Mediated behavioural change in human-machine networks: exploring network characteristics, trust and motivation

Human-machine networks pervade much of contemporary life. Network change is the product of structural modifications along with differences in participant be-havior. If we assume that behavioural change in a human-machine network is the result of changing the attitudes of participants in the network, then the question arises whether network structure can affect participant attitude. Taking citizen par-ticipation as an example, engagement with relevant stakeholders reveals trust and motivation to be the major objectives for the network. Using a typology to de-scribe network state based on multiple characteristic or dimensions, we can pre-dict possible behavioural outcomes in the network. However, this has to be medi-ated via attitude change. Motivation for the citizen participation network can only increase in line with enhanced trust. The focus for changing network dynamics, therefore, shifts to the dimensional changes needed to encourage increased trust. It turns out that the coordinated manipulation of multiple dimensions is needed to bring about the desired shift in attitude.Comment: Paper submitted to SocInfo, organised by the Oxford Internet Institute, September 201

Dispersive analysis of the scalar form factor of the nucleon

Based on the recently proposed Roy-Steiner equations for pion-nucleon scattering, we derive a system of coupled integral equations for the pi pi --> N-bar N and K-bar K --> N-bar N S-waves. These equations take the form of a two-channel Muskhelishvili-Omnes problem, whose solution in the presence of a finite matching point is discussed. We use these results to update the dispersive analysis of the scalar form factor of the nucleon fully including K-bar K intermediate states. In particular, we determine the correction Delta_sigma=sigma(2M_pi^2)-sigma_{pi N}, which is needed for the extraction of the pion-nucleon sigma term from pi N scattering, as a function of pion-nucleon subthreshold parameters and the pi N coupling constant.Comment: 24 pages, 6 figures; version published in JHE

Deep Sequencing of the Oral Microbiome Reveals Signatures of Periodontal Disease

The oral microbiome, the complex ecosystem of microbes inhabiting the human mouth, harbors several thousands of bacterial types. The proliferation of pathogenic bacteria within the mouth gives rise to periodontitis, an inflammatory disease known to also constitute a risk factor for cardiovascular disease. While much is known about individual species associated with pathogenesis, the system-level mechanisms underlying the transition from health to disease are still poorly understood. Through the sequencing of the 16S rRNA gene and of whole community DNA we provide a glimpse at the global genetic, metabolic, and ecological changes associated with periodontitis in 15 subgingival plaque samples, four from each of two periodontitis patients, and the remaining samples from three healthy individuals. We also demonstrate the power of whole-metagenome sequencing approaches in characterizing the genomes of key players in the oral microbiome, including an unculturable TM7 organism. We reveal the disease microbiome to be enriched in virulence factors, and adapted to a parasitic lifestyle that takes advantage of the disrupted host homeostasis. Furthermore, diseased samples share a common structure that was not found in completely healthy samples, suggesting that the disease state may occupy a narrow region within the space of possible configurations of the oral microbiome. Our pilot study demonstrates the power of high-throughput sequencing as a tool for understanding the role of the oral microbiome in periodontal disease. Despite a modest level of sequencing (∼2 lanes Illumina 76 bp PE) and high human DNA contamination (up to ∼90%) we were able to partially reconstruct several oral microbes and to preliminarily characterize some systems-level differences between the healthy and diseased oral microbiomes

Angels and venture capitalists: substitutes or complements?

We analyze the funding of start-up companies across financing rounds, focusing on the dynamic interactions between angel investors and venture capitalists. Using unique data from British Columbia, Canada, we show that angels and venture capitalists are dynamic substitutes. This substitutes pattern applies across the performance range of companies. It is less pronounced for serial angels. An instrumental variable analysis, based on available investor tax credits, suggests that the substitutes pattern is driven by company characteristics. Overall, the evidence points to the existence of parallel streams of angel and venture capital funding, with fewer transitions between streams than is traditionally assumed

Ownership dynamics within founder teams: The role of external financing

Research Summary This paper examines how founders within start‐up teams dynamically readjust their relative ownership stakes. It leverages a unique dataset from British Columbia, Canada, which contains detailed information on founder ownership over time. Two trade‐offs between efficiency and fairness are identified, one at the time of founding, the other as the venture develops. Teams with a preference for fairness at the start, as revealed by an equal division of the founder shares, also exhibit a dynamic preference for fairness, as witnessed by their reluctance to change the ownership structure over time. Relative founder stakes are more likely to change when a company raises investments. Larger rounds and lower valuations are associated with bigger changes in relative founder stakes. Managerial Summary Splitting the equity stakes among founders involves a delicate trade‐off between efficiency and fairness. This trade‐off is made when founders determine their initial division of equity, and also as the venture develops. We find that teams with a preference for fairness, as revealed by an equal split of their original founder equity, are also unlikely to change their relative stakes over time. We also find that changes in the division of founder ownership often coincide with external financing rounds, suggesting that renegotiations within teams are more easily settled in the presence of outside investors. Overall, the evidence suggests that although notions of fairness inhibit changes to the relative founder equity stakes, the stakes are not set in stone, and financing rounds provide opportunities for recalibration.</p