Digital Commons Network^™

Design Of A Multiple Component Geometric Breast Phantom, Karl G. Baum, Kevin Mcnamara, María Helguera

Articles

The quality and realism of simulated images is currently limited by the quality of the digital phantoms used for the simulations. The transition from simple raster based phantoms to more detailed geometric (mesh) based phantoms has the potential to increase the usefulness of the simulated data. A preliminary breast phantom which contains 12 distinct tissue classes along with the tissue properties necessary for the simulation of dynamic positron emission tomography scans was created (activity and attenuation). The phantom contains multiple components which can be separately manipulated, utilizing geometric transformations, to represent populations or a single individual being imaged in multiple …

Further Insight Into Gravitational Recoil, Carlos O. Lousto, Yosef Zlochower

Articles

We test the accuracy of our recently proposed empirical formula to model the recoil velocity imparted to the merger remnant of spinning, unequal-mass black-hole binaries. We study three families of black-hole binary configurations, all with mass ratio q=3/8 (to maximize the unequal-mass contribution to the kick) and spins aligned (or counter aligned) with the orbital angular momentum, two with spin configurations chosen to minimize the spin-induced tangential and radial accelerations of the trajectories respectively, and a third family where the trajectories are significantly altered by spin-orbit coupling. We find good agreement between the measured and predicted recoil velocities for the …

Waveguide Fabrication In Uv-Photocurable Sol–Gel Materials: Influence Of The Photoinitiating System, D.L. Versace, Mohamed Oubaha, R. Copperwhite, C. Croutxé-Barghorn, B.D. Maccraith

Articles

In this paper we identify and explain the different chemical interactions involved between a sol–gel matrix and photoinitiators used in the fabrication of optical waveguides. A well-established sol–gel matrix composed of 3-methacryloxypropyltrimethoxysilane, zirconium n-propoxide and methacrylic acid was developed, and two different photoinitiators (Irgacure® 819 and 1800) were added to the host matrix. Optical microscopy was used to characterise the structure of the waveguides as a function of the photoinitiator nature and concentration, and aging of the hybrid sol–gel material. It is clearly demonstrated that the width of the waveguides is strongly influenced by the sol aging. Furthermore, it is …

Interacting Jets From Binary Protostars, Gareth Murphy, Thibaut Lery, Stephen O'Sullivan, Daniel S. Spicer, Francesca Bacciotti, Alex Rosen

Articles

Aims. We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. Methods. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. Results. We find that the …

A Visual Indication Of Environmental Humidity Using A Colour Changing Hologram Recorded In A Self-Developing Photopolymer, Izabela Naydenova, Raghavendra Jallapuram, Vincent Toal, Suzanne Martin

Articles

A reflection hologram for visual indication of environmental humidity has been studied. The hologram is recorded in a self-developing photopolymer and changes colour when exposed to a change in humidity and is fully reversible. The range of colour change, reversibility and the response time of the hologram have been studied in a controlled humidity environment. Fully reversible holograms with response times from few seconds to tens of minutes have been designed. Extremely sensitive bright visual humidity indicators, capable of dramatic colour change within a few seconds of breathing on them are demonstrated.

Foundations Of Multiple Black Hole Evolutions, Carlos O. Lousto, Yosef Zlochower

Articles

We present techniques for long-term, stable, and accurate evolutions of multiple-black-hole spacetimes using the ‘moving puncture’ approach with fourth- and eighth-order finite difference stencils. We use these techniques to explore configurations of three black holes in a hierarchical system consisting of a third black hole approaching a quasi-circular black-hole binary, and find that, depending on the size of the binary, the resulting encounter may lead to a prompt merger of all three black holes, production of a highly elliptical binary (with the third black hole remaining unbound), or disruption of the binary (leading to three free black holes). We also …

An Fio Calculus For Marine Seismic Imaging: Folds And Cross Caps, Raluca Felea, Allan Greenleaf

Articles

We consider a linearized inverse problem, arising in offshore seismic exploration, for an isotropic wave equation with sound speed assumed to be a small, singular perturbation of a smooth background. Under an assumption of at most fold caustics for the background, we identify the geometry of the canonical relation underlying the linearization, F, which is a Fourier integral operator, and establish a composition calculus sufficient to describe the normal operator F^*F. The resulting artifacts are 1/2 derivative smoother than in the case of a single-source seismic experiment. Refer to PDF file for exact formula.)

