Modeling the structure and evolution of discussion cascades

We analyze the structure and evolution of discussion cascades in four popular websites: Slashdot, Barrapunto, Meneame and Wikipedia. Despite the big heterogeneities between these sites, a preferential attachment (PA) model with bias to the root can capture the temporal evolution of the observed trees and many of their statistical properties, namely, probability distributions of the branching factors (degrees), subtree sizes and certain correlations. The parameters of the model are learned efficiently using a novel maximum likelihood estimation scheme for PA and provide a figurative interpretation about the communication habits and the resulting discussion cascades on the four different websites.Comment: 10 pages, 11 figure

Self-organization using synaptic plasticity

Large networks of spiking neurons show abrupt changes in their collective dynamics resembling phase transitions studied in statistical physics. An example of this phenomenon is the transition from irregular, noise-driven dynamics to regular, self-sustained behavior observed in networks of integrate-and-fire neurons as the interaction strength between the neurons increases. In this work we show how a network of spiking neurons is able to self-organize towards a critical state for which the range of possible inter-spike-intervals (dynamic range) is maximized. Self-organization occurs via synaptic dynamics that we analytically derive. The resulting plasticity rule is defined locally so that global homeostasis near the critical state is achieved by local regulation of individual synapses.Comment: 8 pages, 5 figures, after review NIPS'0

Nucleon distribution amplitudes from lattice QCD

We calculate low moments of the leading-twist and next-to-leading twist nucleon distribution amplitudes on the lattice using two flavors of clover fermions. The results are presented in the MSbar scheme at a scale of 2 GeV and can be immediately applied in phenomenological studies. We find that the deviation of the leading-twist nucleon distribution amplitude from its asymptotic form is less pronounced than sometimes claimed in the literature.Comment: 5 pages, 3 figures, 2 tables. RevTeX style. Normalization for \lambda_i corrected. Discussion of the results extended. To be published in PR

Quantitative Analysis of Bloggers Collective Behavior Powered by Emotions

Large-scale data resulting from users online interactions provide the ultimate source of information to study emergent social phenomena on the Web. From individual actions of users to observable collective behaviors, different mechanisms involving emotions expressed in the posted text play a role. Here we combine approaches of statistical physics with machine-learning methods of text analysis to study emergence of the emotional behavior among Web users. Mapping the high-resolution data from digg.com onto bipartite network of users and their comments onto posted stories, we identify user communities centered around certain popular posts and determine emotional contents of the related comments by the emotion-classifier developed for this type of texts. Applied over different time periods, this framework reveals strong correlations between the excess of negative emotions and the evolution of communities. We observe avalanches of emotional comments exhibiting significant self-organized critical behavior and temporal correlations. To explore robustness of these critical states, we design a network automaton model on realistic network connections and several control parameters, which can be inferred from the dataset. Dissemination of emotions by a small fraction of very active users appears to critically tune the collective states

Irreducible Multiplets of Three-Quark Operators on the Lattice: Controlling Mixing under Renormalization

High luminosity accelerators have greatly increased the interest in semi-exclusive and exclusive reactions involving nucleons. The relevant theoretical information is contained in the nucleon wavefunction and can be parametrized by moments of the nucleon distribution amplitudes, which in turn are linked to matrix elements of three-quark operators. These can be calculated from first principles in lattice QCD. However, on the lattice the problems of operator mixing under renormalization are rather involved. In a systematic approach we investigate this issue in depth. Using the spinorial symmetry group of the hypercubic lattice we derive irreducibly transforming three-quark operators, which allow us to control the mixing pattern.Comment: 13 page

Magnetosensitive e-skins with directional perception for augmented reality

Electronic skins equipped with artificial receptors are able to extend our perception beyond the modalities that have naturally evolved. These synthetic receptors offer complimentary information on our surroundings and endow us with novel means of manipulating physical or even virtual objects. We realize highly compliant magnetosensitive skins with directional perception that enable magnetic cognition, body position tracking, and touchless object manipulation. Transfer printing of eight high-performance spin valve sensors arranged into two Wheatstone bridges onto 1.7-mm-thick polyimide foils ensures mechanical imperceptibility. This resembles a new class of interactive devices extracting information from the surroundings through magnetic tags. We demonstrate this concept in augmented reality systems with virtual knob-turning functions and the operation of virtual dialing pads, based on the interaction with magnetic fields. This technology will enable a cornucopia of applications from navigation, motion tracking in robotics, regenerative medicine, and sports and gaming to interaction in supplemented reality

An overview of innovations in the external peer review of journal manuscripts.

Background: There are currently numerous innovations in peer review and quality assurance in scholarly publishing. The Research on Research Institute conducted a programme of co-produced projects investigating these innovations. This literature review was part of one such project ‘Experiments in peer review’ which created an inventory and framework of peer review innovations. The aim of this literature review was to aid the development of the inventory by identifying innovations in the external peer review of journal manuscripts reported in the scholarly literature and by providing a summary of the different approaches. This did not include interventions in editorial processes. Methods: This review of reviews is based on data identified from Web of Science and Scopus limited from 2010 to 2021. A total of 291 records were screened, with six review articles chosen for the focus of the literature review. Items were selected that described approaches to innovating peer review or illustrated examples. Results: The overview of innovations are drawn from six review articles. The innovations are divided into three high-level categories: approaches to peer review, reviewer focussed initiatives and technology to support peer review with sub-categories of results presented in tabular form and summarised. A summary of all innovations found is also presented. Conclusions: From a simple synthesis of the review authors’ conclusions, three key messages are presented: observations on current practice; authors’ views on the implications of innovations in peer review; and calls for action in peer review research and practice

Innovations in peer review in scholarly publishing : a meta-summary [version 1; under peer-review]

Background: There are currently numerous innovations in peer review and quality assurance in scholarly publishing. The Research on Research Institute conducted a programme of co-produced projects investigating these innovations. This literature review was part of one such project ‘Experiments in peer review’ which created an inventory and framework of peer review innovations. The aim of this literature review was to aid the development of the inventory by identifying innovations in peer review reported in the scholarly literature and by providing a summary of the different approaches. Methods: This meta-summary is based on data identified from Web of Science and Scopus limited from 2010 to 2021. A total of 247 papers were screened, with 6 review articles chosen for the focus of the literature review. Items were selected that described approaches to innovating peer review or illustrated examples. Results: The summary of innovations are drawn from 6 review articles. The innovations are divided into three high-level categories: approaches to peer review, reviewer focussed initiatives and technology to support peer review with sub-categories of results presented in tabular form and summarised. A summary of all innovations found is also presented. Conclusions: From a simple synthesis of the review authors’ conclusions, three key messages are presented: observations on current practice; authors’ views on the implications of innovations in peer review; and calls for action in peer review research and practice

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