131 research outputs found

    Information Synergy Maximizes the Growth Rate of Heterogeneous Groups

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    Collective action and group formation are fundamental behaviors among both organisms cooperating to maximize their fitness, and people forming socioeconomic organizations. Researchers have extensively explored social interaction structures via game theory and homophilic linkages, such as in kin selection and scalar stress, to understand emergent cooperation in complex systems. However, we still lack a general theory capable of predicting how agents benefit from heterogeneous preferences, joint information, or skill complementarities in statistical environments. Here, we derive a general statistical dynamics for the origin of cooperation based on the management of resources and pooled information. Specifically, we show how groups that optimally combine complementary agent knowledge about resources in statistical environments maximize their growth rate. We show that these advantages are quantified by the information synergy embedded in the conditional probability of environmental states given agents' signals, such that groups with greater diversity of signals maximize their collective information. It follows that, when there are constraints placed on group formation, agents must intelligently select with who they cooperate with to maximize the synergy available to their own signal. Our results show how the general properties of information underlie the optimal collective formation and dynamics of groups of heterogeneous agents across social and biological phenomena.Comment: 14 pages, 4 figure

    Multivariate Granger Causality and Generalized Variance

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    Granger causality analysis is a popular method for inference on directed interactions in complex systems of many variables. A shortcoming of the standard framework for Granger causality is that it only allows for examination of interactions between single (univariate) variables within a system, perhaps conditioned on other variables. However, interactions do not necessarily take place between single variables, but may occur among groups, or "ensembles", of variables. In this study we establish a principled framework for Granger causality in the context of causal interactions among two or more multivariate sets of variables. Building on Geweke's seminal 1982 work, we offer new justifications for one particular form of multivariate Granger causality based on the generalized variances of residual errors. Taken together, our results support a comprehensive and theoretically consistent extension of Granger causality to the multivariate case. Treated individually, they highlight several specific advantages of the generalized variance measure, which we illustrate using applications in neuroscience as an example. We further show how the measure can be used to define "partial" Granger causality in the multivariate context and we also motivate reformulations of "causal density" and "Granger autonomy". Our results are directly applicable to experimental data and promise to reveal new types of functional relations in complex systems, neural and otherwise.Comment: added 1 reference, minor change to discussion, typos corrected; 28 pages, 3 figures, 1 table, LaTe

    Psychological type and attitude towards Celtic Christianity among committed Churchgoers in the United Kingdom: an empirical study

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    This article takes the burgeoning interest in Celtic Christianity as a key example of the way in which churches may be responding to the changing spiritual and religious landscape in the United Kingdom today and examines the power of psychological type theory to account for variation in the attitude of committed churchgoers to this innovation. Data provided by a sample of 248 Anglican clergy and lay church officers (who completed the Francis Psychological Type Scales together with the Attitude toward Celtic Christianity Scale) demonstrated that intuitive types, feeling types, and perceiving types reported a more positive attitude towards Celtic Christianity than sensing types, thinking types, and judging types. These findings are interpreted to analyse the appeal of Celtic Christianity and to suggest why some committed churchgoers may find this innovation less attractive

    Chronic Embolic Pulmonary Hypertension Caused by Pulmonary Embolism and Vascular Endothelial Growth Factor Inhibition

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    Our understanding of the pathophysiological basis of chronic thromboembolic pulmonary hypertension (CTEPH) will be accelerated by an animal model that replicates the phenotype of human CTEPH. Sprague-Dawley rats were administered a combination of a single dose each of plastic microspheres and vascular endothelial growth factor receptor antagonist in polystyrene microspheres (PE) + tyrosine kinase inhibitor SU5416 (SU) group. Shams received volume-matched saline; PE and SU groups received only microspheres or SU5416, respectively. PE + SU rats exhibited sustained pulmonary hypertension (62 ± 13 and 53 ± 14 mmHg at 3 and 6 weeks, respectively) with reduction of the ventriculoarterial coupling in vivo coincident with a large decrement in peak rate of oxygen consumption during aerobic exercise, respectively. PE + SU produced right ventricular hypokinesis, dilation, and hypertrophy observed on echocardiography, and 40% reduction in right ventricular contractile function in isolated perfused hearts. High-resolution computed tomographic pulmonary angiography and Ki-67 immunohistochemistry revealed abundant lung neovascularization and cellular proliferation in PE that was distinctly absent in the PE + SU group. We present a novel rodent model to reproduce much of the known phenotype of CTEPH, including the pivotal pathophysiological role of impaired vascular endothelial growth factor-dependent vascular remodeling. This model may reveal a better pathophysiological understanding of how PE transitions to CTEPH in human treatments

    Psychological Type and Attitude towards Celtic Christianity among Committed Churchgoers in the United Kingdom: An Empirical Study

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    This article takes the burgeoning interest in Celtic Christianity as a key example of the way in which churches may be responding to the changing spiritual and religious landscape in the United Kingdom today and examines the power of psychological type theory to account for variation in the attitude of committed churchgoers to this innovation. Data provided by a sample of 248 Anglican clergy and lay church officers (who completed the Francis Psychological Type Scales together with the Attitude toward Celtic Christianity Scale) demonstrated that intuitive types, feeling types, and perceiving types reported a more positive attitude towards Celtic Christianity than sensing types, thinking types, and judging types. These findings are interpreted to analyse the appeal of Celtic Christianity and to suggest why some committed churchgoers may find this innovation less attractive

    Evolution of the knowledge economy: a historical perspective with an application to the case of Europe

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    The goal of the article is to explore the evolution of original concept of knowledge economy based on science intensive production sectors toward service type economies which significantly changed the role of scientific research and technological innovation for economic growth. The paper argues that this transition is due not only to the structural changes in global production, but the theoretical evolution and aradigmatic shift of the concept of “knowledge economy” in general and “knowledge” in particular has played a significant role. The paper examines the different interpretation of knowledge within new types of intangible economies (e.g., new/Internet, weightless, service, creative, cultural economies) where knowledge is perceived to be generated not as a product of scientific research but as a service or creative activity and critically examined the role of scientific research in a service led knowledge economy. Additionally the paper argue how these phenomena, which marked the global economy in the last decades, enable the transition of the standard concept of knowledge economy originated from industrial production and manufacturing to a knowledge economy equalized with various types of expanding intangible economies, primarily those based on service and creative industries

    Uncovering the Molecular Machinery of the Human Spindle—An Integration of Wet and Dry Systems Biology

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    The mitotic spindle is an essential molecular machine involved in cell division, whose composition has been studied extensively by detailed cellular biology, high-throughput proteomics, and RNA interference experiments. However, because of its dynamic organization and complex regulation it is difficult to obtain a complete description of its molecular composition. We have implemented an integrated computational approach to characterize novel human spindle components and have analysed in detail the individual candidates predicted to be spindle proteins, as well as the network of predicted relations connecting known and putative spindle proteins. The subsequent experimental validation of a number of predicted novel proteins confirmed not only their association with the spindle apparatus but also their role in mitosis. We found that 75% of our tested proteins are localizing to the spindle apparatus compared to a success rate of 35% when expert knowledge alone was used. We compare our results to the previously published MitoCheck study and see that our approach does validate some findings by this consortium. Further, we predict so-called “hidden spindle hub”, proteins whose network of interactions is still poorly characterised by experimental means and which are thought to influence the functionality of the mitotic spindle on a large scale. Our analyses suggest that we are still far from knowing the complete repertoire of functionally important components of the human spindle network. Combining integrated bio-computational approaches and single gene experimental follow-ups could be key to exploring the still hidden regions of the human spindle system
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