Joint attention, semiotic mediation and literary narrative

In this paper I discuss the importance for narrative theory of the concept, drawn from developmental psychology, of “joint attention”. In the first part, I explain the basic concept and its significance for the emergence of narrative in young children. In the second part I draw out the implications of this genetic approach for our understanding of the nature of narrative signification: where classical narratology is based on a chain of representational and “communicative” dyads (signifier/signified and sender/receiver), joint attention integrates these functions into a triadic semiotic by which the sign mediates between three poles: the producer of the sign, the receiver of the sign and the object of their joint attention. In the third part, taking Boccaccio’s Decameron as an example, I illustrate how this approach to the semiotics of narrative elucidates aspects of literary narrative that are obscured by the classical semiotic. Joint attention offers affordances for quasi-recursive re-contextualization, since the object of joint attention may consist of another act of joint attention: literary narrative can create complex joint attentional structures by which the story is “seen” through nested perspectival prisms of embedded narrative and character

Closure, observation and coupling: on narrative and autopoiesis

An examination of how narrative fiction can be thought of as a form of Autopoiesis (self-organizing system), drawing on Aristotle, Czech structuralism and Niklas Luhmann's systems theory

An Assessment of Young Cattle Behaviour and Welfare in a Virtual Fencing System

Virtual fencing is a novel technology which uses a combination of audio and electrical stimuli to contain grazing livestock within a GPS boundary. There are however some concerns around the use of such a technology and its potential effects on the behaviour and welfare of animals. To investigate this, 64 dairy-origin calves were assigned to one of two treatments in a randomised complete block design, with 4 groups of 8 calves per treatment. The two treatments were virtual fencing (VF) and electric fencing (EF). The experimental period lasted 31 days in total, consisting of a 10 day training period and a 21 day grazing period. Welfare and behaviour of the animals was measured using faecal cortisol metabolites, activity pedometers, and behavioural recordings. Virtual fence data denoting the number of audio and electrical stimuli delivered for each animal were also recorded. Results show that there was no significant difference in animal welfare and behaviour between EF and VF in the current study. Additionally, there was no significant difference in daily liveweight gain between treatments. In the VF animals the rate of electric pulses declined after an initial learning period however there was a significant degree of variation in the rate of learning between animals. Virtual fencing could therefore offer an alternative to physical fencing for grazing young cattle without negatively impacting animal behaviour or welfare. The individual animal variation in VF systems however warrants further study

Podcasting from PowerPoint Made Easy for Faculty

Student demand, institutional support, and evidence of quality learning through web-based instruction should encourage faculty to experiment with alternative methods of delivering instruction. The authors developed a procedure to produce and deliver classroom lecture material by narrating PowerPoint presentations and converting to podcasts. This procedure requires little to no technical support, even for the technologically impaired, and costs less than $100 in equipment and software combined. It is an example of the many alternative distance education options available to educators today

Simulating Vibronic Spectra without Born-Oppenheimer Surfaces

We show how vibronic spectra in molecular systems can be simulated in an efficient and accurate way using first principles approaches without relying on the explicit use of multiple Born-Oppenheimer potential energy surfaces. We demonstrate and analyse the performance of mean field and beyond mean field dynamics techniques for the \ch{H_2} molecule in one-dimension, in the later case capturing the vibronic structure quite accurately, including quantum Franck-Condon effects. In a practical application of this methodology we simulate the absorption spectrum of benzene in full dimensionality using time-dependent density functional theory at the multi-trajectory mean-field level, finding good qualitative agreement with experiment. These results show promise for future applications of this methodology in capturing phenomena associated with vibronic coupling in more complex molecular, and potentially condensed phase systems

Conditional wavefunction theory: a unified treatment of molecular structure and nonadiabatic dynamics

