The sphynx's new riddle : how to relate the canonical formula of myth to quantum interaction

We introduce Claude Lévi Strauss' canonical formula (CF), an attempt to rigorously formalise the general narrative structure of myth. This formula utilises the Klein group as its basis, but a recent work draws attention to its natural quaternion form, which opens up the possibility that it may require a quantum inspired interpretation. We present the CF in a form that can be understood by a non-anthropological audience, using the formalisation of a key myth (that of Adonis) to draw attention to its mathematical structure. The future potential formalisation of mythological structure within a quantum inspired framework is proposed and discussed, with a probabilistic interpretation further generalising the formula

Applying and testing design for intuitive interaction

Various tools have been developed to assist designers in making interfaces easier to use although none yet offer a complete solution. Through previous work we have established that intuitive interaction is based on past experience. From this we have developed theory around intuitive interaction, a continuum and a conceptual tool for intuitive use. We then trialled our tool. Firstly, one designer used the tool to design a camera. Secondly, seven groups of postgraduate students re-designed various products using our tool. We then chose one of these - a microwave – and prototyped the new and original microwave interfaces on a touchscreen. We tested them on three different age groups. We found that the new design was more intuitive and rated by participants as more familiar. Therefore, design interventions based on our intuitive interaction theory can work. Work is ongoing to develop the tool further.

MiniOrb : a sensor interaction platform for indoor climate preferences [Extended Abstract]

We introduce the MiniOrb platform, a combined sensor and interaction platform built to understand and encourage the gathering of data around personal indoor climate preferences in office environments. The platform consists of a sensor device, gathering localised environmental data and an attached tangible interaction and ambient display device. This device allows users to understand their local environment and record preferences with regards to their preferred level of office comfort. In addition to the tangible device we built a web-based mobile application that allowed users to record comfort preferences through a different interface. This paper describes the design goals and technical setup of the MiniOrb platform.

Evaluating the use of ambient and tangible interaction approaches for personal indoor climate preferences [Extended Abstract]

In this paper we describe the preliminary results of a field study which evaluated the use of MiniOrb, a system that employs ambient and tangible interaction mechanisms to allow inhabitants of office environments to report on subjectively perceived office comfort levels. The purpose of this study was to explore the role of ubiquitous computing in the individual control of indoor climate and specifically answer the question to what extent ambient and tangible interaction mechanisms are suited for the task of capturing individual comfort preferences in a non-obtrusive manner. We outline the preliminary results of an in-situ trial of the system.

Brca2 is involved in meiosis in Arabidopsis thaliana as suggested by its interaction with Dmc1

Two BRCA2-like sequences are present in the Arabidopsis genome. Both genes are expressed in flower buds and encode nearly identical proteins, which contain four BRC motifs. In a yeast two-hybrid assay, the Arabidopsis Brca2 proteins interact with Rad51 and Dmc1. RNAi constructs aimed at silencing the BRCA2 genes at meiosis triggered a reproducible sterility phenotype, which was associated with dramatic meiosis alterations. We obtained the same phenotype upon introduction of RNAi constructs aimed at silencing the RAD51 gene at meiosis in dmc1 mutant plants. The meiotic figures we observed strongly suggest that homologous recombination is highly disturbed in these meiotic cells, leaving aberrant recombination events to repair the meiotic double-strand breaks. The 'brca2' meiotic phenotype was eliminated in spo11 mutant plants. Our experiments point to an essential role of Brca2 at meiosis in Arabidopsis. We also propose a role for Rad51 in the dmc1 context.

Interaction between Arabidopsis Brca2 and its partners Rad51, Dmc1, and Dss1

The Arabidopsis (Arabidopsis thaliana) orthologs of Brca2, a protein whose mutations are involved in breast cancer in humans, were previously shown to be essential at meiosis. In an attempt to better understand the Brca2-interacting properties, we examined four partners of the two isoforms of Brca2 identified in Arabidopsis (AtRad51, AtDmc1, and two AtDss1 isoforms). The two Brca2 and the two Dss1 isoforms are named AtBrca2(IV), AtBrca2(V), AtDss1(I), and AtDss1(V) after their chromosomal localization. We first show that both AtBrca2 proteins can interact with either AtRad51 or AtDmc1 in vitro, and that the N-terminal region of AtBrca2 is responsible for these interactions. More specifically, the BRC motifs (so called because iterated in the Brca2 protein) in Brca2 are involved in these interactions: BRC motif number 2 (BRC2) alone can interact with AtDmc1, whereas BRC motif number 4 (BRC4) recognizes AtRad51. The human Rad51 and Dmc1 proteins themselves can interact with either the complete (HsRad51) or a shorter version of AtBrca2 (HsRad51 or HsDmc1) that comprises all four BRC motifs. We also identified two Arabidopsis isoforms of Dss1, another known partner of Brca2 in other organisms. Although all four Brca2 and Dss1 proteins are much conserved, AtBrca2(IV) interacts with only one of these AtDss1 proteins, whereas AtBrca2(V) interacts with both of them. Finally, we show for the first time that an AtBrca2 protein could bind two different partners at the same time: AtRad51 and AtDss1(I), or AtDmc1 and AtDss1(I).

Dense plasmas in magnetic traps : generation of focused ion beams with controlled ion-to-neutral flux ratios

Customized magnetic traps were developed to produce a domain of dense plasmas with a narrow ion beam directed to a particular area of the processed substrate. A planar magnetron coupled with an arc discharge source created the magnetic traps to confine the plasma electrons and generate the ion beam with the controlled ratio of ion-to-neutral fluxes. Images of the plasma jet patterns and numerical vizualizations help explaining the observed phenomena.