Lattices In Finite Real Reflection Groups, Colum Watt, Thomas Brady

Articles

For a finite real reflection group, $W$, with Coxeter element $\gamma$ we give a uniform proof that the closed interval, $[I, \gamma]$ forms a lattice in the partial order on $W$ induced by reflection length. The proof involves the construction of a simplicial complex which can be embedded in the type W simplicial generalised associahedron.

Novel Calixarene-Schiff Bases That Bind Silver(I) Ion, Mary Deasy, Bernadette Creaven, Brian A. Murray, John Mcginley, Paul M. Flood

Articles

Two novel calix[4]arene-Schiff base receptors have been synthesized. One of the new compounds has two pendant aldimines, while the second has been prepared by two-point attachment of a calixarene-dialdehyde onto a calixarene-diamine to form a “calix-tube”. Preliminary binding studies with AgClO₄ show large complexation-induced shifts in ¹H NMR positions.

Technology-Aided Participative Methods In Environmental Assessment: An International Perspective, Ainhoa Gonzalez, Alan Gilmer, Ronan Foley, John Sweeney, John Fry

Articles

Provisions for citizen involvement in the assessment of potential environmental effects of certain plans, programmes and projects are present in current legislation. An international survey revealed that public participation is common practice in European and some other countries worldwide. However, a number of issues are observed to affect public involvement in EIA/SEA processes and expert opinion differs when evaluating the effectiveness of existing participative methods. Results suggest that technology-aided methods can improve traditional participation processes. In particular, GIS has the potential to increase community knowledge and enhance involvement by communicating information more effectively. Variable accessibility to technology and data quality …

A Reader's Companion To Against Prediction: A Reply To Ariela Gross, Yoram Margalioth, And Yoav Sapir On Economic Modeling, Selective Incapacitation, Governmentality, And Race, Bernard E. Harcourt

Articles

From parole prediction instruments and violent sexual predator scores to racial profiling on the highways, instruments to predict future dangerousness, drug-courier profiles, and IRS computer algorithms to detect tax evaders, the rise of actuarial methods in the field of crime and punishment presents a number of challenging issues at the intersection of economic theory, sociology, history, race studies, criminology, social theory, and law. The three review articles of Against Prediction: Profiling, Policing, and Punishing in an Actuarial Age by Ariela Gross, Yoram Margalioth, and Yoav Sapir, raise these challenges in their very best light. Ranging from the heights of poststructuralist …

The Subprime Crisis: Why One Bad Turn Leads To Another At Pepperdine University School Of Law, Richard A. Epstein

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No abstract provided.

Free Speech In The Twenty-First Century: Ten Lessons From The Twentieth Century Lead Article, Geoffrey R. Stone

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No abstract provided.

Denotational Style Correctness Of A Cps-Transform Based Compiler, Arthur Nunes-Harwitt

Articles

RIT department of computer science technical report. Correctness is a crucial property for compilers; programmers rely on it when writing code. Ideally, correctness should be proved. Work on compiler correctness has focused on direct translation strategies. However, in practice, the continuation passing style (CPS) transform (or a variant) is often used in the translation process. Here a simple source language and its CPS-transform based compiler are introduced. A tractable proof for this compiler is presented, including a denotational proof of the correctness of a CPS-transform. The benefits of the proof are discussed.

Towards Flow Cytometry Data Clustering On Graphics Processing Units, Jeremy Espenshade, Doug Roberts, James Cavenaugh

Articles

Like many modern techniques for scientific analysis, flow cytometry produces massive amounts of data that must be analyzed and clustered intelligently to be useful. Current manual binning techniques are cumbersome and limited in both the quality and quantity of analyses produced. To address the quality of results, a new framework applying two different sets of clustering algorithms and inference methods are implemented. The two methods investigated are fuzzy c-means and minimum description length inference and k-medoids with BIC. These approaches lend themselves to large scale parallel processing. To address the computational demands, the Nvidia CUDA framework and Tesla architecture are …

Bounds Onsome Ramsey Numbers Involving Quadrilateral, Xiaodong Xu, Zehui Shao, Stanislaw Radziszowski