We demonstrate that a conditional wavefunction theory enables a unified and efficient treatment of the equilibrium structure and nonadiabatic dynamics of correlated electron-ion systems. The conditional decomposition of the many-body wavefunction formally recasts the full interacting wavefunction of a closed system as a set of lower dimensional (conditional) coupled `slices'. We formulate a variational wavefunction ansatz based on a set of conditional wavefunction slices, and demonstrate its accuracy by determining the structural and time-dependent response properties of the hydrogen molecule. We then extend this approach to include time-dependent conditional wavefunctions, and address paradigmatic nonequilibrium processes including strong-field molecular ionization, laser driven proton transfer, and Berry phase effects induced by a conical intersection. This work paves the road for the application of conditional wavefunction theory in equilibrium and out of equilibrium ab-initio molecular simulations of finite and extended systems

Revealing Ultrafast Phonon Mediated Inter-Valley Scattering through Transient Absorption and High Harmonic Spectroscopies

Processes involving ultrafast laser driven electron-phonon dynamics play a fundamental role in the response of quantum systems in a growing number of situations of interest, as evidenced by phenomena such as strongly driven phase transitions and light driven engineering of material properties. To show how these processes can be captured from a computational perspective, we simulate the transient absorption spectra and high harmonic generation signals associated with valley selective excitation and intra-band charge carrier relaxation in monolayer hexagonal boron nitride. We show that the multi-trajectory Ehrenfest dynamics approach, implemented in combination with real-time time-dependent density functional theory and tight-binding models, offers a simple, accurate and efficient method to study ultrafast electron-phonon coupled phenomena in solids under diverse pump-probe regimes which can be easily incorporated into the majority of real-time ab-initio software packages.Comment: 16 pages, 9 figure

Simulating Vibronic Spectra without Born-Oppenheimer Surfaces

We show how linear vibronic spectra in molecular systems can be simulated efficiently using first-principles approaches without relying on the explicit use of multiple Born-Oppenheimer potential energy surfaces. We demonstrate and analyze the performance of mean-field and beyond-mean-field dynamics techniques for the H2 molecule in one dimension, in the later case capturing the vibronic structure quite accurately, including quantum Franck-Condon effects. In a practical application of this methodology we simulate the absorption spectrum of benzene in full dimensionality using time-dependent density functional theory at the multitrajectory Ehrenfest level, finding good qualitative agreement with experiment and significant spectral reweighting compared to commonly used single-trajectory Ehrenfest dynamics. These results form the foundation for nonlinear spectral calculations and show promise for future application in capturing phenomena associated with vibronic coupling in more complex molecular and potentially condensed phase systemsThis work was supported by the European Research Council (ERC-2015-AdG694097), the Cluster of Excellence Advanced Imaging of Matter (AIM), JSPS KAKENHI Grant Number 20K14382, Grupos Consolidados (IT1249-19), and SFB925. The Flatiron Institute is a division of the Simons Foundatio

Stand-off runaway electron beam termination by tungsten particulates for tokamak disruption mitigation

Stand-off runaway electron termination by injected tungsten particulates offers a plausible option in the toolbox of disruption mitigation. Tungsten is an attractive material choice for this application due to large electron stopping power and high melting point. To assess the feasibility of this scheme, we simulate runaway collisions with tungsten particulates using the MCNP program for incident runaway energies ranging from 1 to 10 MeV. We assess runaway termination from energetics and collisional kinematics perspectives. Energetically, the simulations show that 99% of runaway beam energy is removed by tungsten particulates on a timescale of 4-9 $\mu$s. Kinematically, the simulations show that 99% of runaways are terminated by absorption or backscattering on a timescale of 3-4 $\mu$s. By either metric, the runaway beam is effectively terminated before the onset of particulate melting. Furthermore, the simulations show that secondary radiation emission by tungsten particulates does not significantly impact the runaway termination efficacy of this scheme. Secondary radiation is emitted at lower particle energies than the incident runaways and with a broad angular distribution such that the majority of secondary electrons emitted will not experience efficient runaway re-acceleration. Overall, the stand-off runaway termination scheme is a promising concept for last-ditch runaway mitigation in ITER, SPARC, and other future burning-plasma tokamaks.Comment: Submitted to: Nuclear Fusion - 16 pages (4 supplementary), 11 figures (5 supplementary), 4 table