Academic literature on the topic 'Selective Exposure Theory'
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Journal articles on the topic "Selective Exposure Theory"
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D'Alessio, Dave, and Mike Allen. "Selective Exposure and Dissonance after Decisions." Psychological Reports 91, no. 2 (October 2002): 527–32. http://dx.doi.org/10.2466/pr0.2002.91.2.527.
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Well-known literature reviews from the 1960s question whether cognitive dissonance underlies experimental participants' selective exposure of themselves to consonant messages and avoidance of dissonant ones. A meta-analytic review of 16 studies published from 1956 to 1996 and involving 1,922 total participants shows that experimental tests consistently support the supposition that dissonance is associated with selective exposure ( r = .22, p < .001). Statistical power exceeded .99. Advances in statistical methodology and increased attention to selecting appropriate tests of dissonance theory were essential to finally resolving this question.
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Camaj, Lindita. "From Selective Exposure to Selective Information Processing: A Motivated Reasoning Approach." Media and Communication 7, no. 3 (July 30, 2019): 8–11. http://dx.doi.org/10.17645/mac.v7i3.2289.
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Literature suggests that while without doubt people engage in selective exposure to information, this does not entail that they also engage in selective avoidance of opinion-challenging information<em>.</em> However, cross-cutting exposure does not always lead to dispassionate deliberation. In this commentary I explore psychological conditions as they apply to attitude-based selection and make an argument that selectivity does not stop at exposure but continues as audiences engage with information they encounter and incorporate in their decision-making. I propose the theory of motivated reasoning as a rich theoretical underpinning that helps us understand selective exposure and selective information processing.
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Zillmann, Dolf. "Mood Management in the Context of Selective Exposure Theory." Annals of the International Communication Association 23, no. 1 (January 2000): 103–23. http://dx.doi.org/10.1080/23808985.2000.11678971.
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Humanes, María Luisa. "Selective Exposure in a Changing Political and Media Environment." Media and Communication 7, no. 3 (July 30, 2019): 1–3. http://dx.doi.org/10.17645/mac.v7i3.2351.
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Currently, the transformations occurring in media systems (especially those relating to technologies, the Internet and social networks) have led to a renewed interest in analysing the conditions that potentially foster selective exposure and, specifically, politically-oriented selection. As a result, that theory is now among the 21st century’s top eight most used approaches (Bryant & Miron, 2004, p. 696). This thematic issue addresses some of the key questions about selective exposure and associated phenomena by means of two comment articles and three research articles.
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Knobloch-Westerwick, Silvia, and Gregory J. Hoplamazian. "Gendering the Self." Communication Research 39, no. 3 (November 14, 2011): 358–84. http://dx.doi.org/10.1177/0093650211425040.
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Based on gender schema theory, social role theory, and social-cognitive theory, this study investigated whether biological sex and gender conformity (femininity and masculinity) predict selective exposure to gender-typed magazines and whether this exposure, in turn, reinforces gender conformity. Participants browsed full issues—three women’s magazines, three associated with male readers, and three news magazines—while being taped. Before and after browsing, participants indicated their femininity and masculinity. Results show a strong impact of biological sex on selective magazine reading, resulting in gender-typed media use. However, gender conformity also influenced exposure. Moreover, mediation analyses showed that selective exposure to gender-typed magazines had a reinforcing effect on the gendered self-concept.
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Barnidge, Matthew, and Cynthia Peacock. "A Third Wave of Selective Exposure Research? The Challenges Posed by Hyperpartisan News on Social Media." Media and Communication 7, no. 3 (July 30, 2019): 4–7. http://dx.doi.org/10.17645/mac.v7i3.2257.
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Hyperpartisan news on social media presents new challenges for selective exposure theory. These challenges are substantial enough to usher in a new era—a third wave—of selective exposure research. In this essay, we trace the history of the first two waves of research in order to better understand the current situation. We then assess the implications of recent developments for selective exposure research.
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Dahlgren, Peter M., Adam Shehata, and Jesper Strömbäck. "Reinforcing spirals at work? Mutual influences between selective news exposure and ideological leaning." European Journal of Communication 34, no. 2 (February 21, 2019): 159–74. http://dx.doi.org/10.1177/0267323119830056.
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The growth of partisan news sources has raised concerns that people will increasingly select attitude-consistent information, which might lead to increasing political polarization. Thus far, there is limited research on the long-term mutual influences between selective exposure and political attitudes. To remedy this, this study investigates the reciprocal influences between selective exposure and political attitudes over several years, using a three-wave panel survey conducted in Sweden during 2014–2016. More specifically, we analyse how ideological selective exposure to both traditional and online news media influences citizens’ ideological leaning. Findings suggest that (1) people seek-out ideologically consistent print news and online news and (2) such attitude-consistent news exposure reinforces citizens’ ideological leaning over time. In practice, however, such reinforcement effects are hampered by (3) relatively low overall ideological selective exposure and a (4) significant degree of cross-cutting news exposure online. These findings are discussed in light of selective exposure theory and the reinforcing spirals model.
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Wojcieszak, Magdalena, Erik C. Nisbet, Lea Kremer, Golnoosh Behrouzian, and Carroll Glynn. "What Drives Media Use in Authoritarian Regimes? Extending Selective Exposure Theory to Iran." International Journal of Press/Politics 24, no. 1 (November 7, 2018): 69–91. http://dx.doi.org/10.1177/1940161218808372.
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Most work on selective exposure comes from the United States or other western democracies and typically examines partisan attitudes as the cognitive or motivational drivers of selectivity. This study extends the boundary conditions of existing literature by studying the factors affecting media choice in the Islamic Republic of Iran, a drastically understudied context. Within the overarching framework of motivated reasoning, we propose two theoretically relevant factors that should drive selective exposure into regime media or non-regime alternatives in authoritarian contexts: (1) system-justifying attitudes and (2) regime-sanctioned identities, here religiosity. Relying on two different surveys conducted within Iran in 2012 and 2016, we find that religiosity strongly predicts the reliance on non-regime media in both studies, whereas system-justifying attitudes predict selectivity in Study 2. Theoretical implications for the selectivity literature are discussed.
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Illarionov, Valery. "Modern concepts of the general theory of physiotherapy." Fizioterapevt (Physiotherapist), no. 3 (June 1, 2020): 70–79. http://dx.doi.org/10.33920/med-14-2006-08.
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The article highlights the causes and eff ects of the interaction of external physical factors with the human body. The author refl ected the concepts of a “specifi c” reaction, a compensatory reaction, and an “selective” sensitivity of an organism to exposure to physiotherapeutic factors, a general adaptation syndrome, an activation reaction, a training reaction, resonance, and synchronization. In the article, the author talks about the main factors in constructing the general theory of physiotherapy.
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Knobloch-Westerwick, Silvia, Cornelia Mothes, and Nick Polavin. "Confirmation Bias, Ingroup Bias, and Negativity Bias in Selective Exposure to Political Information." Communication Research 47, no. 1 (July 18, 2017): 104–24. http://dx.doi.org/10.1177/0093650217719596.
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Selective reading of political online information was examined based on cognitive dissonance, social identity, and news values frameworks. Online reports were displayed to 156 Americans while selective exposure was tracked. The news articles that participants chose from were either conservative or liberal and also either positive or negative regarding American political policies. In addition, information processing styles (cognitive reflection and need-for-cognition) were measured. Results revealed confirmation and negativity biases, per cognitive dissonance and news values, but did not corroborate the hypothesis derived from social identity theory. Greater cognitive reflection, greater need-for-cognition, and worse affective state fostered the confirmation bias; stronger social comparison tendency reduced the negativity bias.
Dissertations / Theses on the topic "Selective Exposure Theory"
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Wang, Di. "The Effect of Motivation on Political Selective Exposure and Selective Perception." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/311554.
