82,365 research outputs found
On the Equivalence of Three-Particle Scattering Formalisms
No full textIn recent years, different on-shell 3→3 scattering formalisms have been proposed to be applied to both lattice QCD and infinite-volume scattering processes. We prove that the formulation in the infinite volume presented by Hansen and Sharpe in [M. T. Hansen and S. R. Sharpe, Phys. Rev. D 92, 114509 (2015).PRVDAQ1550-799810.1103/PhysRevD.92.114509] and subsequently Briceño et al. in [R. A. Briceño, M. T. Hansen, and S. R. Sharpe, Phys. Rev. D 95, 074510 (2017).PRVDAQ2470-001010.1103/PhysRevD.95.074510] can be recovered from the B-matrix representation, derived on the basis of S-matrix unitarity, presented by Mai et al. in [M. Mai, B. Hu, M. Döring, A. Pilloni, and A. Szczepaniak, Eur. Phys. J. A 53, 177 (2017).EPJAFV1434-600110.1140/epja/i2017-12368-4] and Jackura et al. in [A. Jackura, C. Fernández-Ramírez, V. Mathieu, M. Mikhasenko, J. Nys, A. Pilloni, K. Saldaña, N. Sherrill, and A. P. Szczepaniak (JPAC Collaboration), Eur. Phys. J. C 79, 56 (2019).EPCFFB1434-604410.1140/epjc/s10052-019-6566-1] Therefore, both formalisms in the infinite volume are equivalent and the physical content is identical. Additionally, the Faddeev equations are recovered in the nonrelativistic limit of both representations.In recent years, different on-shell scattering formalisms have been proposed to be applied to both lattice QCD and infinite volume scattering processes. We prove that the formulation in the infinite volume presented by Hansen and Sharpe in Phys.~Rev.~D92, 114509 (2015) and subsequently Brice\~no, Hansen, and Sharpe in Phys.~Rev.~D95, 074510 (2017) can be recovered from the -matrix representation, derived on the basis of -matrix unitarity, presented by Mai {\em et al.} in Eur.~Phys.~J.~A53, 177 (2017) and Jackura {\em et al.} in Eur.~Phys.~J.~C79, 56 (2019). Therefore, both formalisms in the infinite volume are equivalent and the physical content is identical. Additionally, the Faddeev equations are recovered in the non-relativistic limit of both representations
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
How to compare market efficiency? The Sharpe ratio based on the ARMA-GARCH forecast
No full textThis paper derives a new method for comparing the weak-form efficiency of markets. The author derives the formula of the Sharpe ratio from the ARMA-GARCH model and finds that the Sharpe ratio just depends on the coefficients of the AR and MA terms and is not affected by the GARCH process. For empirical purposes, the Sharpe ratio can be formulated with a monotonic increasing function of R-squared if the sample size is large enough. One can utilize the Sharpe ratio to compare weak-form efficiency among different markets. The results of stochastic simulation demonstrate the validity of the proposed method. The author also constructs empirical AR-GARCH models and computes the Sharpe ratio for S&P 500 Index and the SSE Composite Index
Refining gear measurement uncertainty calculations by using the WelchSatterthwaite equation for effective degrees of freedom
No full textWhen carrying out any form of precision measurement, early consideration should be given to the uncertainty of the measurement results. The primary reference document for evaluation is the "ISO Guide to the expression of uncertainty in measurement". When dealing with variable measurement data on a continuous scale, the structure and mathematical methods will remain similar over different instruments, however the specific sources of error and uncertainty will be dependent upon the instrument and nature of the quantity under study. Various mathematical models are used to calculate uncertainty (such as partial derivatives and the MonteCarlo method). In gear measurement BS ISO 18653:2003 addresses traceability, calibration intervals, sources of measurement uncertainty or errorsincluding mechanical alignment and drift (among others). Basic instrument checks include environmental factors and methods to evaluate gear uncertainty. The UK National Gear Metrology Laboratory (NGML) utilises the "spreadsheet model"to evaluate measurement uncertainty. The evaluation of gear dimensions defined in ISO 1328-1:2013 requires specific elements of the gear (profile, lead or helix, and pitch) to be considered independently, so a series of spreadsheets are utilised. Since each of the various sources of uncertainty generally have a small number of repeat checks (if any), applying the Welch-Satterthwaite equation allows effective degrees of freedom (veff) to be calculated for all the sources related to the specific element under study. This will result in a working model which can calculate a coverage factor (k) based on a confidence interval that will compensate for any number of repeat measurements (n) from each source, and therefore result in a more statistically sound outcome
Poecilodryas cinerea
No full textOn a new species of Poecilodryas.
By R. Bowdler Sharpe, F. L. S. etc
Rhipidura elegantula
No full textOn a new Rhipidura from the Island of Lettie.
By R. Bowdler Sharpe, F. L. S. etc
Clytomyias insignis
No full textOn a new genus of Flycatchers from the Arfak Mountains. By R. Bowdler Sharpe, F. L. S. etc.
This new form appeared to me to be one of the most interesting of all th
Supporting practitioners' design for learning: principles of effective resources and interventions
No full textRecommended from our members
An introduction to rethinking learning for a digital age
No full textRethinking Learning for a Digital Age addresses the complex and diverse experiences of learners in a world embedded with digital technologies. The text combines first-hand accounts from learners with extensive research and analysis, including a developmental model for effective e-learning, and a wide range of strategies that digitally-connected learners are using to fit learning into their lives. A companion to Rethinking Pedagogy for a Digital Age (2007), this book focuses on how learners’ experiences of learning are changing and raises important challenges to the educational status quo. [from book abstract
Model based defect characterization in composites
No full textWork is reported on model-based defect characterization in CFRP composites. The work utilizes computational models of the interaction of NDE probing energy fields (ultrasound and thermography), to determine 1) the measured signal dependence on material and defect properties (forward problem), and 2) an assessment of performance-critical defect properties from analysis of measured NDE signals (inverse problem). Work is reported on model implementation for inspection of CFRP laminates containing multi-ply impact-induced delamination, with application in this paper focusing on ultrasound. A companion paper in these proceedings summarizes corresponding activity in thermography. Inversion of ultrasound data is demonstrated showing the quantitative extraction of damage properties.This proceeding may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
This proceeding appeared in Roberts, R., and S. Holland. "Model based defect characterization in composites." In AIP Conference Proceedings, vol. 1806, no. 1, p. 090015. AIP Publishing LLC, 2017, and may be found at
DOI: 10.1063/1.4974659.
Copyright 2017 Author(s).
Posted with permission
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