Strong negative self regulation of Prokaryotic transcription factors increases the intrinsic noise of protein expression

Background Many prokaryotic transcription factors repress their own transcription. It is often asserted that such regulation enables a cell to homeostatically maintain protein abundance. We explore the role of negative self regulation of transcription in regulating the variability of protein abundance using a variety of stochastic modeling techniques. Results We undertake a novel analysis of a classic model for negative self regulation. We demonstrate that, with standard approximations, protein variance relative to its mean should be independent of repressor strength in a physiological range. Consequently, in that range, the coefficient of variation would increase with repressor strength. However, stochastic computer simulations demonstrate that there is a greater increase in noise associated with strong repressors than predicted by theory. The discrepancies between the mathematical analysis and computer simulations arise because with strong repressors the approximation that leads to Michaelis-Menten-like hyperbolic repression terms ceases to be valid. Because we observe that strong negative feedback increases variability and so is unlikely to be a mechanism for noise control, we suggest instead that negative feedback is evolutionarily favoured because it allows the cell to minimize mRNA usage. To test this, we used in silico evolution to demonstrate that while negative feedback can achieve only a modest improvement in protein noise reduction compared with the unregulated system, it can achieve good improvement in protein response times and very substantial improvement in reducing mRNA levels. Conclusions Strong negative self regulation of transcription may not always be a mechanism for homeostatic control of protein abundance, but instead might be evolutionarily favoured as a mechanism to limit the use of mRNA. The use of hyperbolic terms derived from quasi-steady-state approximation should also be avoided in the analysis of stochastic models with strong repressors

Social media in democratic transitions and consolidations: what can we learn from the case of Tunisia?

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. The aim of this paper is to analyse the use of social media in the stages of uprising, democratic transition and democratic consolidation using the case study of Tunisia. While the impact of social media in uprisings has been widely documented in past research about the MENA region, Tunisia provides new evidence to the use of Internet in the processes of democratisation. Consequently, this research focuses in detail on the benefits but also the pitfalls of social media in transitions and consolidations. Data collection was based on interviews with Tunisian social media activists. The analysis is valuable to social media practitioners and researchers alike

Media Peace Discourse: Constraints, Concepts and Building Blocks

Normative, professional, and academic premises steer the discussion of the importance and the absence of a peace discourse in the media, and of the need and possibility to invent one. Among the possible points of departure are that the media should be involved in the promotion of peace; that peace coverage is hindered by the absence of a peace discourse in the professional media repertoire; and that the creation, development, and marketing of a media peace discourse should be included in the current research agenda. The development of a peace-oriented media discourse can be assisted by three conceptual elements, namely, the existing strategies employed by the media to cover peace; the competition in the media among dominant and alternative frames, in which news-value is the measure of success; and the concept of “constitutive rhetoric” – the creation, change and legitimization of realities through texts, rhetorical constructs and the manipulation of symbols – as a discourse-building device. Research on the three major strategies used by the media in the coverage of peace – Framing Peace Coverage in War Discourse; Trivialization; and Ritualization – suggests that the latter fits this conceptual framework better than the others, and thus is more suitable for the development of a media peace discourse. Some findings and models of media research can be used for conceptual leverage by providing paradigmatic frameworks and variables. Good examples include the media events and the textual analysis genres, as they are particularly related to professional effects; narrative techniques; and performance styles; and concepts such as “master-frames” and “super-texts” – major motifs, composed of many smaller frames or sub-texts – to suggest the potential contents of a media peace discourse. Finally, it is proposed that research and development efforts of media peace coverage along these lines should include work on adapting the current powerful status of the media in international relations to overcome negative peace-related attitudes; on increasing the news-value of peace coverage rather than undertaking missionary efforts to change media structures and professional codes of conduct; on devising professional policies that might reduce media self-manipulation and similar pressures; and on creating and “marketing” a media peace discourse with satisfactory news value based on innovative projects, and on the appropriate application of existing findings

