystem models, with positive consequences for ocean carbon uptake

Herbivore defence compounds occur in pollen and reduce bumblebee colony fitness

Herbivory defence chemicals in plants can affect higher trophic levels such as predators and parasitoids, but the impact on pollinators has been overlooked. We show that defensive plant chemicals can damage pollinator fitness when expressed in pollen. Crop lupins (Lupinus species from Europe and South America) accumulate toxic quinolizidine alkaloids in vegetative tissues, conferring resistance to herbivorous pests such as aphids. We identified the alkaloid lupanine and its derivatives in lupin pollen, and then provided this compound at ecologically-relevant concentrations to queenless microcolonies of bumblebees (Bombus terrestris) in their pollen to determine how foraging on these crops may impact bee colony health and fitness. Fewer males were produced by microcolonies provided with lupanine-treated pollen and they were significantly smaller than controls. This impact on males was not linked to preference as workers willingly fed lupanine-treated pollen to larvae, even though it was deleterious to colony health. Agricultural systems comprising large monocultures of crops bred for herbivore resistance can expose generalist pollinators to deleterious levels of plant compounds, and the broader environmental impacts of crop resistance must thus be considered

Assessing the number of users who are excluded by domestic heating controls

This is the pre-print version of the Article. This Article is also referred to as: "Assessing the 'Design Exclusion' of Heating Controls at a Low-Cost, Low-Carbon Housing Development". - Copyright @ 2011 Taylor & FrancisSpace heating accounts for almost 60% of the energy delivered to housing which in turn accounts for nearly 27% of the total UK's carbon emissions. This study was conducted to investigate the influence of heating control design on the degree of ‘user exclusion’. This was calculated using the Design Exclusion Calculator, developed by the Engineering Design Centre at the University of Cambridge. To elucidate the capability requirements of the system, a detailed hierarchical task analysis was produced, due to the complexity of the overall task. The Exclusion Calculation found that the current design placed excessive demands upon the capabilities of at least 9.5% of the UK population over 16 years old, particularly in terms of ‘vision’, ‘thinking’ and ‘dexterity’ requirements. This increased to 20.7% for users over 60 years old. The method does not account for the level of numeracy and literacy and so the true exclusion may be higher. Usability testing was conducted to help validate the results which indicated that 66% of users at a low-carbon housing development could not programme their controls as desired. Therefore, more detailed analysis of the cognitive demands placed upon the users is required to understand where problems within the programming process occur. Further research focusing on this cognitive interaction will work towards a solution that may allow users to behave easily in a more sustainable manner

Protein fiber linear dichroism for structure determination and kinetics in a low-volume, low-wavelength couette flow cell

High-resolution structure determination of soluble globular proteins relies heavily on x-ray crystallography techniques. Such an approach is often ineffective for investigations into the structure of fibrous proteins as these proteins generally do not crystallize. Thus investigations into fibrous protein structure have relied on less direct methods such as x-ray fiber diffraction and circular dichroism. Ultraviolet linear dichroism has the potential to provide additional information on the structure of such biomolecular systems. However, existing systems are not optimized for the requirements of fibrous proteins. We have designed and built a low-volume (200 μL), low-wavelength (down to 180 nm), low-pathlength (100 μm), high-alignment flow-alignment system (couette) to perform ultraviolet linear dichroism studies on the fibers formed by a range of biomolecules. The apparatus has been tested using a number of proteins for which longer wavelength linear dichroism spectra had already been measured. The new couette cell has also been used to obtain data on two medically important protein fibers, the all-β-sheet amyloid fibers of the Alzheimer's derived protein Aβ and the long-chain assemblies of α1-antitrypsin polymers