Electronic properties of sculpturenes

We investigate the electronic properties of sculpturenes, formed by sculpting selected shapes from bilayer graphene, boron nitride or graphene-boron nitride hetero-bilayers and allowing the shapes to spontaneously reconstruct. The simplest sculpturenes are periodic nanotubes, containing lines of non-hexagonal rings. More complex sculpturenes formed from shapes with non-trivial topologies, connectivities and materials combinations may also be constructed. Results are presented for the reconstructed geometries, electronic densities of states and current-voltage relations of these new structures

Sculpting molecular structures from bilayer graphene and other materials

We demonstrate a technique for creating unique forms of pure sp(2)-bonded carbon and unprecedented heteromolecules. These new structures, which we refer to as sculpturenes, are formed by sculpting selected shapes from bilayer graphene, heterobilayers, or multilayered materials and allowing the shapes to spontaneously reconstruct. The simplest sculpturene is topologically equivalent to a torus, with dimensions comparable to those of fullerenes. The topology of these new molecular structures is stable against atomic-scale defects. We demonstrate that sculpturenes can form the basic building blocks of hollow, multiconnected structures, with potential applications to nanofluidics and nanoelectronics

The Universe at Extreme Scale: Multi-Petaflop Sky Simulation on the BG/Q

Remarkable observational advances have established a compelling cross-validated model of the Universe. Yet, two key pillars of this model -- dark matter and dark energy -- remain mysterious. Sky surveys that map billions of galaxies to explore the `Dark Universe', demand a corresponding extreme-scale simulation capability; the HACC (Hybrid/Hardware Accelerated Cosmology Code) framework has been designed to deliver this level of performance now, and into the future. With its novel algorithmic structure, HACC allows flexible tuning across diverse architectures, including accelerated and multi-core systems. On the IBM BG/Q, HACC attains unprecedented scalable performance -- currently 13.94 PFlops at 69.2% of peak and 90% parallel efficiency on 1,572,864 cores with an equal number of MPI ranks, and a concurrency of 6.3 million. This level of performance was achieved at extreme problem sizes, including a benchmark run with more than 3.6 trillion particles, significantly larger than any cosmological simulation yet performed.Comment: 11 pages, 11 figures, final version of paper for talk presented at SC1

Development and optimisation of a sex pheromone lure for monitoring populations of saddle gall midge, Haplodiplosis marginata

Saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae), is a sporadic pest of cereals in Northern and Central Europe and is of increasing importance in the UK. Recently the major component of the sex pheromone produced by adult female H. marginata was reported to be 2-nonyl butyrate. The importance of absolute configuration on attractiveness, the effects on trap catches of the addition of minor pheromone components, dispenser type, and pheromone loading are described in the development of an optimised pheromone lure with which to trap H. marginata males. In analyses of volatiles collected from virgin female H. marginata by gas chromatography (GC) coupled to electroantennographic recording (EAG) from the antenna of a male H. marginata, two EAG responses were observed. Analyses by coupled GC-mass spectrometry (MS) indicated these were due to 2-nonyl butyrate and a trace amount (1%) of 2-heptyl butyrate. A similar trace amount of 2-nonanol was detected in GC-MS analyses but this compound did not elicit an EAG response when the synthetic compound was tested, whereas while the other two compounds did. These three compounds were not observed in collections of volatiles made from male H. marginata. The 2-nonyl butyrate was shown to be the (R)-enantiomer, and i. In field trapping tests (R)-2-nonyl butyrate was at least ten times10× more attractive to male H. marginata than the racemic compound, and while the (S)-enantiomer was unattractive. Addition of the potential minor components individually or together at the naturally -occurring ratios did not increase or reduce the attractiveness of the lure. Polyethylene vials and rubber septa were equally effective as pheromone dispensers, lasting for at least five 5 weeks in the field in the UK, although laboratory tests indicated release from the former was more uniform and more likely to last longer in the field. Increasing loading of pheromone in the dispenser increased attractiveness. Traps baited with polyethylene vials containing 0.5 mg of (R)-2-nonyl butyrate are recommended for monitoring H. marginata and these are far more sensitive than water or sticky traps currently used for monitoring this pest

