"Condoms Are Reliable but I Am Not": A Qualitative Analysis of AIDS-Related Beliefs and Attitudes of Young Heterosexual Adults in Budapest, Hungary and St. Petersburg, Russia

HIV and STD prevention is an essential component of public health initiatives in countries throughout Central and Eastern Europe. Liberalization in sexual values, declining age at first sex, higher levels of sexual activity, and inconsistent condom use have been well-documented among young people in the region following the political, economic, and cultural transitions after the end of the state socialism era. Less well-understood are the reasons for high-risk sexual behavior and psychosocial factors that must be addressed in the development of effective HIV/STD prevention programs. This study recruited members of 12 high-risk social networks of young adult men and women (n= 66 participants) in two cities, St. Petersburg, Russia, and Budapest, Hungary. In-depth focus groups were conducted with all members of each network, and qualitatively analyzed to examine factors surrounding high-risk sexual behavior. Main themes that emerged were that STDs are less known and less feared than AIDS, HIV risk factors were relatively well known among young adults in both countries but vulnerability is perceived differently, pregnancy prevention is a more immediate concern than protection from HIV or STDs, condom use declines quickly following first sex with a new partner, reintroducing condom use in a relationship is very difficult, and young adults report many barriers to condom use including those related to alcohol or other substance use. HIV/STD prevention programs are needed that extend beyond risk education alone and that also address critical psychological, social, and relationship factors related to sexual risk behavior

Noise in Coevolving Networks

Coupling dynamics of the states of the nodes of a network to the dynamics of the network topology leads to generic absorbing and fragmentation transitions. The coevolving voter model is a typical system that exhibits such transitions at some critical rewiring. We study the robustness of these transitions under two distinct ways of introducing noise. Noise affecting all the nodes destroys the absorbing-fragmentation transition, giving rise in finite-size systems to two regimes: bimodal magnetisation and dynamic fragmentation. Noise Targeting a fraction of nodes preserves the transitions but introduces shattered fragmentation with its characteristic fraction of isolated nodes and one or two giant components. Both the lack of absorbing state for homogenous noise and the shift in the absorbing transition to higher rewiring for targeted noise are supported by analytical approximations.Comment: 20 page

Nonlinear signaling on biological networks: the role of stochasticity and spectral clustering

Signal transduction within biological cells is governed by networks of interacting proteins. Communication between these proteins is mediated by signaling molecules which bind to receptors and induce stochastic transitions between different conformational states. Signaling is typically a cooperative process which requires the occurrence of multiple binding events so that reaction rates have a nonlinear dependence on the amount of signaling molecule. It is this nonlinearity that endows biological signaling networks with robust switch-like properties which are critical to their biological function. In this study, we investigate how the properties of these signaling systems depend on the network architecture. Our main result is that these nonlinear networks exhibit bistability where the network activity can switch between states that correspond to a low and high activity level. We show that this bistable regime emerges at a critical coupling strength that is determined by the spectral structure of the network. In particular, the set of nodes that correspond to large components of the leading eigenvector of the adjacency matrix determines the onset of bistability. Above this transition, the eigenvectors of the adjacency matrix determine a hierarchy of clusters, defined by its spectral properties, which are activated sequentially with increasing network activity. We argue further that the onset of bistability occurs either continuously or discontinuously depending upon whether the leading eigenvector is localized or delocalized. Finally, we show that at low network coupling stochastic transitions to the active branch are also driven by the set of nodes that contribute more strongly to the leading eigenvector.Comment: 30 pages, 12 figure

Ships passing in the night?: re-thinking the relationship between entrepreneurial agency and purposive transitions

In this paper, we examine the ways in which the phenomenon of entrepreneurial agency has been represented in the transitions literature with particular reference to purposive sustainability transitions. The aim of the paper is to encourage critical reflection on the relationship between transitions and entrepreneurship research. We present provisional findings from a content analysis conducted on sample publications, covering historical transitional and contemporary purposive transitions. We find that while entrepreneurial agency is clearly evident in both conceptual and empirical works, there are a number of limitations regarding: i) the role of context in relation to the dynamics of entrepreneurial agency; ii) differences in the types of entrepreneurs engaged in socio-technical transitions and the ways in which they interact with other key actors; iii) the predominantly individualistic interpretation accorded to entrepreneurship in the literature. We also review recent developments in entrepreneurship research, including work on: entrepreneurial opportunity, dynamic capabilities, networks and institutions, and indicate how these ideas might be integrated into transitions research, with reference to two sample studies. In the concluding remarks, we suggest ways in which a closer engagement with entrepreneurial agency might contribute to future transitions research and policy-making

A grassroots sustainable energy niche? Reflections on community energy case studies

System changing innovations for sustainability transitions are proposed to emerge in radical innovative niches. ‘Strategic Niche Management’ theory predicts that niche level actors and networks will aggregate learning from local projects, distilling and disseminating best practice. This should lower the bar for new projects to form and establish, thereby encouraging the innovation to diffuse through replication. Within this literature, grassroots innovations emerging from civil society are an under researched site of sociotechnical innovation for sustainable energy transitions. We consider the emerging community energy sector in the UK, in order to empirically test this model. Community energy is a diverse grassroots led sector including both demand and supply side initiatives for sustainable energy such as community owned renewable energy generation, village hall refurbishments, behaviour change initiatives and energy efficiency projects. Our analysis draws on in depth qualitative case study research with twelve local projects, and a study of how intermediary organisations aim to support local projects and encourage replication. This rich data allows us to examine the extent and nature of interactions between projects and intermediary actors in order to evaluate the utility of niche theories in the civil society context. In particular, we investigate which types of knowledge, support and resources were needed by our case study projects to become established and thrive, and compare and contrast this with those offered by the emerging community energy niche. Our findings indicate that while networking and intermediary organisations can effectively collate and spread some types of learning and information necessary for replication, this is not sufficient: tacit knowledge, trust and confidence are essential to these projects’ success, but are more difficult to abstract and translate to new settings. We draw out the implications of our findings for niche theory, for community energy and other grassroots practitioners aiming to build robust influential niches, and for policymakers eager to harness civil society’s innovative potential for sustainability

Multiple Tipping Points and Optimal Repairing in Interacting Networks

Systems that comprise many interacting dynamical networks, such as the human body with its biological networks or the global economic network consisting of regional clusters, often exhibit complicated collective dynamics. To understand the collective behavior of such systems, we investigate a model of interacting networks exhibiting the fundamental processes of failure, damage spread, and recovery. We find a very rich phase diagram that becomes exponentially more complex as the number of networks is increased. In the simplest example of $n=2$ interacting networks we find two critical points, 4 triple points, 10 allowed transitions, and two "forbidden" transitions, as well as complex hysteresis loops. Remarkably, we find that triple points play the dominant role in constructing the optimal repairing strategy in damaged interacting systems. To support our model, we analyze an example of real interacting financial networks and find evidence of rapid dynamical transitions between well-defined states, in agreement with the predictions of our model.Comment: 7 figures, typos corrected, references adde