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This study examines the effect of motivation on political selective exposure and selective perception using an online experiment. Studies have found that though people have a preference for like-minded political information over counter-attitudinal information, they do not avoid counter-attitudinal political information altogether (Garrett, 2009; Garrett, Carnahan, & Lynch, 2011; Stroud, 2008). This study examines under what conditions people are likely to expose themselves to more like-minded information than counter-attitudinal information and under what conditions people are likely to seek out more counter-attitudinal information than like-minded information. Based on the theory of motivated reasoning and Hart et al. (2009)'s model, I proposed a model that explained selective exposure and selective perception based on motivation. Defense motivation, the motivation to hold attitude-consistent cognitions with one's original attitudes, beliefs, or behaviors, was predicted to increase selective exposure and selective perception. Accuracy motivation, the motivation to arrive at the correct conclusion, was predicted to reduce selective exposure and selective perception. Finally, information utility motivation, the motivation to choose information that has the highest utility, was predicted to reduce selective exposure when counter-attitudinal information was equally useful as attitude-consistent information, but increase selective exposure when attitude-consistent information was more useful than counter-attitudinal information. In both cases, it was predicted that the selective perception pattern would not be changed. The study also tested the additive effect of the three motivations and examined which motivation can override other motivations in determining selective exposure and selective perception. Results showed that accuracy motivation was effective in reducing selective exposure for both strong partisans and those who were not strong partisans. Accuracy motivation can override defense motivation in affecting selective exposure. Information utility alone, defense motivation alone, and the combination of the three motivations produced mixed results. Accuracy motivation was effective in reducing selective perception for those who were not strong partisans. The link between selective exposure and selective perception was not found.
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Alotaibi, Mohammad. "SELECTIVE EXPOSURE THEORY IN THE SOCIAL MEDIA ERA: EXAMINING SELECTIVITY ON TWITTER AMONG STUDENTS AT KUWAIT UNIVERSITY." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1673.
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The aim of this dissertation is to examine selective exposure theory on Twitter among student users at Kuwait University, and to revisit selective exposure theory’s assumptions in the social media era. Two studies for this dissertation have been conducted among a total of 1391 participants to examine the selective exposure theory among student Twitter users. In both studies, the researcher conducted an online experiment by developing simulated Twitter interface pages and a simulated news app to study selective exposure theory among Kuwait University students. The first study aimed to examine whether the students at Kuwait University tend to be exposed to politicians in Kuwait’s parliament who share the same political ideologies. The second study aimed to examine to what extent student users selectively expose themselves to specific content on Twitter, or more specifically to their like-minded group, and what drives them to do so. Moreover, the effect of Twitter’s social endorsement features on users' news selection has been examined. Each study sample has been drawn from different classes of students at Kuwait University. This study also looked at the role of incidental exposure as a means of encouraging cross-ideological exposure. One noticeable trend in the two experiments conducted for this dissertation is that partisan selective exposure was clear among students participating in both studies, but at different levels. Also, data showed that there was no clear role for the social endorsements on Twitter among students in this experiment to reduce selectivity. Moreover, a person's political leaning is more likely to surpass the impact of the social endorsements when users are browsing Twitter on a daily basis. Results showed that students in the second study read tweets from accounts they did not follow in real life and they asserted that they experienced that on a high basis. Implications of these two online experiment studies are discussed.
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Saleem, Fathima Zahara. "The symbiotic relationship of social media content creation and consumption: a mood management and selective exposure theory perspective." Doctoral thesis, Universitat Ramon Llull, 2014. http://hdl.handle.net/10803/283807.
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En la recerca sobre el consum dels llocs personals a les xarxes socials, com Facebook, YouTube i Instagram, han predominat els projectes basats en la identitat en què les persones utilitzen l’espai online per crear i projectar les identitats que coldrien tenir per mitjà d’un procés de gestió de la imatge. En aquest recerca, es presenta una conceptualització alternativa de l’ús de les xarxes socials, incloent-hi la creació i el consum de continguts, que utilitza la teoria de la gestió dels estats d’ànim i l’exposició selectiva que es deriva de la psicologia dels mitjans. La teoria de la gestió dels estats d’ànim estipula que les persones intenten readaptar el seu entorn d’estímuls per incrementar la durada i la intensitat dels bons moments i reduir la intensitat i la durada dels mals moments. En conseqüència, aquesta recerca té una triple finalitat: 1) explicar amb detall el procés de gestió de l’estat d’ànim col•lectiu en els llocs personals de les xarxes socials, incloent-hi la creació selectiva i el consum selectiu de continguts; 2) il•lustrar sobre les conseqüències d’una cultura de gestió de l’estat d’ànim col•lectiu en les xarxes socials, i 3) identificar formes en què les marques es poden afermar en una cultura de gestió dels estats d’ànim a les xarxes socials i a través d’elles. A partir de 15 llargues entrevistes de més de dues hores de durada cadascuna i de les dades recollides durant vuit mesos d’informació online dels perfils de Facebook dels enquestats, trobem que les persones creen col•lectivament uns continguts en els seus llocs personals de les xarxes socials que són bàsicament positius i divertits, que fan que els continguts visibles a les xarxes socials siguin predominantment positius i divertits. Aquest fenomen s’explica estudiant detingudament els tipus de continguts que creen les persones, els tipus de continguts que no creen, els tipus de continguts que consumeixen online i els que no consumeixen. Les nostres conclusions demostren que l’ús de les xarxes socials implica una combinació de comportaments contraris i contradictoris. Les marques necessiten entendre la cultura que han creat els consumidors de les xarxes socials, no tan sols per determinar com penetrar i actuar en aquesta cultura, sinó també per trobar noves vies al creixement, més enllà de la comunicació bidireccional i de la construcció de relacions, en què les experiències també s’ofereixin a través de les xarxes socials.En la investigación sobre el consumo de los sitios personales en las redes sociales, como Facebook, YouTube e Instagram, han predominado los proyectos de base identitaria en que las personas utilizan el espacio online para crear y proyectar aquellas identidades que desearían tener a través de un proceso de gestión de la imagen. En esta investigación, se presenta una conceptualización alternativa del uso de las redes sociales, incluyendo la creación y el consumo de contenidos, que utiliza la teoría de la gestión de los estados de ánimo y la exposición selectiva que se deriva de la psicología de los medios. La teoría de la gestión de los estados de ánimo estipula que las personas intentan readaptar su entorno de estímulos para incrementar la duración y la intensidad del buen humor y reducir la intensidad y la duración del mal humor. En consecuencia, esta investigación tiene una triple finalidad: 1) explicar en detalle el proceso de gestión del estado de ánimo colectivo en los sitios personales de las redes sociales, incluyendo la creación selectiva y el consumo selectivo de contenidos; 2) arrojar luz sobre las consecuencias de una cultura de gestión del estado de ánimo colectivo sobre las redes sociales, y 3) identificar formas en que las marcas pueden afianzarse en una cultura de gestión de los estados de ánimo en y a través de las redes sociales. Utilizando 15 largas entrevistas de más de dos horas de duración cada una y datos recogidos de ocho meses de información online de los perfiles de Facebook de los encuestados, hallamos que las personas crean colectivamente unos contenidos en sus sitios personales de las redes sociales que son básicamente positivos y divertidos, que hacen que los contenidos visibles en las redes sociales sean predominantemente positivos y divertidos. Este fenómeno se explica estudiando en detalle los tipos de contenidos que crean las personas, los tipos de contenidos que no crean, los tipos de contenidos que consumen online y los que no consumen. Nuestras conclusiones demuestran que el uso de las redes sociales implica una combinación de comportamientos contrarios y contradictorios. Las marcas necesitan entender la cultura creada por los consumidores de las redes sociales no solo para determinar cómo penetrar y actuar en dicha cultura, sino también para hallar nuevas vías al crecimiento más allá de la comunicación bidireccional y de la construcción de relaciones, en que las experiencias también se ofrezcan a través de las redes sociales.