Articles

For graphs G_1,G_2,...,G_m the Ramsey number R(G_1,G_2,...,G_m) is defined to be the smallest integer n such that any m-coloring of the edges of the complete graph K_n must include a monochromatic G_i in color i, for some i. In this note we establish several lower and upper bounds for some Ramsey numbers involving quadrilateral C_4, including R(C_4,K_9) < = 32, 19 < = R(C_4,C_4,K_4) < = 22, 31 < = R(C_4,C_4,C_4,K_4) < = 50, 52 < = R(C_4,K_4,K_4) < = 72, 42 < = R(C_4,C_4,K_3,K_4) < = 76, and 87 < = (C_4,C_4,K_4,K_4) < = 179.

Proving Causation: The Holism Of Warrant And The Atomism Of Daubert, Susan Haack

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No abstract provided.

Judicial Transparency In An Age Of Prediction, Adam M. Samaha

Articles

The Empirical Legal Studies (ELS) movement is making strides toward understanding judicial behavior, and ELS models could become the foundation for more accurate prediction of judicial decisions. This essay raises two questions. First, what would an age of predictable judicial behavior look like? Second, would satisfying the informational needs of ELS prediction models also exhaust the demands for 'judicial transparency"? The essay concludes that a state of predictable judicial behavior, if somehow stable, would leave almost no litigation to observe; and that a prediction-oriented information policy would nearly meet the demands of today's transparency advocates. One shortfall involves the intrinsic …

The Rationality Of Preference Construction (And The Irrationality Of Rational Choice), Claire Hill

Articles

Economists typically assume that preferences are fixed - that people know what they like and how much they like it relative to all other things, and that this rank-ordering is stable over time. But this assumption has never been accepted by any other discipline. Economists are increasingly having difficulty arguing that the assumption is true enough to generate useful predictions and explanations. Indeed, law and economics scholars increasingly acknowledge that preferences are constructed, and that the law itself can help construct preferences. Still, fixed preferences are often treated as a normative ideal: Even if people don't have fixed preferences, they …

Fair Use And Copyright Overenforcement, Thomas F. Cotter

Articles

Economic analysis has long suggested that there are two distinct categories of cases in which the fair use defense, which permits the unauthorized reproduction and other use of copyrighted materials, should apply: first, when the transaction cost of negotiating with the copyright owner for permission to use exceeds the private value of the use to the would-be user; and second, when the individual use is thought to generate some positive externality, such that the net social value of the use exceeds the value to the copyright owner of preventing the use, which in turn may exceed the value of the …

Equation Of State For A Van Der Waals Universe During Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev

Articles

In a previous work [E.M. Prodanov, R.I. Ivanov and V.G. Gueorguiev, Reissner-Nordström expansion, Astropart. Phys. 27 (2007) 150], we proposed a classical model for the expansion of the Universe during the radiation-dominated epoch based on the gravitational repulsion of the Reissner-Nordström geometry — naked singularity description of particles that "grow" with the drop of the temperature. In this work we model the Universe during the Reissner-Nordström expansion as a van der Waals gas and determine the equation of state.

Nearly-Hamiltonian Structure For Water Waves With Constant Vorticity, Adrian Constantin, Rossen Ivanov, Emil Prodanov

Articles

We show that the governing equations for two-dimensional gravity water waves with constant non-zero vorticity have a nearly-Hamiltonian structure, which becomes Hamiltonian for steady waves.

Development Of Neuro-Fuzzy Models To Account For Temporal And Spatial Variations In A Lumped Rainfall-Runoff Model, Ahmed Nasr, Michael Bruen

Articles

For many good and practical reasons, lumped rainfall-runoff models are widely used to represent a catchment‟s response to rainfall. However, they have some acknowledged limitation, some of which are addressed here using a neuro-fuzzy model to combine, in an optimal way, a number of lumped-sub-models. For instance, to address temporal variation, one of the sub-models in the combination may perform well under flood conditions and another under drier conditions and the neuro- fuzzy system would combine their outputs for each time-step in a manner depending on the prevailing conditions. Similarly to address spatial variation, one of the sub-models may perform …

