A Tale of Two Current Sheets

I outline a new model of particle acceleration in the current sheet separating the closed from the open field lines in the force-free model of pulsar magnetospheres, based on reconnection at the light cylinder and "auroral" acceleration occurring in the return current channel that connects the light cylinder to the neutron star surface. I discuss recent studies of Pulsar Wind Nebulae, which find that pair outflow rates in excess of those predicted by existing theories of pair creation occur, and use those results to point out that dissipation of the magnetic field in a pulsar's wind upstream of the termination shock is restored to life as a viable model for the solution of the "$\sigma$" problem as a consequence of the lower wind 4-velocity implied by the larger mass loading.Comment: 17 pages, 6 figures, Invited Review, Proceedings of the "ICREA Workshop on The High-Energy Emission from Pulsars and their Systems", Sant Cugat, Spain, April 12-16, 201

Social Expectations Bias Decision-Making in Uncertain Inter-Personal Situations

Understanding the role that social cues have on interpersonal choice, and their susceptibility to contextual effects, is of core importance to models of social decision-making. Language, on the other hand, is one of the main means of communication during social interactions in our culture. The present experiments tested whether positive and negative linguistic descriptions of alleged partners in a modified Ultimatum Game biased decisions made to the same set of offers, and whether the contextual uncertainty of the game modulated this biasing effect. The results showed that in an uncertain context, the same offers were accepted with higher probability when they were preceded by positive rather than by negative valenced trait-words. Participants also accepted fair offers with higher probability than unfair offers, but this effect did not interact with the valence of the social descriptive words. In addition, the speed of the decision was affected by valence: acceptance choices were faster when they followed a positive adjective, whereas rejection responses were faster after a negative-valenced word. However, these effects were highly reduced when the uncertainty was eliminated from the game. This suggests that positive and negative relevant social information can bias decisions made to the same pieces of evidence during interpersonal interactions, but that this mainly takes place when the uncertainty associated with the choices is high

Recognising peri-urban ecosystem services in urban development policy and planning: A framework for assessing agri-ecosystem services, poverty and livelihood dynamics

Peri-urban ecosystem services (ES) play a vital role in the health and livelihoods of urban and peri-urban residents, but have received relatively little attention in the literature to date. Here we focus on agriculture-related peri-urban ecosystem services in south Asia: examining the relationships with multiple dimensions of poverty, and cross-scale interactions that affect the livelihoods and well-being of both urban and peri-urban residents across city regions. We present a novel analytical framework to reveal the dynamics of ES, poverty and livelihood interactions in rapidly urbanising contexts. Our framework adapts concepts from three complementary literatures and augments these with insights from our long-term empirical research in peri-urban India. We demonstrate the iterative development and operationalisation of this framework through an in-depth case study of the peri-urban village of Karhera in Ghaziabad, India. Transdisciplinary field research was carried out between 2014 and 2016 and involved a household census, in-depth interviews and participatory mapping exercises with peri-urban agricultural communities; alongside policy process analysis, and interviews and workshops with government officials, representatives from civil society organisations and other policy stakeholders. The analysis demonstrates how the wider political economy, associated peri-urban transformations and changes in urban consumer’ demand have multiple interacting impacts on agri-ecosystems, and how the ES derived from agri-ecosystems are accessed and utilised in diverse livelihood. We highlight specific drivers and processes of urbanisation that impact on the value and management of ecosystems, and the distinctive political, institutional, and socio-economic characteristics of peri-urban transformations that influence ES-poverty interactions. Our framework supports an enhanced understanding of the implications of mainstream development trajectories and governance arrangements for peri-urban ES and for the health and livelihoods of diverse stakeholders in the city regions that depend upon them. In doing so it draws attention to the potential to build synergies between environmental, poverty and health objectives.</p

X-ray free-electron lasers

With intensities 10(8)-10(10) times greater than other laboratory sources, X-ray free-electron lasers are currently opening up new frontiers across many areas of science. In this Review we describe how these unconventional lasers work, discuss the range of new sources being developed worldwide, and consider how such X-ray sources may develop over the coming years