Developing a semiochemical baited “smart” trap to monitor vine weevil (Otiorhynchus sulcatus)

Conference poster - No Abstract available

Creativity and the computer nerd: an exploration of attitudes

This study arises from our concern that many of our best art and design students are failing to make the most of the opportunities provided by IT because of their fear or dislike of computers. This not only deprives them of useful skills, but, even more importantly, deprives many IT based developments of their input. In this paper we investigate the relationship between attitudes to creativity and to computers among students. We quickly discard an approach based on theories of personality types as philosophically and educationally problematic. An approach based on the self-concept of artists and designers, in relation to their own creativity and to their feelings about computers, offers more hope of progress. This means that we do not try to define the attributes of "creative people". Rather, we ask what creativity means to students of art and design and relate these responses to their attitudes to computers. Self-concept depends on how the subjects see themselves within society and culture, and is liable to change as culture changes. One major instrument of cultural change at the present time is the growth of IT itself. We then describe a first attempt at using a psychological method - Kelly's Repertory Grids - to investigate the self-concept of artists and designers. It is hoped to continue with this approach in further studies over the next few years

The contribution of AGN to the sub-mm population

We find that X-ray sources in the Extended Chandra Deep Field South are strongly spatially correlated with LABOCA 870 micron sources. We investigate the dependence of this correlation on X-ray flux, hardness ratio and column density, finding that specifically faint and absorbed X-ray sources are significant sub-mm emitters. In the X-ray source redshift subsample we confirm the previous result that higher luminosity sources (L_X>10^44 ergs/s) have greater 870um fluxes but we also find that this subsample selects against absorbed sources, faint in X-ray flux. Overall, we find that X-ray sources contribute 1.5 \pm 0.1 Jy/deg^2 to the sub-mm background, ~3% of the total, in agreement with the prediction of an obscured AGN model which also gives a reasonable fit to the bright sub-mm source counts. This non-unified model also suggests that when Compton-thick, X-ray-undetected sources are included, then the fractional AGN contribution to the sub-mm background would rise from ~3% to a total of 25-40%, although in a unified model the AGN contribution would only reach ~13%, because the sub-mm flux of the X-ray sources is then more representative of the whole AGN population. Measurements of the dependence of sub-mm flux on X-ray flux, luminosity and column density all agree well with the predictions of the non-unified AGN model. Heavily absorbed, X-ray-undetected AGN could explain the further cross-correlation we find between sub-mm sources and z > 0.5 red galaxies. We conclude that sub-mm galaxies may contain the long-sought absorbed AGN population needed to explain the X-ray background.Comment: 15 pages, 13 figures; submitted to MNRA

Electrophysiological and behavioral responses of vine weevil, Otiorhynchus sulcatus (Coleoptera: Curculionidae), adults to host plant odors

Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is an economically important pest species in many soft-fruit and ornamental crops. Economic losses arise from damage to the roots, caused by larvae, and to the leaves, caused by adults. As adults are nocturnal and larvae feed below ground, infestations can initially be missed, and controls may, as a result, be applied too late. In the absence of a vine weevil sex or aggregation pheromone being identified, the development of an effective semiochemical lure for better management of this pest is likely to focus on host-plant volatiles. Here, we investigate the electrophysiological and behavioral responses of adult vine weevils to volatile organic compounds (VOCs) originating from their preferred host plant Euonymus fortunei, and synthetic VOCs associated with this host when presented individually or as blends. Consistent electroantennographic responses were observed to a range of generalist VOCs. Behavioral responses to VOCs, when presented individually, were found to be influenced by the concentration of the compound to which the weevils were exposed. Vine weevil adults showed directional movement towards a mixture of seven plant volatiles (methyl salicylate, 1-octen-3-ol, (E)-2-hexenol, (Z)-3-hexenol, 1-hexanol, (E)-2-pentenol, and linalool) even though either no response or negative responses were recorded to each of these compounds when presented individually. Similarly, vine weevils showed directional movement towards a 1:1 ratio mixture of (Z)-2-pentenol and methyl eugenol. Results presented here point to the importance of blends of generalist compounds and concentrations of VOCs in the optimization of a lure