Spin Polarizabilities of the Nucleon from Polarized Low Energy Compton Scattering

As guideline for forthcoming experiments, we present predictions from Chiral Effective Field Theory for polarized cross sections in low energy Compton scattering for photon energies below 170 MeV, both on the proton and on the neutron. Special interest is put on the role of the nucleon spin polarizabilities which can be examined especially well in polarized Compton scattering. We present a model-independent way to extract their energy dependence and static values from experiment, interpreting our findings also in terms of the low energy effective degrees of freedom inside the nucleon: The polarizabilities are dominated by chiral dynamics from the pion cloud, except for resonant multipoles, where contributions of the Delta(1232) resonance turn out to be crucial. We therefore include it as an explicit degree of freedom. We also identify some experimental settings which are particularly sensitive to the spin polarizabilities.Comment: 30 pages, 19 figure

Initial data for stationary space-times near space-like infinity

We study Cauchy initial data for asymptotically flat, stationary vacuum space-times near space-like infinity. The fall-off behavior of the intrinsic metric and the extrinsic curvature is characterized. We prove that they have an analytic expansion in powers of a radial coordinate. The coefficients of the expansion are analytic functions of the angles. This result allow us to fill a gap in the proof found in the literature of the statement that all asymptotically flat, vacuum stationary space-times admit an analytic compactification at null infinity. Stationary initial data are physical important and highly non-trivial examples of a large class of data with similar regularity properties at space-like infinity, namely, initial data for which the metric and the extrinsic curvature have asymptotic expansion in terms of powers of a radial coordinate. We isolate the property of the stationary data which is responsible for this kind of expansion.Comment: LaTeX 2e, no figures, 12 page

Fast matrix computations for pair-wise and column-wise commute times and Katz scores

We first explore methods for approximating the commute time and Katz score between a pair of nodes. These methods are based on the approach of matrices, moments, and quadrature developed in the numerical linear algebra community. They rely on the Lanczos process and provide upper and lower bounds on an estimate of the pair-wise scores. We also explore methods to approximate the commute times and Katz scores from a node to all other nodes in the graph. Here, our approach for the commute times is based on a variation of the conjugate gradient algorithm, and it provides an estimate of all the diagonals of the inverse of a matrix. Our technique for the Katz scores is based on exploiting an empirical localization property of the Katz matrix. We adopt algorithms used for personalized PageRank computing to these Katz scores and theoretically show that this approach is convergent. We evaluate these methods on 17 real world graphs ranging in size from 1000 to 1,000,000 nodes. Our results show that our pair-wise commute time method and column-wise Katz algorithm both have attractive theoretical properties and empirical performance.Comment: 35 pages, journal version of http://dx.doi.org/10.1007/978-3-642-18009-5_13 which has been submitted for publication. Please see http://www.cs.purdue.edu/homes/dgleich/publications/2011/codes/fast-katz/ for supplemental code

An Alternative Procedure to Quantify Soot in Engine Oil by Ultraviolet-Visible Spectroscopy

