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Full-Text Articles in Physical Sciences and Mathematics

Newly Identified Vitamin K-Producing Bacteria Isolated From The Neonatal Faecal Flora, Gordon Cooke, John Behan, Mary Costello Sep 2006

Newly Identified Vitamin K-Producing Bacteria Isolated From The Neonatal Faecal Flora, Gordon Cooke, John Behan, Mary Costello

Articles

Fat-soluble vitamin K is an essential component of the blood clotting process. Menaquinones are the naturally occurring form of vitamin K identified in bacteria. Lipid extracts were made from three bacteria originally isolated from the human neonatal gut and identified as Enterobacter agglomerans, Serratia marcescens and Enterococcus faecium. Following preparative thin layer chromatography (TLC), the lipid extracts were subjected to liquid chromatography-mass spectrometry (LC-MS) analysis. Peak analysis of the LC-MS data showed that the three bacteria produce various forms of menaquinone.

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Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor Aug 2006

Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor

Articles

The following paper discusses the implications of government policy for widening access and participation in third level institutes. The increase in ‘non-traditional’ students has been widely recognised on an international scale; however, some issues of inequality still exist. The ‘struggles’ associated with widening participation and the creation of a ‘new’ student type are discussed, with particular reference to chemistry education. A change is needed with regard to the pedagogical approach taken by staff in order to cater for a diverse student body comprising a broad range of learner types, and this must be supported both at departmental and institutional levels. …

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The Synthesis Of Zinc Oxide By Direct And Indirect Methods, Grainne Duffy Jul 2006

The Synthesis Of Zinc Oxide By Direct And Indirect Methods, Grainne Duffy

Masters

The synthesis of zinc oxide through three routes was investigated; carboxylic acid chelation, polymer assisted synthesis in an alcoholic medium and slow thermolysis of precursor. In the case of carboxylic acid chelation, it was determined that the rate at which the precursor is formed has a significant effect on the quality of zinc oxide particles produced. Investigation of the effect of concentration, pH and species of chelating agent used on the purity and structure of product was undertaken. Examination of the composition and morphology of materials produced revealed the presence of single-crystalline spheres, the packing density and aggregation morphology of …

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The Nonlinear Amplification Of Magnetic Fields By Cosmic Rays At Supernova Remnant Shocks, Brian Reville, Peter Duffy, Stephen O'Sullivan Jan 2006

The Nonlinear Amplification Of Magnetic Fields By Cosmic Rays At Supernova Remnant Shocks, Brian Reville, Peter Duffy, Stephen O'Sullivan

Conference papers

A central problem in the theory of cosmic ray acceleration at supernova shock fronts is the generation of turbulent magnetic fields needed to scatter particles across a shock front. In this paper we build on previous studies [1], [2] into the effect of streaming cosmic rays produced by the outer shocks of supernova remnants on the stochastic component of the magnetic field. A three dimensional, MHD code has been constructed which demonstrates the nonlinear growth of the turbulent field.

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Replay At Optical Communications Wavelengths Of Holographic Gratings Recorded In The Visible, Vincent Toal, Maurice Whelan, Alberto Volcan, Izabela Naydenova, Suzanne Martin Jan 2006

Replay At Optical Communications Wavelengths Of Holographic Gratings Recorded In The Visible, Vincent Toal, Maurice Whelan, Alberto Volcan, Izabela Naydenova, Suzanne Martin

Conference Papers

In this paper we report on holographic diffraction gratings recorded at visible light wavelength, which can be probed at telecommunication wavelengths. The recording material is an easily prepared, self-processing photopolymer, all of whose components are water soluble. Transmission gratings of various types, namely unslanted, slanted, totally internally reflecting and Bragg gratings were all fabricated. Diffraction efficiencies at telecommunications wavelengths compare favourably with those obtained in visible light.

