Optimal growth of structures governed by spatially stochastic dynamics arises in many scientific settings, for example in processes such as solution-based crystallization and the formation of microbial biofilms on patterned substrates or microfluidic networks. In this work, we investigate lattice growth using a two-dimensional, zero-temperature stochastic model of short-range spin interactions. Our goal is to determine how external perturbations can be optimized to steer the system efficiently toward the uniformly positive state, starting from two initial clusters of positive sites. To achieve this, we cast the problem as a Markov decision process adapted for a two-dimensional Ising model with zero-temperature dynamics. Within this framework, we compare alternative growth geometries and identify the structure of optimal strategies across three representative regimes.
Energy system models are increasingly dependent on representative climate input. Yet, a fundamental mismatch persists between the hundreds of simulated years often used in climate science and the handful of years that computationally demanding power system models can process. Current practice, including ENTSO-E’s European Resource Adequacy Assessment, relies on climate year selections that have not been validated against explicit representativeness criteria. This risks biased investment decisions and blind spots for plausible weather conditions. This study proposes simulated annealing as an optimisation method for selecting representative subsets of complete climate years from large climate ensembles. Representativeness is quantified using the seasonal sliced Wasserstein distance, a metric from optimal transport theory that captures representativeness of marginal distributions, inter-variable correlations, and seasonal structure simultaneously. We evaluate simulated annealing against the alternative methods of random search, filtered random search, and K-Medoids clustering across three test cases spanning the Netherlands and Europe, using 180 climate years from the Pan-European Climate Database as a reference. Simulated annealing consistently produces the most representative subsets and outperforms the compared methods. Simulated annealing achieves an effective sample size three to five times the actual subset size. The resulting subsets are roughly 2.5–4 times more representative than the current ENTSO-E practice. The method is application-agnostic and its output can serve as a validated climate data input to any subsequent (energy) impact study.
The EU advances consumer empowerment as one of the pillars of energy legislation, aiming to transfer ownership of the energy transition to citizens. Rights and instruments have been introduced that offer citizens new ways of engaging with energy. However, EU energy legislation lacks a clear conceptual understanding of empowerment, which is required for crafting fit-for-purpose policy measures. We aim to provide a structured overview of current articulations of consumer empowerment in EU energy law by conducting a legislative analysis. To this end, we introduce a framework based on sustainability transitions theory that conceptualises empowerment according to four dimensions: 1) as identity-oriented or centred around resource-mobilisation, 2) more focused on autonomy or power-shift, 3) addressing the general public or specifically marginalised groups within society, and 4) more passive or more active. Application of the framework shows that EU energy legislation recognises consumer empowerment covering all four dimensions, and confirms the legislation’s ambition to provide a comprehensive empowerment agenda for citizens. Nonetheless, our findings also reveal limited reflection on the conceptual implications of such a broad empowerment agenda and the challenge of maintaining policies consistently. By drawing on insights from sustainability transitions we hope to encourage policy makers to strengthen conceptual clarity about the potential role and limitations of consumer empowerment in EU energy legislation. Conversely, we aim to raise awareness among transition scholars of the impacts of legislation on empowerment of actors in the energy transition by connecting legal and sustainability transition perspectives.
While research on the politics of transitions has examined power dynamics, coalitions, and value contestations, the ‘hidden’ sides of operational governance, such as micro-political dynamics, strategies and tensions within decision-making spaces, remained largely underexplored. Considering the increased attention to politics in the governance of sustainability transitions, we argue for a better understanding of the complex, often messy policy processes behind the scenes. Drawing on insights from political science and policy studies, we propose a ‘policy-as-practice’ perspective for transition studies to explore how actors shape and negotiate the content of policies, and the often concealed arenas in which they operate. We discuss the roles of state and non-state actors, interest groups, policy advisors and experts, and how their day-to-day practices shape policy outcomes. Furthermore, we discuss hidden processes such as nondecisions, policy inaction and watering down of policy initiatives as research topics that highlight how a policy-as-practice perspective can provide valuable insights. These aspects of policymaking are difficult to observe from the study of policy documents, decisions or instruments, and require studying policy processes up-close and immersively. We also outline important ontological and methodological implications of our micro-political perspective for the field of transition policy studies.
A comparison of Precambrian striate, discoid acritarchs with Circulisporites parvus de Jersey originally described from the Triassic of Queensland, significantly expands the stratigraphic distribution of a morphotype previously shown to be aligned with cysts of species belonging to the Euglenophyceae. These organic walled microfossils (owms) are described systematically and placed into three species of Ouroboros gen. nov.: O. soroboruo gen. et sp. nov., O. vulgaris gen et sp. nov. and O. torus gen. et sp. nov. These species are widespread in the 1078 Ma Nonesuch Formation in the United States with minor occurrences in the Torridonian Sequence of northwest Scotland. These microfossil cysts were originally buried in the bottom sediments of a rift valley lake, and they share a common ecology with modern freshwater euglenids, including an association with cyanobacteria. As a member of the Discobid clade, the euglenids are positioned close to the base of the eukaryote tree in some molecular phylogenetic studies, so their occurrence as documented here would appear to support models of earlier rather than later Neoproterozoic diversification of eukaryote lineages. Ouroboros gen. nov. becomes one of only a handful of examples of Precambrian owms that have found a place in crown group eukaryotic lineages.