Research on the consumption of personal social media sites, such as Facebook, YouTube and Instagram, has been dominated by identity-based projects in which individuals use the online space to create and project their desired identities through the process of image-management. In this research, an alternative conceptualization of social media usage, comprising content creation and consumption, is presented using mood management and selective exposure theory derived from media psychology. Mood management theory stipulates that individuals attempt to rearrange their stimulus environment so as to increase the duration and intensity of good moods and reduce the intensity and duration of bad ones. Subsequently, the aims of this research are threefold: (1) to elaborate on the process of collective mood management on personal social media sites, including selective content creation and selective content consumption; (2) to shed light on the consequences of a culture of collective mood management on social media networks; and (3) to identify ways in which brands can leverage themselves in a culture of mood management on and through social media. Using 15 long interviews spanning two hours each and data collected from eight months of online observation of the respondents’ Facebook profiles, I find that individuals collectively create content on their personal social media sites that is primarily positive and entertaining, leading to predominantly positive and entertaining content visible on social media networks. This phenomenon is explained by elaborating on the types of content that individuals create, the types of content they do not create, the types of content that persons consume online and those which they do not consume. The findings demonstrate that social media usage involves a combination of contrary and contradictory behaviours. Understanding the culture created by consumers of social media is not only necessary for brands to determine how to penetrate and engage in such a culture, but is also relevant for brands to find avenues for growth beyond two-way communication and relationship building, in which experiences are also delivered through social media networks.
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Cui, Xiyan. "Self-Disclosure Relies on Social Context: Examining the Similarity and Differences of Chinese Students in the U.S. and China when Disclosing Information on WeChat." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etd/2604.
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This research aims to fill a research gap by examining WeChat to explore whether changes of social context would exert any influence on the information disclosure of social networking site (SNS) users. Selective Exposure Theory and Uses and Gratification Theory were used as the theoretical foundation for this study. Four-hundred Chinese college students in China and the U.S. who have a WeChat App and have logged in to use it within the last 30 days from the day administered were asked to participate in a survey about their motivations and consequences when using WeChat. Results from MANOVA showed that the motivations and consequences of female participants’ self-disclosure were significantly higher than were male participants on WeChat. Moreover, the social context of Chinese students studying in the U.S. is perceived to be more individualized than the traditionally collective context that is perceived by Chinese students studying in China.
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Holesova, Gabriela. "The role of digital media in the dissemination of Covid-19 conspiracy theories: The case of Czech conspiracy theory believers." Thesis, Malmö universitet, Institutionen för konst, kultur och kommunikation (K3), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-44407.
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The spread of the Covid-19 pandemic has been since its early beginnings accompanied by the spread of the so called 'infodemic' of misinformation and conspiracy theories about the virus in the media. This infodemic swiftly started to present a matter of significant concern especially in the dynamic landscape of digital media which due to an ease of sharing and content contribution allowed for Covid-19 conspiracy theories to continue to gain momentum. Because of the severe implications that the potential ill-informed actions of conspiracy theory believers could have on the public health, it is necessary to gain a better understanding of the conspiracy theory believers and the way that they spread Covid-19 conspiracy theories. With this in mind, this thesis through the use of qualitative interviews probed into the worldviews of Covid-19 conspiracy theory believers in the Czech Republic. The analytical scrutiny of the interviews through the lens of the theories of network society, context collapse and echo chambers provided important insights into how Czech Covid-19 conspiracy theory believers use digital media in order to learn about and disseminate Covid-19 conspiracy theories. Additionally, this thesis provides an understanding of how the way the conspiracy theory believers navigate context collapse on Facebook drives them to seek echo chambers on e-mail which strengthen their beliefs in Covid-19 conspiracy theories. Moreover, my thesis also sheds light onto how the echo chambers are instrumental in the individuals' distrust in traditional media.
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Ahn, Sun Young, and Sun Young Ahn. "Change to Sustainable Choice: The Role of Preference-Inconsistent Information." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621748.
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Cognitive dissonance theory and selective information exposure literature postulate that individuals ignore preference-inconsistent information and selectively process new information. Previous studies on selective information exposure have shown that preference-inconsistent information is not persuasive for consumer decision making. Given the limited amount of past research about the effect of preference-inconsistent information on decision-making in broad domains of consumer behavior studies, the current study investigated how preference-inconsistent information can persuade consumers to switch to a sustainable product alternative. The purpose of this study is to investigate the process how preference-inconsistent sustainability-related information can be considered as important, consequently changing consumers' initial preference to green alternatives. A series of online experiments was conducted using a shampoo product category. Study 1 tested a baseline effect on whether consumers in the preference-inconsistent condition were persuaded to change their initial choice significantly compared to those in the preference-consistent condition. Study 2 tested the effect of preference-inconsistent sustainability-related information in the acceptance process, focusing on the role of brand commitment and information quality. Study 3 examined the effect of preference-inconsistent sustainability-related information in the evaluation process, investigating the impact of consumer environmental concern and PCE. Findings of Study 1 revealed that consumers in the preference-inconsistent condition were significantly persuaded to change choice to a sustainable alternative, which is not consistent with selective exposure literature. However, Study 1 findings were not sufficient to determine what specific factors influenced respondents to be persuaded, which provides justifications for Study 2 and Study 3. Findings in Study 2 and Study 3 conclusively demonstrated the importance of the credibility of preference-inconsistent information in the acceptance process. Also, findings suggested that the effect of credibility is stronger than that of brand commitment in the acceptance process. Regarding brand commitment, the results have shown that high commitment consumers had a higher acceptance of inconsistent information which is opposite to expectations. Further, the findings demonstrated the importance of environmental concern and the conditional effect of PCE in the evaluation process. Moreover, results supported that the relative weighting of sustainability attributes is driving the effects of environmental concern and PCE as a mediator on persuasion outcomes in the evaluation process. The current study contributes to understanding the process in which the preference-inconsistent information can be effective in influencing consumer choice. Moreover, findings from this research can provide implications for selective exposure literature and sustainable consumption literature. Practically, the results of the study provide implications to guide marketers and information providers in establishing effective ways to change consumers' behavior in sustainable consumption context.
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Lindahl, Jesper. "Papegojornas ekokammare : En argumentationsanalys av kommentarer på Reddit." Thesis, Högskolan för lärande och kommunikation, Högskolan i Jönköping, HLK, Medie- och kommunikationsvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-38760.
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Den här studien undersöker hur diskussioner på ekokammare ser ut i sociala medier. Mer specifikt undersöks kommentarsfälten i två olika länkar från den sociala länkaggregatorn Reddit och underforumet /r/Politics. Undersökningen görs i syfte att se hur diskussioner tar form på Reddit för att ge en klarare bild av ekokammare som fenomen på internet. Studiens teoretiska grund ligger i teorierna om selektiv exponering och partisk assimilering, samt i en teoretisering av hur grupper formas på de sociala medierna Twitter och Reddit. Studien använder sig av både en kvantitativ innehållsanalys och en kvalitativ textanalys, vilka främst grundar sig i argumentationsanalysen. Innehållsanalysen används först för att jämföra /r/Politics användares ställningstagande till de länkar som de kommenterar på och sedan för att möjliggöra en korrelationsanalys av arguments styrka och dess användargivna poäng på Reddit. Textanalysen görs med hjälp av begrepp från argumentationsanalysen och används för att sätta in studiens material i fem olika teman. Det mest framträdande temat får namnet Kommentarer av papegojor och beskriver kommentarer som konstrueras likadant som tidigare kommentarer utan försök till att föra något nytt till diskussionen. Överlag visar studiens resultat att responsen ser likadan ut för båda länkarna och att en stor majoritet av kommentarerna är på samma sida i argumentet. Resultatet visar också att argumentens styrka är oberoende av om en kommentar får en positiv respons eller inte.This study explores how discussions in echo chambers take form on social media. More specifically, the study explores the comment section of two different links on the social news-aggregator website Reddit and the sub-forum /r/Politics. The purpose of the aforementioned exploration is to give a clearer picture of echo chambers as a phenomena on the Internet. The study’s theoretical background is based on selective exposure and biased assimilation theory, as well as a theorization of how groups form on Twitter and Reddit. The study uses a quantitative content analysis and a qualitative text analysis, which are both based on argumentation theory. The content analysis is first used to compare the viewpoint of /r/Politics users with the subject of the links they comment on, and then to make a correlation analysis of the strength of arguments and the arguments’ user-given points on Reddit. Last a qualitative text analysis is done using concepts from argumentation theory, which allows for the observation of five different themes. The most prominent of these themes was given the name Comments by parrots and describes comments that are constructed in a similar fashion to older comments, without an attempt to bring something new to the discussion. Overall, the study’s result shows that the response to the two links is similar, and that both have an overwhelming majority of comments supporting one side. The result also shows that a strong argument does not necessarily mean that the comment will get a positive response.
