311 research outputs found
‘Fake news’ is the invention of a liar: How false information circulates within the hybrid news system
Alarmed by the oversimplifications related to the ‘fake news’ buzzword, researchers have started to unpack the concept, defining diverse types and forms of misleading news. Most of the existing works in the area consider crucial the intent of the content creator in order to differentiate among different types of problematic information. This article argues for a change of perspective that, by leveraging the conceptual framework of sociocybernetics, shifts from exclusive attention to creators of misleading information to a broader approach that focuses on propagators and, as a result, on the dynamics of the propagation processes. The analytical implications of this perspective are discussed at a micro level (criteria to judge the falsehood of news and to decide to spread it), at a meso level (four possible relations between individual judgements and decisions), and at a macro level (global circulation cascades). The authors apply this theoretical gaze to analyse ‘fake news’ stories that challenge existing models
Multiple openings and competitiveness of forward markets: experimental evidence
We test the competition enhancing effect of selling forward in experimental Cournot duopoly and quadropoly with multiple forward markets. We find that having two forward periods yields competitive outcomes and that the results are very close to the predicted theoretical results for both quantity setting duopolies and quadropolies. Our experiments lend strong support to the hypothesis that forward markets are competition enhancing. We then test a new market that allows for endogenously determined indefinitely many forward periods that only close when sellers coordinate on selling a zero amount in a forward market. We find that the outcomes under an endogenous close rule are also very competitive. These results hold for both duopolies and quadropolies
Molecular evolution of HoxA13 and the multiple origins of limbless morphologies in amphibians and reptiles
Developmental processes and their results, morphological characters, are inherited through transmission of genes regulating development. While there is ample evidence that cis-regulatory elements tend to be modular, with sequence segments dedicated to different roles, the situation for proteins is less clear, being particularly complex for transcription factors with multiple functions. Some motifs mediating protein-protein interactions may be exclusive to particular developmental roles, but it is also possible that motifs are mostly shared among different processes. Here we focus on HoxA13, a protein essential for limb development. We asked whether the HoxA13 amino acid sequence evolved similarly in three limbless clades: Gymnophiona, Amphisbaenia and Serpentes. We explored variation in ω (dN/dS) using a maximum-likelihood framework and HoxA13sequences from 47 species. Comparisons of evolutionary models provided low ω global values and no evidence that HoxA13 experienced relaxed selection in limbless clades. Branch-site models failed to detect evidence for positive selection acting on any site along branches of Amphisbaena and Gymnophiona, while three sites were identified in Serpentes. Examination of alignments did not reveal consistent sequence differences between limbed and limbless species. We conclude that HoxA13 has no modules exclusive to limb development, which may be explained by its involvement in multiple developmental processes
Rapidity and Centrality Dependence of Proton and Anti-proton Production from Au+Au Collisions at sqrt(sNN) = 130GeV
We report on the rapidity and centrality dependence of proton and anti-proton
transverse mass distributions from Au+Au collisions at sqrt(sNN) = 130GeV as
measured by the STAR experiment at RHIC. Our results are from the rapidity and
transverse momentum range of |y|<0.5 and 0.35 <p_t<1.00GeV/c. For both protons
and anti-protons, transverse mass distributions become more convex from
peripheral to central collisions demonstrating characteristics of collective
expansion. The measured rapidity distributions and the mean transverse momenta
versus rapidity are flat within |y|<0.5. Comparisons of our data with results
from model calculations indicate that in order to obtain a consistent picture
of the proton(anti-proton) yields and transverse mass distributions the
possibility of pre-hadronic collective expansion may have to be taken into
account.Comment: 4 pages, 3 figures, 1 table, submitted to PR
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Management and resistance in the digital newsroom