"This is an Accepted Manuscript of an article published by Taylor & Francis in Tribology Transactions on 02-11-2019, available online: https://www.tandfonline.com/doi/full/10.1080/10402004.2019.1645255."[EN] Due to new pollutant emissions standards, internal combustion engines need several emission control strategies (and related procedures) such as exhaust gas recirculation, diesel/gasoline particulate filters, and selective catalyst reduction that allow them to comply with complete requirements defined on those standards. These strategies result in faster degradation of engine oil, one of the most relevant consequences of which is an increase in soot contamination level. All of these strategies facilitate soot generation. Consequently, soot is one of the most important contaminants present in engine oil. The main technique to measure the content of soot in oil is thermogravimetric analysis (TGA), but this technique has certain limitations. TGA requires a long and specific procedure and has limitations in measuring small concentrations of soot in oil. Therefore, the design of an alternative technique to quantify soot in oil is relevant. One alternative is Fourier transform infrared (FTIR) spectroscopy, but it also has limitations related to low concentrations of soot in oil. This work presents an alternative technique based on ultraviolet-visible (UV-Vis) spectroscopy that allows quantification of small soot contents in used engine oil samples and avoids potential interference from other typical contaminants or those related to measurement processes, such as sample cuvette material.Antonio Garcia-Barbera was supported through the Programa Nacional de Formacion de Recursos Humanos de Investigacion of Spanish Ministerio de Ciencia e Innovacion (Grant Number BES-2016-078073).Macian Martinez, V.; Tormos, B.; Ruiz-Rosales, S.; García-Barberá, A. (2019). An Alternative Procedure to Quantify Soot in Engine Oil by Ultraviolet-Visible Spectroscopy. Tribology Transactions. 62(6):1063-1071. https://doi.org/10.1080/10402004.2019.1645255S10631071626Squaiella, L. L. F., Martins, C. A., & Lacava, P. T. (2013). Strategies for emission control in diesel engine to meet Euro VI. Fuel, 104, 183-193. doi:10.1016/j.fuel.2012.07.027Piock, W., Hoffmann, G., Berndorfer, A., Salemi, P., & Fusshoeller, B. (2011). Strategies Towards Meeting Future Particulate Matter Emission Requirements in Homogeneous Gasoline Direct Injection Engines. SAE International Journal of Engines, 4(1), 1455-1468. doi:10.4271/2011-01-1212Johnson, B. T. (2008). Diesel Engine Emissions and Their Control. Platinum Metals Review, 52(1), 23-37. doi:10.1595/147106708x248750Johnson, T. V. (2008). Diesel Emission Control in Review. SAE International Journal of Fuels and Lubricants, 1(1), 68-81. doi:10.4271/2008-01-0069Mohan, B., Yang, W., & Chou, S. kiang. (2013). Fuel injection strategies for performance improvement and emissions reduction in compression ignition engines—A review. Renewable and Sustainable Energy Reviews, 28, 664-676. doi:10.1016/j.rser.2013.08.051ALKEMADE, U., & SCHUMANN, B. (2006). Engines and exhaust after treatment systems for future automotive applications. Solid State Ionics, 177(26-32), 2291-2296. doi:10.1016/j.ssi.2006.05.051Bensaid, S., Caroca, C. J., Russo, N., & Fino, D. (2011). Detailed investigation of non-catalytic DPF regeneration. The Canadian Journal of Chemical Engineering, 89(2), 401-407. doi:10.1002/cjce.20408E, J., Xie, L., Zuo, Q., & Zhang, G. (2016). Effect analysis on regeneration speed of continuous regeneration-diesel particulate filter based on NO 2 -assisted regeneration. Atmospheric Pollution Research, 7(1), 9-17. doi:10.1016/j.apr.2015.06.012Tripathi, A., & Vinu, R. (2015). Characterization of Thermal Stability of Synthetic and Semi-Synthetic Engine Oils. Lubricants, 3(1), 54-79. doi:10.3390/lubricants3010054Karacan, Ö., Kök, M. V., & Karaaslan, U. (1999). Journal of Thermal Analysis and Calorimetry, 55(1), 109-114. doi:10.1023/a:1010136222719Heredia-Cancino, J. A., Ramezani, M., & Álvarez-Ramos, M. E. (2018). Effect of degradation on tribological performance of engine lubricants at elevated temperatures. Tribology International, 124, 230-237. doi:10.1016/j.triboint.2018.04.015Wattrus, M. (2013). Fuel Property Effects on Oil Dilution in Diesel Engines. SAE International Journal of Fuels and Lubricants, 6(3), 794-806. doi:10.4271/2013-01-2680Sharma, V., Uy, D., Gangopadhyay, A., O’Neill, A., Paxton, W. A., Sammut, A., … Aswath, P. B. (2016). Structure and chemistry of crankcase and exhaust soot extracted from diesel engines. Carbon, 103, 327-338. doi:10.1016/j.carbon.2016.03.024Pfau, S. A., La Rocca, A., Haffner-Staton, E., Rance, G. A., Fay, M. W., Brough, R. J., & Malizia, S. (2018). Comparative nanostructure analysis of gasoline turbocharged direct injection and diesel soot-in-oil with carbon black. Carbon, 139, 342-352. doi:10.1016/j.carbon.2018.06.050George, S., Balla, S., Gautam, V., & Gautam, M. (2007). Effect of diesel soot on lubricant oil viscosity. Tribology International, 40(5), 809-818. doi:10.1016/j.triboint.2006.08.002Antusch, S., Dienwiebel, M., Nold, E., Albers, P., Spicher, U., & Scherge, M. (2010). On the tribochemical action of engine soot. Wear, 269(1-2), 1-12. doi:10.1016/j.wear.2010.02.028Green, D. A., & Lewis, R. (2008). The effects of soot-contaminated engine oil on wear and friction: A review. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 222(9), 1669-1689. doi:10.1243/09544070jauto468Bredin, A., Larcher, A. V., & Mullins, B. J. (2011). Thermogravimetric analysis of carbon black and engine soot—Towards a more robust oil analysis method. Tribology International, 44(12), 1642-1650. doi:10.1016/j.triboint.2011.06.002VAN DE VOORT, F. R., SEDMAN, J., COCCIARDI, R. A., & PINCHUK, D. (2006). FTIR Condition Monitoring of In-Service Lubricants: Ongoing Developments and Future Perspectives. Tribology Transactions, 49(3), 410-418. doi:10.1080/10402000600781432Van de Voort, F. R., Ghetler, A., García-González, D. L., & Li, Y. D. (2008). Perspectives on Quantitative Mid-FTIR Spectroscopy in Relation to Edible Oil and Lubricant Analysis: Evolution and Integration of Analytical Methodologies. Food Analytical Methods, 1(3), 153-163. doi:10.1007/s12161-008-9031-6Ess, M. N., Ferry, D., Kireeva, E. D., Niessner, R., Ouf, F.-X., & Ivleva, N. P. (2016). In situ Raman microspectroscopic analysis of soot samples with different organic carbon content: Structural changes during heating. Carbon, 105, 572-585. doi:10.1016/j.carbon.2016.04.056Russo, C., Apicella, B., Lighty, J. S., Ciajolo, A., & Tregrossi, A. (2017). Optical properties of organic carbon and soot produced in an inverse diffusion flame. Carbon, 124, 372-379. doi:10.1016/j.carbon.2017.08.07