La guerra y la paz como noticia: el caso del Medio Oriente

Los actuales procesos de paz provocan interés respecto de la naturaleza de los conflictos políticos y culturales de fines de siglo, de los métodos utilizados para solucionarlos y del papel de los medios en estos procesos. Considerando el Medio Oriente como un caso representativo de conflicto cultural, dos series de argumentos sirven para orientar la discusión de estos temas. La primera afirma que los conflictos culturales son los más difíciles de resolver y que el actual proceso de paz no es una reconciliación cultural sino un cambio estructural. La segunda propone que la creciente importancia de los medios en las relaciones internacionales puede y debe ser utilizada en el fomento de la paz, especialmente en la resolución y en la reestructuración de conflictos culturales

Epilogue: Peace Journalism – The State of the Art

This epilogue aims at integrating the series of articles offered by the Toda Peace Journalism group in cco (4/2 2005; 5/2 2006; 6/1, 2007) into a framework designed to orient the reader, without repeating the arguments presented in the articles; to encourage instructors and students to use these materials; and to stimulate thinking on "where do we go next". Coherence is sought through looking at critical analyses of the conventional coverage of war and peace and at the promise and performance of Peace Journalism, analyzing epistemological and professional constraints, presenting ways to improve Peace Journalism concepts and practices, and offering an agenda and some development strategies. The initial premise that Peace Journalism (PJ) is a mode of responsible and conscientious media representation of conflict, alternative to conventional coverage, develops into a summary of critical evaluations of such coverage, and of the efforts to conceptualize PJ. A discussion of the promises offered by PJ follows suit, including professional improvement, the enhancement of journalistic values, the provision of better public service, and the widening of scholarly and professional horizons. Also PJ performance is analyzed, suggesting some explanations for its lack of popularity and some of its built-in problems, such as in the debate over the tradition of objectivity and other normative alternatives. Epistemological and professional considerations converge in the discussion of needs for clearer formulation and application of concepts, expectations, and procedures, and for an agenda that includes the production of persuasive evidence of PJ value; for overcoming rejection by journalists, for avoiding self-manipulation in field staff-editor relations, and for encouraging the development of a media peace discourse

Reflections on media war coverage: Dissonance, dilemmas, and the need for improvement

Media preference of war has been diagnosed as resulting from correlations of media psychology, culture, and interests with war. Such correlations encourage personal, professional and institutional dissonance, and provoke dilemmas of coverage adequacy; selectivity of narratives and contexts; manipulation, and narrow ranges of discourse and focus. Efforts to curb these difficulties might succeed, with research and applied efforts aimed at updating the media culture of war coverage; helping identify media controls; encouraging gradual and cumulative reporting; employing "thick coverage" and "thick training"; promoting the cooperation of established media with newer types of journalism; assisting journalists in resolving war coverage dilemmas; promoting ongoing field monitoring and empirical research; helping post-war establishment of appropriate media structures, regulatory frameworks, and program production

Journalists' development journalism role perceptions

Development journalism remains an important concept in the journalism studies literature, but it has, at the same time, suffered from a lack of empirical research. Drawing on a survey of 2598 journalists from eight South Asian, Southeast Asian, and sub-Saharan African countries, which was conducted as part of the Worlds of Journalism Study, this study assesses the importance journalists ascribe to three key development journalism roles—social intervention, national development, and educating people. It also compares these perceptions across the countries, between government- and privately owned news media in these countries, and between these countries and 19 Worlds of Journalism Study countries in Western Europe and North America, which profess to adhere to an objective and democratic press function. Findings suggest that journalists from the eight countries, across government- and privately owned media, considered development journalism important, and detached, adversarial journalism as less important. Their rating of the latter roles differed considerably from those of journalists from the 19 comparison countries. Results suggest that journalists were more likely socialized into their roles rather than being forced into the same by the heavy hand of government