713 research outputs found

    Universality and Evolution of TMDs

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    In this talk, we summarize how QCD evolution can be exploited to improve the treatment of transverse momentum dependent (TMD) parton distribution and fragmentation functions. The methods allow existing non-perturbative fits to be turned into fully evolved TMDs that are consistent with a complete TMD-factorization formalism over the full range of kT. We argue that evolution is essential to the predictive power of calculations that utilize TMD parton distribution and fragmentation functions, especially TMD observables that are sensitive to transverse spin.Comment: To appear in the proceedings of the Third International Workshop on Transverse Polarization Phenomena in Hard Scattering (Transversity 2011), in Veli Losinj, Croatia, 29 August - 2 September 2011. 5 pages, 1 figur

    Calculation of TMD Evolution for Transverse Single Spin Asymmetry Measurements

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    The Sivers transverse single spin asymmetry (TSSA) is calculated and compared at different scales using the TMD evolution equations applied to previously existing extractions. We apply the Collins-Soper-Sterman (CSS) formalism, using the version recently developed by Collins. Our calculations rely on the universality properties of TMD-functions that follow from the TMD-factorization theorem. Accordingly, the non-perturbative input is fixed by earlier experimental measurements, including both polarized semi-inclusive deep inelastic scattering (SIDIS) and unpolarized Drell-Yan (DY) scattering. It is shown that recent COMPASS measurements are consistent with the suppression prescribed by TMD evolution.Comment: 4 pages, 2 figures. Version published in Physical Review Letter

    The use of the I3E model in macroeconomic analysis for the Irish economy. ESRI Working Paper 679 September 2020.

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    The I3E (Ireland Environment, Energy and Economy) model is a single-country, intertemporal computable general equilibrium (CGE) model focusing on environmental policies in Ireland. However, the depth of its modelling, which incorporates the economic interactions between production sectors and other agents, also facilitates its use in wider macroeconomic policy analysis. In the Economic and Social Research Institute (ESRI), there are several macroeconomic models developed and applied to investigate macroeconomic policy issues. These are HERMES (Harmonised Econometric Research for Modelling Economic Systems), COSMO (COre Structural MOdel), and FIR-GEM (Fiscal Irish General Equilibrium Model). As with all economic models, the four models vary in their underlying mechanisms and methodologies, and each model has its associated advantages and disadvantages. The focus of this paper is to show the consistency of the I3E model when compared with these existing models. To do so, we compare the results of four different scenarios, and we find that the results of these shocks when applied to the I3E model are largely in line with the respective results of the other three models. Furthermore, any differences can be explained by the different modelling techniques and/or assumptions. As such, we consider the I3E model to be a reliable tool to be used for both environmental policy analysis, and wider macroeconomic policy analysis on the whole

    Technical documentation of I3E model, Version 3. ESRI Survey and Statistical Report Series 91 May 2020.

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    This paper provides a technical description of the Ireland Environment, Energy and Economy (I3E) model. The I3E model is an intertemporal computable general equilibrium model with multiple firms, one representative household group, multiple commodities, government, enterprises, and rest of the world accounts. It describes the Irish economy in sectoral detail. This model includes a detailed description of energy inputs and concomitant greenhouse gas emissions and has been developed with the purpose of investigating the economic and environmental impacts of climate policies for Ireland. After each major development of the model, an updated version of this report is published. The current report belongs to the third version of the model

    The Two-loop Anomalous Dimension Matrix for Soft Gluon Exchange

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    The resummation of soft gluon exchange for QCD hard scattering requires a matrix of anomalous dimensions. We compute this matrix directly for arbitrary 2 to n massless processes for the first time at two loops. Using color generator notation, we show that it is proportional to the one-loop matrix. This result reproduces all pole terms in dimensional regularization of the explicit calculations of massless 2 to 2 amplitudes in the literature, and it predicts all poles at next-to-next-to-leading order in any 2 to n process that has been computed at next-to-leading order. The proportionality of the one- and two-loop matrices makes possible the resummation in closed form of the next-to-next-to-leading logarithms and poles in dimensional regularization for the 2 to n processes.Comment: 5 pages, 1 figure, revte

    Real exchange rate, wealth, wages and foreign direct investment in Turkey

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    Ankara : The Department of Management and the Institute of Management Sciences of Bilkent Univ., 1996.Thesis (Master's) -- Bilkent University, 1996.Includes bibliographical references leaves 28-31.In this study, the relationship between real exchange rates, relative wealth, relative wages and foreign direct investment inflows to Turkey is examined. Fixed effects regressions are used on foreign direct investment inflow data from eight countries over the period 1986-1995, The results show that a depreciation of the Turkish lira, an increase in Turkish wages relative to the corresponding source country wages, and a decrease in relative wealth are associated with increases in FDI inflows to Turkey.Böke, C MertM.S

    ChatGPT Exhibits Gender and Racial Biases in Acute Coronary Syndrome Management

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    Recent breakthroughs in large language models (LLMs) have led to their rapid dissemination and widespread use. One early application has been to medicine, where LLMs have been investigated to streamline clinical workflows and facilitate clinical analysis and decision-making. However, a leading barrier to the deployment of Artificial Intelligence (AI) and in particular LLMs has been concern for embedded gender and racial biases. Here, we evaluate whether a leading LLM, ChatGPT 3.5, exhibits gender and racial bias in clinical management of acute coronary syndrome (ACS). We find that specifying patients as female, African American, or Hispanic resulted in a decrease in guideline recommended medical management, diagnosis, and symptom management of ACS. Most notably, the largest disparities were seen in the recommendation of coronary angiography or stress testing for the diagnosis and further intervention of ACS and recommendation of high intensity statins. These disparities correlate with biases that have been observed clinically and have been implicated in the differential gender and racial morbidity and mortality outcomes of ACS and coronary artery disease. Furthermore, we find that the largest disparities are seen during unstable angina, where fewer explicit clinical guidelines exist. Finally, we find that through asking ChatGPT 3.5 to explain its reasoning prior to providing an answer, we are able to improve clinical accuracy and mitigate instances of gender and racial biases. This is among the first studies to demonstrate that the gender and racial biases that LLMs exhibit do in fact affect clinical management. Additionally, we demonstrate that existing strategies that improve LLM performance not only improve LLM performance in clinical management, but can also be used to mitigate gender and racial biases.Comment: 19 pages, 2 tables, 2 figure

    Stability of Scalar Fields in Warped Extra Dimensions

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    This work sets up a general theoretical framework to study stability of models with a warped extra dimension where N scalar fields couple minimally to gravity. Our analysis encompasses Randall-Sundrum models with branes and bulk scalars, and general domain-wall models. We derive the Schrodinger equation governing the spin-0 spectrum of perturbations of such a system. This result is specialized to potentials generated using fake supergravity, and we show that models without branes are free of tachyonic modes. Turning to the existence of zero modes, we prove a criterion which relates the number of normalizable zero modes to the parities of the scalar fields. Constructions with definite parity and only odd scalars are shown to be free of zero modes and are hence perturbatively stable. We give two explicit examples of domain-wall models with a soft wall, one which admits a zero mode and one which does not. The latter is an example of a model that stabilizes a compact extra dimension using only bulk scalars and does not require dynamical branes.Comment: 25 pages, 2 figures; v2: minor changes to text, references added, matches published versio
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