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Articles 1 - 21 of 21
Full-Text Articles in Physical Sciences and Mathematics
The Minimum And Other Free Energies For Non-Linear Materials With Memory., John Murrough Golden
The Minimum And Other Free Energies For Non-Linear Materials With Memory., John Murrough Golden
Articles
Expressions are obtained for free energies of materials with a certain type of non-linear constitutive relation. In particular, the minimum and related free energies are considered in some detail. Minimal states are defined for these materials, and it is shown that any free energy yielding a linear constitutive equation that is a functional of the minimal state has a counterpart in the non-linear case which is also a minimal state functional in this more general context. These results are explored for simple examples, including discrete spectrum materials.
Audiovisual Processing Is Abnormal In Parkinson's Disease And Correlates With Freezing Of Gait And Disease Duration, Conor Fearon, John Butler, Louise Newman, Timothy Lynch, Richard B. Reilly
Audiovisual Processing Is Abnormal In Parkinson's Disease And Correlates With Freezing Of Gait And Disease Duration, Conor Fearon, John Butler, Louise Newman, Timothy Lynch, Richard B. Reilly
Articles
Background: Sensory and perceptual disturbances progress with disease duration in Parkinson’s disease (PD) and probably contribute to motor deficits such as bradykinesia and gait disturbances, including freezing of gait (FOG). Simple reaction time tests are ideal to explore sensory processing, as they require little cognitive processing. Multisensory integration is the ability of the brain to integrate sensory information from multiple modalities into a single coherent percept, which is crucial for complex motor tasks such as gait. 9 10 11 12 13 Objectives: The aims of this study were to: 1. Assess differences in unisensory (auditory and visual) and multisensory processing …
Free Energies And Minimal States For Scalar Linear Viscoelasticity, John Murrough Golden
Free Energies And Minimal States For Scalar Linear Viscoelasticity, John Murrough Golden
Articles
The concept of a minimal state was introduced in recent decades, based on earlier work by Noll. The property that a given quantity is a functional of the minimal state is of central interest in the present work. Using a standard representation of a free energy associated with a linear memory constitutive relation, a new condition, involving linear functionals, is derived which, if satisfied, ensures that the free energy is a functional of the minimal state. Using this result and recent work on constructing free energy functionals, it is shown that if the kernel of the rate of dissipation functional …
Age-Related Sexual Dimorphism In Temporal Discrimination And In Adult-Onset Dystonia Suggests Gabaergic Mechanisms, John Butler, Ines M. Beiser, Laura Williams, Eavan Mcgovern, Fiona Molloy, Timothy Lynch, Dan G. Healy, Helena Moore, Richard Walsh, Richard B. Reilly, Sean O'Riordan, Cathal Walsh, Michael Hutchinson
Age-Related Sexual Dimorphism In Temporal Discrimination And In Adult-Onset Dystonia Suggests Gabaergic Mechanisms, John Butler, Ines M. Beiser, Laura Williams, Eavan Mcgovern, Fiona Molloy, Timothy Lynch, Dan G. Healy, Helena Moore, Richard Walsh, Richard B. Reilly, Sean O'Riordan, Cathal Walsh, Michael Hutchinson
Articles
Background: Adult-onset isolated focal dystonia (AOIFD) presenting in early adult life is more frequent in men, whereas in middle age it is female predominant. Temporal discrimination, an endophenotype of adult-onset idiopathic isolated focal dystonia, shows evidence of sexual dimorphism in healthy participants. Objectives: We assessed the distinctive features of age-related sexual dimorphism of (i) sex ratios in dystonia phenotypes and (ii) sexual dimorphism in temporal discrimination in unaffected relatives of cervical dystonia patients. Methods: We performed (i) a meta-regression analysis of the proportion of men in published cohorts of phenotypes of adult-onset dystonia in relation to their mean age of …
Congruent Visual Speech Enhances Entrainment To Continuous Auditory Speech In Noise-Free Conditions, Michael Crosse, John S. Butler, Edmumd Lalor
Congruent Visual Speech Enhances Entrainment To Continuous Auditory Speech In Noise-Free Conditions, Michael Crosse, John S. Butler, Edmumd Lalor
Articles
Congruent audiovisual speech enhances our ability to comprehend a speaker, even in noise-free conditions. When incongruent auditory and visual information is presented concurrently, it can hinder a listener’s perception and even cause him or her to perceive information that was not presented in either modality. Efforts to investigate the neural basis of these effects have often focused on the special case of discrete audiovisual syllables that are spatially and temporally congruent, with less work done on the case of natural, continuous speech. Recent electrophysiological studies have demonstrated that cortical response measures to continuous auditory speech can be easily obtained using …
On Mikhailov's Reduction Group, Tihomir Valchev
On Mikhailov's Reduction Group, Tihomir Valchev
Articles
We present a generalization of the notion of reduction group which allows one to study in a uniform way certain classes of nonlocal $S$-integrable equations like Ablowitz-Musslimani's nonlocal Schr\"odinger equation. Another aspect of the proposed generalization is the possibility to derive in a systematic way solutions to S-integrable equations with prescribed symmetries.
Multivariate Statistical Methodologies Applied In Biomedical Raman Spectroscopy: Assessing The Validity Of Partial Least Squares Regression Using Simulated Model Datasets., Mark Keating
Articles
Raman spectroscopy is fast becoming a valuable analytical tool in a number of biomedical scenarios, most notably disease diagnostics. Importantly, the technique has also shown increasing promise in the assessment of drug interactions on a cellular and subcellular level, particularly when coupled with multivariate statistical analysis. However, an important consideration, both with Raman spectroscopy and the associated statistical methodologies, is the accuracy of these techniques and more specifically the sensitivities which can be achieved and ultimately the limits of detection of the various methods. The purpose of this study is thus the construction of a model simulated data set with …
Exploring The Unknown: Electrophysiological And Behavioural Measures Of Visuospatial Learning, Brendan Quinlivan, John Butler, Abdur R. Ridwan, Ines Beiser, Laura Williams, Eavan Mcgovern, Sean O'Riordan, Michael Hutchinson, Richard B. Reilly
Exploring The Unknown: Electrophysiological And Behavioural Measures Of Visuospatial Learning, Brendan Quinlivan, John Butler, Abdur R. Ridwan, Ines Beiser, Laura Williams, Eavan Mcgovern, Sean O'Riordan, Michael Hutchinson, Richard B. Reilly
Articles
Visuospatial memory describes our ability to temporarily store and manipulate visual and spatial information, and is employed for a wide variety of complex cognitive tasks. Here, a visuospatial learning task requiring fine motor control is employed to investigate visuospatial learning in a group of typically developing adults. Electrophysiological and behavioural data are collected during a target location task under two experimental conditions: Target Learning and Target Cued. Movement times (MTs) are employed as a behavioural metric of performance, while dynamic P3b amplitudes and power in the alpha band (approximately 10 Hz) are explored as electrophysiological metrics during visuospatial learning. Results …
Vacuum Polarization On The Brane, Cormac Breen, Matthew Hewitt,, Elizabeth Winstanley, Adrian Ottewill
Vacuum Polarization On The Brane, Cormac Breen, Matthew Hewitt,, Elizabeth Winstanley, Adrian Ottewill
Articles
We compute the renormalized expectation value of the square of a massless, conformally coupled, quantum scalar field on the brane of a higher-dimensional black hole. Working in the AADD braneworld scenario, the extra dimensions are flat and we assume that the compactification radius is large compared with the size of the black hole. The four-dimensional on-brane metric corresponds to a slice through a higher-dimensional Schwarzschild-Tangherlini black hole geometry and depends on the number of bulk space-time dimensions. The quantum scalar field is in a thermal state at the Hawking temperature. An exact, closed-form expression is derived for the renormalized expectation …
Will Oscillating Wave Surge Converters Survive Tsunamis?, Laura Cooke, P. Christodoulides, E. Renzi, T. Stefanakis, F. Dias
Will Oscillating Wave Surge Converters Survive Tsunamis?, Laura Cooke, P. Christodoulides, E. Renzi, T. Stefanakis, F. Dias
Articles
With an increasing emphasis on renewable energy resources, wave power technology is becoming one of the realistic solutions. However, the 2011 tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed, creating large destructive waves. The question posed here is whether an oscillating wave surge converter (OWSC) could withstand the force of an incoming tsunami. Several tools are used to provide an answer: an analytical 3D model developed within the framework of linear theory, …
Maximizing The Impact Of Digital Supports In Mathematics Learning Support In Higher Education – An Overview Of The 9th Annual Imlsn Workshop, Cormac Breen, Anthony Cronin
Maximizing The Impact Of Digital Supports In Mathematics Learning Support In Higher Education – An Overview Of The 9th Annual Imlsn Workshop, Cormac Breen, Anthony Cronin
Articles
In this article we give a short description of the 9th Annual Workshop of the Irish Mathematics Learning Support Network (IMLSN). The workshop theme was ‘Maximizing the impact of digital supports in Mathematics Learning Support in Higher Education’. We briefly describe the Irish Mathematics Learning Support Network (IMLSN) and outline the factors that motivated this workshop theme. We will also discuss the presentations, some of the issues that were raised during the workshop and we close with some brief conclusions on this very successful event.
Derivatives Pricing With Accelerated Trinomial Trees, Conall O'Sullivan, Stephen O'Sullivan
Derivatives Pricing With Accelerated Trinomial Trees, Conall O'Sullivan, Stephen O'Sullivan
Articles
Accelerated Trinomial Trees (ATTs) are a derivatives pricing lattice method that circumvent the restrictive time step condition inherent in standard trinomial trees and explicit finite difference methods (FDMs) in which the time step must scale with the square of the spatial step. ATTs consist of L uniform supersteps each of which contains an inner lattice/trinomial tree with N non-uniform subtime steps. Similarly to implicit FDMs, the size of the superstep in ATTs, a function of N, are constrained primarily by accuracy demands. ATTs can price options up to N times faster than standard trinomial trees (explicit FDMs). ATTs can be …
Professional Formation Of Engineers: Enhancing The First Year Student Experience, Eileen Goold
Professional Formation Of Engineers: Enhancing The First Year Student Experience, Eileen Goold
Conference Papers
This paper reports on a study investigating engineering students’ perceptions of engineering practice and whether engineering students’ cognitive engagement benefits from bridging the gap between the technical issues in their education and the practical realities of modern engineering practice.
Algebraic And Numerical Exploration Of Free Energies For Materials With Memory, John Murrough Golden, Giovambattista Amendola, Mauro Fabrizio
Algebraic And Numerical Exploration Of Free Energies For Materials With Memory, John Murrough Golden, Giovambattista Amendola, Mauro Fabrizio
Articles
Abstract. We study the forms of a range of free energy functionals for materials with memory for two types of strain history, namely sinusoidal and ex- ponential behaviours. The work deals with discrete spectrum materials, which are those with relaxation functions given by sums of decaying exponentials.
A Hamiltonian Approach To Wave-Current Interactions In Two-Layer Fluids, Adrian Constantin, Rossen Ivanov
A Hamiltonian Approach To Wave-Current Interactions In Two-Layer Fluids, Adrian Constantin, Rossen Ivanov
Articles
We provide a Hamiltonian formulation for the governing equations describing the two-dimensional nonlinear interaction between coupled surfacewaves, internalwaves, and an underlying current with piecewise constant vorticity, in a two-layered fluid overlying a flat bed. This Hamiltonian structure is a starting point for the derivation of simpler models, which can be obtained systematically by expanding the Hamiltonian in dimensionless parameters. These enable an in-depth study of the coupling between the surface and internal waves, and how both these wave systems interact with the background current.
Investigating The Engagement Of Mature Students With Mathematics Learning Support, Cormac Breen, Michael Carr, Mark Prendergast
Investigating The Engagement Of Mature Students With Mathematics Learning Support, Cormac Breen, Michael Carr, Mark Prendergast
Articles
The Maths Learning Support Centre (MLSC) in the Dublin Institute of Technology (DIT) provides free mathematical support to all DIT students. This support is primarily delivered through a drop-in service, where students can receive one-to-one tuition, without an appointment, in any area of mathematics. In the first semester of the 2013/14 academic year, a significant proportion of students that availed of this drop-in service were mature students enrolled in Engineering programmes. This is of particular interest as mature students constitute a relatively small proportion of the total student body, motivating a deeper study of the reasons for the high levels …
Efficient Computational Strategies For Doubly Intractable Problems With Applications To Bayesian Social Networks, Alberto Caimo, Antonietta Mira
Efficient Computational Strategies For Doubly Intractable Problems With Applications To Bayesian Social Networks, Alberto Caimo, Antonietta Mira
Articles
Powerful ideas recently appeared in the literature are adjusted and combined to design improved samplers for doubly intractable target distributions with a focus on Bayesian exponential random graph models. Different forms of adaptive Metropolis–Hastings proposals (vertical, horizontal and rectangular) are tested and merged with the delayed rejection (DR) strategy with the aim of reducing the variance of the resulting Markov chain Monte Carlo estimators for a given computational time. The DR is modified in order to integrate it within the approximate exchange algorithm (AEA) to avoid the computation of intractable normalising constant that appears in exponential random graph models. This …
Knowledge Sharing In Organisations: A Bayesian Analysis Of The Role Of Reciprocity And Formal Structure, Alberto Caimo, Alessandro Lomi
Knowledge Sharing In Organisations: A Bayesian Analysis Of The Role Of Reciprocity And Formal Structure, Alberto Caimo, Alessandro Lomi
Articles
We examine the conditions under which knowledge embedded in advice relations is likely to reach across intraorganizational boundaries and be shared between distant organizational members. We emphasize boundary-crossing relations because activities of knowledge transfer and sharing across subunit boundaries are systematically related to desirable organizational outcomes. Our main objective is to understand how organizational and social processes interact to sustain the transfer of knowledge carried by advice relations. Using original fieldwork and data that we have collected on members of the top management team in a multiunit industrial group, we show that knowledge embedded in task advice relations is unlikely …
Simultaneous Modelling Of Initial Conditions And Time Heterogeneity In Dynamic Networks: An Application To Foreign Direct Investments, Johan Koskinen, Alberto Caimo, Alessandro Lomi
Simultaneous Modelling Of Initial Conditions And Time Heterogeneity In Dynamic Networks: An Application To Foreign Direct Investments, Johan Koskinen, Alberto Caimo, Alessandro Lomi
Articles
In dynamic networks, the presence of ties are subject both to endogenous network dependencies and spatial dependencies. Current statistical models for change over time are typically defined relative to some initial condition, thus skirting the issue of where the first network came from. Additionally, while these longitudinal network models may explain the dynamics of change in the network over time, they do not explain the change in those dynamics. We propose an extension to the longitudinal exponential random graph model that allows for simultaneous inference of the changes over time and the initial conditions, as well as relaxing assumptions of …
Hamiltonian Approach To Internal Wave-Current Interactions In A Two-Media Fluid With A Rigid Lid, Alan Compelli, Rossen Ivanov
Hamiltonian Approach To Internal Wave-Current Interactions In A Two-Media Fluid With A Rigid Lid, Alan Compelli, Rossen Ivanov
Articles
We examine a two-media 2-dimensional fluid system consisting of a lower medium bounded underneath by a flatbed and an upper medium with a free surface with wind generated surface waves but considered bounded above by a lid by an assumption that surface waves have negligible amplitude. An internal wave driven by gravity which propagates in the positive x-direction acts as a free common interface between the media. The current is such that it is zero at the flatbed but a negative constant, due to an assumption that surface winds blow in the negative x-direction, at the lid. We are concerned …
On The Dynamics Of Internal Waves Interacting With The Equatorial Undercurrent, Alan Compelli, Rossen Ivanov
On The Dynamics Of Internal Waves Interacting With The Equatorial Undercurrent, Alan Compelli, Rossen Ivanov
Articles
The interaction of the nonlinear internal waves with a nonuniform current with a specific form, characteristic for the equatorial undercurrent, is studied. The current has no vorticity in the layer, where the internal wave motion takes place. We show that the nonzero vorticity that might be occuring in other layers of the current does not affect the wave motion. The equations of motion are formulated as a Hamiltonian system.