Research suggests that reporting suicide has the potential to influence vulnerable individuals to emulate suicide behaviour. Media guidelines for the responsible reporting of suicide have been developed and disseminated worldwide, but with mixed success. One factor that may influence guideline uptake is the degree to which health professionals have collaborated with the media professionals in guideline development, dissemination and implementation. The study used semi-structured interviews with media professionals to understand attitudes towards the guidelines, to explore the ways in the media were engaged in communication regarding the guidelines, and to identify whether this engagement bears upon media attitudes toward the guidelines. Findings indicate that media professionals view the guidelines as useful information within the bounds of normal reporting, but find them difficult to implement. Excellence theory indicates that the predominantly one-way and asymmetrical strategies used to engage the media in communication around the guidelines may play a role in these attitudes. The study echoes literature suggesting that collaborative guideline development and implementation is essential to meaningfully change suicide reporting practices.

This project considers a new application of crowd control, namely, keeping the public safe during large scale demonstrations. This problem is difficult for a variety of reasons, including limited access to informative sensing and effective actuation mechanisms, as well as limited understanding of crowd psychology and dynamics. This project takes a first step towards solving this problem by formulating a crowd state prediction problem in consideration of recent work involving crowd behavior identification, crowd movement modeling, and crowd psychology modeling. We build a non-linear crowd behavior model incorporating components of personality modeling, human emotion modeling, group opinion dynamics, and group movement modeling. This model is then linearized and used to build a state observer whose effectiveness is then tested on system outputs from both non-linear and linearized models. We show that knowledge of the crowd emotion equilibrium is necessary for zero-error convergence; however, other parameters, such as individual personality parameters of crowd agents, may be approximated and zero-error convergence still achieved given the crowd equilibrium point and sign of agent opinions. We conclude that using this model class to predict live crowd emotion may be impractical due to the need for knowledge of individual agent personality parameters to simulate the crowd equilibrium. Directions for future work are discussed.

No description available.

Thesis (Ed.D.)--Boston University / Background: Season-ending injuries, particularly those to the anterior cruciate ligament (ACL), continue at a high-rate in many sports, particularly ski racing. Although many factors are thought to contribute to this injury rate in both genders, no study has looked at possible psychological influences. Hypothesis: There is a form of post-traumatic stress disorder (PTSD) that affects athletes after seeing someone in their own sport sustain a serious injury. The result could be a decrease in performance both on and off the mountain. In the worst-case scenario, this change in tactics could result in injury to themselves, representing an "injury contagion". Study Design: Case-control study; Level of evidence, 3. Methods: Students at four Eastern ski academies were studied for 3 consecutive years (2002-2005). The subjects ranged in age from 13-19 and consisted of 277 men (60.3%) and 182 women (39.7% ). When a subject sustained a season-ending injury, a peer group of that subject was tested for both psychological and performance effects. The results of this testing was compared to previous baseline testing and a similarly constructed control group from an academy without such an injury. Results: There were twelve season-ending injuries sustained over the three-year period. Significant data results were obtained from one aspect of the psychological testing of the peer group. There was a trend toward a possible "injury contagion" i.e. injury to a member of the peer group soon after injury to a teammate. Conclusions: Although the results of this study were inconclusive in establishing the existence of an "injury contagion", there were data to establish a psychological affect on some athletes after injury to one of their teammates. Clinical Relevance: Although a teammate's injury did not measurably effect performance and only showed mild evidence of a possible injury contagion, there were significant psychological affects noted in female subjects. School personnel should be trained in basic counseling techniques specific to this problem.

No description available.

Three experiments investigated the phenomenon of war contagion in the context of international relations, hypothesizing that past inter- (but not intra-) state war will facilitate future, unrelated interstate war. Americans showed stronger support for violent responses to new, unrelated interstate tensions after being reminded of an historical war between the U.S. and another state, as compared to an historical domestic war within the U.S. (Study 1). This war contagion effect was mediated by heightened perceived threat from, and negative images of, a fictitious country unrelated to the past war, indicating a generalized effect of past interstate war on perceived threat/images from any foreign country. The war contagion effect was further moderated by national glorification (Study 2). Largely replicating these effects with an additional baseline condition, Study 3 yielded further support for the generalized effect of past interstate war on perceived threat and images, this time with a real third-party country.

