19,535 research outputs found

    On The Validity of the Streaming Model for the Redshift-Space Correlation Function in the Linear Regime

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    The relation between the galaxy correlation function in real and redshift-space is derived in the linear regime by an appropriate averaging of the joint probability distribution of density and velocity. The derivation recovers the familiar linear theory result on large scales but has the advantage of clearly revealing the dependence of the redshift distortions on the underlying peculiar velocity field; streaming motions give rise to distortions of O(Ω0.6/b){\cal O}(\Omega^{0.6}/b) while variations in the anisotropic velocity dispersion yield terms of order O(Ω1.2/b2){\cal O}(\Omega^{1.2}/b^2). This probabilistic derivation of the redshift-space correlation function is similar in spirit to the derivation of the commonly used ``streaming'' model, in which the distortions are given by a convolution of the real-space correlation function with a velocity distribution function. The streaming model is often used to model the redshift-space correlation function on small, highly non-linear, scales. There have been claims in the literature, however, that the streaming model is not valid in the linear regime. Our analysis confirms this claim, but we show that the streaming model can be made consistent with linear theory {\it provided} that the model for the streaming has the functional form predicted by linear theory and that velocity distribution is chosen to be a Gaussian with the correct linear theory dispersion.Comment: 14 pages, no figures, uuencoded compressed postscrip

    Sentiment Analysis on New York Times Articles Data

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    Sentiment Analysis on New York Times Coverage Data Departmental Affiliation: Data Science/ Political Science College of Arts and Sciences The extant political science literature examines media coverage of immigration and assesses the effect of that coverage on partisanship in the United States. Immigration is believed to be a unique factor that induces large- scale changes in partisanship based on race and ethnicity. The negative tone of media coverage pushes non-Latino Whites into the Republican Party, while Latinos trend toward the Democratic Party. The aim for this project is to look at New York time data in order to identify how much immigration is covered in newspaper outlets, specifically Latino immigration, and to determine the overall tone of these stories. In this research, we seek to determine individual articles take a positive, neutral or negative stance. We achieve this using a dictionary-based approach, meaning we look at individual words to assess if it has a positive, neutral or negative connotation. We train our data using publicly accessible sentiment dictionaries such as VADER (Valence Aware Dictionary and Sentiment Reasoner). However, this task can be difficult because certain words can be dynamic and may pertain to a positive or negative sentiment in context of the article. In order to resolve this issue, we use reliability measures to ensure that the words of high frequencies are in the correct sphere of negative, neutral, and positive light. Information about the Author(s): Faculty Sponsor(s): Professor Gregg B. Johnson and Professor Karl Schmitt Student Contact: Gabriel Carvajal – [email protected]

    Essential Strangeness in Nucleon Magnetic Moments

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    Effective quark magnetic moments are extracted from experimental measurements as a function of the strangeness magnetic moment of the nucleon. Assumptions made in even the most general quark model analyses are ruled out by this investigation. Ab initio QCD calculations demand a non-trivial role for strange quarks in the nucleon. The effective moments from QCD calculations are reproduced for a strangeness magnetic moment contribution to the proton of 0.11 μN\mu_N, which corresponds to F2s(0)=−0.33 μNF_2^s(0) = -0.33\ \mu_N.Comment: HYP '94 presentation. File is a uuencoded postscript file of a 2 page manuscript including figures. Also available via anonymous ftp from pacific.mps.ohio-state.edu in pub/NTG/Leinweber as StrQrkNmom.ps(.gz) OSU PP #94-063

    Private Saving and Public Policy

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    The evidence presented in this paper supports the view that many Americans, particularly those without a college education, save too little. Our analysis also indicates that it should be possible to increase total personal saving among lower income households by encouraging the formation and expansion of private pension plans. It is doubtful that favorable tax treatment of capital income would stimulate significant additional saving by this group. Conversely, the expansion of private pensions would probably have little effect on saving by higher income households. However, these households are more likely to increase saving significantly in response to favorable tax treatment of capital income. Currently, eligibility for IRAs is linked to an AGI cap, and pension coverage is more common among higher income households than among low income households. The most effective system for promoting personal saving would have precisely the opposite features. Extending tax incentives for saving to higher income households is problematic. We discuss three competing policy options, IRAs with AGI caps, the universal IRA, and the Premium Saving Account (PSA). Our analysis reveals that the PSA system is a more cost-effective vehicle for providing saving incentives to, all households, particularly those in the top quintile of the income distribution.
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