Evaluation Of A Naive Model For Square Wave Voltammetry At A Microelectrode, Patrick Enright, John Cassidy, Tony Betts

Articles

A square wave voltammetric waveform ( SWV) was applied to an inlaid microdisk electrode in a solution of K4[Fe(CN)6]. A simple model relying on the assumption of steady state current throughout the scan was used to model the current potential behaviour. However, experimental peak current magnitudes were between 30% and 50% greater than those predicted by the model. The model predicts an increase of peak current and peak width at half height with pulse height Esw and no effect of the parameters frequency, f and step height, ΔEs. Experimental peak current magnitudes and peak current magnitudes predicted by the model …

Luminescent Solar Concentrators: A Review Of Recent Results, Wilfrid G.J.H.M. Van Sark, Keith W.J. Barnham, Lenneke H. Slooff, Amanda J. Chatten, Andreas Buchtemann, Andreas Meyer, Sarah Mccormack, Rolf Koole, Daniel J. Farrell, Rahul Bose, Evert E. Bende, Antonius R. Burgers, Tristram Budel, Jana Quilitz, Manus Kennedy, Toby Meyer, C. De Mello Donega, Andries Meijerink

Articles

Luminescent solar concentrators (LSCs) generally consist of transparent polymer sheets doped with luminescent species. Incident sunlight is absorbed by the luminescent species and emitted with high quantum efficiency, such that emitted light is trapped in the sheet and travels to the edges where it can be collected by solar cells. LSCs offer potentially lower cost per Wp. This paper reviews results mainly obtained within the framework of the Fullspectrum project. Two modeling approaches are presented, i.e., a thermodynamic and a ray-trace one, as well as experimental results, with a focus on LSC stability.

Application Of The Fractal Market Hypothesis For Modelling Macroeconomic Time Series, Jonathan Blackledge

Articles

This paper explores the conceptual background to financial time series analysis and financial signal processing in terms of the Efficient Market Hypothesis. By revisiting the principal conventional approaches to market analysis and the reasoning associated with them, we develop a Fractal Market Hypothesis that is based on the application of non-stationary fractional dynamics using an operator of the type
∂² / ∂x² − σ^q(t) * ∂ ^q(t)/ ∂t^q(t)

where σ⁻¹ is the fractional diffusivity and q is the Fourier dimension which, for the topology considered, (i.e. the one-dimensional case) is related to the Fractal …

Forcing Analogies In Law: Badiou, Set Theory, And Models, William H. Widen

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No abstract provided.

Do Investors In Controlled Firms Value Insider Trading Laws? International Evidence, Laura Nyantung Beny

Articles

This article characterizes insider trading as an agency problem in firms that have a controlling shareholder. Using a standard agency model of corporate value diversion through insider trading by the controlling shareholder, I derive testable hypotheses about the relationship between corporate value and insider trading laws among such firms. The article tests these hypotheses using firm-level cross-sectional data from twenty-seven developed countries. The results show that stringent insider trading laws and enforcement are associated with greater corporate valuation among the sample firms in common law countries, a result that is consistent with the claim that insider trading laws mitigate agency …

Higher Derivatives Of Spectral Functions Associated With One-Dimensional Schrodinger Operators, Daphne Gilbert, B.J. Harris, S.M. Riehl

Articles

We investigate the existence and asymptotic behaviour of higher derivatives of the spectral function in the context of one-dimensional Schr¨odinger operators on the half-line with integrable potentials. In particular, we identify sufficient conditions on the potential for the existence and continuity of the n-th derivative, and outline a systematic procedure for estimating numerical upper bounds for the turning points of such derivatives. Explicit worked examples illustrate the development and application of the theory.

Contextualising Nanotechnology In Chemistry Education, Christine O'Connor, Hugh Hayden

Articles

This paper will give an example of a pedagogical approach taken in integrating nanotechnology into a chemistry degree course. In recent years nanotechnology has widely become part of the course content for undergraduate chemistry and physics degree curriculum. How contextualised the delivery of the subject matter may vary. The role of contextualisation of nanotechnology in the delivery of the content is the main focus of this paper, as to date in Ireland and many other countries nanotechnology has not been integrated into many chemistry degree courses but is slowly becoming the case. An evaluative methodology of the pedagogical approach for …