317 research outputs found
Jointly they edit: examining the impact of community identification on political interaction in Wikipedia
In their 2005 study, Adamic and Glance coined the memorable phrase "divided
they blog", referring to a trend of cyberbalkanization in the political
blogosphere, with liberal and conservative blogs tending to link to other blogs
with a similar political slant, and not to one another. As political discussion
and activity increasingly moves online, the power of framing political
discourses is shifting from mass media to social media. Continued examination
of political interactions online is critical, and we extend this line of
research by examining the activities of political users within the Wikipedia
community. First, we examined how users in Wikipedia choose to display (or not
to display) their political affiliation. Next, we more closely examined the
patterns of cross-party interaction and community participation among those
users proclaiming a political affiliation. In contrast to previous analyses of
other social media, we did not find strong trends indicating a preference to
interact with members of the same political party within the Wikipedia
community. Our results indicate that users who proclaim their political
affiliation within the community tend to proclaim their identity as a
"Wikipedian" even more loudly. It seems that the shared identity of "being
Wikipedian" may be strong enough to triumph over other potentially divisive
facets of personal identity, such as political affiliation.Comment: 33 pages, 5 figure
Too Big to Manage: US Megabanks’ Competition by Innovation and the Microfoundations of Financialization
Disagreements over the systemic implications—the future—of financialization can be traced in part to the absence of sustained attention to the role of banking firms in driving this secular shift forward. That is, the financialization literature lacks an adequate microfoundation. Accounting for the drivers of financialization processes solely at the macro level overlooks the problems of how these processes came about and whether they are sustainable. This paper addresses this explanatory gap, arguing that a key independent microeconomic driver of increasing financialization did exist: the incessant efforts by money-centre banks in the USA to break out of Depression-era restrictions on their size, activities, and markets. These banks’ growth strategies in turbulent times led to an institutional (meso) shift—the rise of a megabank-centred shadow banking system—that now shapes global financial architecture even while operating in ways that are unsustainable. In short, too-big-to-manage megabanks are at the heart of the fragility and instability of the economy today
Nucleon distribution amplitudes from lattice QCD
We calculate low moments of the leading-twist and next-to-leading twist
nucleon distribution amplitudes on the lattice using two flavors of clover
fermions. The results are presented in the MSbar scheme at a scale of 2 GeV and
can be immediately applied in phenomenological studies. We find that the
deviation of the leading-twist nucleon distribution amplitude from its
asymptotic form is less pronounced than sometimes claimed in the literature.Comment: 5 pages, 3 figures, 2 tables. RevTeX style. Normalization for
\lambda_i corrected. Discussion of the results extended. To be published in
PR
Irreducible Multiplets of Three-Quark Operators on the Lattice: Controlling Mixing under Renormalization
High luminosity accelerators have greatly increased the interest in
semi-exclusive and exclusive reactions involving nucleons. The relevant
theoretical information is contained in the nucleon wavefunction and can be
parametrized by moments of the nucleon distribution amplitudes, which in turn
are linked to matrix elements of three-quark operators. These can be calculated
from first principles in lattice QCD. However, on the lattice the problems of
operator mixing under renormalization are rather involved. In a systematic
approach we investigate this issue in depth. Using the spinorial symmetry group
of the hypercubic lattice we derive irreducibly transforming three-quark
operators, which allow us to control the mixing pattern.Comment: 13 page
Quantitative Analysis of Bloggers Collective Behavior Powered by Emotions
Large-scale data resulting from users online interactions provide the
ultimate source of information to study emergent social phenomena on the Web.
