Kinetic Limit for Wave Propagation in a Random Medium

We study crystal dynamics in the harmonic approximation. The atomic masses are weakly disordered, in the sense that their deviation from uniformity is of order epsilon^(1/2). The dispersion relation is assumed to be a Morse function and to suppress crossed recollisions. We then prove that in the limit epsilon to 0 the disorder averaged Wigner function on the kinetic scale, time and space of order epsilon^(-1), is governed by a linear Boltzmann equation.Comment: 71 pages, 3 figure

Reflexive use of methods: a framework for navigating different types of knowledge and power in transformative research

In transformative sustainability science, reflexivity is considered critical for ethically sound and socially relevant research. In practice, many transdisciplinary knowledge co-production processes have faced problems in mitigating power hierarchies among the participating actors and the different types of knowledge. In this paper, we develop and test a reflexive framework that enables transdisciplinary researchers to convey more explicitly how their methodological choices play a role in im/balancing power relations in knowledge co-production. The reflexive framework allows researchers to distinguish the different types of knowledge co-produced by the methods, as well as tracking the movements between them. We utilize the framework to reflect upon the methodological choices made through the application of three different transformative methods, namely the Transition Arena, Theory of Change, and Participatory Food Sustainability Assessment and Transformation Framework in different contexts. The results illuminate how the agility between the knowledge types is critical for navigating tensions in power imbalances, as well as producing transformative knowledge. Moreover, the results call further attention to the co-production of critical knowledge in sustainability science

Test-retest reliability of diffusion tensor imaging scalars in 5-year-olds

Diffusion tensor imaging (DTI) has provided great insights into the microstructural features of the developing brain. However, DTI images are prone to several artifacts and the reliability of DTI scalars is of paramount importance for interpreting and generalizing the findings of DTI studies, especially in the younger population. In this study, we investigated the intrascan test-retest repeatability of four DTI scalars: fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in 5-year-old children (N = 67) with two different data preprocessing approaches: a volume censoring pipeline and an outlier replacement pipeline. We applied a region of interest (ROI) and a voxelwise analysis after careful quality control, tensor fitting and tract-based spatial statistics. The data had three subsets and each subset included 31, 32, or 33 directions thus a total of 96 unique uniformly distributed diffusion encoding directions per subject. The repeatability of DTI scalars was evaluated with intraclass correlation coefficient (ICC(3,1)) and the variability between test and retest subsets. The results of both pipelines yielded good to excellent (ICC(3,1) > 0.75) reliability for most of the ROIs and an overall low variability (<10%). In the voxelwise analysis, FA and RD had higher ICC(3,1) values compared to AD and MD and the variability remained low (<12%) across all scalars. Our results suggest high intrascan repeatability in pediatric DTI and lend confidence to the use of the data in future cross-sectional and longitudinal studies

Too big to succeed? Institutional inertia in low-carbon district heating experiment

Highlights • Experimenting with district heating network spotlights the multi-regime dynamics in transitions. • Inertia from different sources of socio-technical system hinders the experimentation. • Ambiguous technology visions can water down the more transformative expectations. • Social aspects of low-carbon transitions in district heat require further attention. Abstract The energy transitions are in an acceleration phase, where less carbon intensive technologies emerge, but their applicability is uncertain creating a need for real-life experimentation. Cities have become a focal context, where novel constellations of technologies and practices are introduced to reconfigure patterns of production and consumption. One area of urban energy governance gaining increasing attention especially in a Northern context is the low carbon transition in district heating systems that provide the majority of heating in the residential sector and has been primarily built around combustion technologies relying on fossil energy reserves. This article analyses a bidirectional low heat experiment in district heat in Finland by examining what are the dimensions of institutional inertia and how it impacts the reconfiguration of an urban energy system. Institutional inertia emerges from the technical innovation itself, land-use planning practices, the absence of formal regulations and via organisational inertia in the implementation of the experiment. We find that visions about the innovation can become constraints of the experiment, which limit learning and reshaping of innovation, thus preventing radical transformation of the district heating system and watering down the initial target of the experiment. We contribute to the conceptualisation of institutional inertia within the energy transition