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Kalinowski, Kevin E. Henson Robin K. "Stratified item selection and exposure control in unidimensional adaptive testing in the presence of two-dimensional data." [Denton, Tex.] : University of North Texas, 2009. http://digital.library.unt.edu/permalink/meta-dc-11029.
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Kalinowski, Kevin E. "Stratified item selection and exposure control in unidimensional adaptive testing in the presence of two-dimensional data." Thesis, University of North Texas, 2009. https://digital.library.unt.edu/ark:/67531/metadc11029/.
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It is not uncommon to use unidimensional item response theory (IRT) models to estimate ability in multidimensional data. Therefore it is important to understand the implications of summarizing multiple dimensions of ability into a single parameter estimate, especially if effects are confounded when applied to computerized adaptive testing (CAT). Previous studies have investigated the effects of different IRT models and ability estimators by manipulating the relationships between item and person parameters. However, in all cases, the maximum information criterion was used as the item selection method. Because maximum information is heavily influenced by the item discrimination parameter, investigating a-stratified item selection methods is tenable. The current Monte Carlo study compared maximum information, a-stratification, and a-stratification with b blocking item selection methods, alone, as well as in combination with the Sympson-Hetter exposure control strategy. The six testing conditions were conditioned on three levels of interdimensional item difficulty correlations and four levels of interdimensional examinee ability correlations. Measures of fidelity, estimation bias, error, and item usage were used to evaluate the effectiveness of the methods. Results showed either stratified item selection strategy is warranted if the goal is to obtain precise estimates of ability when using unidimensional CAT in the presence of two-dimensional data. If the goal also includes limiting bias of the estimate, Sympson-Hetter exposure control should be included. Results also confirmed that Sympson-Hetter is effective in optimizing item pool usage. Given these results, existing unidimensional CAT implementations might consider employing a stratified item selection routine plus Sympson-Hetter exposure control, rather than recalibrate the item pool under a multidimensional model.
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Lavigne-Desnoyers, Gabrielle. "Le processus d'adhésion aux citoyens souverains : une étude exploratoire du phénomène au Québec." Thèse, 2016. http://hdl.handle.net/1866/19525.
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Il est difficile de définir le groupe des citoyens souverains car il a été très peu étudié. Selon les sources, il s’agit d’un groupe terroriste, d’un groupe sectaire ou d’un mouvement radical. La Gendarmerie royale du Canada, les tribunaux et certains services fédéraux et provinciaux prennent des mesures pour contrer l’impact des actions criminelles qu’ils commettent. Pour sa part, le Service canadien du renseignement de sécurité (SCRS) n’identifie pas ce groupe comme une entité terroriste. L’objectif de ce mémoire n’est pas de définir le groupe des citoyens souverains, mais plutôt de comprendre le processus d’adhésion à ce groupe au Québec. À l’aide de la théorie de l’action situationnelle, il démontre les étapes de la création d’un filtre moral chez les adhérents au mouvement. Par induction analytique à partir de témoignages de membres du groupe, il présente les conditions nécessaires à l’adhésion aux citoyens souverains. Parmi celles-ci, on retrouve la victimisation et l’exposition sélective aux théories du complot. Ce mémoire est la première étude qui sonde le point de vue des adhérents pour permettre de comprendre comment ils en viennent à commettre des gestes illégaux qu’eux considèrent légitimes.Groups of sovereign citizens are hard to define since they are the subject of very few studies. According to sources, they are terrorist groups or sectarian groups or they are part of a radical movement. The Royal Canadian Mounted Police, courts and some federal and provincial departments and agencies are taking measures to offset the impact of criminal actions they commit. As for the Canadian Security Intelligence Service (CSIS), it does not consider these groups as terrorist entities. The purpose of this thesis is not to define these groups per se, but rather to understand the enrolment process for Quebec sovereign citizens. Through situational action theory, it shows the various steps involved in the creation of a moral filter by this movement’s members. By analytic induction based on testimonies of group members, it shows the prerequisites for enrolling in the sovereign citizen movement – such as victimization and selective exposure to conspiracy theories. This thesis is the first study to poll the views of these members in order to understand how they get to commit illegal acts that they consider to be totally legitimate.
Books on the topic "Selective Exposure Theory"
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Stroud, Natalie Jomini. Selective Exposure Theories. Edited by Kate Kenski and Kathleen Hall Jamieson. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199793471.013.009.
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This chapter provides an overview of the theory of selective exposure, the idea that people purposefully select messages matching their beliefs. After reviewing several psychological explanations for why the phenomenon occurs, the chapter turns to describing various forms of selective exposure. Selective exposure can be studied in terms of whether people select news or entertainment, the issues about which people seek information, which medium is selected in obtaining information, and the extent to which like-minded information is preferred. Numerous moderators of the links between citizens’ beliefs and their information selection are presented. Next, the chapter details four different methodological techniques that have been used to study selective exposure. Finally, the chapter outlines a host of unanswered questions about selective exposure for future researchers to tackle.
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Stroud, Natalie Jomini. Selective Exposure Theories. Edited by Kate Kenski and Kathleen Hall Jamieson. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199793471.013.009_update_001.
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This chapter provides an overview of the theory of selective exposure, the idea that people purposefully select messages matching their beliefs. After reviewing several psychological explanations for why the phenomenon occurs, the chapter turns to describing various forms of selective exposure. Selective exposure can be studied in terms of whether people select news or entertainment, the issues about which people seek information, which medium is selected in obtaining information, and the extent to which like-minded information is preferred. Numerous moderators of the links between citizens’ beliefs and their information selection are presented. Next, the chapter details four different methodological techniques that have been used to study selective exposure. Finally, the chapter outlines a host of unanswered questions about selective exposure for future researchers to tackle.
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Suls, Jerry, and Ladd Wheeler. On the Trail of Social Comparison. Edited by Stephen G. Harkins, Kipling D. Williams, and Jerry Burger. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199859870.013.13.
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Social comparison, a major source of social influence, refers to the selection and utilization of information about other people’s standings and opinions to make accurate self-assessments or to protect or enhance self-esteem. We survey the development of comparison theory over six decades, its ambiguities, and reformulations based on the psychology of attribution and social cognition. Selective comparisons allow people to gauge how well they have fulfilled their potential and capacity to accomplish important tasks, and whether their beliefs, values, and actions are appropriate and worthwhile. Exposure to superior and inferior targets shifts self-evaluations toward (assimilation) or away (contrast) from the targets, depending on the kinds of information made cognitively accessible by the situation or by individual differences. To illustrate comparison’s effects on social influence, applications, such as the effects of academic tracking on self-esteem and effects of large social networks on mental and physical health outcomes, are described.
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Costello, Sadie, Jennifer M. Cavallari, David H. Wegman, Marie S. O’Neill, and Ellen A. Eisen. Epidemiology. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190662677.003.0005.
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This chapter describes the basic principles of epidemiology, emphasizing the aspects most relevant to studies of health effects from occupational and environmental exposures. Numerous examples are provided of how epidemiology can be used to identify and quantify the relations between recent or long-term exposure and health outcomes, such as prevalence or incidence of disease, injury, or mortality. The chapter describes the common study designs, including cohort studies, case-control studies, and cross-sectional studies, with examples of their application. Key aspects of exposure assessment and characterizing and quantifying exposure, are described. The three types of bias in epidemiology, information, selection, and confounding, are defined as well as the healthy worker effect, a potential source of bias unique in occupational studies. Study designs and analytic methods that can reduce or eliminate specific types of bias are also described. Finally, the chapter provides guidance on how to interpret the results of studies, with an eye toward causal inference.
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Iyengar, Shanto. A Typology of Media Effects. Edited by Kate Kenski and Kathleen Hall Jamieson. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199793471.013.49.
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This chapter discusses the progression of mass media effects research from early preoccupation with attitude change through minimal effects paradigms to the current resurgence in persuasion research. Implications of contemporary changes in the media environment on media effects research are considered. After surveying and classifying definitions of media effects, the chapter discusses how fundamental transformations in the media environment brought about by information technology may work to reshape scholarly understandings of the relationship between news sources and audiences. The availability of multiple sources makes it possible for consumers to be more selective in their exposure to news programs. Selective exposure means that people with limited interest in politics may bypass the news entirely, while the more attentive may tailor their exposure to suit their political preferences. Both these trends imply a weakening of persuasion effects.
