Uplift Quadratic Program in Irish Electricity Price Setting

Bord Gis required a deeper insight into the dynamics of Uplift prices. The aim of the group was to apply a variety of analytical tools to the problem in order to satisfy Bord Gis requirements. The group conducted a KKT Optimality Analysis of the quadratic program used to determine the Uplift prices, performed statistical analysis to identify the binding constraints and their sensitives to the Uplift prices, simulated a synthetic stochastic process that is consistent with the Uplift pricing series and investigated alternative objective functions for the quadratic program

Assessing plantar sensation in the foot using the FOot Roughness Discrimination Test (FoRDT™): a reliability and validity study in stroke

BACKGROUND: The foot sole represents a sensory dynamometric map and is essential for balance and gait control. Sensory impairments are common, yet often difficult to quantify in neurological conditions, particularly stroke. A functionally oriented and quantifiable assessment, the Foot Roughness Discrimination Test (FoRDT™), was developed to address these shortcomings. OBJECTIVE: To evaluate inter- and intra-rater reliability, convergent and discriminant validity of the Foot Roughness Discrimination Test (FoRDT™). DESIGN: Test-retest design. SETTING: Hospital Outpatient. PARTICIPANTS: Thirty-two people with stroke (mean age 70) at least 3 months after stroke, and 32 healthy, age-matched controls (mean age 70). MAIN OUTCOME MEASURES: Roughness discrimination thresholds were quantified utilising acrylic foot plates, laser-cut to produce graded spatial gratings. Stroke participants were tested on three occasions, and by two different raters. Inter- and intra-rater reliability and agreement were evaluated with Intraclass Correlation Coefficients and Bland-Altman plots. Convergent validity was evaluated through Spearman rank correlation coefficients (rho) between the FoRDT™ and the Erasmus modified Nottingham Sensory Assessment (EmNSA). RESULTS: Intra- and inter rater reliability and agreement were excellent (ICC =.86 (95% CI .72-.92) and .90 (95% CI .76 -.96)). Discriminant validity was demonstrated through significant differences in FoRDT™ between stroke and control participants (p.05). CONCLUSIONS: This simple and functionally oriented test of plantar sensation is reliable, valid and clinically feasible for use in an ambulatory, chronic stroke and elderly population. It offers clinicians and researchers a sensitive and robust sensory measure and may further support the evaluation of rehabilitation targeting foot sensation. This article is protected by copyright. All rights reserved

Magnetic domain wall propagation in a submicron spin-valve stripe: influence of the pinned layer

The propagation of a domain wall in a submicron ferromagnetic spin-valve stripe is investigated using giant magnetoresistance. A notch in the stripe efficiently traps an injected wall stopping the domain propagation. The authors show that the magnetic field at which the wall is depinned displays a stochastic nature. Moreover, the depinning statistics are significantly different for head to head and tail-to-tail domain walls. This is attributed to the dipolar field generated in the vicinity of the notch by the pinned layer of the spin-valve

Twisted K-theory and finite-dimensional approximation

We provide a finite-dimensional model of the twisted K-group twisted by any degree three integral cohomology class of a CW complex. One key to the model is Furuta's generalized vector bundle, and the other is a finite-dimensional approximation of Fredholm operators.Comment: 26 pages, LaTeX 2e, Xypic; main theorem improve

Pairwise Well-Formed Modes and Transformations

One of the most significant attitudinal shifts in the history of music occurred in the Renaissance, when an emerging triadic consciousness moved musicians towards a new scalar formation that placed major thirds on a par with perfect fifths. In this paper we revisit the confrontation between the two idealized scalar and modal conceptions, that of the ancient and medieval world and that of the early modern world, associated especially with Zarlino. We do this at an abstract level, in the language of algebraic combinatorics on words. In scale theory the juxtaposition is between well-formed and pairwise well-formed scales and modes, expressed in terms of Christoffel words or standard words and their conjugates, and the special Sturmian morphisms that generate them. Pairwise well-formed scales are encoded by words over a three-letter alphabet, and in our generalization we introduce special positive automorphisms of $F3$, the free group over three letters.Comment: 12 pages, 3 figures, paper presented at the MCM2017 at UNAM in Mexico City on June 27, 2017, keywords: pairwise well-formed scales and modes, well-formed scales and modes, well-formed words, Christoffel words, standard words, central words, algebraic combinatorics on words, special Sturmian morphism

