Browsing by Author "Valenzuela, Sebastian"

Now showing 1 - 7 of 7
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    A Panel Study on the Dynamics of Social Media Use and Conspiracy Thinking
    (SPRINGER INTERNATIONAL PUBLISHING AG, 2023) Valenzuela, Sebastian; Diehl, Trevor; Lee, Sangwon; Halpern, Daniel
    Studies exploring the association between social media use and belief in conspiracy theories have yielded mixed evidence. To address this inconsistency, we focus on conspiracy thinking - a predisposition to interpret events as products of secret, malevolent plots - for which contextual confounds can be better isolated. We posit that social media use and conspiracy thinking are positively related, and examine whether this relationship stems from selectivity effects, media effects, or reinforcing effects. The analysis relies on a random intercept cross-lagged panel model estimated with data from an original three-wave panel survey (N = 331) fielded in Chile. Results support the existence of a reciprocal, lagged relationship between frequency of use of social media platforms, and conspiracy thinking. In line with recent studies on social media, the association becomes manifest at the within-, rather than between-, person level. We close with a discussion of how these results align with the reinforcing spirals model.
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    Amplifying Counter-Public Spheres on Social Media: News Sharing of Alternative Versus Traditional Media After the 2019 Chilean Uprising
    (2022) Luna, Juan Pablo; Toro, Sergio; Valenzuela, Sebastian
    While much research exists on the role of digital media use in protest movements, few studies compare the long-term impact of protests on online use of alternative and mainstream digital media. This holds particularly true in countries of the global south. Our study addresses this knowledge gap by examining the massive demonstrations that occurred in Chile on 18 October 2019. Based on data from 1,221,487 Facebook posts from 31 media outlets collected 10 months before and after the protests, we detected significant discontinuities in users' interactions with news content. Whereas both media types display different baseline levels, for alternative media, the time series reflects a "step" type of shock-a long-lasting increase in news sharing-whereas for mainstream media, it is a "pulse" type of shock-a burst of interactions that quickly returned to pre-existing levels. These results suggest that social media users relied on alternative news media to amplify counterpublic spheres in Chile.
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    Corruption and Political Knowledge Erosion. A Cautionary Tale from Latin America
    (OXFORD UNIV PRESS, 2022) Bargsted, Matias; Bachmann, Ingrid; Valenzuela, Sebastian
    Previous research has shown that corruption diminishes citizens' level of political support and engagement. We extend this line of reasoning and evaluate whether previous levels of perceived corruption can influence subsequent levels of political knowledge. We test this proposition with data from a two-wave panel probability survey applied in Chile between 2016 and 2017, just after a 2-year period in which an avalanche of corruption scandals shook the country. Our estimates confirm that perceived corruption reduces subsequent political knowledge, while controlling for prior knowledge. This pattern is particularly strong among non-ideologues and people ideologically distant from the incumbent government. Given the status of political knowledge as a democratically valuable trait, our results uncover some normatively disturbing consequences of corruption.
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    MEDIA AND POLITICAL TRUST IN LATIN AMERICA: AN INDIVIDUAL AND CONTEXTUAL ANALYSIS OF THE ROLE OF NEWS ON GOVERNMENT AND STATE TRUST
    (2022) Labarca, Claudia; Valenzuela, Sebastian; Bachmann, Ingrid; Grassau, Daniela
    What is the relationship between news exposure and political trust in Latin America? Does this relationship change according to freedom levels of media systems and degrees of political polarization? To answer these questions, this study analyzes data from 10 Latin American countries included in the last round of the World Values Survey (2017-2020) (N = 11,769), as well as indices of governments' intervention in the news system and polarization by the V-Dem project. Statistical results show that, in general, exposure to news on social media is negatively related to trust in government and state institutions. However, context makes a significant difference: the higher the level of media freedom and polarization, the more negative this relationship becomes. In contrast, traditional media news use is positively associated with political trust, regardless of contextual factors. This confirms the importance of considering micro and macro news media contexts when analyzing trust in Latin America.