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Comparison Of Three Electronic Speckle Pattern Shearing Interferometers Using Photopolymer Holographic Optical Elements., Emilia Mihaylova, Izabela Naydenova, Vincent Toal, Suzanne Martin Jan 2006

Comparison Of Three Electronic Speckle Pattern Shearing Interferometers Using Photopolymer Holographic Optical Elements., Emilia Mihaylova, Izabela Naydenova, Vincent Toal, Suzanne Martin

Conference Papers

Three electronic speckle pattern shearing interferometers (ESPSI) using photopolymer holographic gratings to produce the sheared image are presented. In the first ESPSI system two holographic gratings are used. The gratings are placed between the object and an imaging lens in front of the CCD camera. In the second ESPSI system one grating is used in combination with a sheet of ground glass. The sheared images on the ground glass are further imaged onto a CCD camera. In the third ESPSI system only one grating is used - it is placed in front of the object. The image and the sheared …

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Characterization Of An Acrylamide Based Photopolymer For Fabrication Of Liquid Crystal Devices, Pavani Kotakonda, Izabela Naydenova, Suzanne Martin, Vincent Toal Jan 2006

Characterization Of An Acrylamide Based Photopolymer For Fabrication Of Liquid Crystal Devices, Pavani Kotakonda, Izabela Naydenova, Suzanne Martin, Vincent Toal

Conference Papers

Photopolymers are increasingly interesting as new materials for the fabrication of electro optical liquid crystal devices. Photoinduced surface relief gratings in dry, self developing acrylamide based photopolymers can be used to align liquid crystals (LCs) as an alternative to the rubbing technique. These optically recorded surface relief patterns can be used to fabricate electro-optical switchable LC Bragg gratings. An investigation of the dependence of photoinduced surface relief gratings on recording intensity and thickness of the photopolymer layer is reported. The surface relief gratings were filled with E7 LCs and a switchable LC diffraction grating was fabricated.

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A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond Jan 2006

A Chloride Selective Calix[4]Arene Optical Sensor Combining Urea Functionality With Pyrene Excimer Transduction, Benjamin Schazmann, Dermot Diamond

Articles

A neutral 2-site chloride selective compound has been developed (3), based on a 1,3- alternate tetrasubstituted calix[4]arene providing a preorganised supramolecular scaffold. The resultant supramolecular cavity is amongst the first to combine urea functional groups bridged with single methylene spacers to pyrene moieties. It combines a naturally and synthetically proven H-bonding system with the elegant ratiometric fluorescent signalling properties of an intramolecular pyrene excimer system, triggered by conformational changes upon anion coordination. The excimer emission of 3 is quenched, with a simultaneous rise in the monomer emission solely by the chloride anion amongst a wide variety of anions tested. 3 …

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Classifying E-Algebras Over Dedekind Domains, Brendan Goldsmith, R. Gobel Jan 2006

Classifying E-Algebras Over Dedekind Domains, Brendan Goldsmith, R. Gobel

Articles

An R-algebra A is said to be a generalized E-algebra if A is isomorphic to the algebra EndR(A). Generalized E-algebras have been extensively investigated. In this work they are classified ‘modulo cotorsion-free modules’ when the underlying ring R is a Dedekind domain.

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Poisson Structure And Action-Angle Variables For The Camassa-Holm Equation, Adrian Constantin, Rossen Ivanov Jan 2006

Poisson Structure And Action-Angle Variables For The Camassa-Holm Equation, Adrian Constantin, Rossen Ivanov

Articles

The Poisson brackets for the scattering data of the Camassa-Holm equation are computed. Consequently, the action-angle variables are expressed in terms of the scattering data.

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Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond Jan 2006

Development Of A Calix[4]Arene Sensor For Soft Metals Based On Nitrile Functionality, Benjamin Schazmann, Dermot Diamond

Articles

The current work is amongst the first to examine the potential usefulness of the nitrile functional group in potentiometric analytical sensors for soft metals. Nitrile functionality has hereby been incorporated into a calix[4]arene skeleton to give a series of new cation selective hosts. The analytical sensing behaviour of these hosts was examined by Ion Selective Electrode (ISE) based potentiometry. In all cases a preference for soft metals was observed, explained primarily in terms of soft–soft compatibility between calix[4]arene nitrile hosts and metal guests in combination with a classical ‘lock and key’ best fit mechanism. Hosts 2, 3 and 4 showed …

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An Explicit Scheme For Multifluid Magnetohydrodynamics, Stephen O'Sullivan, Turlough Downes Jan 2006

An Explicit Scheme For Multifluid Magnetohydrodynamics, Stephen O'Sullivan, Turlough Downes