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Weil, Andrew. Integrative Environmental Medicine. Edited by Aly Cohen and Frederick S. vom Saal. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190490911.001.0001.
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Integrative Environmental Medicine looks at the history and changing landscape of environmental issues in the United States, including water supply, air quality, extensive plastic pollution, harmful chemicals in cleaning and personal care products, radiofrequency radiation, food additives, pesticides, and medications. The unique properties of compounds such as endocrine-disrupting chemicals are explored along with their ability to disturb the body’s normal signaling pathways, genetic profile, and gut microbiome. Resulting molecular derangements promote thyroid and other autoimmune diseases, diabetes, cardiovascular disease, cancer, and influence developmental problems in children. Analysis of current research identifies ways to reduce exposures and health risks, improve regulations and appropriate testing for chemicals, remediate environmental pollution, and design healthier products for the future. Best practices are considered for clinicians to ascertain exposure history, test for toxins, and teach patients how to avoid harmful exposures. Patients will be prepared and empowered with information about healthier food choices and cooking practices, appropriate supplement use, water filtration, cleaning and personal care product selection, improved sleep, stress reduction, sauna, fasting, chelation, safe cell phone use, and other means of reducing harmful environmental exposures. Solutions at every level require interdisciplinary collaboration to advance assessment, design, stewardship, and regulation of chemicals to promote environmental and human health.
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Amirian, E. Susan, Quinn T. Ostrom, Yanhong Liu, Jill Barnholtz-Sloan, and Melissa L. Bondy. Nervous System. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190238667.003.0056.
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Although brain and other nervous system tumors are relatively rare, constituting up to 4% of incident primary cancer diagnoses, they are often associated with high morbidity and mortality. Several etiologic factors have been examined in relation to nervous system tumors, with the majority of studies focusing on central nervous system tumors. Despite decades of research, the only established risk factors for brain tumors are family history and moderate to high levels of ionizing radiation exposure. Differences in study designs, case ascertainment, control selection, and accuracy of exposure assessment are challenges associated with studying risk factors for nervous system tumors, and may partly explain why the majority of risk for these tumors remains unexplained. There is now substantial evidence that gliomas are inversely associated with allergies and atopy and positively associated with taller height.
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Cappella, Joseph N., Jingwen Zhang, and Vincent Price. Collective Intelligence. Edited by Kate Kenski and Kathleen Hall Jamieson. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199793471.013.014.
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The rise of the Internet and social media reignites interest in collective intelligence. We frame collective intelligence as follows: (1) Simple aggregation of individual opinion is a poor substitute for reasoned opinion by collectives (i.e., deliberation) except in limited circumstances. (2) What constitutes an intelligent decision on complex matters requires approximations to the ideal of what is intelligent. There is no “gold standard” for intelligent decisions. (3) If collective deliberation is to be useful, then its outcomes must be improved decisions—in short, intelligent outcomes. (4) Deliberation can lead to more intelligent outcomes when opinion, knowledge, and judgment within a collective is diverse and this diversity is expressed. (5) The trends within emerging media toward increasingly narrow, partisan sources of information, toward selective exposure and avoidance, and toward balkanization of collectives will depress the possibilities of collective intelligence that emerging media would on their surface seem to enhance.
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Barr, Christina S. Gene-by-Environment Interactions in Primates. Edited by Turhan Canli. Oxford University Press, 2014. http://dx.doi.org/10.1093/oxfordhb/9780199753888.013.006.
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Because of their complex social structures, behaviors, and genetic similarities to humans, nonhuman primates are useful for studying how genetic factors influence alcohol consumption. The neurobiological systems that influence addiction vulnerability may do so by acting on alcohol response, reward pathways, behavioral dyscontrol, and vulnerability to stress and anxiety. Rhesus macaques show individual differences in alcohol response and temperament, and such differences are influenced by genetic variants that are similar functionally to those present in humans. Genes in which variation moderates these phenotypes provide opportunities for modeling how genetic and environmental factors (i.e., stress exposure, individual’s sex, or alcohol response) interact to influence alcohol consumption. Studies in primates may also reveal selective factors that have driven maintenance or fixation of alleles that increase risk for alcohol use disorders in modern humans.
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Boido, Claudio. Asset Allocation Strategies and Commodities. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190656010.003.0021.
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As a result of the financial crisis of 2007–2008 and subsequent central banking decisions, the asset management industry changed its asset allocation choices. Asset managers are focusing their attention on the search for new asset classes by taking advantage of the new opportunities to capture risk premia with the aim of exceeding the returns given by traditional investments, including traded equities, fixed income securities, and cash. By doing so, they are trying to improve the selection of alternative assets, such as commodities that sometimes have relatively low correlations with traditional assets. The chapter begins by describing the principles of asset allocation, distinguishing between passive and active asset allocation, also focusing on beta and alternative beta. It then concentrates on how investors can gain exposure to commodities through different investment vehicles and strategies.
Book chapters on the topic "Selective Exposure Theory"
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Vrijenhoek, Sanne, and Natali Helberger. "Pitch Proposal: Recommenders with a Mission - Assessing Diversity in News Recommendations." In ECML PKDD 2020 Workshops, 554–61. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-65965-3_38.
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AbstractBy helping the user find relevant and important online content, news recommenders have the potential to fulfill a crucial role in a democratic society. Simultaneously, recent concerns about filter bubbles, fake news and selective exposure are symptomatic of the disruptive potential of these digital news recommenders. Recommender systems can make or break filter bubbles, and as such can be instrumental in creating either a more closed or a more open internet. This document details a pitch for an ongoing project that aims to bridge the gap between normative notions of diversity, rooted in democratic theory, and quantitative metrics necessary for evaluating the recommender system. Our aim is to get feedback on a set of proposed metrics grounded in social science interpretations of diversity.
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Stroud, Natalie Jomini. "Selective Exposure in Theory and in Practice." In Niche News, 14–33. Oxford University Press, 2011. http://dx.doi.org/10.1093/acprof:oso/9780199755509.003.0002.
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Prieto Curiel, Rafael. "Opinion Dynamics and the Inevitability of a Polarised and Homophilic Society." In Theory of Complexity - Definitions, Models, and Applications [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96989.
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A polarised society is frequently observed among ideological extremes, despite individual and collective efforts to reach a consensual opinion. Human factors, such as the tendency to interact with similar people and the reinforcement of such homophilic interactions or the selective exposure and assimilation to distinct views are some of the mechanisms why opinions might evolve into a more divergent distribution. A complex model in which individuals are exposed to alternating waves of propaganda which fully support different extreme views is considered here within an opinion dynamics model. People exposed to different extreme narratives adopt and share them with their peers based on the persuasiveness of the propaganda and are mixed with their previous opinions based on the volatility of opinions to form a new individual view. Social networks help capture elements such as homophily, whilst persuasiveness and memory capture bias assimilation and the exposure to ideas inside and outside echo chambers. The social levels of homophily and polarisation after iterations of people being exposed to extreme narratives define distinct trajectories of society becoming more or less homophilic and reaching extremism or consensus. There is extreme sensitivity to the parameters so that a small perturbation to the persuasiveness or the memory of a network in which consensus is reached could lead to the polarisation of opinions, but there is also unpredictability of the system since even under the same starting point, a society could follow substantially different trajectories and end with a consensual opinion or with extreme polarising views.
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Kearney, Christopher A. "Exposure-Based Practice." In Helping Children with Selective Mutism and Their Parents, 52–72. Oxford University Press, 2010. http://dx.doi.org/10.1093/med:psych/9780195394542.003.0003.
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Kearney, Christopher A. "Exposure-Based Practice." In Helping Children with Selective Mutism and Their Parents, 73–95. Oxford University Press, 2010. http://dx.doi.org/10.1093/med:psych/9780195394542.003.0004.
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Kaye, Barbara K., Thomas J. Johnson, and Peter Muhlberger. "Blogs as a Source of Democratic Deliberation." In Blogging in the Global Society, 1–18. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-60960-744-9.ch001.
