547 research outputs found
Introduction: Mass media effects and the political agenda: Assessing its scope and conditions
Do the mass media influence the issue priorities of politicians? This question has been present in the literature on the media and political agenda-setting since the mid-1970s when scholars first addressed it within the broader agenda-setting research. While only eighteen empirical pieces examined this topic until the mid-2000s (Walgrave & Van Aelst, 2006), in the last decade the number of studies on the media and the political agenda has expanded considerably (Van Aelst & Walgrave, 2016). In fact, in the last ten years (2005â2015), more than thirty studies focused on the mediaâs political agenda-setting power. The research now features a wider geographical scope, richer datasets, and more contingent factors have been investigated in detail. Studying the relationship between the media agenda and
the political agenda has therefore become a flourishing subfield in political communication. In addition, it connects a community of political scientists interested in factors that influence public policy with communication scholars who work on the political influence of the mass media.info:eu-repo/semantics/acceptedVersio
Making sense of Twitter buzz
The Institutions of Politics; Design, Workings, and implications ( do not use, ended 1-1-2020
Phosphoinositide 3-kinase-dependent membrane recruitment of p62(dok) is essential for its negative effect on mitogen-activated protein (MAP) kinase activation
A major pathway by which growth factors, such as platelet-derived growth factor (PDGF), regulate cell proliferation is via the receptor tyrosine kinase/Ras/niitogen-activated protein kinase (MAPK) signaling cascade. The output of this pathway is subjected to tight regulation of both positive and negative regulators. One such regulator is p62(dok), the prototype of a newly identified family of adaptor proteins. We recently provided evidence, through the use of p62(dok)-deficient cells, that p62(dok) acts as a negative regulator of growth factor-induced cell proliferation and the Ras/MAPK pathway. We show here that reintroduction of p62(dok) into P62(dok-/-) cells can suppress the increased cell proliferation and prolonged MAPK activity seen in these cells, and that plasma membrane recruitment of p62(dok) is essential for its function. We also show that the PDGF-triggered plasma membrane translocation of p62(dok) requires activation of phosphoinositide 3-kinase (PI3-kinase) and binding of its pleckstrin homology (PH) domain to 3 ' -phosphorylated phosphomositides. Furthermore, we demonstrate that p62(dok) can exert its negative effect on the PDGFR/MAPK pathway independently of its ability to associate with RasGAP and Nck. We conclude that p62(dok) functions as a negative regulator of the PDGFR/Ras/MAPK signaling pathway through a mechanism involving P13-kinase-dependent recruitment of p62(dok) to the plasma membrane
Measuring and explaining the diversity of voices and viewpoints in the news
News media can be considered to fulfil their democratic role as a âmarketplace of
ideasâ only if they present a diverse content that gives space to a wider range of ideas
and viewpoints. But how can content diversity be assessed? And what determines
actor and viewpoint diversity in the first place? By employing measurements of actor
and viewpoint diversity at the article and newspaper level, this study provides a
complete overview on the content diversity of immigration news, and it investigates
factors that have an impact on content diversity of immigration newspaper articles in
Belgium, Germany, Italy and the United Kingdom (2013-2014). The results of a
multilevel analysis indicate that both the articlesâ size and the elite character of a
newspaper play a key role in enhancing newsâ multiperspectivalness. Also, the
findings show that these two measurements of content diversity are different yet
related to each other
Sulfur analysis of Bolu-Mengen lignite before and after microbiological treatment using reductive pyrolysis and gas chromatography/mass spectrometry
Atmospheric pressure-temperature programmed reduction coupled with on-line mass spectrometry (AP-TPR/MS) is used for the first time on microbiologically treated coal samples as a technique to monitor the degree of desulfurization of the various sulfur functionalities. The experimental procedure enables the identification of both organic and inorganic sulfur species present in the coal matrix. A better insight in the degradation of the coal matrix and the accompanying processes during the AP-TPR experiment is obtained by a quantitative differentiation of the sulfur. The determination of the sulfur balance for the reductive pyrolysis gives an overview of the side reactions and their relative contribution in the total process. The volatile sulfur species are unambiguously identified using AP-TPR off-line coupled with gas chromatography/mass spectrometry (GC/MS). In this way, fundamental mechanisms and reactions that occur during the reductive pyrolysis could be quantified, explaining the differences in AP-TPR recoveries. Therefore, this study gives a clearer view on the possibilities and limitations of AP-TPR as a technique to monitor sulfur functionalities in coal
