2,056 research outputs found
Representations of the -algebra and the loop representation in -dimensions
We consider the phase-space of Yang-Mills on a cylindrical space-time () and the associated algebra of gauge-invariant functions, the
-variables. We solve the Mandelstam identities both classically and
quantum-mechanically by considering the -variables as functions of the
eigenvalues of the holonomy and their associated momenta. It is shown that
there are two inequivalent representations of the quantum -algebra. Then we
compare this reduced phase space approach to Dirac quantization and find it to
give essentially equivalent results. We proceed to define a loop representation
in each of these two cases. One of these loop representations (for ) is
more or less equivalent to the usual loop representation.Comment: 15 pages, LaTeX, 1 postscript figure included, uses epsf.sty,
G\"oteborg ITP 93-3
Comparing international coverage of 9/11 : towards an interdisciplinary explanation of the construction of news
This article presents an interdisciplinary model attempting to explain how news is constructed by relying on the contributions of different fields of study: News Sociology, Political Communications, International Communications, International Relations. It is a first step towards developing a holistic theoretical approach to what shapes the news, which bridges current micro to macro approaches. More precisely the model explains news variation across different media organization and countries by focusing on the different way the sense of newsworthiness of journalists is affected by three main variables: national interest, national journalistic culture, and editorial policy of each media organization. The model is developed on the basis of an investigation into what shaped the media coverage of 9/11 in eight elite newspapers across the US, France, Italy and Pakistan
Comment on ``Evidence for Narrow Baryon Resonances in Inelastic pp Scattering''
Compton scattering data are sensitive to the existence of low-mass resonances
reported by Tatischeff et al. We show that such states, with their reported
properties, are excluded by previous Compton scattering experiments.Comment: One page, submitted to PR
Quasi-free Compton Scattering from the Deuteron and Nucleon Polarizabilities
Cross sections for quasi-free Compton scattering from the deuteron were
measured for incident energies of 236--260 MeV at the laboratory angle -135
degrees. The recoil nucleons were detected in a liquid-scintillator array
situated at 20 degrees. The measured differential cross sections were used,
with the calculations of Levchuk et al., to determine the polarizabilities of
the bound nucleons. For the bound proton, the extracted values were consistent
with the accepted value for the free proton. Combining our results for the
bound neutron with those from Rose et al., we obtain one-sigma constraints of
alpha_n = 7.6-14.0 and beta_n = 1.2-7.6.Comment: 4 pages, 3 figures, accepted in PR
Scheduling science on television: A comparative analysis of the representations of science in 11 European countries
While science-in-the-media is a useful vehicle for understanding the media, few scholars have used it that way: instead, they look at science-in-the-media as a way of understanding science-in-the-media and often end up attributing characteristics to science-in-the-media that are simply characteristics of the media, rather than of the science they see there. This point of view was argued by Jane Gregory and Steve Miller in 1998 in Science in Public. Science, they concluded, is not a special case in the mass media, understanding science-in-the-media is mostly about understanding the media (Gregory and Miller, 1998: 105). More than a decade later, research that looks for patterns or even determinants of science-in-the-media, be it in press or electronic media, is still very rare. There is interest in explaining the media’s selection of science content from a media perspective. Instead, the search for, and analysis of, several kinds of distortions in media representations of science have been leading topics of science-in-the-media research since its beginning in the USA at the end of the 1960s and remain influential today (see Lewenstein, 1994; Weigold, 2001; Kohring, 2005 for summaries). Only a relatively small amount of research has been conducted seeking to identify factors relevant to understanding how science is treated by the mass media in general and by television in particular. The current study addresses the lack of research in this area. Our research seeks to explore which constraints national media systems place on the volume and structure of science programming in television. In simpler terms, the main question this study is trying to address is why science-in-TV in Europe appears as it does. We seek to link research focussing on the detailed analysis of science representations on television (Silverstone, 1984; Collins, 1987; Hornig, 1990; Leon, 2008), and media research focussing on the historical genesis and current political regulation of national media systems (see for instance Hallin and Mancini, 2004; Napoli, 2004; Open Society Institute, 2005, 2008). The former studies provide deeper insights into the selection and reconstruction of scientific subject matters, which reflect and – at the same time – reinforce popular images of science. But their studies do not give much attention to production constraints or other relevant factors which could provide an insight into why media treat science as they do. The latter scholars inter alia shed light on distinct media policies in Europe which significantly influence national channel patterns. However, they do not refer to clearly defined content categories but to fairly rough distinctions such as information versus entertainment or fictional versus factual. Accordingly, we know more about historical roots and current practices of media regulation across Europe than we do about the effects of these different regimes on the provision of specific content in European societies