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This chapter examines the deliberative potential of blogs and blog users. It investigates whether heavy reliance on blogs promotes positive characteristics—political efficacy, political interest, and political involvement—needed to foster democratic deliberation, or whether it leads to negative attributes—low trust, selective exposure, and political partisanship—that hinder democratic deliberation. Results show that unlike those who rarely rely on blogs, heavily dependent individuals are more involved in current events and are more trusting of the government, but they are also more likely to practice selective exposure by reading ideologically consistent blogs. Further, heavy reliance predicts involvement and selective exposure. The deliberative potential of blogs is boosted by users’ involvement in political issues but impeded by their propensity to seek out blogs that contain agreeable information. Instead of evolving into a public sphere, blogs may be becoming issue-oriented zones in which deliberation is limited to an ideological perspective.
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Saxena, Richa, and Shweta Saxena. "A Review on Chemsensors." In Environmental Exposures and Human Health Challenges, 133–46. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-7635-8.ch006.
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Chemsensors have been playing a crucial role in various aspects of biomedical science, analytical and environmental chemistry. The toxic metal ions like Zn, Cd, Cu, Pb and Hg have increased gradually but now have reached an alarming situation, crossing the threshold value. Due to high toxicity of these heavy metals there is an obvious need for a sensor system to detect their presence. Chemsensors including surface acoustic wave sensors, enzymes, carbon nanotubes, nanoparticles, and chromophore-based sensors have attracted increasing attention over the last few years. Chemsensors prove very promising as the system is rapid, selective, sensible, low-cost, easy-to-use, and has the ability to provide real-time signals. However, recently, considerable effort has been devoted to the synthesis of sterically encumbered selenium containing species reported to display strong affinities with Hg2+ or Ag2+. This chapter reviews the basic principles involved in the design of chemsensors, their variety and applications in various established and emerging fields.
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McCarty, Richard. "Stress and Anxiety Disorders." In Stress and Mental Disorders: Insights from Animal Models, 329–64. Oxford University Press, 2020. http://dx.doi.org/10.1093/med-psych/9780190697266.003.0011.
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Much of the research relating to animal models of anxiety has been devoted to developing more effective drugs for the treatment of the various anxiety disorders. Using selective breeding of laboratory mice and rats, investigators have developed high-anxiety and low-anxiety lines that have been especially valuable for basic research purposes. Other approaches to enhance the expression of an anxiety-like phenotype have included prenatal or early postnatal exposure to stressors, maternal immune activation, or selecting offspring based upon differences in the maternal behaviors of their mothers. In addition, risk genes for anxiety disorders have been studied in animal models, including genes related to serotonin, neuropeptide Y, neuropeptide S, and corticotropin-releasing factor signaling in the brain. Finally, some infant rhesus monkeys display an anxious temperament and extreme behavioral inhibition when separated from their mothers. This nonhuman primate model affords many opportunities to explore brain mechanisms and interventions that may be effective in preventing the further development of an anxious phenotype as these monkeys mature.
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Senapati, Sibananda, and Vijaya Gupta. "Vulnerability to Climate Change." In Advances in Environmental Engineering and Green Technologies, 82–104. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-8814-8.ch005.
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This paper is based on a detail review of literature available in the area of climate change, vulnerability and impact assessment. Methodological issues pertaining to vulnerability like; development of vulnerability indicators, process of indicator selection etc are the main focus in this paper. As discussed indicators are more acceptable, easy to understand and help in comparing across regions. However, indicators also possess a number of limitations. There are issues in selecting indicators and how to aggregate their values. The current study tries to overcome those issues through a primary study. The study region is Mumbai, India and ‘Koli' fishing communities reside in the city. The socio-economic implications of climate change and vulnerability of communities depending on fishery are estimated by developing vulnerability indicators using Sustainable Livelihood Approach (SLA), and Analytic Hierarchy Process (AHP). Further experts opinions are considered while selecting indicators. Vulnerability indicators are derived from literature and validated through experts' opinion. Experts are chosen from higher learning institutes in the city. In the climate change literature vulnerability mainly divided into exposure, sensitivity and adaptive capacity. The indicators of sensitivity and exposure under vulnerability are combined here and categorized into two: livelihood and perceived changes. Similarly the indicators of adaptive capacity are of five categories comprising human, physical, financial, social and government policy related indicators. Thus a total 30 indicators are selected. Among five fishing villages surveyed, fishermen from Madh and Worli are found more vulnerable because of their high sensitivity and low adaptive capacity. The derived vulnerability scores are further compared and analyzed against the scores derived from experts. The overall result shows the experts value of indicators are similar with the indicator score derived in the study using simple aggregate method. This study further provides policy implications for reducing vulnerability of fishing villages.
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Senapati, Sibananda, and Vijaya Gupta. "Vulnerability to Climate Change." In Natural Resources Management, 1393–416. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-0803-8.ch066.
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This paper is based on a detail review of literature available in the area of climate change, vulnerability and impact assessment. Methodological issues pertaining to vulnerability like; development of vulnerability indicators, process of indicator selection etc are the main focus in this paper. As discussed indicators are more acceptable, easy to understand and help in comparing across regions. However, indicators also possess a number of limitations. There are issues in selecting indicators and how to aggregate their values. The current study tries to overcome those issues through a primary study. The study region is Mumbai, India and ‘Koli' fishing communities reside in the city. The socio-economic implications of climate change and vulnerability of communities depending on fishery are estimated by developing vulnerability indicators using Sustainable Livelihood Approach (SLA), and Analytic Hierarchy Process (AHP). Further experts opinions are considered while selecting indicators. Vulnerability indicators are derived from literature and validated through experts' opinion. Experts are chosen from higher learning institutes in the city. In the climate change literature vulnerability mainly divided into exposure, sensitivity and adaptive capacity. The indicators of sensitivity and exposure under vulnerability are combined here and categorized into two: livelihood and perceived changes. Similarly the indicators of adaptive capacity are of five categories comprising human, physical, financial, social and government policy related indicators. Thus a total 30 indicators are selected. Among five fishing villages surveyed, fishermen from Madh and Worli are found more vulnerable because of their high sensitivity and low adaptive capacity. The derived vulnerability scores are further compared and analyzed against the scores derived from experts. The overall result shows the experts value of indicators are similar with the indicator score derived in the study using simple aggregate method. This study further provides policy implications for reducing vulnerability of fishing villages.
Conference papers on the topic "Selective Exposure Theory"
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Ozbek, Simon, Esther Foo, J. Walter Lee, Nicholas Schleif, and Brad Holschuh. "Low-Power, Minimal-Heat Exposure Shape Memory Alloy (SMA) Actuators for On-Body Soft Robotics." In 2019 Design of Medical Devices Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/dmd2019-3287.
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In the world of soft-robotic medical devices, there is a growing need for low profile, non-rigid, and lower power actuators for soft exoskeletons and dynamic compression garments. Advanced compression garments with integrated shape memory materials have been developed recently to alleviate the functional and usability limitations associated with traditional compression garments. These advanced garments use contractile shape memory alloy (SMA) coil actuators to produce dynamic compression on the body through selective heating of the SMA material. While these garments can create spatially- and temporally-controllable compression, typical SMA materials (e.g., 70°C Flexinol) consume considerable power and require considerable thermal insulation to protect the wearer during the heating phase of the SMA actuation. Alternative SMA materials (e.g., NiTi #8 by Fort Wayne Metals, Inc.) transform below room temperature and do so using no applied electrical power and generate no waste heat. However, these materials are challenging to dynamically control and require active refrigeration to reset to material. In theory, low-temperature SMA actuators made from materials like NiTi #8 may maintain additional dynamic actuation capacity once equilibrated to room temperature (i.e., the material may not fully transform), as the SMA phase transformation temperature window expands when the material experiences applied stress. This paper investigates this possibility: we manufactured and tested low-temperature NiTi coil actuators to determine the magnitude of the additional force that can be generated via Joule heating once the material has equilibrated to room temperature. SMA spring actuators made from NiTi #8 consumed 84% less power and stabilized at significantly lower temperatures (26.0°C vs. 41.2°C) than SMA springs made from 70°C Flexinol, when actuated at identically fixed displacements (100% nominal strain) and when driven to produce equal forces (∼3.35N). This demonstration of low-power, minimal-heat exposure SMA actuation holds promise for many future wearable actuation applications, including dynamic compression garments.