Oncogenic Ras activation of Raf/mitogen-activated protein kinase-independent pathways is sufficient to cause tumorigenic transformation
Substantial evidence supports a critical role for the activation of the Raf-1/MEK/mitogen-activated protein kinase pathway in oncogenic Ras-mediated transformation. For example, dominant negative mutants of Raf-1, MEK, and mitogen-activated protein kinase all inhibit Ras transformation. Furthermore, the observation that plasma membrane-localized Raf-1 exhibits the same transforming potency as oncogenic Ras suggests that Raf-1 activation alone is sufficient to mediate full Ras transforming activity. However, the recent identification of other candidate Ras effectors (e.g., RalGDS and phosphatidylinositol-3 kinase) suggests that activation of other downstream effector-mediated signaling pathways may also mediate Ras transforming activity. In support of this, two H-Ras effector domain mutants, H-Ras(12V, 37G) and H-Ras(12V, 40C), which are defective for Raf binding and activation, induced potent tumorigenic transformation of some strains of NIH 3T3 fibroblasts. These Raf-binding defective mutants of H-Ras induced a transformed morphology that was indistinguishable from that induced by activated members of Rho family proteins. Furthermore, the transforming activities of both of these mutants were synergistically enhanced by activated Raf-1 and inhibited by the dominant negative RhoA(19N) mutant, indicating that Ras may cause transformation that occurs via coordinate activation of Raf-dependent and -independent pathways that involves Rho family proteins. Finally, cotransfection of H-Ras(12V, 37G) and H-Ras(12V, 40C) resulted in synergistic cooperation of their focus-forming activities, indicating that Ras activates at least two Raf-independent, Ras effector-mediated signaling events
DOK2 inhibits EGFR-mutated lung adenocarcinoma
Somatic mutations in the EGFR proto-oncogene occur in ~15% of human lung adenocarcinomas and the importance of EGFR mutations for the initiation and maintenance of lung cancer is well established from mouse models and cancer therapy trials in human lung cancer patients. Recently, we identified DOK2 as a lung adenocarcinoma tumor suppressor gene. Here we show that genomic loss of DOK2 is associated with EGFR mutations in human lung adenocarcinoma, and we hypothesized that loss of DOK2 might therefore cooperate with EGFR mutations to promote lung tumorigenesis. We tested this hypothesis using genetically engineered mouse models and find that loss of Dok2 in the mouse accelerates lung tumorigenesis initiated by oncogenic EGFR, but not that initiated by mutated Kras. Moreover, we find that DOK2 participates in a negative feedback loop that opposes mutated EGFR; EGFR mutation leads to recruitment of DOK2 to EGFR and DOK2-mediated inhibition of downstream activation of RAS. These data identify DOK2 as a tumor suppressor in EGFR-mutant lung adenocarcinoma
Robust high-dimensional precision matrix estimation
The dependency structure of multivariate data can be analyzed using the
covariance matrix . In many fields the precision matrix
is even more informative. As the sample covariance estimator is singular in
high-dimensions, it cannot be used to obtain a precision matrix estimator. A
popular high-dimensional estimator is the graphical lasso, but it lacks
robustness. We consider the high-dimensional independent contamination model.
Here, even a small percentage of contaminated cells in the data matrix may lead
to a high percentage of contaminated rows. Downweighting entire observations,
which is done by traditional robust procedures, would then results in a loss of
information. In this paper, we formally prove that replacing the sample
covariance matrix in the graphical lasso with an elementwise robust covariance
matrix leads to an elementwise robust, sparse precision matrix estimator
computable in high-dimensions. Examples of such elementwise robust covariance
estimators are given. The final precision matrix estimator is positive
definite, has a high breakdown point under elementwise contamination and can be
computed fast
Trump vs. Hillary: What went Viral during the 2016 US Presidential Election
In this paper, we present quantitative and qualitative analysis of the top
retweeted tweets (viral tweets) pertaining to the US presidential elections
from September 1, 2016 to Election Day on November 8, 2016. For everyday, we
tagged the top 50 most retweeted tweets as supporting or attacking either
candidate or as neutral/irrelevant. Then we analyzed the tweets in each class
for: general trends and statistics; the most frequently used hashtags, terms,
and locations; the most retweeted accounts and tweets; and the most shared news
and links. In all we analyzed the 3,450 most viral tweets that grabbed the most
attention during the US election and were retweeted in total 26.3 million times
accounting over 40% of the total tweet volume pertaining to the US election in
the aforementioned period. Our analysis of the tweets highlights some of the
differences between the social media strategies of both candidates, the
penetration of their messages, and the potential effect of attacks on bothComment: Paper to appear in Springer SocInfo 201
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