Citizen energy lost in sustainability transitions : Knowledge co-production in a complex governance context

Funding Information: In the European Union, the Clean Energy Package with revised directives has created a framework for the member states to provide stronger legislative support for citizen engagement in community-level energy actions [10,11]. These regulatory reforms are geared towards transforming the operational conditions for active, efficient and inclusive citizen-led energy communities to emerge in diverse contexts [12–14]. More specifically, the market access rules and the information supporting the distributed energy producers have been improved [10]. The legitimacy of the EU policies on renewable energy, energy efficiency and market reforms is considered to be improved by enabling citizen energy action at the community level [15].This work was supported by the Finnish Strategic Research Council project Collaborative remedies for fragmented societies [grant numbers 313013, 313014, 313015] and Academy of Finland project Digitally mediated decarbon communities in energy transition [grant number 348626]. The authors would like to thank reviewers for their thoughtful comments on the earlier manuscript versions as well as Hanna-Liisa Kangas and Lasse Peltonen for their input to the wider project. Funding Information: This work was supported by the Finnish Strategic Research Council project Collaborative remedies for fragmented societies [grant numbers 313013 , 313014 , 313015 ] and Academy of Finland project Digitally mediated decarbon communities in energy transition [grant number 348626 ]. The authors would like to thank reviewers for their thoughtful comments on the earlier manuscript versions as well as Hanna-Liisa Kangas and Lasse Peltonen for their input to the wider project. Publisher Copyright: © 2022Countries are moving towards renewable energy systems, which creates new requirements and pressures for the established energy policy frameworks. One emerging issue is citizen energy production in community level that has been given a central role also in recent policy reforms in the EU. However, one understudied topic is how the decision-making and action in the existing and potential citizen energy communities connects to broader energy governance. In this paper, we focus on one such type of actor, housing companies in Finland, in which mobilising collective energy action has become a policy priority. We build empirically and methodologically on a facilitated knowledge co-production process utilising mid-range transition arena method to understand the main challenges in engaging citizen energy action in the Finnish policy context. The process was organised with central government authorities, and it involved a diverse mix of stakeholders from housing companies, business, knowledge production and different levels of administration. The analysis shows how different types of knowledge from system knowledge to target knowledge and transformative knowledge are generated in transition arena process, and how the shared production of knowledge increases on each step, which is necessary for drawing systemic lessons in sustainability transitions context. Therefore, we learn that the enhanced role of citizen energy communities requires active and simultaneous coordination of multiple policy pathways, illustrated as digital information, policy coordination, energy service and neighbourhood collaboration pathways. We also conclude that the traditional roles given to citizen energy agency become transformed and require more nuanced conceptualisation.Peer reviewe

Citizen energy lost in sustainability transitions : Knowledge co-production in a complex governance context

Countries are moving towards renewable energy systems, which creates new requirements and pressures for the established energy policy frameworks. One emerging issue is citizen energy production in community level that has been given a central role also in recent policy reforms in the EU. However, one understudied topic is how the decision-making and action in the existing and potential citizen energy communities connects to broader energy governance. In this paper, we focus on one such type of actor, housing companies in Finland, in which mobilising collective energy action has become a policy priority. We build empirically and methodologically on a facilitated knowledge co-production process utilising mid-range transition arena method to understand the main challenges in engaging citizen energy action in the Finnish policy context. The process was organised with central government authorities, and it involved a diverse mix of stakeholders from housing companies, business, knowledge production and different levels of administration. The analysis shows how different types of knowledge from system knowledge to target knowledge and transformative knowledge are generated in transition arena process, and how the shared production of knowledge increases on each step, which is necessary for drawing systemic lessons in sustainability transitions context. Therefore, we learn that the enhanced role of citizen energy communities requires active and simultaneous coordination of multiple policy pathways, illustrated as digital information, policy coordination, energy service and neighbourhood collaboration pathways. We also conclude that the traditional roles given to citizen energy agency become transformed and require more nuanced conceptualisation.peerReviewe

Etude de la photodissociation de l'ozone par une methode dependant du temps

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 78316 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc