Stochastic reaction networks within interacting compartments

Stochastic reaction networks, which are usually modeled as continuous-time Markov chains on $\mathbb Z^d_{\ge 0}$, and simulated via a version of the "Gillespie algorithm," have proven to be a useful tool for the understanding of processes, chemical and otherwise, in homogeneous environments. There are multiple avenues for generalizing away from the assumption that the environment is homogeneous, with the proper modeling choice dependent upon the context of the problem being considered. One such generalization was recently introduced in (Duso and Zechner, PNAS, 2020), where the proposed model includes a varying number of interacting compartments, or cells, each of which contains an evolving copy of the stochastic reaction system. The novelty of the model is that these compartments also interact via the merging of two compartments (including their contents), the splitting of one compartment into two, and the appearance and destruction of compartments. In this paper we begin a systematic exploration of the mathematical properties of this model. We (i) obtain basic/foundational results pertaining to explosivity, transience, recurrence, and positive recurrence of the model, (ii) explore a number of examples demonstrating some possible non-intuitive behaviors of the model, and (iii) identify the limiting distribution of the model in a special case that generalizes three formulas from an example in (Duso and Zechner, PNAS, 2020).Comment: 38 page

Shaping the formation of university-industry research collaborations: what type of proximity does really matter?

Research collaborations between universities and industry (U-I) are considered to be one important channel of potential localized knowledge spillovers (LKS). These collaborations favour both intended and unintended flows of knowledge and facilitate learning processes between partners from different organizations. Despite the copious literature on LKS, still little is known about the factors driving the formation of U-I research collaborations and, in particular, about the role that geographical proximity plays in the establishment of such relationships. Using collaborative research grants between universities and business firms awarded by the UK Engineering and Physical Sciences Research Council (EPSRC), in this article we disentangle some of the conditions under which different kinds of proximity contribute to the formation of U-I research collaborations, focusing in particular on clustering and technological complementarity among the firms participating in such partnerships

CHANGES OVER TIME IN PERCEPTIONS OF SPECIES VALUE: THE CASE OF AUSTROPOTAMOBIUS PALLIPES IN WALES

The perception of “value” placed on a species, here Austropotamobius pallipes, is related both to its conservation significance as well as economic social and legislative factors. Although the species may have had culinary significance in monastic Britain of the Middle Ages, there is no written record of its presence in Wales until the late eighteenth century. We know that before it was protected by law, it was collected for annual “crayfish feasts” into the twentieth century at a school on the River Usk. The rapid decline in the late twentieth century of this animal with full British and European legislative protection rekindled at least scientific interest in its survival. Currently funding for its survival comes mainly from EU sources

Reviews

Review of Jurisdiction under the Industrial Relations Act 1973: Some Problems and Issues, Employment: Towards an Active Employment Policy, Labor in the American Economy, Strikes and Participation, Democracy in the Work Place

Putting the ‘app’ in Happiness: A Randomised Controlled Trial of a Smartphone-Based Mindfulness Intervention to Enhance Wellbeing

Smartphones are revolutionizing approaches to wellbeing investment. Those seeking greater happiness can engage with thousands of downloadable self-help applications instantly, yet their effectiveness remains largely unknown. This investigation explored the viability of delivering a positive psychological intervention in application format to authentic happiness seekers. A smartphone-based randomized-controlled trial was conducted with a diverse self-selecting pool, randomly assigned to engage with an empirically supported mindfulness intervention (n = 57) or a control intervention (n = 64) for ten days. The study explored smartphone methodology, the importance of empirically based content for wellbeing enhancement and the extent to which user experience related to wellbeing gains. Results of repeated measures ANOVAs showed statistically significant increases in positive affect with a medium effect size and reduced depressive symptoms with a small effect size, although no statistically significant differences in satisfaction with life, flourishing or negative affect were found. No statistically significant gains were observed in the control condition. Ratings of task enjoyment were positively correlated (Pearson's r) with positive affect increase. Findings support the viability of smartphone-based interventions to significantly enhance elements of wellbeing, underscoring the importance of application content and the role of person-activity fit. This investigation presents implications for happiness seeking strategies in the real world whilst showcasing a dynamic method of intervention delivery that can benefit future research and practice. If the greatest mission of positive psychology is to enhance global flourishing, the potential of smartphone-based interventions may play a vital role

Photoelectron diffraction: from phenomenological demonstration to practical tool

The potential of photoelectron diffraction—exploiting the coherent interference of directly-emitted and elastically scattered components of the photoelectron wavefield emitted from a core level of a surface atom to obtain structural information—was first appreciated in the 1970s. The first demonstrations of the effect were published towards the end of that decade, but the method has now entered the mainstream armoury of surface structure determination. This short review has two objectives: First, to outline the way that the idea emerged and the way this evolved in my own collaboration with Neville Smith and his colleagues at Bell Labs in the early years: Second, to provide some insight into the current state-of-the art in application of (scanned-energy mode) photoelectron diffraction to address two key issue in quantitative surface structure determination, namely, complexity and precision. In this regard a particularly powerful aspect of photoelectron diffraction is its elemental and chemical-state specificity

Soft X-ray spectromicroscopy and its application to semiconductor microstructure characterization

The universal trend towards device miniaturization has driven the semiconductor industry to develop sophisticated and complex instrumentation for the characterization of microstructures. Many significant problems of relevance to the semiconductor industry cannot be solved with conventional analysis techniques, but can be addressed with soft x-ray spectromicroscopy. An active spectromicroscopy program is being developed at the Advanced Light Source, attracting both the semiconductor industry and the materials science academic community. Examples of spectromicroscopy techniques are presented. An ALS {mu}-XPS spectromicroscopy project is discussed, involving the first microscope completely dedicated and designed for microstructure analysis on patterned silicon wafers

Investigating the Validity of the Australian Early Development Census

This article continues evaluation of the construct validity of the Australian Early Development Census (AEDC) through comparison with linked data from a sample of 2216 4–5 year old children collected as part of the Longitudinal Study of Australian Children (LSAC). This builds on the construct validity assessment of Brinkman et al. (Early Educ Dev 18(3):427–451, 2007) based on a smaller sample of linked Australian Early Development Instrument (AvEDI) and LSAC children, in which moderate to large correlations were apparent between teacher-rated AvEDI domains and subconstructs and LSAC measures, with lower levels apparent for parent reported LSAC measures. In the current study, the data showed moderate to low correlations between the domains and subdomains from the AEDC and teacher reported LSAC data. Diferences in testing times, data sources (e.g. teachers versus carers) and levels of exposure to formal schooling at the time of testing are all discussed to account for the observed outcomes.Sarah Howells, Ha Trong Nguyen, Sally Brinkman, Francis Mitro