Thermal Effects on the Magnetic Field Dependence of Spin Transfer Induced Magnetization Reversal

We have developed a self-aligned, high-yield process to fabricate CPP (current perpendicular to the plane) magnetic sensors of sub 100 nm dimensions. A pinned synthetic antiferromagnet (SAF) is used as the reference layer which minimizes dipole coupling to the free layer and field induced rotation of the reference layer. We find that the critical currents for spin transfer induced magnetization reversal of the free layer vary dramatically with relatively small changes the in-plane magnetic field, in contrast to theoretical predictions based on stability analysis of the Gilbert equations of magnetization dynamics including Slonczewski-type spin-torque terms. The discrepancy is believed due to thermal fluctuations over the time scale of the measurements. Once thermal fluctuations are taken into account, we find good quantitative agreement between our experimental results and numerical simulations.Comment: 14 pages, 4 figures, Submitted to Appl. Phys. Lett., Comparison of some of these results with a model described by N. Smith in cond-mat/040648

Suppression of spin-torque in current perpendicular to the plane spin-valves by addition of Dy cap layers

We demonstrate that the addition of Dy capping layers in current perpendicular to the plane giant magneto-resistive spin-valves can increase the critical current density beyond which spin-torque induced instabilities are observed by about a factor of three. Current densities as high as 5e7 A/cm2 are measured provided that the electron current flows from the free to the reference layer. While Dy capped samples exhibit nonmagnetic 1/f noise, it is sufficiently small to be unimportant for read head operation at practical data rates.Comment: 13 pages (manuscript form), with 5 figures. Submitted for publicatio

L^2 torsion without the determinant class condition and extended L^2 cohomology

We associate determinant lines to objects of the extended abelian category built out of a von Neumann category with a trace. Using this we suggest constructions of the combinatorial and the analytic L^2 torsions which, unlike the work of the previous authors, requires no additional assumptions; in particular we do not impose the determinant class condition. The resulting torsions are elements of the determinant line of the extended L^2 cohomology. Under the determinant class assumption the L^2 torsions of this paper specialize to the invariants studied in our previous work. Applying a recent theorem of D. Burghelea, L. Friedlander and T. Kappeler we obtain a Cheeger - Muller type theorem stating the equality between the combinatorial and the analytic L^2 torsions.Comment: 39 page

Measuring the muon's anomalous magnetic moment to 0.14 ppm

The anomalous magnetic moment (g-2) of the muon was measured with a precision of 0.54 ppm in Experiment 821 at Brookhaven National Laboratory. A difference of 3.2 standard deviations between this experimental value and the prediction of the Standard Model has persisted since 2004; in spite of considerable experimental and theoretical effort, there is no consistent explanation for this difference. This comparison hints at physics beyond the Standard Model, but it also imposes strong constraints on those possibilities, which include supersymmetry and extra dimensions. The collaboration is preparing to relocate the experiment to Fermilab to continue towards a proposed precision of 0.14 ppm. This will require 20 times more recorded decays than in the previous measurement, with corresponding improvements in the systematic uncertainties. We describe the theoretical developments and the experimental upgrades that provide a compelling motivation for the new measurement.Comment: 5 pages, 1 figure, presented at International Nuclear Physics Conference 2010 (INPC 2010

The spectral shift function and spectral flow

This paper extends Krein's spectral shift function theory to the setting of semifinite spectral triples. We define the spectral shift function under these hypotheses via Birman-Solomyak spectral averaging formula and show that it computes spectral flow.Comment: 47 page