Articles

When modelling astrophysical fluid flows, it is often appropriate to discard the canonical magnetohydrodynamic approximation, thereby freeing the magnetic field to diffuse with respect to the bulk velocity field. As a consequence, however, the induction equation can become problematic to solve via standard explicit techniques. In particular, the Hall diffusion term admits fast-moving whistler waves which can impose a vanishing time-step limit.Within an explicit differencing framework, a multifluid scheme for weakly ionized plasmas is presented which relies upon a new approach to integrating the induction equation efficiently. The first component of this approach is a relatively unknown method of accelerating …

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Inverse Scattering Transform For The Camassa-Holm Equation, Adrian Constantin, Vladimir Gerdjikov, Rossen Ivanov Jan 2006

Inverse Scattering Transform For The Camassa-Holm Equation, Adrian Constantin, Vladimir Gerdjikov, Rossen Ivanov

Articles

An Inverse Scattering Method is developed for the Camassa-Holm equation. As an illustration of our approach the solutions corresponding to the reflectionless potentials are constructed in terms of the scattering data. The main difference with respect to the standard Inverse Scattering Transform lies in the fact that we have a weighted spectral problem. We therefore have to develop different asymptotic expansions.

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The Sonic Representation Of Mathematical Data, Charlie Cullen Jan 2006

The Sonic Representation Of Mathematical Data, Charlie Cullen

Doctoral

Conveying data and information using non-speech audio is an ever growing field of research. Existing work has been performed investigating sonfication and its applications, and this research seeks to build upon these ideas while also suggesting new areas of potential. In this research, initial work focused on the sonification of DNA and RNA nucleotide base sequences for analysis. A case study was undertaken into the potential of rhythmic parsing of such data sequences, with test results indicating that a more effective method of representing data in a sonification was required. Sonification of complex data such as DNA and RNA was …

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Samats : Semi-Automated Modelling And Texturing System, Joe Hegarty Jan 2006

Samats : Semi-Automated Modelling And Texturing System, Joe Hegarty

Masters

The creation of detailed 3D (three-dimensional) building models has become an area of considerable research over the last couple of decades. The accurate modelling of buildings offers LBS (Location Based Services) applications in planning, cultural heritage, tourism and e-commerce among others. The approach taken by the majority of contemporary modelling systems that use terrestrial imagery taken from arbitrary locations requires the user to carry out manual correspondences across the image set. These correspondences are used for two purposes. Firstly, the correspondences are used to determine the exterior orientation parameters (position and orientation) of the cameras used to capture each image. …

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Discourse On The Interface Of Matheatics And Physics: A Panel Discussion Sponsored By Dit And The Ria., Brendan Goldsmith Jan 2006

Discourse On The Interface Of Matheatics And Physics: A Panel Discussion Sponsored By Dit And The Ria., Brendan Goldsmith

Articles

No abstract available

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The Asymptotics Of Neutral Curve Crossing In Taylor–Dean Flow, C. P. Hills, A. P. Bassom Jan 2006

The Asymptotics Of Neutral Curve Crossing In Taylor–Dean Flow, C. P. Hills, A. P. Bassom

Articles

The fluid flow between a pair of coaxial circular cylinders generated by the uniform rotation of the inner cylinder and an azimuthal pressure gradient is susceptible to both Taylor and Dean type instabilities. The flow can be characterised by two parameters: a measure of the relative magnitude of the rotation and pressure effects and a non-dimensional Taylor number. This work considers the small gap, large wavenumber limit for linear perturbations when the onset of the Taylor and Dean instabilities is concurrent. A consistent, matched asymptotic solution is found across the whole annular domain and identifies five regions of interest: two …

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Hamiltonian Formulation And Integrability Of A Complex Symmetric Nonlinear System, Rossen Ivanov Jan 2006

Hamiltonian Formulation And Integrability Of A Complex Symmetric Nonlinear System, Rossen Ivanov

Articles

The integrability of a complex generalisation of the ’elegant’ system, proposed by D. Fairlie and its relation to the Nahm equation and the Manakov top is discussed.

