Domain Model Explains Propagation Dynamics and Stability of Histone H3K27 and H3K36 Methylation Landscapes

Chromatin states must be maintained during cell proliferation to uphold cellular identity and genome integrity. Inheritance of histone modifications is central in this process. However, the histone modification landscape is challenged by incorporation of new unmodified histones during each cell cycle, and the principles governing heritability remain unclear. We take a quantitative computational modeling approach to describe propagation of histone H3K27 and H3K36 methylation states. We measure combinatorial H3K27 and H3K36 methylation patterns by quantitative mass spectrometry on subsequent generations of histones. Using model comparison, we reject active global demethylation and invoke the existence of domains defined by distinct methylation endpoints. We find that H3K27me3 on pre-existing histones stimulates the rate of de novo H3K27me3 establishment, supporting a read-write mechanism in timely chromatin restoration. Finally, we provide a detailed quantitative picture of the mutual antagonism between H3K27 and H3K36 methylation and propose that it stabilizes epigenetic states across cell division

The mutual shaping of technology in a news establishment : social journalism and organizational change

"July 2011"The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on May 18, 2012).Dissertation advisor: Dr. Margaret Duffy.Vita.Efforts to understand the relationship between technological change and organizational change in the journalism industry have taken on a new meaning over the past decade. The survival of professional news organizations may rely on their ability to manage technological change. This dissertation proposes the use of the mutual shaping of technology (MST) construct, based on the Diffusion of Innovations theoretical paradigm, as a means to examine the relationship between technological and organizational change in a newsroom. The MST construct imagines a dynamic relationship between efforts to diffuse technological innovations and efforts to shape those innovations, both in terms of physical design changes and abstract, socially constructed meanings. The MST construct is applied to the introduction and development of an innovative journalism platform, featuring social networking tools and a level of citizen participation that is rarely seen, in a news organization with more than 100 years of experience publishing a newspaper. I use the five levels of analysis from Shoemaker's hierarchical model to organize my discussion of this extreme case. Using data from in-depth interviews, I explore the introduction, adoption and iterative development of this news platform and related organizational change. I then ask if such a platform is sustainable economically and analyze institutional influences that may aid or inhibit growth. I also compare the model to the ideal models discussed and tested in the public journalism movement and to the model some scholars consider the highest ideal -- Habermas' public sphere.Includes bibliographical reference

Are All Voices Created Equal?: Conditional Indirect Effects of Directness of One\u27s Voice on Perceived Uncertainty and Performance

The purpose of the current investigations was to examine the effects of the amount of voice one is given during decision-making on group behaviors. In particular, across two studies, participants were members of groups that needed to make a decision. In these situations, participants were provided varying degrees of voice during a decision-making process. Depending on the study, participants were either given a direct voice (Personal Voice), an indirect voice (Group Voice), a direct voice and an indirect voice (Composite Voice), or were not allowed a voice (No Voice). The results of Study 1 found that having Personal Voice or Composite Voice is related to increased perceptions of control, trust, and certainty, and is related to more predicted effort put forth for the group. In contrast, having Group Voice or No Voice was shown to be related to low levels of control, trust, and certainty. Furthermore, Group Voice was related to less predicted effort given toward achieving group goals. The findings of Study 1 suggest that the reason more voice is related to more positive group effort is because of how trust in the decision-maker is positively related to being more certain of what that decision-maker will do, which in turn predicts more certainty of how the decision will affect one\u27s self as a member of the group in the future. The results of Study 2 found that Personal Voice was related to increased perceptions of voice and certainty, with Group Voice and No Voice related to low levels of certainty. Interestingly, Study 2 found that more voice given to group members was related to less behavioral output on behalf of the group. The relationship between having more voice and less effort was explained by perceptions of certainty. The findings of the current research suggest that groups must take care to ensure their members are treated in a fair manner because there are both benefits and limitations to providing members a voice during decision-making

Alternative Media and Normative Theory: A Case of Ferguson, Missouri

This paper, based on in-depth interviews with journalists at alternative and advocacy papers in St. Louis as well as interviews with live streaming protestors, a new breed of citizen journalist, applies six characteristics commonly associated with the alternative press to coverage of the protests and police crackdown in Ferguson, Missouri, between August 9, 2014, and March 2015. Journalists from the alternative newspaper in St. Louis focused on progressive or radical values less than the literature predicted. The African-American newspaper in St. Louis found itself influencing the national and global agenda regarding Ferguson and the ongoing oppression of blacks in the city and surrounding municipalities. Mobile media-savvy protesters broadcast police actions from the front lines of dissent in nearly constant live streams day after day from August to November, altering the scope of counternarrative and providing distilled counter­propaganda. In this study, researchers provide a snapshot of the alternative/advocacy press as it rose to fill in gaps in coverage and to find untold stories in one of the most widely broadcast events of 2014

Media Literacy and News Credibility: Does knowledge of media ownership increase skepticism in news consumers?

