Current screens

The architecture of screen design, including LCD, LED and DLP projection, is analysed in terms of the political economy and their aesthetics and phenomenological impacts, in association with the use of codecs as constraining as well as enabling tools in the control and management of visual data transmission

Youth athlete leaders\u27 use of transformational behaviours and relations to trust in the leader and sport outcomes

Leadership is one of the most crucial factors determining whether a group succeeds or fails (Bass, 1990). Furthermore, leaders displaying transformational behaviours are thought to lift followers to higher levels of motivation to get them to perform beyond expectations (Bass, 1985), and they tend to have followers who are more committed and satisfied (Bass & Riggio, 2006). Another outcome of transformational leadership in organizations is that followers are more willing to trust leaders who show care and concern for the follower (Dirks & Ferrin, 2002). The purpose of the present study was to determine if the use of full range leadership behaviours by formal peer leaders on youth sport teams would relate to trust in the leader. Data were collected at two time points, once near the beginning of the season and again near the end of the season, using several questionnaires including the Multifactor Leadership Questionnaire – Form 5 (Bass & Avolio, 2004). Only data from participants who were present at both data collection points were included in the analyses of study hypotheses, which included 126 athletes (77 females, 49 males; mean age = 15.49) from 12 interdependent sport teams. It was found that perceptions of full range leadership were related to cognitive- and affect-based trust at both time points. Interestingly, the transformational components inspirational motivation and idealized influence (attributed) contributed positively, and the non-leadership component laissez-faire negatively, to the relationship with affect-based trust at both time points. The results of the current study also found that both transformational leadership behaviours and higher levels of trust related to athletes perceiving their leader as being effective and satisfying, as well as being willing to put in extra effort. The results lead to the suggestion that youth peer leaders’ use of transformational behaviours will promote higher levels of trust from their teammates, over and above the use of transactional and non-leadership behaviours

A constructive commutative quantum Lovasz Local Lemma, and beyond

The recently proven Quantum Lovasz Local Lemma generalises the well-known Lovasz Local Lemma. It states that, if a collection of subspace constraints are "weakly dependent", there necessarily exists a state satisfying all constraints. It implies e.g. that certain instances of the kQSAT quantum satisfiability problem are necessarily satisfiable, or that many-body systems with "not too many" interactions are always frustration-free. However, the QLLL only asserts existence; it says nothing about how to find the state. Inspired by Moser's breakthrough classical results, we present a constructive version of the QLLL in the setting of commuting constraints, proving that a simple quantum algorithm converges efficiently to the required state. In fact, we provide two different proofs, one using a novel quantum coupling argument, the other a more explicit combinatorial analysis. Both proofs are independent of the QLLL. So these results also provide independent, constructive proofs of the commutative QLLL itself, but strengthen it significantly by giving an efficient algorithm for finding the state whose existence is asserted by the QLLL. We give an application of the constructive commutative QLLL to convergence of CP maps. We also extend these results to the non-commutative setting. However, our proof of the general constructive QLLL relies on a conjecture which we are only able to prove in special cases.Comment: 43 pages, 2 conjectures, no figures; unresolved gap in the proof; see arXiv:1311.6474 or arXiv:1310.7766 for correct proofs of the symmetric cas

Common reasoning in games: a Lewisian analysis of common knowledge of rationality

The game-theoretic assumption of ‘common knowledge of rationality’ leads to paradoxes when rationality is represented in a Bayesian framework as cautious expected utility maximisation with independent beliefs (ICEU). We diagnose and resolve these paradoxes by presenting a new class of formal models of players’ reasoning, inspired by David Lewis’s account of common knowledge, in which the analogue of common knowledge is derivability in common reason. We show that such models can consistently incorporate any of a wide range of standards of decision-theoretic practical rationality. We investigate the implications arising when the standard of decision-theoretic rationality so assumed is ICEU.Common reasoning; common knowledge; common knowledge of rationality; David Lewis; Bayesian models of games

Ecomedia: Key Issues

Ecomedia: Key Issues is a comprehensive textbook introducing the burgeoning field of ecomedia studies to provide an overview of the interface between environmental issues and the media globally. Linking the world of media production, distribution, and consumption to environmental understandings, the book addresses ecological meanings encoded in media texts, the environmental impacts of media production, and the relationships between media and cultural perceptions of the environment. [From the publisher]https://cupola.gettysburg.edu/books/1084/thumbnail.jp

Universal Quantum Hamiltonians

Quantum many-body systems exhibit an extremely diverse range of phases and physical phenomena. Here, we prove that the entire physics of any other quantum many-body system is replicated in certain simple, "universal" spin-lattice models. We first characterise precisely what it means for one quantum many-body system to replicate the entire physics of another. We then show that certain very simple spin-lattice models are universal in this very strong sense. Examples include the Heisenberg and XY models on a 2D square lattice (with non-uniform coupling strengths). We go on to fully classify all two-qubit interactions, determining which are universal and which can only simulate more restricted classes of models. Our results put the practical field of analogue Hamiltonian simulation on a rigorous footing and take a significant step towards justifying why error correction may not be required for this application of quantum information technology.Comment: 78 pages, 9 figures, 44 theorems etc. v2: Trivial fixes. v3: updated and simplified proof of Thm. 9; 82 pages, 47 theorems etc. v3: Small fix in proof of time-evolution lemma (this fix not in published version