Fine-tuning stellar population models

In this work we present new, high-to-intermediate spectral resolution evolutionary population synthesismodels, complementing and extending the widely used Maraston models. The new models are based on four popular libraries of empirical stellar spectra, which has necessitated some modifications to the original code, while keeping much of the original ingredients – such as stellar energetics, treatment of the thermally pulsating asymptotic giant branch, and mass loss recipe – intact. In addition, we have computed models at very high resolution (R = 20000) based on the theoretical MARCS library, that extends far into the infrared region of the electromagnetic spectrum. A library-dependent, but modelindependent comparison is made, where both photometric and spectroscopic similarities and discrepancies are highlighted. We find that stellar population models employing empirical stellar spectra exhibit considerably bluer (B-V) colours compared to models adopting theoretical spectra synthesised from the Kurucz model atmospheres (such as the BaSeL library), but that some differences arise between the empirical libraries due to, in particular, the adopted temperature scale. Furthermore, the results obtained with the theoretical MARCS library are fully consistent with the empirical libraries in this respect. The same effect can be found also in other EPS models that are based on empirical stars. We show that this discovery, whose origin can be traced mainly to cool stars (Teff < 5000 K), leads to improved photometric agreement with both galaxy and Milky Way globular cluster data. Spectral energy distributions of the latter are also used for testing the models concerning their ability to reproduce, through full SED-fitting, the cluster ages and metallicities as derived through independent fitting in colour-magnitude diagrams. In general, the agreement is very promising, although the higher resolution of the new models cannot alleviate the age-metallicity degeneracy in the optical in any significant way. A comparison with models of absorption line indices with variable abundance ratios is also made, both for the full SED-fitting procedure and when measuring indices directly on the SED. We obtain satisfying agreement in the first case, but in the second case only when a subsample of indices are used, the combination of which is little sensitive to abundance ratio effects. As a side track we exploit for the first time for population synthesis purposes the vast stellar database of the Sloan Digital Sky Survey, but find that the metallicity and age range of the stars is currently too narrow for computing sensible population models. Finally, we re-invigorate the Ca K line for the purpose of absorption feature diagnostics, presenting a new version of the index which will help in separating solutions for a key case of the age-metallicity degeneracy.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Populist communication in the new media environment: a cross-regional comparative perspective

The changing terms of mediation place new demands, opportunities and risks on the performance of the political persona. Visibility has become a double-edged sword, leaving representatives vulnerable to exposure while new tools provide opportunities for emerging entrepreneurial actors. This double risk to elites’ mediated personas—exposure and challenge from entrepreneurs—renders their armour of authenticity dangerously fragile, which nourishes a public sense of being inefficaciously represented. It is this climate in which populism currently flourishes around the globe. Three primary criteria of mediated self-representation by politicians—visibility, authenticity and efficacy—form the focus of this paper: how do populists negotiate such demands in different democratic contexts, and wherein lies the symbiosis between populism and the new media environment suggested by the literature? To answer this, the paper compares two populist cases responding to different democratic contexts: UKIP, a right-wing party from an established democracy (UK), and the Economic Freedom Fighters (EFF), a left-wing party from a transitional democracy (South Africa). The objects of study are disruptive performances by these parties, which are considered emblematic manifestations of populist ideology as they establish a Manichaean relationship between the elite and populist actors who embody the people. The paper introduces disruption as a multi-faceted and significant analytical concept to explain the populist behaviour and strategies that underlie populist parties’ responses to the demands for visibility, authenticity and efficacy that the new media environment places upon political representatives. Using mixed methods with an interpretive focus, the paper paints a rich picture of the contexts, meanings and means of construction of populist performances

PSM Contribution to democracy: News, editorial standards and informed citizenship

This chapter examines the questions that PSM face about their continued role and relevance against the backdrop of a fast-changing and increasingly commercialised media landscape. It examines the evidence about news produced by PSM and considers the implications for democracy in two ways. First, it draws on the latest academic scholarship to examine the evidence about whether PSM produce news that is distinctive from their market-driven rivals. Second, it considers how informative PSM coverage is compared to their commercial competitors. The chapter assesses the latest research to establish whether public or commercial media systems offer the most effective way of raising public knowledge about politics and public affairs

Trends in modeling Biomedical Complex Systems

In this paper we provide an introduction to the techniques for multi-scale complex biological systems, from the single bio-molecule to the cell, combining theoretical modeling, experiments, informatics tools and technologies suitable for biological and biomedical research, which are becoming increasingly multidisciplinary, multidimensional and information-driven. The most important concepts on mathematical modeling methodologies and statistical inference, bioinformatics and standards tools to investigate complex biomedical systems are discussed and the prominent literature useful to both the practitioner and the theoretician are presented

Political news journalism : Mediatization across three news reporting contexts

Election coverage has a tendency to frame politics as a strategic game, to increase the role of journalists as interpreters of issues and events and to include a conflict frame, and thus indicating increased mediatization. However, political news research outside of the election indicates that news media are less independent from political actors. Drawing on literature on mediatization, media interventionism, political news journalism, news framing and source use, the purpose of this article is to empirically investigate whether election coverage is representative of other political journalism in terms of degree of mediatization. The study is based on a systematic comparison of three content analyses using the same coding schedule and procedure from coverage of the Financial Crisis 2008, the Election Campaign 2010 and routine political news coverage 2012 in Sweden. The main conclusion from this study is that mediatization of media coverage is substantially influenced by the specific context of the news.Publ online Jul 2014</p