The uses and functions of ageing celebrity war reporters
This article starts from the premise that recognition of professional authority and celebrity status depends on the embodiment and performance of field-specific dispositional practices: there’s no such thing as a natural, though we often talk about journalistic instinct as something someone simply has or doesn’t have. Next, we have little control over how we are perceived by peers and publics, and what we think are active positioning or subjectifying practices are in fact, after Bourdieu, revelations of already-determined delegation. The upshot is that two journalists can arrive at diametrically opposed judgements on the basis of observation of the same actions of a colleague, and as individuals we are blithely hypocritical in forming (or reciting) evaluations of the professional identity of celebrities. Nowhere is this starker than in the discourse of age-appropriate behaviour, which this paper addresses using the examples of ‘star’ war reporters John Simpson, Kate Adie and Martin Bell. A certain rough-around-the-edges irreverence is central to dispositional authenticity amongst war correspondents, and for ageing hacks this incorporates gendered attitudes to sex and alcohol as well as indifference to protocol. And yet perceived age-inappropriate sexual behaviour is also used to undermine professional integrity, and the paper ends by outlining the phenomenological context that makes possible this effortless switching between amoral and moralising recognition by peers and audiences alike
Deeply Virtual Compton Scattering
We study in QCD the physics of deeply-virtual Compton scattering (DVCS)---the
virtual Compton process in the large s and small t kinematic region. We show
that DVCS can probe a new type of off-forward parton distributions. We derive
an Altarelli-Parisi type of evolution equations for these distributions. We
also derive their sum rules in terms of nucleon form-factors of the twist-two
quark and gluon operators. In particular, we find that the second sum rule is
related to fractions of the nucleon spin carried separately by quarks and
gluons. We estimate the cross section for DVCS and compare it with the
accompanying Bethe-Heitler process at CEBAF and HERMES kinematics.Comment: 20 pages, 2 figures, replaced with the version to appear in Phys.
Rev.
Virtual versus Real Nuclear Compton Scattering in the Delta(1232) Region
In this paper we calculate the cross section for Virtual Compton Scattering
off nuclei in the delta resonance region. We also calculate the background for
the process from Coherent Bremsstrahlung in nuclei and explore the regions
where the Virtual Compton Scattering cross section dominates. The study also
shows that it is possible to extract the cross section for Real Compton
Scattering from the Virtual Compton one in a wide range of scattering angles.Comment: latex , 11 pages, ps.gz file, 16 figure
Compton scattering on the nucleon at intermediate energies and polarizabilities in a microscopic model
A microscopic calculation of Compton scattering on the nucleon is presented
which encompasses the lowest energies -- yielding nucleon polarizabilities --
and extends to energies of the order of 600 MeV. We have used the covariant
"Dressed K-Matrix Model" obeying the symmetry properties which are appropriate
in the different energy regimes. In particular, crossing symmetry, gauge
invariance and unitarity are satisfied. The extent of violation of analyticity
(causality) is used as an expansion parameter.Comment: 35 pages, 15 figures, using REVTeX. Modified version to be published
in Phys. Rev. C, more extensive comparison with data for Compton scattering,
all results unchange
Substantiating a political public sphere in the Scottish press : a comparative analysis
This article uses content analysis to characterize the performance of the media in a national public sphere, by setting apart those qualities that typify internal press coverage of a political event. The article looks at the coverage of the 1999 devolved Scottish election from the day before the election until the day after. It uses a word count to measure the election material in Scottish newspapers the Herald, the Press and Journal and the Scotsman, and United Kingdom newspapers the Guardian, the Independent and The Times, and categorizes that material according to discourse type, day and page selection. The article finds a number of qualities that typify the Scottish sample in particular, and might be broadly indicative of a political public sphere in action. Firstly, and not unexpectedly, it finds that the Scottish newspapers carry significantly more election coverage. Just as tellingly, though, the article finds that the Scottish papers offer a greater proportion of advice and background information, in the form of opinion columns and feature articles. It also finds that the Scottish papers place a greater concentration of both informative and evaluative material in the period before the vote, consistent with their making a contribution to informed political action. Lastly, the article finds that the Scottish sample situates coverage nearer the front of the paper and places a greater proportion on recto pages. The article therefore argues that the Scottish papers display features that distinguish them from the UK papers, and are broadly consistent with their forming part of a deliberative public sphere, and suggests that these qualities might be explored as a means of judging future media performance
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