Change in quality of life of stage IA lung cancer patients after sublobar resection and lobectomy

© Journal of Thoracic Disease. All rights reserved. Background: Few studies have examined the differential impact of sublobar resection (SL) and lobectomy (L) on quality of life (QoL) during the first postoperative year. Methods: We used a prospective cohort of Stage IA lung cancer patients undergoing video-assisted thoracoscopic surgery (VATS) from the Initiative for Early Lung Cancer Research on Treatment. QoL was measured before surgery, and within 4, 6, and 12 months post-surgery using three validated instruments: SF-12 [physical (PCS) and mental health (MCS)], FACT-LCS (lung-cancer-symptoms), and the PHQ-4 (anxiety and depression subscales). Locally weighted smoothing curve (LOWESS) was fitted to identify the best interval knot for the change in the QoL trend post-surgery. After adjusting for demographic and clinical variables, an adjusted piecewise linear mixed effects model was developed to estimate differences in baseline and 12-month scores, and rates of change for each QoL measure. Results: SL resection was performed in 127 (63.2%) and L in 74 (36.8%) patients. LOWESS plots suggested that the shift of QoL (interval knot) was at 2 months post-surgery. Decreases in PCS scores were less severe for SL than L patients 2 months post-surgery (−0.18 vs. −2.30, P=0.02); while subsequent improvements were observed for both groups (SL: +0.29 vs. L: +0.74, P=0.06). SL patients reported significantly better scores a year post-surgery compared to baseline (P=0.003), while L patients did not. Anxiety decreased at similar rates for both SL and L patients within 2 months post-surgery (P=0.18), then stabilized for the remaining months. MCS and depression scores remained stable in both groups throughout. QoL scores were lower for women than for men, but only significantly worse for the lung-cancer-symptoms (P=0.003) and anxiety (P=0.04). Conclusions: SL patients fared better in physical health and lung cancer symptoms than L patients. The first two postoperative months showed the most significant change which suggests targeting postoperative intervention during that time

