Radiolysis of water ice in the outer solar system: Sputtering and trapping of radiation products

We performed quantitative laboratory radiolysis experiments on cubic water ice between 40 and 120 K, with 200 keV protons. We measured sputtering of atoms and molecules and the trapping of radiolytic molecular species. The experiments were done at fluences corresponding to exposure of the surface of the Jovian icy satellites to their radiation environment up to thousands of years. During irradiation, O2 molecules are ejected from the ice at a rate that grows roughly exponentially with temperature; this behavior is the main reason for the temperature dependence of the total sputtering yield. O2 trapped in the ice is thermally released from the ice upon warming; the desorbed flux starts at the irradiation temperature and increases strongly above 120 K. Several peaks in the desorption spectrum, which depend on irradiation temperature, point to a complex distribution of trapping sites in the ice matrix. The yield of O2 produced by the 200 keV protons and trapped in the ice is more than 2 orders of magnitude smaller than used in recent models of Ganymede. We also found small amounts of trapped H2O2 that desorb readily above 160 K.Fil: Bahr, D.A.. University of Virginia; Estados UnidosFil: Famá, M.. University of Virginia; Estados UnidosFil: Vidal, Ricardo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Baragiola, Raul Antonio. University of Virginia; Estados Unido

Eco-evolutionary dynamics, density-dependent dispersal and collective behaviour:implications for salmon metapopulation robustness

The spatial dispersal of individuals plays an important role in the dynamics of populations, and is central to metapopulation theory. Dispersal provides connections within metapopulations, promoting demographic and evolutionary rescue, but may also introduce maladapted individuals, potentially lowering the fitness of recipient populations through introgression of heritable traits. To explore this dual nature of dispersal, we modify a well-established eco-evolutionary model of two locally adapted populations and their associated mean trait values, to examine recruiting salmon populations that are connected by density-dependent dispersal, consistent with collective migratory behaviour that promotes navigation. When the strength of collective behaviour is weak such that straying is effectively constant, we show that a low level of straying is associated with the highest gains in metapopulation robustness and that high straying serves to erode robustness. Moreover, we find that as the strength of collective behaviour increases, metapopulation robustness is enhanced, but this relationship depends on the rate at which individuals stray. Specifically, strong collective behaviour increases the presence of hidden low-density basins of attraction, which may serve to trap disturbed populations, and this is exacerbated by increased habitat heterogeneity. Taken as a whole, our findings suggest that density-dependent straying and collective migratory behaviour may help metapopulations, such as in salmon, thrive in dynamic landscapes. Given the pervasive eco-evolutionary impacts of dispersal on metapopulations, these findings have important ramifications for the conservation of salmon metapopulations facing both natural and anthropogenic contemporary disturbances.This article is part of the theme issue 'Collective movement ecology'

The research journey: Travels across the idiomatic and axiomatic toward a better understanding of complexity

In this paper, seven researchers reflect on the journeys their research projects have taken when they engage with and synthesize complex problems. These journeys embody an adaptive approach to tackling problems characterized by their interconnectedness and emergence, and that transcend traditional units of analysis such as ecosystems. In this paper we argue that making such a process deliberate and explicit will help researchers better combine different research paradigms such as expert-driven and participant-directed work, thus resulting in both broad explanations and specific phenomenon; research tensions traditionally defined as oppositional must be approached as complimentary. This paper includes researchers. personal journeys as they dealt with the emergent properties of complex problems and participant involvement. This paper argues that that research journey should be more than accidental but is a methodological necessity and should guide the theoretical and practical approaches to complex problems

Organising a safe space for navigating social-ecological transformations to sustainability.

The need for developing socially just living conditions for the world's growing population whilst keeping human societies within a 'safe operating space' has become a modern imperative. This requires transformative changes in the dominant social norms, behaviours, governance and management regimes that guide human responses in areas such as urban ecology, public health, resource security (e.g., food, water, energy access), economic development and biodiversity conservation. However, such systemic transformations necessitate experimentation in public arenas of exchange and a deepening of processes that can widen multi-stakeholder learning. We argue that there is an emergent potential in bridging the sustainability transitions and resilience approaches to create new scientific capacity that can support large-scale social-ecological transformations (SETs) to sustainability globally, not just in the West. In this article, we elucidate a set of guiding principles for the design of a 'safe space' to encourage stronger interactions between these research areas and others that are relevant to the challenges faced. We envisage new opportunities for transdisciplinary collaboration that will develop an adaptive and evolving community of practice. In particular, we emphasise the great opportunity for engaging with the role of emerging economies in facilitating safe space experimentation

Governing and accelerating transformative entrepreneurship: exploring the potential for small business innovation on urban sustainability transitions

The alluring yet nebulous concept of transformative change is increasingly gaining traction in conversations about pathways to more sustainable futures. As such, new conceptual tools are needed to illuminate variety of actors, interests, and capacities at play in potentially radical experiments. This paper draws upon multi-level governance theory, sustainability transitions scholarship, and sustainability entrepreneurship literature, to interrogate the transformative potential of small and medium-sized enterprises (SMEs). We (1) identify characteristics of SMEs that might make them relatively more able to produce radical innovations, (2) explore dimensions of the broader socio-political context that influence the likelihood of this potential to be translated into action in urban spaces, and (3) discuss implications of these dynamics for transformative sustainability governance

Governing and accelerating transformative entrepreneurship: exploring the potential for small business innovation on urban sustainability transitions

The alluring yet nebulous concept of transformative change is increasingly gaining traction in conversations about pathways to more sustainable futures. As such, new conceptual tools are needed to illuminate variety of actors, interests, and capacities at play in potentially radical experiments. This paper draws upon multi-level governance theory, sustainability transitions scholarship, and sustainability entrepreneurship literature, to interrogate the transformative potential of small and medium-sized enterprises (SMEs). We (1) identify characteristics of SMEs that might make them relatively more able to produce radical innovations, (2) explore dimensions of the broader socio-political context that influence the likelihood of this potential to be translated into action in urban spaces, and (3) discuss implications of these dynamics for transformative sustainability governance

The impact of armed civil conflict on household welfare and policy

This paper offers a framework for analysing the effects of armed conflicts on households and the ways in which households in turn respond to and cope with the conflicts. It distinguishes between direct and indirect effects, and shows that the indirect effects are channelled through (i) markets, (ii) political institutions, and (iii) social networks. Drawing upon the recent empirical literature, the paper portrays the processes running along these various channels and offers policy suggestions to be adopted at both national and international levels. Keywords: armed conflict; civil conflict; household welfare; transmission mechanism; coping mechanism; remittances