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Chirality Studies On Metallo-Cyclodextrins For The Separation Of L/D-Dopa, Ciaran Potter, Noel Russell, Mary Mcnamara Jan 2006

Chirality Studies On Metallo-Cyclodextrins For The Separation Of L/D-Dopa, Ciaran Potter, Noel Russell, Mary Mcnamara

Articles

The derivatives 6-Deoxy-6-[1-(2-amino)ethylamino]-b-Cyclodextrin (CDEn), 6-Deoxy-6-[1-(3-amino)propylamino]- b-Cyclodextrin (CDPn) and 6-Deoxy-6-[1-(4-amino)butylamino]-b-Cyclodextrin (CDBn) were assessed with a view to demonstrating that increasing the chain length of the diaminoalkane moiety can affect the chiral selectivity of the metallo-complexes of these materials. It was shown that IR and Raman spectroscopies can be used to characterise these compounds. The results obtained from the electronic absorption spectra suggested the formation of CuCDAm binary complexes and that the derivatives CDEn and CDPn act as bidentate ligands while CDBn acts as a monodentate ligand due to its longer alkane chain. This study also showed that in the ternary complexes …

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Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor Jan 2006

Implications Of Mass Education On Chemistry Higher Education, Christine O'Connor

Conference Papers

The following paper discusses the implications of government policy on widening of participation at third level institutes. The increase in ‘non-traditional’ students has been widely recognised on an international scale; however some inequality issues still exist. The ‘struggles’ associated with widening of participation and creating a ‘new’ student type is discussed in particular reference to chemistry education. A change in mindset of staff on their pedagogical approach to cater for a diverse student body with a broad range of learner types is required. This must be supported from a departmental and institutional level. A look at the literature to investigate …

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Generalised E-Algebras Over Valuation Domains, Brendan Goldsmith, P. Zanardo Jan 2006

Generalised E-Algebras Over Valuation Domains, Brendan Goldsmith, P. Zanardo

Articles

Let R be a valuation domain. We investigate the notions of E(R)- algebra and generalized E(R)-algebra and show that for wide classes of maximal valuation domains R, all generalized E(R)-algebras have rank one. As a by-product we prove if R is a maximal valuation domain of finite Krull dimension, then the two notions coincide. We give some examples of E(R)-algebras of finite rank that are decomposable, but show that over Nagata domains of small degree, the E(R)-algebras are, with one exception, the indecomposable finite rank algebras.

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Extended Camassa-Holm Hierarchy And Conserved Quantities, Rossen Ivanov Jan 2006

Extended Camassa-Holm Hierarchy And Conserved Quantities, Rossen Ivanov

Articles

An extension of the Camassa-Holm hierarchy is constructed in this letter. The conserved quantities of the hierarchy are studied and a recurrent formula for the integrals of motion is derived.

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Measured Stark Widths And Shifts Of The Neutral Argon Spectral Lines In 4s–4p And 4s–4p′ Transitions, Vladimir Milosavljevic, Albert R. Ellingboe, Stevan Djenize Jan 2006

Measured Stark Widths And Shifts Of The Neutral Argon Spectral Lines In 4s–4p And 4s–4p′ Transitions, Vladimir Milosavljevic, Albert R. Ellingboe, Stevan Djenize

Articles

We investigate the Stark widths (W) and the shift (d), of the seven neutral argon (Ar I) spectral lines from the 4s–4p and 4s–4p′ transitions. The line shapes are measured in a linear, low-pressure, optically thin pulsed arc discharge at about 16 000 K electron temperature (T) and about 7.0 × 1022 m− 3 electron density (N). The new data separates the electron width (We) and ion width Wi from the total Stark width (Wt), as well the separation of electron total Stark …

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Potential Of Vibrational Spectroscopy In The Diagnosis Of Human Tumours., Eoghan O'Faolain Jan 2006

Potential Of Vibrational Spectroscopy In The Diagnosis Of Human Tumours., Eoghan O'Faolain

Doctoral

Just fewer than 20,000 people are annually diagnosed with some form of cancer in Ireland and one in three people are likely to contract some form of cancer by age 74. With the number of cases increasing at an annual rate of 2%, the early detection and treatment of cancer is becoming increasingly important. Both IR and Raman spectroscopy offer the potential for real time, quantitative detection of cancer and even precancer. This study investigates the potential of Raman and Fourier transform infrared, both benchtop and synchrotron spectroscopies for the detection of cervical cancer. The tissue was classified and its …

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Solubilisation, Purification And Processing Of Single Walled Carbon Nanotubes Using Organic Molecules, Theresa Hedderman Jan 2006

Solubilisation, Purification And Processing Of Single Walled Carbon Nanotubes Using Organic Molecules, Theresa Hedderman