Dynamics of social processes in populations, such as the spread of emotions, influence, language, mass movements, and warfare (often referred to individually and collectively as contagions), are increasingly studied because of their social, political, and economic impacts. Discrete dynamical systems (discrete in time and discrete in agent states) are often used to quantify contagion propagation in populations that are cast as graphs, where vertices represent agents and edges represent agent interactions. We refer to such formulations as graph dynamical systems. For social applications, threshold models are used extensively for agent state transition rules (i.e., for vertex functions). In its simplest form, each agent can be in one of two states (state 0 (1) means that an agent does not (does) possess a contagion), and an agent contracts a contagion if at least a threshold number of its distance-1 neighbors already possess it. The transition to state 0 is not permitted. In this study, we extend threshold models in three ways. First, we allow transitions to states 0 and 1, and we study the long-term dynamics of these bithreshold systems, wherein there are two distinct thresholds for each vertex; one governing each of the transitions to states 0 and 1. Second, we extend the model from a binary vertex state set to an arbitrary number r of states, and allow transitions between every pair of states. Third, we analyze a recent hierarchical model from the literature where inputs to vertex functions take into account subgraphs induced on the distance-1 neighbors of a vertex. We state, prove, and analyze conditions characterizing long-term dynamics of all of these models. / Master of Science

Cette thèse est articulée autour de trois risques financiers que sont : la liquidité, la contagion et le risque systémique. Ces derniers sont au centre de toutes les attentions depuis la crise de 2007-08 et resteront d’actualité à la vue des évènements que rencontrent les marchés financiers. Le premier chapitre de cette thèse présente un facteur de liquidité de financement obtenu par l’interprétation d’un phénomène de contagion en termes de risque de liquidité de marché. Nous proposons dans le second chapitre, une méta-mesure de cette liquidité de marché. Cette dernière tient compte de l’ensemble des dimensions présentes dans la définition de la liquidité en s’intéressant à la dynamique de plusieurs mesures de liquidité simultanément. L’objectif du troisième chapitre est de présenter une modélisation des rendements du marché permettant la prise en compte de la liquidité de financement dans l’estimation de la DCoVaR. Ainsi, ce travail propose une nouvelle mesure du risque systémique ayant un comportement contracyclique. Pour finir, nous nous intéressons à l’hypothèse de non-linéarité de la structure de dépendance entre les rendements de marché et ceux des institutions financières. Au cœur de la mesure du risque systémique, cette hypothèse apparait contraignante puisqu’elle n’a que peu d’impact sur l’identification des firmes les plus risquées mais peut compliquer considérablement l’estimation de ces mesures. / The aim of this thesis is to improve the management of financial risks through the employment of econometric methods. We focus on liquidity (market and funding), contagion and systemic risk, which have attracted a particularly large interest in the last years of financial turmoil. Firstly, we construct a funding liquidity factor based on the contagion effects that market liquidity risks encounter. This procedure can be useful to provide a better management of the liquidity mismatch among the assets and liabilities of a fund. Secondly, we propose a meta-measure of liquidity which incorporates multiple liquidity measures through the use of a conditional correlation model. As a result, we are able to detect drastic liquidity problems by using a single measure. Thirdly, we propose a new modeling framework for financial returns by adding an extra component related to funding liquidity to the standard DCoVaR model. In this way we obtain a countercyclical measure of systemic risk. Finally, we study to which extent a change in the estimation method affects the identification of systemically relevant Financial Institutions. In particular, the most popular measures aim at capturing the nonlinearity of the dependence structure between financial firms and market returns. We show, however, that similar results can be obtained by simply assuming a linear dependence, which can also largely simplify the estimation.

