Transient Analysis for Music and Moving Images: Consideration for Television Advertising

In audiovisual composition, coupling montage moving images with music is common practice. Interpretation of the effect on an audioviewer's consequent interpretation of the composition is discursive and unquantified. Meth-odology for evaluating the audiovisual multimodal inter-activity is proposed, developing an analysis procedure via the study of modality interdependent transient structures, explained as forming the foundation of perception via the concept of Basic Exposure response to the stimulus. The research has implications for analysis of all audiovisual media, with practical implications in television advertis-ing as a discrete typology of target driven audiovisual presentation. Examples from contemporary advertising are used to explore typical transient interaction patterns and the consequences of which are discussed from the practical viewpoint of the audiovisual composer

Audiovisual synchrony: Cross-modal transient structure and tempo

What are the considerations of the composer when designing music to accompany a visual? Music is purposefully included within audiovisual products with considered reason; motivic, thematic, emotive, semantic or otherwise. Ultimately, music is employed to affect an audiovieweri, yet the consequences of this multi-modal interaction lacks clarity. Investigating cross-modal interaction at the level of basic exposure to audiovisual works provides a foundation in understanding the audioviewer's percept. The moving image and music are intrinsically temporal and consequently carry rhythmic potential. In the context of concurrent non-literal music (often referred to as ‘background’ or ‘non-digetic’ music) and moving images, our unified perception of the presentation is structured upon the interpretation of intrinsic audiovisual rhythms. Such rhythms are constructed via the periodic structure of transients within their individual modalities, and crucially cross-modally as auditory and visual transient patterns interact. Multimodal integration studies have shown that synchronous audiovisual stimuli will bind, creating a unified percept functioning to increase the 'transientness' of such events. Dynamic attending theory understands that attention is subject to internalised oscillations, following peaks and troughs to create an oscillation of attentional magnitude cycles. The potential for auditory rhythmic manipulation to influence the unified audiovisual percept is engaging

The generalized Lindemann melting coefficient

Lindemann developed the melting temperature theory over 100 years ago, known as the Lindemann criterion. Its main assumption is that melting occurs when the root-mean-square vibration amplitude of ions and atoms in crystals exceeds a critical fraction, h of the inter-atomic spacing in crystals. The Lindemann coefficient h is undefined and scientific papers report different h values for different elements. Here we present previously unobserved data trends pointing to the fact that the Lindemann coefficient could be linked to the periodic groups of the periodic table, having an exact value for each element belonging to a given periodic group. We report 12 distinctive Lindemann coefficient values corresponding to 12 groups of the periodic table containing solid elements with identifiable melting temperature. Using these vales, the recalculation of the melting temperatures indicates a good match to the experimental values for 39 elements, corresponding to 12 out of 15 periodic groups. This newly observed result opens up the possibility of further refining the Lindemann melting criterion by stimulating analytical studies of the Lindemann coefficient in the light of this newly discovered result

Measuring the effects of reaction coordinate and electronic treatments in the QM/MM reaction dynamics of Trypanosoma cruzi trans-sialidase

The free energy of activation, as defined in transition state theory, is central to calculating reaction rates, distinguishing between mechanistic paths and elucidating the catalytic process. Computational free energies are accessible through the reaction space that is comprised of the conformational and electronic degrees of freedom orthogonal to the reaction coordinate. The overarching aim of this thesis was to address theoretical and methodological challenges facing current methods for calculating reaction free energies in glycoenzyme systems. Tractable calculations balance chemical accuracy and sampling efficiency that necessitates simplification of these complex reaction spaces through quantum mechanics/molecular mechanics partitioning and use of a semi-empirical electronic method to sample an approximated reaction coordinate. Here I directly and indirectly interrogate both the appropriate levels of sampling as well as the accuracy of the semi-empirical method required for reliable analysis of glycoenzyme reaction pathways. Free Energies from Adaptive Reaction Coordinates Forces, a method that builds the potential of mean force from multiple iterations of reactive trajectories, was used to construct reaction surfaces and volumes for the glycosylation and deglycosylation reactions comprising the T. cruzi trans-sialidase catalytic itinerary. This enzyme was chosen for the wealth of experimental data available for it built from its significance as a potential drug target against Chagas disease. Of equal importance is the identification of an elimination reaction competing with the primary transferase activity. The identification of this side reaction, that is observable only in the absence of the trans-sialidase or sialic acid acceptor, presented the opportunity to study the means by which enzymes selectivity bias in favor of a single reaction path. I therefore set out to explore the molecular details of how T. cruzi transsialidase asserts a precision and selectivity synonymous with enzyme catalysis. The chemical nature of the transition sate, formally defined as a dividing hypersurface separating the reactant and product regions of phase space, was characterized for the deglycosylation reaction. More than 40 transition state configurations were isolated from reactive trajectories, and the sialic acid substrate conformations were analyzed as well as the substrate interactions with the nucleophile and catalytic acid/base. A successful barrier crossing requires that the substrate pass through a family of E₅, ⁴H₅ and ⁶H₅ puckered conformations, all of which interact slightly differently with the enzyme. This work brings new evidence to the prevailing premise that there are several pathways from reactant to product passing through the saddle and successful product formation is not restricted to the minimum energy path. Increasing the reaction space with use of a multi-dimensional (3-D) reaction coordinate allowed simultaneous monitoring of the hitherto unexplored competition between a minor elimination reaction and the dominant displacement reaction present in both steps of the catalytic cycle. The dominant displacement reactions display lower barriers in the free energy profiles, greater sampling of favorable reactant stereoelectronic alignments and a greater number of possible transition paths leading to successful crossing reaction trajectories. The effects on the electronic degrees of freedom in reaction space were then investigated by running density functional theory reactive trajectories on the semi-empirical free energy. In order to carry out these simulations Free Energies from Adaptive Reaction Coordinates Forces was ported as a Fortran 90 library that interfaces with the NWChem molecular dynamics package. The resulting B3LYP/6-31G/CHARMM crossing trajectory provides a molecular orbital description of the glycosylation reaction. Direct investigation of the underlying potential energy functions for B3LYP/6-31G(d), B3LYP/6-31G and SCC-DFTB/MIO point to the minimal basis set as the primary limitation in using self-consistent charge density functional tight binding as the quantum mechanical model for modeling of enzymatic reactions transforming sialic acid substrates