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    Politics and Media in Journalism & Mass Communication Quarterly: A Centennial Research Retrospective
    (2023) Valenzuela, Sebastian; Bachmann, Ingrid; Lawrence, Regina G.; de Zuniga, Homero Gil
    Based on computerized and manual content analyses, we examined the theories, methods, topics, and authors' backgrounds of the empirical articles revolving around politics and media published by Journalism & Mass Communication Quarterly (JMCQ) in its 100 years (N = 424). The most common theories are agenda-setting, framing, and selective exposure, and quantitative methods prevail with single-country studies being more prevalent than comparative analyses. A considerable portion of research has focused on political news, particularly during campaigns. Male, U.S.-based authors dominate, but female-authored work has increased in the past decade. Challenges remain to make the research on politics and media in JMCQ more generalizable globally.
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    Targeting antisense mitochondrial ncRNAs inhibits murine melanoma tumor growth and metastasis through reduction in survival and invasion factors
    (IMPACT JOURNALS LLC, 2016) Lobos Gonzalez, Lorena; Silva, Veronica; Araya, Mariela; Restovic, Franko; Echenique, Javiera; Oliveira Cruz, Luciana; Fitzpatrick, Christopher; Briones, Macarena; Villegas, Jaime; Villota, Claudio; Vidaurre, Soledad; Borgna, Vincenzo; Socias, Miguel; Valenzuela, Sebastian; Lopez, Constanza; Socias, Teresa; Varas, Manuel; Diaz, Jorge; Burzio, Luis O.; Burzio, Veronica A.
    We reported that knockdown of the antisense noncoding mitochondrial RNAs (ASncmtRNAs) induces apoptotic death of several human tumor cell lines, but not normal cells, suggesting this approach for selective therapy against different types of cancer. In order to translate these results to a preclinical scenario, we characterized the murine noncoding mitochondrial RNAs (ncmtRNAs) and performed in vivo knockdown in syngeneic murine melanoma models. Mouse ncmtRNAs display structures similar to the human counterparts, including long double-stranded regions arising from the presence of inverted repeats. Knockdown of ASncmtRNAs with specific antisense oligonucleotides (ASO) reduces murine melanoma B16F10 cell proliferation and induces apoptosis in vitro through downregulation of pro-survival and metastasis markers, particularly survivin. For in vivo studies, subcutaneous B16F10 melanoma tumors in C57BL/6 mice were treated systemically with specific and control antisense oligonucleotides (ASO). For metastasis studies, tumors were resected, followed by systemic administration of ASOs and the presence of metastatic nodules in lungs and liver was assessed. Treatment with specific ASO inhibited tumor growth and metastasis after primary tumor resection. In a metastasis-only assay, mice inoculated intravenously with cells and treated with the same ASO displayed reduced number and size of melanoma nodules in the lungs, compared to controls. Our results suggest that ASncmtRNAs could be potent targets for melanoma therapy. To our knowledge, the ASncmtRNAs are the first potential non-nuclear targets for melanoma therapy.
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    What "Emergency Sources" Expect From Journalists: Applying the Hierarchy of Influences Model to Disaster News Coverage
    (2021) Grassau, Daniela; Valenzuela, Sebastian; Puente, Soledad
    This study analyzes what "emergency sources" (authorities, emergency managers, and experts) expect from journalists during a disaster, using a mixed-method approach with six focus groups and a survey of 166 official Chilean sources. Based on the first three levels of the hierarchy of influences model, we explore how they perceive journalists' roles and performance when covering disasters. The results suggest that emergency sources' evaluations, while affected by a combination of individual, routine, and organizational variables, are mostly shaped by sources' direct and mediated experience with journalists. Thus, a more fluid relationship between journalists and emergency sources, as well as more communication experience by sources, could lead to a better understanding between both groups, which, ultimately, may lead to delivering more accurate and timely information.