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Opara, Chibuzor Nonye, and John H. Stroger. "Duration of Antibiotic Therapy in VLBW Infants with Exposure to Chorioamnionitis and Negative Blood Culture: Their Outcomes." In Selection of Abstracts From NCE 2015. American Academy of Pediatrics, 2017. http://dx.doi.org/10.1542/peds.140.1_meetingabstract.67.
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Guo, Zhongxian, Qiantao Cai, and Zhaoguang Yang. "Determination of Water-Soluble Organophosphorus Herbicides by Ion Chromatography With Inductively Coupled Plasma Mass Spectrometry Detection." In 1st Water Quality, Drought, Human Health and Engineering Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/water2006-20024.
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There is a high risk for human exposure to organophosphorus pesticides through contaminated drinking water. Glyphosate, glufosinate, fosamine and ethephon are among the water-soluble herbicides used currently. Sensitive and rapid analytical methodologies are critical for evaluating their residuals in a broad variety of samples, including environmental waters. However, challenges arise from the inherent chemical properties of the herbicides: strong polarity, high solubility in water, insolubility in organic solvent (except ethephon), absence of chromophore or fluorophore in their molecular structures. So far very rare analytical methods are available for ethephon [1] and fosamine [2], while glyphosate and glufosinate are often determined by gas chromatography [3], high performance liquid chromatography (HPLC) [4] and capillary electrophoresis (CE) [5]. Inductively coupled plasma mass spectrometry (ICP-MS) is sensitive, rapid, selective, and is more powerful when hyphenated with appropriate separation. For the analysis of glufosinate, glyphosate and its metabolite aminomethylphosphonic acid (AMPA), ICP-MS was recently coupled to CE [6] or ion-pairing reversed-phase LC [7].
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Fifield, Leonard S., Robert Duckworth, and Samuel W. Glass. "Long Term Operation Issues for Electrical Cable Systems in Nuclear Power Plants." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60729.
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Nuclear power plants contain hundreds of kilometers of electrical cables including cables used for power, for instrumentation, and for control. It is essential that safety-related cable systems continue to perform following a design-basis event. Wholesale replacement of electrical cables in existing plants facing licensing period renewal may be both impractical and cost-prohibitive. It is therefore important to understand the long term aging of cable materials to have confidence that aged cables will perform when needed. It is equally important in support of cable aging management to develop methods to evaluate the health of installed cables and inform selective cable replacement decisions. The most common insulation materials for electrical cables in nuclear power plants are cross-linked polyethylene and ethylene-propylene rubber. The mechanical properties of these materials degrade over time in the presence of environmental stresses including heat, gamma irradiation, and moisture. Mechanical degradation of cable insulation beyond a certain threshold is unacceptable because it can lead to insulation cracking, exposure of energized conductors, arcing and burning or loss of the ability of the cable system to function during a design-basis accident. While thermal-, radiation-, and moisture-related degradation of polymer insulation materials has been extensively studied over the last few decades, questions remain regarding the long term performance of cable materials in nuclear plant-specific environments. Identified knowledge gaps include an understanding of the temperature-dependence of activation energies for thermal damage and an understanding of the synergistic effects of radiation and thermal stress on polymer degradation. Many of the outstanding questions in the aging behavior of cable materials relate to the necessity of predicting long-term field degradation using accelerated aging results from the laboratory. Materials degrade faster under more extreme conditions, but extension of behavior to long term degradation under more mild conditions, such as those experienced by most installed cables in nuclear power plants, is complicated by the fact that different degradation mechanisms may be involved in extreme and mild scenarios. The discrepancy in predicted results from short term, more extreme exposure and actual results from longer term, more mild exposures can be counter intuitive. For instance, due to the attenuation of oxidation penetration in material samples rapidly aged through exposure to high temperatures, the bulk of the samples may be artificially protected from thermal aging. In another example, simultaneous exposure of cable insulation material to heat and radiation may actually lead to less damage at higher temperatures than may be observed at lower temperatures. The Light Water Reactor Sustainability program of the United States (US) Department of Energy (DOE) Office of Nuclear Energy is funding research to increase the predictive understanding of electrical cable material aging and degradation in existing nuclear power plants in support of continued safe operation of plants beyond their initial license periods. This research includes the evaluation and development of methods to assess installed cable condition.
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Rouser, Kurt P., Caitlin R. Thorn, Aaron R. Byerley, Charles F. Wisniewski, Scott R. Nowlin, and Kenneth W. Van Treuren. "Integration of a Turbine Cascade Facility Into an Undergraduate Thermo-Propulsion Sequence." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-94744.
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The Department of Aeronautics at the United States Air Force Academy utilizes a closed-loop, two-dimensional turbine cascade wind tunnel to reinforce a learning-focused undergraduate thermo-propulsion sequence. While previous work presented in the literature outlined the Academy thermo-propulsion sequence and the contextual framework for instruction, this current paper addresses how the Academy turbine cascade facility is integrated into the aeronautical engineering course sequence. Cadets who concentrate in propulsion are to some extent prepared for each successive course through their contact with the cascade, and ultimately they graduate with an exposure to experimental research that enhances their grasp of gas turbine engine fundamentals. Initially, the cascade is used to reinforce airfoil theory to all cadets in the Fundamentals of Aeronautics course. Aeronautical engineering majors take this course during the first semester of their sophomore year. The next semester all aeronautical engineering majors take Introduction to Aero-thermodynamics. In this course, the closed-loop aspect of the cascade facility is used to reinforce concepts of work addition to the flow. Heat transfer is also discussed, using the heat exchanger that regulates test section temperature. Exposure to the cascade also prepares cadets for the ensuing Introduction to Propulsion and Aeronautics Laboratory courses, taken in the junior and senior year, respectively. In the propulsion course, cadets connect thermodynamic principles to component analysis. In the laboratory course, cadets work in pairs on propulsion projects sponsored by the Air Force Research Laboratory, including projects in the cascade wind tunnel. Individual cadets are selected from the cascade research teams for summer internships, working at an Air Force Research Laboratory turbine cascade tunnel. Ultimately, cadet experiences with the Academy turbine cascade help lay the foundation for a two-part senior propulsion capstone sequence in which cadets design a gas turbine engine starting with the overall cycle selection leading to component-level design. The turbine cascade also serves to integrate propulsion principles and fluid mechanics through a senior elective Computational Fluid Dynamics course. In this course, cadets may select a computational project related to the cascade. Cadets who complete the thermo-propulsion sequence graduate with a thorough understanding of turbine engine fundamentals from both conceptual and applied perspectives. Their exposure to the cascade facility is an important part of the process. An assessment of cadet learning is presented to validate the effectiveness of this integrated research-classroom approach.
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Sakaruassen, K. S., J. S. Powell, E. W. Raines, and R. Ross. "SELECTIVE EXPRESSION OF PLATELET-DERIVED GROWTH FACTOR B-CHAIN mRNA BY HUMAN ENDOTHELIAL CELLS AND BY HUMAN PERIPHERAL BLOOD MONOCYTES, BUT NOT BY HUMAN SMOOTH MUSCLE CELLS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643752.
