Separability in 2xN composite quantum systems

We analyze the separability properties of density operators supported on \C^2\otimes \C^N whose partial transposes are positive operators. We show that if the rank of $\rho$ equals N then it is separable, and that bound entangled states have rank larger than N. We also give a separability criterion for a generic density operator such that the sum of its rank and the one of its partial transpose does not exceed 3N. If it exceeds this number we show that one can subtract product vectors until decreasing it to 3N, while keeping the positivity of $\rho$ and its partial transpose. This automatically gives us a sufficient criterion for separability for general density operators. We also prove that all density operators that remain invariant after partial transposition with respect to the first system are separable.Comment: Extended version of quant-ph/9903012 with new results. 11 page

Equality of Participation Online Versus Face to Face: Condensed Analysis of the Community Forum Deliberative Methods Demonstration

Online deliberation may provide a more cost-effective and/or less inhibiting environment for public participation than face to face (F2F). But do online methods bias participation toward certain individuals or groups? We compare F2F versus online participation in an experiment affording within-participants and cross-modal comparisons. For English speakers required to have Internet access as a condition of participation, we find no negative effects of online modes on equality of participation (EoP) related to gender, age, or educational level. Asynchronous online discussion appears to improve EoP for gender relative to F2F. Data suggest a dampening effect of online environments on black participants, as well as amplification for whites. Synchronous online voice communication EoP is on par with F2F across individuals. But individual-level EoP is much lower in the online forum, and greater online forum participation predicts greater F2F participation for individuals. Measured rates of participation are compared to self-reported experiences, and other findings are discussed.Comment: 14 pages, 10 tables, to appear in Efthimios Tambouris, Panos Panagiotopoulos, {\O}ystein S{\ae}b{\o}, Konstantinos Tarabanis, Michela Milano, Theresa Pardo, and Maria Wimmer (Editors), Electronic Participation: Proceedings of the 7th IFIP WG 8.5 International Conference, ePart 2015 (Thessaloniki, August 30-September 2), Springer LNCS Vol. 9249, 201

Political Messaging Over Time: A Comparison of US Presidential Candidate Facebook Posts and Tweets in 2016 and 2020

Political campaigns have a temporal nature, which means that the strategic environment shapes the nature of candidate communication, especially the stages of campaigning—from surfacing to the general election. As social media platforms have matured and political campaigns have normalized their use of those platforms in this decade, this study examines the 2016 and 2020 US presidential campaign communication on Facebook and Twitter using data from the Illuminating project at Syracuse University. Our objective is to explore how the stages of the campaign cycle shape political communication. We also explore social media platforms as additional factors. Moreover, given the distinct and anti-normative communication style of Donald Trump, we examine whether his communication is an outlier relative to his competition in the primaries and the general election, and while a challenger in 2016 and an incumbent in 2020. Our results suggest that campaign messaging changes over the stages of the campaign, with candidates more likely to advocate for themselves during the crowded primaries, and then engage in high volumes of calls to action in the general election. The 2016 posts were substantially more attack-focused than in 2020. There is some evidence to suggest that the global pandemic affected the ways in which campaigns used their social media accounts. Of note, campaigns seem to heavily rely on Facebook for all types of strategic communication, even as the academic community primarily analyzes Twitter. Finally, Trump’s sum-total of his discourse is less negative than Clinton’s in 2016 and more advocacy-focused, overall

Effective Mitigation of Anchoring Bias, Projection Bias, and Representativeness Bias from Serious Game-based Training

AbstractAlthough human use of heuristics can result in ‘fast and frugal’ decision-making, those prepotent tendencies can also impair our ability to make optimal choices. Previous work had suggested such cognitive biases are resistant to mitigation training. Serious games offer a method to incorporate desirable elements into a training experience, and allow the use of mechanisms that enhance learning and retention. We developed a game to train recognition and mitigation of three forms of cognitive bias: anchoring, a tendency to be inordinately influenced by one piece of information; projection, an implicit assumption that others think or know what you do; and representativeness, judging the likelihood of a hypothesis by how much the available data resembles it. Participants were randomly assigned to play the training game once, twice spaced by 10 to 12 days, or a control condition that used a training video. External questionnaire-based assessments were given immediately post-training and 12 weeks later. Superior training was seen from the game. An independent group using our training game with their own novel bias assessment instruments (to which the researchers and game-developers had no access or content information) validated the key finding. These results demonstrate the viability and high value of using serious computer games to train mitigation of cognitive biases

Twitter: a useful tool for studying elections?

