Lagrangian interactions within a special class of covariant mixed-symmetry type tensor gauge fields

Consistent nontrivial interactions within a special class of covariant mixed-symmetry type tensor gauge fields of degree three are constructed from the deformation of the solution to the master equation combined with specific cohomological techniques. In spacetime dimensions strictly greater than four, the only consistent interaction terms are those gauge invariant under the original symmetry. Only in four spacetime dimensions the gauge symmetry is found deformed.Comment: 24 pages; two equations corrected; matches the published versio

Extracting Topic-Specific Ideological Positions from News Articles

This is the final version.In this paper, we test three methods of estimating ideological bias in news media stories. This forms the basis for the development of a news reading app. We find that WordScores offers the most reliable estimate and reliability is improved when applied after identifying topic.Economic and Social Research Council (ESRC

Imaging of atomic orbitals with the Atomic Force Microscope - experiments and simulations

Atomic force microscopy (AFM) is a mechanical profiling technique that allows to image surfaces with atomic resolution. Recent progress in reducing the noise of this technique has led to a resolution level where previously undetectable symmetries of the images of single atoms are observed. These symmetries are related to the nature of the interatomic forces. The Si(111)-(7x7) surface is studied by AFM with various tips and AFM images are simulated with chemical and electrostatic model forces. The calculation of images from the tip-sample forces is explained in detail and the implications of the imaging parameters are discussed. Because the structure of the Si(111)-(7x7) surface is known very well, the shape of the adatom images is used to determine the tip structure. The observability of atomic orbitals by AFM and scanning tunneling microscopy is discussed.Comment: 21 pages, 17 figure

Different news for different views: Political news-sharing communities on social media through the UK General Election in 2015

This is the final version of the article. Available from AAAI via the URL in this record.Media exposure is a central concept in understanding the dynamics of public opinion and political change. Traditional models of media exposure have been severely challenged by the shift to online news consumption and news-sharing on social media. Here we use network analysis and automated content analysis to examine the interaction between news media and social media around the UK General Election in 2015. We study a large corpus of UK newspaper articles and Twitter content, finding significant temporal correlations between newspaper topic coverage and the content discussed on Twitter. We also identify news-sharing communities around groups of news sources that are ideologically clustered. Analysis of topics covered within each group shows that different communities are exposed to different news content during the election. Our results confirm that ideological bias and selective news-sharing affect patterns of online media exposure in social media.This work was supported by the UK Economic and Social Research Council ES/N012283/1

Irreducible Hamiltonian BRST symmetry for reducible first-class systems

An irreducible Hamiltonian BRST quantization method for reducible first-class systems is proposed. The general theory is illustrated on a two-stage reducible model, the link with the standard reducible BRST treatment being also emphasized.Comment: Latex 2.09, 23 pages, to appear in Int. J. Mod. Phys.

First-Class Approaches to Massive 2-Forms

Massive 2-forms are analyzed from the point of view of the Hamiltonian quantization using the gauge-unfixing approach and respectively the Batalin--Fradkin method. Both methods finally output the manifestly Lorentz covariant path integral for 1- and 2-forms with Stueckelberg coupling.Comment: 14 page

To Polarize or Not: Comparing Networks of News Consumption

This is the final version. Available via the link in this record.We use individual data on browsing histories combined with survey data to examine whether online news exposure exhibits signs of segregation and selectivity. By using online news behaviour combined with survey reports of attitudes, we can capture exposure to both traditional news sources and news shared via social media platforms. Most importantly, we can also examine what types of individuals (e.g. partisans, educated) are more likely to exhibit selective tendencies. We find, consistent with recent empirical work, the extent of segregation in exposure may be overstated. Furthermore, the degree of segregation and selectivity varies across groups that are defined by holding shared political preferences. For example, in the case of Brexit, those who supported the ‘Leave’ side were more selective in their news exposure. Our approach allows comparison of news exposure patterns by domains versus news exposure to topics. To our knowledge, this is the first analysis to allow this comparison.This work was supported by the Economic and Social Research Council ES/N012283/1 "Measuring Information Exposure in Dynamic and Dependent Networks (ExpoNet)