This study explores how increased knowledge of media ownership may affect judgments of credibility in responding to print news. An experiment was conducted with 80 undergraduate journalism students. Subjects were randomly exposed to either an informational article about the pros and cons of consolidation in media ownership or poetry. Then subjects read and analyzed four news stories, analyzing each using a credibility scale that includes judgments of truth, superficiality, general accuracy and completeness. Results show statistically significant differences in judgments of general accuracy and superficiality, suggesting that exposure to informational print about media ownership may promote modest increases in critical responses to news media

Media, Society, Culture and You

117 p.Media, Society, Culture, and You is an approachable introductory Mass Communication text that covers major mass communication terms and concepts including "digital culture." It discusses various media platforms and how they are evolving as Information and Communication Technologies change. This book has been peer-reviewed by 6 subject experts and is now available for adoption or adaptation

Schreibkompetenz von Schülern einer Schule für Sprachbehinderte und Möglichkeiten der Förderung

Die wissenschaftliche Hausarbeit „Schreibkompetenz von Schülern einer Schule für Sprachbehinderte und Möglichkeiten der Förderung“ beschäftigt sich mit der Thematik, ob und wie sich die Schreibfähigkeiten von Schülern einer Schule für Sprachbehinderte von Schülern einer Grundschule unterscheiden und inwieweit Schreibkompetenz-Modelle auf Kinder, die eine Schule für Sprachbehinderte besuchen, bezogen werden können. Hierfür wurden in Bezug dessen auch die Bildungs- und Lehrpläne aller Bundesländer für die Grundschulen sowie Haupt- und Realschulen und der Schule für Sprachbehinderte mit einbezogen und kritisch reflektiert. Es wurden Modelle zur Schreibkompetenz und zu Schreibprozessen dargestellt, kritisch analysiert und daraufhin ein eigenes Schreibkompetenzmodell entwickelt, anhand dessen ein Bewertungsraster erstellt wurde, um die Texte der Schüler, welche die Schule für Sprachbehinderte besuchen, zu analysieren und mit denen der Grundschüler zu vergleichen. Im Anschluss an die Analyse wurden für die Schüler der Schule für Sprachbehinderte individuelle Fördermöglichkeiten entwickelt, welche sie beim weiteren Schreibprozess unterstützen sollen

Latin American Community Telecenters: "It's a long way to TICperary"

Community Telecenters, that is centers for community development using ICT (Information and Communications Technologies) , have become the focus of attention in international development circles over the past ten years, especially in Latin America. A virtual community called Somos@Telecentros is progressively taking shape in the region (http://www.tele-centros.org) with a specific interest in supporting and enabling these Community Telecenters. As part of the build up effort an inventory of telecenters was conducted, followed by a review of the situation. The latter involved self description, recording of stories on the web and through Email, and Email and face to face interviews. The results were synthesized into an analytical panorama of the telecenters movement in the region, the challenges faced, the solutions encountered and the lessons learned. This paper will summarize these findings and highlight a number of key issues, in particular, the trade-off between top-down connectivity and computer literacy programs; and horizontal and community-led and controlled comprehensive development efforts

Streptavidin-Affinity Grid Fabrication for Cryo-Electron Microscopy Sample Preparation.

Streptavidin affinity grids provide strategies to overcome many commonly encountered cryo-electron microscopy (cryo-EM) sample preparation challenges, including sample denaturation and preferential orientations that can occur due to the air-water interface. Streptavidin affinity grids, however, are currently utilized by few cryo-EM labs because they are not commercially available and require a careful fabrication process. Two-dimensional streptavidin crystals are grown onto a biotinylated lipid monolayer that is applied directly to standard holey-carbon cryo-EM grids. The high-affinity interaction between streptavidin and biotin allows for the subsequent binding of biotinylated samples that are protected from the air-water interface during cryo-EM sample preparation. Additionally, these grids provide a strategy for concentrating samples available in limited quantities and purifying protein complexes of interest directly on the grids. Here, a step-by-step, optimized protocol is provided for the robust fabrication of streptavidin affinity grids for use in cryo-EM and negative-stain experiments. Additionally, a trouble-shooting guide is included for commonly experienced challenges to make the use of streptavidin affinity grids more accessible to the larger cryo-EM community

Activation of automethylated PRC2 by dimerization on chromatin.

Polycomb repressive complex 2 (PRC2) is an epigenetic regulator that trimethylates lysine 27 of histone 3 (H3K27me3) and is essential for embryonic development and cellular differentiation. H3K27me3 is associated with transcriptionally repressed chromatin and is established when PRC2 is allosterically activated upon methyl-lysine binding by the regulatory subunit EED. Automethylation of the catalytic subunit enhancer of zeste homolog 2 (EZH2) stimulates its activity by an unknown mechanism. Here, we show that human PRC2 forms a dimer on chromatin in which an inactive, automethylated PRC2 protomer is the allosteric activator of a second PRC2 that is poised to methylate H3 of a substrate nucleosome. Functional assays support our model of allosteric trans-autoactivation via EED, suggesting a previously unknown mechanism mediating context-dependent activation of PRC2. Our work showcases the molecular mechanism of auto-modification-coupled dimerization in the regulation of chromatin-modifying complexes