A limiting velocity for quarkonium propagation in a strongly coupled plasma via AdS/CFT

We study the dispersion relations of mesons in a particular hot strongly coupled supersymmetric gauge theory plasma. We find that at large momentum k the dispersion relations become omega = v_0 k + a + b/k + ..., where the limiting velocity v_0 is the same for mesons with any quantum numbers and depends only on the ratio of the temperature to the quark mass T/m_q. We compute a and b in terms of the meson quantum numbers and T/m_q. The limiting meson velocity v_0 becomes much smaller than the speed of light at temperatures below but close to T_diss, the temperature above which no meson bound states at rest in the plasma are found. From our result for v_0, we find that the temperature above which no meson bound states with velocity v exist is T_diss(v) \simeq (1-v^2)^(1/4) T_diss, up to few percent corrections.We thus confirm by direct calculation of meson dispersion relations a result inferred indirectly in previous work via analysis of the screening length between a static quark and antiquark in a moving plasma. Although we do not do our calculations in QCD, we argue that the qualitative features of the dispersion relation we compute, including in particular the relation between dissociation temperature and meson velocity, may apply to bottomonium and charmonium mesons propagating in the strongly coupled plasma of QCD. We discuss how our results can contribute to understanding quarkonium physics in heavy ion collisions.Comment: 57 pages, 12 figures; references adde

Amicable pairs and aliquot cycles for elliptic curves

An amicable pair for an elliptic curve E/Q is a pair of primes (p,q) of good reduction for E satisfying #E(F_p) = q and #E(F_q) = p. In this paper we study elliptic amicable pairs and analogously defined longer elliptic aliquot cycles. We show that there exist elliptic curves with arbitrarily long aliqout cycles, but that CM elliptic curves (with j not 0) have no aliqout cycles of length greater than two. We give conjectural formulas for the frequency of amicable pairs. For CM curves, the derivation of precise conjectural formulas involves a detailed analysis of the values of the Grossencharacter evaluated at a prime ideal P in End(E) having the property that #E(F_P) is prime. This is especially intricate for the family of curves with j = 0.Comment: 53 page

IEA EBC Annex 57 ‘Evaluation of Embodied Energy and CO_2eq for Building Construction'

The current regulations to reduce energy consumption and greenhouse gas emissions (GHG) from buildings have focused on operational energy consumption. Thus legislation excludes measurement and reduction of the embodied energy and embodied GHG emissions over the building life cycle. Embodied impacts are a significant and growing proportion and it is increasingly recognized that the focus on reducing operational energy consumption needs to be accompanied by a parallel focus on reducing embodied impacts. Over the last six years the Annex 57 has addressed this issue, with researchers from 15 countries working together to develop a detailed understanding of the multiple calculation methods and the interpretation of their results. Based on an analysis of 80 case studies, Annex 57 showed various inconsistencies in current methodological approaches, which inhibit comparisons of results and difficult development of robust reduction strategies. Reinterpreting the studies through an understanding of the methodological differences enabled the cases to be used to demonstrate a number of important strategies for the reduction of embodied impacts. Annex 57 has also produced clear recommendations for uniform definitions and templates which improve the description of system boundaries, completeness of inventory and quality of data, and consequently the transparency of embodied impact assessments