The stochastic dynamics of nanoscale mechanical oscillators immersed in a viscous fluid

The stochastic response of nanoscale oscillators of arbitrary geometry immersed in a viscous fluid is studied. Using the fluctuation-dissipation theorem it is shown that deterministic calculations of the governing fluid and solid equations can be used in a straightforward manner to directly calculate the stochastic response that would be measured in experiment. We use this approach to investigate the fluid coupled motion of single and multiple cantilevers with experimentally motivated geometries.Comment: 5 pages, 5 figure

Ambiguity and therapy in risk management

Ambiguity, the existence of multiple plausible (though possibly contested) ways of making sense of the characteristics of decision situations, can present significant difficulties for a wide range of risk management tasks. We will argue that ambiguity is present in risk management situations to a far greater extent that is commonly appreciated. The concept of ambiguity has arisen in different forms across disciplinary literatures and domains of practice. In this paper, we situate our experience of finding ways of supporting planning and decision-making processes concerned with ambiguous risks in the context of those wider perspectives. Our own efforts have employed a hybrid form of problem structuring methods (drawn from operational research and management science) and ethnography (drawn from sociology and anthropology). These engagements with organisational and inter-organisational risk management issues have led us to recognise that ‘untangling’ otherwise intractable risk management problems may be regarded, in some sense, as a therapeutic process. In this paper, we develop this therapeutic interpretation of the untangling of collective ambiguities using illustrations from a concrete problem situation. We set this therapeutic reading of decision processes in the context of wider perspectives, including those drawn from Habermas’ theorisation of communication, the sociology of science and the literature on citizen engagement and deliberation processes

Declining confidence in electoral fairness from those on the losing side is a serious problem – and it is getting worse

Cees van der Eijk and Jonathan Rose estimate the causal effects of the EU referendum on public perceptions of its fairness. They demonstrate that worryingly large groups of citizens have rather dim views of the fairness of electoral processes in the UK

Evidences of lay people’s reasoning related to climate change: per country and cross country results

This deliverable is about lay citizens’ reasoning about sustainability, in particular environmental protection and climate change, in various consumption domains, and the relation of this reasoning to the day-to-day lives of the participants. It presents country and cross-country findings from all 18 STAVE trials conducted between May 2011 and February 2012 in all six PACHELBEL partner countries. Analyses demonstrate that participants in the STAVE trials predominantly display a clear awareness that citizen consumption as demonstrated in their everyday practices of energy use, mobility, waste etc. are strongly connected with issues of environmental sustainablility. The STAVE trials also demonstrated that to live sustainably is a daily challenge, and people are often not able to organize their everyday routines in an environmental-friendly manner. Frequently there is a gap between participants’ aspirations and their practical behaviours. Significantly, the group conversations enabled participants to become aware that the self-assessed soundness of their everyday lives in terms of sustainability was at variance from the actual impact of e.g. their energy use or or mobility practices

Strategic policy advice: group-based processes as a tool to support policymaking

This deliverable is about the group discussions (STAVE trials) that have been carried out in the partner countries of project PACHELBEL on various substantive policy issues in the field of sustainability. It focuses on the methods that have been used to interact with lay citizens in the STAVE groups, and on the feedback that has been provided to policy makers on findings from the groups. Building upon these elaborations, conclusions will be drawn as to STAVE as a policy tool. Furthermore, this deliverable provides key features of STAVE groups on a country-by-country basis

Evidence about the policy assumptions about lay behaviour

This deliverable provides an analysis of the early fieldwork reports that have been produced as part of WP3. Its focus is on identifying the assumptions that are evident in the approaches of the policy partners to human behaviour around sustainability. The themes of this early work will form one focus of subsequent interactions with the policy partners and will be used as the basis for developing a schedule for further investigations to be deployed with policy makers in each countr

Dynamical Response of Nanomechanical Oscillators in Immiscible Viscous Fluid for in vitro Biomolecular Recognition

Dynamical response of nanomechanical cantilever structures immersed in a viscous fluid is important to in vitro single-molecule force spectroscopy, biomolecular recognition of disease-specific proteins, and the detection of microscopic dynamics of proteins. Here we study the stochastic response of biofunctionalized nanomechanical cantilevers beam in a viscous fluid. Using the fluctuation-dissipation theorem we derive an exact expression for the spectral density of the displacement and a linear approximation for the resonance frequency shift. We find that in a viscous solution the frequency shift of the nanoscale cantilever is determined by surface stress generated by biomolecular interaction with negligible contributions from mass loading.Comment: 4 pages, 2 figures, RevTex4. See http://nano.bu.edu/ for related paper

Optimal Design of Robust Combinatorial Mechanisms for Substitutable Goods

In this paper we consider multidimensional mechanism design problem for selling discrete substitutable items to a group of buyers. Previous work on this problem mostly focus on stochastic description of valuations used by the seller. However, in certain applications, no prior information regarding buyers' preferences is known. To address this issue, we consider uncertain valuations and formulate the problem in a robust optimization framework: the objective is to minimize the maximum regret. For a special case of revenue-maximizing pricing problem we present a solution method based on mixed-integer linear programming formulation

The Stochastic Dynamics of an Array of Atomic Force Microscopes in a Viscous Fluid

We consider the stochastic dynamics of an array of two closely spaced atomic force microscope cantilevers in a viscous fluid for use as a possible biomolecule sensor. The cantilevers are not driven externally, as is common in applications of atomic force microscopy, and we explore the stochastic cantilever dynamics due to the constant buffeting of fluid particles by Brownian motion. The stochastic dynamics of two adjacent cantilevers are correlated due to long range effects of the viscous fluid. Using a recently proposed thermodynamic approach the hydrodynamic correlations are quantified for precise experimental conditions through deterministic numerical simulations. Results are presented for an array of two readily available atomic force microscope cantilevers. It is shown that the force on a cantilever due to the fluid correlations with an adjacent cantilever is more than 3 times smaller than the Brownian force on an individual cantilever. Our results indicate that measurements of the correlations in the displacement of an array of atomic force microscopes can detect piconewton forces with microsecond time resolution.Comment: 7 page article with 11 images submitted to the International Journal of Nonlinear Mechanic