The 2015 General Election in the UK was the first to take place in the UK with Twitter as an important part of the social media landscape. This pilot project looked at 16 constituencies along England’s South Coast in order to investigate what impact, if any, Twitter had had on the campaign and the result and to investigate the efficacy, or otherwise, of using Twitter as a tool for studying election campaigns in terms of candidate and local party activism. On the basis of an analysis of almost half a million tweets the analysis concluded that there appeared to be a correlation between the rate at which parties and/or candidates responded to incoming tweets and their relative electoral performance but this was not demonstrable for all parties (it applied in particular to Labour and UKIP candidates). In addition, high rates of reply also appeared to have a positive impact on constituency turnout figures. The findings are not yet conclusive but suggest that Twitter could be a good indicator of general levels of local party activism. The research also sought to understand how candidates used Twitter differently and established a number of candidate ‘classifiers’. It also investigated the issues agenda that was dominating Twitter conversations during the campaign and found that Twitter’s agenda was closer to the public’s than was that of the national media. The research also monitored the regional and local media in the 16 constituencies and discovered that their issues agenda was closer still to the public’s. Overall it is difficult to conclude that Twitter had a major impact on the election campaign

A New Eusuchian Crocodyliform with Novel Cranial Integument and Its Significance for the Origin and Evolution of Crocodylia

Crocodyliforms were one of the most successful groups of Mesozoic tetrapods, radiating into terrestrial, semiaquatic and marine environments, while occupying numerous trophic niches, including carnivorous, insectivorous, herbivorous, and piscivorous species. Among these taxa were the enigmatic, poorly represented flat-headed crocodyliforms from the late Cretaceous of northern Africa. Here we report a new, giant crocodyliform from the early Late Cretaceous (Cenomanian) Kem Kem Formation of Morocco. Represented by a partial braincase, the taxon has an extremely long, flat skull with large jaw and craniocervical muscles. The skull roof is ridged and ornamented with a broad, rough boss surrounded by significant vascular impressions, likely forming an integumentary structure unique among crocodyliforms. Size estimates using endocranial volume indicate the specimen was very large. The taxon possesses robust laterosphenoids with laterally oriented capitate processes and isolated epipterygoids, features allying it with derived eusuchians. Phylogenetic analysis finds the taxon to be a derived eusuchian and sister taxon to Aegyptosuchus, a poorly understood, early Late Cretaceous taxon from the Bahariya formation. This clade forms the sister clade of crown-group Crocodylia, making these taxa the earliest eusuchian crocodyliforms known from Africa. These results shift phylogenetic and biogeographical hypotheses on the origin of modern crocodylians towards the circum-Tethyean region and provide important new data on eusuchian morphology and evolution

Comparing online campaigning: The evolution of interactive campaigning from Royal to Obama to Hollande

© 2016 Macmillan Publishers Ltd.Studies of election campaigning from a comparative perspective have a long history; this study approaches the topic through a most-similar regime perspective to explore the ebb and flow of innovations in digital campaigning between presidential campaigns in France and the United States. The hype surrounding the 2008 Obama campaign overshadowed innovations in France the previous year, while the 2011 contest gained little serious academic attention. Using a well-established content analysis methodology the research explains the strategic design of the digital dimension of the campaigns of the leading candidates (Sarkozy and Royal in 2007, Obama and McCain in 2008, Hollande and Sarkozy in 2011, and Obama and Romney in 2012). The research then assesses the strategic contribution of each feature using schematics for understanding the flow of communication, as well as the strategy employed by each candidate. The key findings are that the campaigns are becoming more interactive, with the citizens increasingly more able to enter into conversations with the campaign teams, however interactivity when it happens is carefully controlled. Largely, however, there is a strong similarity masked by the sophistication of US contests. Despite the advances in communication technology and the social trends they have instigated, campaign communication remains top-down and digital technologies are used to gather data and push supporters towards activism than creating an inclusive space for the co-creation that cyberoptimists argued would revitalise the structures of democracy

One moment, please: can the speed and quality of political contact affect democratic health

Contact between politicians and their constituents is the cornerstone of democracies globally but an area of scholarship that remains relatively underdeveloped. Political contact can help convey authority, provide legitimacy and facilitate governance. This article goes beyond the assumption that representatives need to communicate more with the public and suggests, instead, that the quality of contact matters. Focusing on four processes by which citizens can contact their representatives (face-to-face, by letter, email or social media), we employ an experimental vignette methodology to test whether the character and timeliness of politicians’ responses to citizen communication affects two indicators of democratic health: (a) the latter’s satisfaction with political contact and (b) their likelihood to re-contact representatives. Our findings provide evidence that personalised communication and to a smaller extent, speed of response, can influence citizen satisfaction and their likelihood of re-engagement. This suggests politicians can improve these indicators of democratic health by adjusting the style of political contact and communication