What happens when there is conflict between the profit motivations of a news outlet and the professional values of its journalists? Questions of managerial influence and journalistic autonomy have interested media scholars from the seminal work of Warren Breed onwards. However, there have only been a handful of studies since the introduction of audience metrics which, this research suggests, allow managers to more efficiently monitor and discipline their journalists. This article presents an ethnographic case study of a Reuters newswire bureau during a time of conflict between the management and journalists. The article outlines the strategies that management used to incentivize their journalists to change their reporting priorities. These included the strategic dissemination of audience metrics and praise, and the hiring and promotion of ‘appropriate’ journalists to positions of influence. These interventions changed who was considered a ‘good journalist’ at the newswire, disrupting existing hierarchies, and eventually changing the culture of the newsroom. The article draws on the insights of Pierre Bourdieu’s field theory to help explain how managerial power operates, and the role that individual journalists play producing and reinforcing newsroom norms
Azimuthal anisotropy and correlations at large transverse momenta in and Au+Au collisions at = 200 GeV
Results on high transverse momentum charged particle emission with respect to
the reaction plane are presented for Au+Au collisions at =
200 GeV. Two- and four-particle correlations results are presented as well as a
comparison of azimuthal correlations in Au+Au collisions to those in at
the same energy. Elliptic anisotropy, , is found to reach its maximum at
GeV/c, then decrease slowly and remain significant up to
-- 10 GeV/c. Stronger suppression is found in the back-to-back
high- particle correlations for particles emitted out-of-plane compared to
those emitted in-plane. The centrality dependence of at intermediate
is compared to simple models based on jet quenching.Comment: 4 figures. Published version as PRL 93, 252301 (2004
Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV
The results from the STAR Collaboration on directed flow (v_1), elliptic flow
(v_2), and the fourth harmonic (v_4) in the anisotropic azimuthal distribution
of particles from Au+Au collisions at sqrtsNN = 200 GeV are summarized and
compared with results from other experiments and theoretical models. Results
for identified particles are presented and fit with a Blast Wave model.
Different anisotropic flow analysis methods are compared and nonflow effects
are extracted from the data. For v_2, scaling with the number of constituent
quarks and parton coalescence is discussed. For v_4, scaling with v_2^2 and
quark coalescence is discussed.Comment: 26 pages. As accepted by Phys. Rev. C. Text rearranged, figures
modified, but data the same. However, in Fig. 35 the hydro calculations are
corrected in this version. The data tables are available at
http://www.star.bnl.gov/central/publications/ by searching for "flow" and
then this pape
Azimuthal anisotropy and correlations in the hard scattering regime at RHIC
Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at roots(NN) = 130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T) 3 GeV/c, a saturation of v(2) is observed which persists up to p(T) = 6 GeV/c
Cross sections and transverse single-spin asymmetries in forward neutral-pion production from proton collisions at root s=200 GeV
Measurements of the production of forward high-energy pi(0) mesons from transversely polarized proton collisions at root200 GeV are reported. The cross section is generally consistent with next-to-leading order perturbative QCD calculations. The analyzing power is small at x(F) below about 0.3, and becomes positive and large at higher x(F), similar to the trend in data at roots less than or equal to20 GeV. The analyzing power is in qualitative agreement with perturbative QCD model expectations. This is the first significant spin result seen for particles produced with p(T)>1 GeV/c at a polarized proton collider
Azimuthal anisotropy at the relativistic heavy ion collider: The first and fourth harmonics
We report the first observations of the first harmonic (directed flow, v(1)) and the fourth harmonic (v(4)), in the azimuthal distribution of particles with respect to the reaction plane in Au+Au collisions at the BNL Relativistic Heavy Ion Collider (RHIC). Both measurements were done taking advantage of the large elliptic flow (v(2)) generated at RHIC. From the correlation of v(2) with v(1) it is determined that v(2) is positive, or in-plane. The integrated v(4) is about a factor of 10 smaller than v(2). For the sixth (v(6)) and eighth (v(8)) harmonics upper limits on the magnitudes are reported
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