From individual actions of users to observable collective behaviors, different
mechanisms involving emotions expressed in the posted text play a role. Here we
combine approaches of statistical physics with machine-learning methods of text
analysis to study emergence of the emotional behavior among Web users. Mapping
the high-resolution data from digg.com onto bipartite network of users and
their comments onto posted stories, we identify user communities centered
around certain popular posts and determine emotional contents of the related
comments by the emotion-classifier developed for this type of texts. Applied
over different time periods, this framework reveals strong correlations between
the excess of negative emotions and the evolution of communities. We observe
avalanches of emotional comments exhibiting significant self-organized critical
behavior and temporal correlations. To explore robustness of these critical
states, we design a network automaton model on realistic network connections
and several control parameters, which can be inferred from the dataset.
Dissemination of emotions by a small fraction of very active users appears to
critically tune the collective states
SRG/eROSITA-triggered XMM-Newton observations of three Be/X-ray binaries in the LMC: Discovery of X-ray pulsations
Using data from eROSITA, the soft X-ray instrument aboard
Spectrum-Roentgen-Gamma (SRG), we report the discovery of two new hard
transients, eRASSU J050810.4-660653 and eRASSt J044811.1-691318, in the Large
Magellanic Cloud. We also report the detection of the Be/X-ray binary RX
J0501.6-7034 in a bright state. We initiated follow-up observations to
investigate the nature of the new transients and to search for X-ray pulsations
coming from RX J0501.6-7034. We analysed the X-ray spectra and light curves
from our XMM-Newton observations, obtained optical spectra using the South
African Large Telescope to look for Balmer emission lines and utilised the
archival data from the Optical Gravitational Lensing Experiment (OGLE) for the
long-term monitoring of the optical counterparts. We find X-ray pulsations for
eRASSU J050810.4-660653, RX J0501.6-7034, and eRASSt J044811.1-691318 of 40.6
s, 17.3 s, and 784 s, respectively. The Halpha emission lines with equivalent
widths of -10.4 A (eRASSU J050810.4-660653) and -43.9 A (eRASSt
J044811.1-691318) were measured, characteristic for a circumstellar disc around
Be stars. The OGLE I- and V-band light curves of all three systems exhibit
strong variability. A regular pattern of deep dips in the light curves of RX
J0501.6-7034 suggests an orbital period of ~451 days. We identify the two new
hard eROSITA transients eRASSU J050810.4-660653 and eRASSt J044811.1-691318 and
the known Be/X-ray binary RX J0501.6-7034 as Be/X-ray binary pulsars.Comment: Accepted for publication in Astronomy & Astrophysic
Non-perturbative improvement of stout-smeared three flavour clover fermions
We discuss a 3-flavour lattice QCD action with clover improvement in which
the fermion matrix has single level stout smearing for the hopping terms
together with unsmeared links for the clover term. With the (tree-level)
Symanzik improved gluon action this constitutes the Stout Link Non-perturbative
Clover or SLiNC action. To cancel O(a) terms the clover term coefficient has to
be tuned. We present here results of a non-perturbative determination of this
coefficient using the Schroedinger functional and as a by-product a
determination of the critical hopping parameter. Comparisons of the results are
made with lowest order perturbation theory.Comment: 30 pages, 13 figures, minor changes, published versio
Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors
The development of highly-sensitive and miniaturized sensors that capable of
real-time analytes detection is highly desirable. Nowadays, toxic or colorless
gas detection, air pollution monitoring, harmful chemical, pressure, strain,
humidity, and temperature sensors based on photonic crystal fiber (PCF) are
increasing rapidly due to its compact structure, fast response and efficient
light controlling capabilities. The propagating light through the PCF can be
controlled by varying the structural parameters and core-cladding materials, as
a result, evanescent field can be enhanced significantly which is the main
component of the PCF based gas/chemical sensors. The aim of this chapter is to
(1) describe the principle operation of PCF based gas/ chemical sensors, (2)
discuss the important PCF properties for optical sensors, (3) extensively
discuss the different types of microstructured optical fiber based gas/
chemical sensors, (4) study the effects of different core-cladding shapes, and
fiber background materials on sensing performance, and (5) highlight the main
challenges of PCF based gas/ chemical sensors and possible solutions
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