Magnetic control of breakdown : toward energy-efficient hollow-cathode magnetron discharges

Characteristics of electrical breakdown of a planar magnetron enhanced with an electromagnet and a hollow-cathode structure, are studied experimentally and numerically. At lower pressures the breakdown voltage shows a dependence on the applied magnetic field, and the voltage necessary to achieve the self-sustained discharge regime can be significantly reduced. At higher pressures, the dependence is less sensitive to the magnetic field magnitude and shows a tendency of increased breakdown voltage at the stronger magnetic fields. A model of the magnetron discharge breakdown is developed with the background gas pressure and the magnetic field used as parameters. The model describes the motion of electrons, which gain energy by passing the electric field across the magnetic field and undergo collisions with neutrals, thus generating new bulk electrons. The electrons are in turn accelerated in the electric field and effectively ionize a sufficient amount of neutrals to enable the discharge self-sustainment regime. The model is based on the assumption about the combined classical and near-wall mechanisms of electron conductivity across the magnetic field, and is consistent with the experimental results. The obtained results represent a significant advance toward energy-efficient multipurpose magnetron discharges.

Single-step synthesis and magnetic separation of graphene and carbon nanotubes in arc discharge plasmas

The unique properties of graphene and carbon nanotubes made them the most promising nanomaterials attracting enormous attention, due to the prospects for applications in various nanodevices, from nanoelectronics to sensors and energy conversion devices. Here we report on a novel deterministic, single-step approach to simultaneous production and magnetic separation of graphene flakes and carbon nanotubes in an arc discharge by splitting the high-temperature growth and low-temperature separation zones using a non-uniform magnetic field and tailor-designed catalyst alloy, and depositing nanotubes and graphene in different areas. Our results are very relevant to the development of commercially-viable, single-step production of bulk amounts of high-quality graphene.

Simulation and visualization of self-assembled nanodevice networks synthesized via plasma–surface interaction

Using advanced visualization techniques, a comprehensive visualization of all the stages of the self-organized growth of internetworked nanostructures on plasma-exposed surface has been made. Atomistic kinetic Monte Carlo simulation for the initial stage of deposition, with 3-D visualization of the whole system and half-tone visualization of the density field of the adsorbed atoms, makes it possible to implement a multiscale predictive modeling of the development of the nanoscale system.

Suppression of current fluctuations in a crossed E×B field system for low-voltage plasma immersion treatment

Plasma transport in a hybrid dc vacuum arc plasma source for ion deposition and plasma immersion treatment is considered. It is found that external crossed electric and magnetic fields near the substrate can significantly reduce the relative amplitude of ion current fluctuations I-f at the substrate surface. In particular, I-f decreases with the applied magnetic field when the bias voltage exceeds 300 V, thus allowing one to reduce the deviations from the rated process parameters. This phenomenon can be attributed to an interaction between the metal-plasma jet from the arc source and the discharge plasma in the crossed fields. © 2006 American Institute of Physics.

Electron transport across magnetic field in low-temperature plasmas : an alternative approach for obtaining evidence of Bohm mechanism

A comparative study involving both experimental and numerical investigations was made to resolve a long-standing problem of understanding electron conductivity mechanism across magnetic field in low-temperature plasmas. We have calculated the plasma parameters from experimentally obtained electric field distribution, and then made a 'back' comparison with the distributions of electron energy and plasma density obtained in the experiment. This approach significantly reduces an influence of the assumption about particular phenomenology of the electron conductivity in plasma. The results of the experiment and calculations made by this technique have showed that the classical conductivity is not capable of providing realistic total current and electron energy, whereas the phenomenological anomalous Bohm mobility has demonstrated a very good agreement with the experiment. These results provide an evidence in favor of the Bohm conductivity, thus making it possible to clarify this pressing long-living question about the main driving mechanism responsible for the electron transport in low-temperature plasmas.

Effective control of ion fluxes over large areas by magnetic fields : from narrow beams to highly uniform fluxes

An effective control of the ion current distribution over large-area (up to 103 cm2) substrates with the magnetic fields of a complex structure by using two additional magnetic coils installed under the substrate exposed to vacuum arc plasmas is demonstrated. When the magnetic field generated by the additional coils is aligned with the direction of the magnetic field generated by the guiding and focusing coils of the vacuum arc source, a narrow ion density distribution with the maximum current density 117 A m-2 is achieved. When one of the additional coils is set to generate the magnetic field of the opposite direction, an area almost uniform over the substrate of 103 cm2 ion current distribution with the mean value of 45 A m-2 is achieved. Our findings suggest that the system with the vacuum arc source and two additional magnetic coils can be effectively used for the effective, high throughput, and highly controllable plasma processing.

A quantification of the interaction and spatial ordering in nano-arrays

This paper reports on the use of a local order measure to quantify the spatial ordering of a quantum dot array (QDA). By means of electron ground state energy analysis in a quantum dot pair, it is demonstrated that the length scale required for such a measure to characterize the opto-electronic properties of a QDA is of the order of a few QD radii. Therefore, as local order is the primary factor that affects the opto-electronic properties of an array of quantum dots of homogeneous size, this order was quantified through using the standard deviation of the nearest neighbor distances of the quantum dot ensemble. The local order measure is successfully applied to quantify spatial order in a range of experimentally synthesized and numerically generated arrays of nanoparticles. This measure is not limited to QDAs and has wide ranging applications in characterizing order in dense arrays of nanostructures.

Heating mechanism of self-interaction of surface polaritons at n-type semiconductor-metal interface

The influence of electron heating in the high-frequency surface polariton (SP) field on the dispersion properties of the SPs considered is investigated. High frequency SPs propagate at the interface between an n-type semiconductor with finite electron pressure, and a metal. The nonlinear dispersion relation for the SPs is derived and investigated.