This Thesis expands on the current developments of the theory of stochastic diffusion processes of rumours. This is done by advancing the current mathematical characterisation of the solution to the Daley-Kendall model of the simple S-I-R rumour to a physical solution of the sub-population distribution over time of the generalised simple stochastic spreading process in social situations. After discussing stochastic spreading processes in social situations such as the simple epidemic, the simple rumour, the spread of innovations and ad hoc communications networks, it uses the three sub-population simple rumour to develop the theory for the identification of the exact sub-population distribution over time. This is done by identifying the generalised form of the Laplace Transform Characterisation of the solution to the three sub-population single rumour process and the inverse Laplace Transform of this characterisation. In this discussion the concept of the Inter-Changeability Principle is introduced. The general theory is validated for the three population Daley-Kendall Rumour Model and results for the three, five and seven population Daley-Kendall Rumour Models are pre- sented and discussed. The α - p model results for pseudo-Maki-Thompson Models are presented and discussed. In subsequent discussion it presents for the first time a statement of the Threshold Problem for Stochastic Spreading Processes in Social settings as well as stating the associated Threshold Theorem. It also investigates limiting conditions. Aspects of future research resulting from the extension of the three subpopulation model to more than three subpopulations are discussed at the end of the thesis. The computational demands of applying the theory to more than three subpopulations are restrictive; the size of the total population that can be considered at one time is considerably reduced. To retain the ability to compute a large population size, with an increase in the number of possible subpopulations, a possible method of repeated application of the three population solution is identified. This is done through the medium of two competing mutually exclusive rumours. The final discussion occurs on future investigation into the existence of limit values, zero states, cyclic states and absorbing states for the M subpopulation case. The generalisation and inversion of the Laplace Transform as well as the consequential statement of the threshold theorem, derivation of the transition probabilities and discussion of the limiting conditions are significant advances in the theory of rumours and similar social phenomena. / Thesis (Ph.D.) -- University of Adelaide, School of Mathematical Sciences, 2008

L’achat d’occasion est un phénomène de consommation en plein essor. Alors que les motivations du consommateur à acheter d’occasion ont suscité de nombreuses recherches, les freins sont rarement étudiés, notamment dans le contexte de l’achat en ligne. Pourtant, une meilleure compréhension de ces freins présente des enjeux aussi bien économiques qu’environnementaux ou sociétaux. Dans ce travail, nous nous intéressons aux freins relatifs à la perception d’une contagion physique ou symbolique des produits d’occasion. En effet, ces freins – qui sont soulignés dans la littérature sur l’achat hors ligne – sont remis en question par le contexte spécifique de l’achat sur Internet. Nous mobilisons ainsi la théorie des lois de la magie sympathique pour étudier dans quelle mesure la loi de contagion et la loi de similitude peuvent influencer l’achat d’un produit d’occasion en ligne. Cette thèse repose sur un design expérimental comportant trois études empiriques. Les résultats obtenus permettent d’identifier des déterminants situationnels et individuels de la contagion physique ou symbolique des produits d’occasion vendus en ligne et d’étudier leur influence négative sur l’intention d’achat. Contrairement à l’achat hors ligne, nous montrons que la contagion physique repose alors sur un mécanisme cognitif. De plus, les résultats indiquent que la loi de similitude permet de limiter les effets de la contagion. En conclusion, cette recherche permet de proposer plusieurs solutions pour améliorer la vente des produits d’occasion en ligne. / Secondhand shopping is a growing phenomenon. While secondhand shopping motivations received a lot of attention in marketing literature, consumer reluctance to shop secondhand remains under-Researched, especially in an online context. Yet, the stakes in better understanding this reluctance are not only economic, but also environmental and societal. In this research, we focus on consumer reluctance that is related to the perception of a physical or symbolic contagion of secondhand products. Indeed, while this reluctance is highlighted in literature on secondhand shopping offline, its role is questioned in an online context. Hence, we use the theoretical framework of the laws of sympathetic magic to study to what extent the contagion or similarity laws influence the intention to shop secondhand online. We use an experimental design made of three empirical studies. Results enable us to identify several situational and individual antecedents of the physical or symbolic contagion associated to a secondhand product sold online, and to study how contagion negatively influences the intention to purchase. In opposite to offline shopping, we show that physical contagion relies on a cognitive mechanism. Moreover, results show that the similarity law can reduce the effects of contagion. To conclude with, this research suggests various solutions to improve the sales of secondhand products online.