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Vascular injury may occur by a variety of mechanisms. Episodes of local hypoxia or conditions leading to local generation of thrombin may influence local cells to release growthregulatory molecules such as platelet-derivedgrowth factor (PDGF) in the surrounding connective tissue. The roles of the cells and of PDGF in these processes are not entirely understood, and this prompted us to investigate effects of hypoxia (5% O2) on cultured human saphenous vein endothelial cells andhuman thoracic aorta smooth muscle cells. Freshly isolated human peripheral blood monocytes were exposed to 3.0 U/ml a-thrombin. PDGF-A and PDGF-B mRNAs were analyzed by Northern blots, and their levels were assessed by dot blots utilizing 32P nick-translated cDNA probes. Selective expressionof PDGF-B mRNA occurred in endothelial cells during hypoxia and in monocytes exposed to thrombin. Genes coding for PDGF-A and PDGF-B are expressed cons tit utively, in endothelium, and after 48 hr of hypoxia a nine-fold increase of PDGF-B mRNA is detected (9 pg mRNA/ug total RNA). No detectable levels of mRNA encoding PDGF-A and PDGF-B were observed in freshly isolated monocytes; however, a 4-hr exposure to a-thrombin resulted in a selective and transitory increase in PDGF-B mRNA, amountingto 1 pg mRNA/ug toted RNA. No PDGF-B mRNA wasdetected after 20 hr. Hypoxic conditions did not trigger any selective expression of PDGF-B mRNA in smooth muscle, including arterialsmooth muscle derived from 1-day- and 3-month-old individuals, or from adult venous smoot muscle. However, constitutive expression of PDGF-A mRNA was observed in each of these, amounting to 0.4 pg mRNA/ug total RNA in the 1-day- and 3-month-old cells, and 0.2 pg mRNA/ugtotal RNA in the venous smooth muscle. Our datashow that endothelium and monocytes selectively express PDGF-B mRNA in vitro in response to conditions mimicking those encountered during vascular injury in some in-vivo situation.The data imply that both endothelial cells and monocyte/macrophages may be sources for mitogens that induce intimal hyperplasia and eventually plaque formation.
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Sodhi, Jaskirat S., and I. Joga Rao. "Modeling and Simulation of Light Activated Shape Memory Polymers." In ASME 2010 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2010. http://dx.doi.org/10.1115/smasis2010-3696.
Full textAbstract:
This paper focuses on developing a model for light activated shape memory polymers (LASMP’s) undergoing deformation using the framework based on multiple natural configurations and simulating results for boundary value problems. LASMP’s are novel polymeric materials that are different in many ways from the first generation thermally controlled Shape Memory Polymers (SMP’s). Instead of using phase change to produce a mechanism, LASMP’s have photosensitive molecules grafted on their polymer chains. These photosensitive molecules, when exposed to light at certain wavelengths, form covalent bonds that act as crosslinks to give this class of SMP’s their temporary shape. By virtue of their different mechanism, LASMP’s provide a wide array of advantages such as remote activation and selective exposure, thus opening new doors as a potential for vast applications in the biomedical and aerospace industries [1].
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Price, Jeffrey R., Oscar Jimenez, Vijay Parthasarathy, and Narendernath Miriyala. "Ceramic Stationary Gas Turbine Development Program: Sixth Annual Summary." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-351.
Full textAbstract:
The Ceramic Stationary Gas Turbine (CSGT) program is being performed under the sponsorship of the United States Department of Energy, Office of Industrial Technologies. The objective of the program is to improve the performance of stationary gas turbines in cogeneration through the selective replacement of cooled metallic hot section components with uncooled ceramic parts. This review summarizes the progress on Phase III of the program which involves field testing of the ceramic components at a cogeneration end user site and characterization of the ceramic components following the field test exposure. The Solar Centaur 50S engine, which operates a turbine rotor inlet temperature (TRIT) of 1010°C (1850°F), was selected for the developmental program. The program goals include an increase in the TRIT to 1121°C (2050 °F), accompanied by increases in thermal efficiency and output power. This will be accomplished by the incorporation of uncooled ceramic first stage blades and nozzles, and a “hot wall” ceramic combustor liner. The performance improvements are attributable to the increase in TRIT and the reduction in cooling air requirements for the ceramic parts. The “hot wall” ceramic liners also enable a reduction in gas turbine emissions of NOx and CO. The component design and material selection have been definitized for the ceramic blades, nozzles and combustor liners. Each of these ceramic component designs were successfully tested in short term engine tests in the Centaur 50S engine test cell facility at Solar. Based on the results of the engine testing of the ceramic components, minor redesigns of the ceramic/metallic attachments were conducted where necessary. Based on their performance in a 100 hour cyclic in-house engine test, the ceramic components are approved for field testing. To date, four field installations of the CSGT Centaur 50S engine totaling over 4000 hours of operation have been initiated under the program at an industrial cogeneration site. This paper discusses the component design and material selection, in house engine testing, field testing, and component characterization.
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Singh, Rupinder, and Sehijpal Singh. "Experimental Investigations for Reducing Effect of Sensitization in Tungsten Inert Gas Welding." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61078.
Full textAbstract:
Stainless steels are considered to have very good resistance to general and localized corrosion due to their chromium content. This property of corrosion resistance constitutes the main criterion for selecting austenitic grades of steels for service in the chemical, nuclear and aerospace industries although their mechanical properties are relatively modest. However, this resistance can degrade when structural components manufactured from these steels are used in a chemically aggressive environment, especially when service involves exposure to high temperatures like in welding. This exposure gives rise to precipitation of chromium carbides producing chromium depletion at grain boundaries that brings about the inter-granular corrosion or sensitization of these materials. Austenitic stainless steel (316L) is one of the corrosion resistance material used extensively in the oil production, chemical and power generation industries for transportation and reservoir of corrosive products. In spite of its corrosion resistance property there exist severe problems of sensitization. In the present work an effort has been made to reduce the effect of sensitization in Tungsten Inert Gas welding of Austenitic stainless steel (316L). Three welding procedures (namely conventional, back step and skip welding) in Tungsten Inert Gas welding have been used to control exposure time of the weld pool to higher temperatures, in order to study the effect of sensitization on mechanical properties (such as tensile strength, yield strength, percentage elongation and hardness). The results of this study suggested that the better mechanical properties were attained by the skip welding procedure and recommended welding parameters are 90 Amp current and 10 L/min of gas flow rate for a 5 mm thick work piece. Noticeable change in amount/extent of sensitization was observed using a scanning electron microscope (SEM) analysis within the various welding specimens prepared using the various procedures. Further mechanical properties (like strength and hardness) have been correlated with the extent of sensitization, which show remarkable decreases when the amount/extent of sensitization increases.
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Tomosawa, Fuminori, Shigeo Tsujikawa, Teruyuki Nakatsuji, Keisuke Yonemaru, Koji Saka, and Hiroyasu Kawaguchi. "Research on Applicability of New Materials to Marine Structures in Tropical Climates: Specimens Exposed for 1 Year." In ASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/omae2002-28184.
Full textAbstract:
This study aims to investigate the applicability of newly developed structural materials, which are lightweight and highly durable, to marine structures from the aspect of reducing their life-cycle cost. Since corrosion is primarily the determining factor of the service life of marine structures, exposure tests have been conducted in this study with the focus on corrosion resistance of new structural materials. Twenty-one new materials have been exposed to the environment at three sites: the tropical island Okinotori-shima and subtropical island Miyako-jima, both in Japan, and a hygro-thermostatic room in a laboratory. These experiments started in 1999 as five-year exposure tests. The authors have reported on the selection of potential new structural materials for marine structures (six nonferrous metals, eight steels, four composite materials, and three rope materials), outline of exposure tests, and results of initial performance tests on these materials. As of October 2001, specimens at an age of 2 years were retrieved and are now being examined. This paper reports on the findings obtained after the publication of the previous paper, including the observation and test results of specimens retrieved in 2000 at an age of 1 year. After publishing the previous paper on the ongoing tests, tension tests on unjointed and jointed specimens and SEM observation of corrosion specimens were conducted. Some of the steels exhibited severe corrosion, as well as significant strength losses. Specimens other than those began to exhibit tendencies towards strength changes depending on the material type and specimen type (unjointed/jointed), though not very evident. SEM observation of corroded specimens revealed differences in the state of corrosion among materials.
Reports on the topic "Selective Exposure Theory"
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Busso, Matías, and Verónica Frisancho. Research Insights: Can Good Peers Hurt?: The Effect of Top Students on Girls' Educational Outcomes. Inter-American Development Bank, July 2021. http://dx.doi.org/10.18235/0003565.
Full textAbstract:
Exposure to good peers of either sex during middle school reduces the probability that top-performing girls are placed in one of their preferred high schools. High-achieving boys have a detrimental effect on the selectiveness of the schools in which top female students are placed. These placement effects are driven by both lower admission scores and weakened preferences for selective and academic schools. Exposure to high-achieving girls improves the admission exam scores of poor-performing girls. This protective effect on scores translates into an average increase in the selectivity of the high schools in which low-performing girls are placed.