Doctoral

The aims of this research are seven fold; • To enhance the solubility of SWNTs in organic solvents. • To purify an untreated sample of SWNTs that contains many side products. • To gain a greater understanding of the interaction between the polycyclic aromatic hydrocarbons and SWNTs. • To debundle and disperse SWNTs. • To select SWNTs of a specific structure based on the structures of the polycyclic aromatic hydrocarbons used. • To observe and compare the interaction of polycyclic aromatic hydrocarbons with SWNTs produced by different methods. • To elucidate factors which contribute to different degrees of interaction between …

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Point Of Care Healthcare Quality Control For Patients Using Mobile Devices, Owen Lynch Jan 2006

Point Of Care Healthcare Quality Control For Patients Using Mobile Devices, Owen Lynch

Masters

The advances made in the domain of mobile telecommunications over the last decade offer great potential for developments in many areas. One such area that can benefit from mobile communications is telemedicine, which is the provision of medical assistance, in one form or another, to patients who are geographically separated from the healthcare provider. When a person is ill, individual attention from medical professionals is of the utmost importance until they have returned to full health. However, people who suffer with long term and chronic illnesses may need life long care and often must manage their condition at home. Many …

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$H$-Vectors Of Generalized Associahedra And Noncrossing Partitions, Colum Watt, Thomas Brady, Christos A. Athanasiadis, Jon Mccammond Jan 2006

$H$-Vectors Of Generalized Associahedra And Noncrossing Partitions, Colum Watt, Thomas Brady, Christos A. Athanasiadis, Jon Mccammond

Articles

A uniform proof is given that the entries of the $h$-vector of the cluster complex $\Delta (\Phi)$, associated by S. Fomin and A. Zelevinsky to a finite root system $\Phi$, count elements of the lattice $\mathbf{L}$ of noncrossing partitions of corresponding type by rank. Similar interpretations for the $h$-vector of the positive part of $\Delta (\Phi)$ are provided. The proof utilizes the appearance of the complex $\Delta (\Phi)$ in the context of the lattice $\mathbf{L}$ in recent work of two of the authors, as well as an explicit shelling of $\Delta (\Phi)$.

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Feature Based And Feature Free Textual Cbr: A Comparison In Spam Filtering, Sarah Jane Delany, Derek Bridge Jan 2006

Feature Based And Feature Free Textual Cbr: A Comparison In Spam Filtering, Sarah Jane Delany, Derek Bridge

Conference papers

Spam filtering is a text classification task to which Case-Based Reasoning (CBR) has been successfully applied. We describe the ECUE system, which classifies emails using a feature-based form of textual CBR. Then, we describe an alternative way to compute the distances between cases in a feature-free fashion, using a distance measure based on text compression. This distance measure has the advantages of having no set-up costs and being resilient to concept drift. We report an empirical comparison, which shows the feature-free approach to be more accurate than the feature-based system. These results are fairly robust over different compression algorithms in …

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Proximity In Context: An Empirically Grounded Computational Model Of Proximity For Processing Topological Spatial Expression., John D. Kelleher, Geert-Jan Kruijff, Fintan Costello Jan 2006

Proximity In Context: An Empirically Grounded Computational Model Of Proximity For Processing Topological Spatial Expression., John D. Kelleher, Geert-Jan Kruijff, Fintan Costello

Conference papers

The paper presents a new model for context-dependent interpretation of linguistic expressions about spatial proximity between objects in a natural scene. The paper discusses novel psycholinguistic experimental data that tests and verifies the model. The model has been implemented, and enables a conversational robot to identify objects in a scene through topological spatial relations (e.g. ''X near Y''). The model can help motivate the choice between topological and projective prepositions.

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A Computational Model Of The Referential Semantics Of Projective Prepositions, John D. Kelleher, Josef Van Genabith Jan 2006

A Computational Model Of The Referential Semantics Of Projective Prepositions, John D. Kelleher, Josef Van Genabith

Conference papers

In this paper we present a framework for interpreting locative expressions containing the prepositions in front of and behind. These prepositions have different semantics in the viewer-centred and intrinsic frames of reference (Vandeloise, 1991). We define a model of their semantics in each frame of reference. The basis of these models is a novel parameterized continuum function that creates a 3-D spatial template. In the intrinsic frame of reference the origin used by the continuum function is assumed to be known a priori and object occlusion does not impact on the applicability rating of a point in the spatial template. …

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