Modeling protein network evolution under genome duplication and domain shuffling

<p>Abstract</p> <p>Background</p> <p>Successive whole genome duplications have recently been firmly established in all major eukaryote kingdoms. Such <it>exponential </it>evolutionary processes must have largely contributed to shape the topology of protein-protein interaction (PPI) networks by outweighing, in particular, all <it>time-linear </it>network growths modeled so far.</p> <p>Results</p> <p>We propose and solve a mathematical model of PPI network evolution under successive genome duplications. This demonstrates, from first principles, that evolutionary conservation and scale-free topology are intrinsically linked properties of PPI networks and emerge from <it>i) </it>prevailing <it>exponential </it>network dynamics under duplication and <it>ii) asymmetric divergence </it>of gene duplicates. While required, we argue that this asymmetric divergence arises, in fact, spontaneously at the level of protein-binding sites. This supports a refined model of PPI network evolution in terms of protein domains under exponential and asymmetric duplication/divergence dynamics, with multidomain proteins underlying the combinatorial formation of protein complexes. Genome duplication then provides a powerful source of PPI network innovation by promoting local rearrangements of multidomain proteins on a genome wide scale. Yet, we show that the overall conservation and topology of PPI networks are robust to extensive domain shuffling of multidomain proteins as well as to finer details of protein interaction and evolution. Finally, large scale features of <it>direct </it>and <it>indirect </it>PPI networks of <it>S. cerevisiae </it>are well reproduced numerically with only two adjusted parameters of clear biological significance (<it>i.e</it>. network effective growth rate and average number of protein-binding domains per protein).</p> <p>Conclusion</p> <p>This study demonstrates the statistical consequences of genome duplication and domain shuffling on the conservation and topology of PPI networks over a broad evolutionary scale across eukaryote kingdoms. In particular, scale-free topologies of PPI networks, which are found to be robust to extensive shuffling of protein domains, appear to be a simple consequence of the conservation of protein-binding domains under asymmetric duplication/divergence dynamics in the course of evolution.</p

A New Contract between Business and Business Analysts

Part 1: KeynoteInternational audienceSince the advent of business processes management it has been recognized that its main objective is optimization of enterprise’s performance. However, the focus of business analysis has changed significantly over the years. Initially business analysts focused on discovery and modelling of business processes. They aimed to identify opportunities for application of information technologies in business process automation and to determine resources needed for business process execution. More recently, the attention has shifted towards business process monitoring and optimization, while the current trends concern with business process intelligence for agile decision-making. Businesses expect that the business analysts will identify opportunities for continuous business process improvement by providing contextualized, high quality and secure information. In the light of these new business expectations, the keynote speech identifies today’s challenges faced by the business analysts and describes the current practice in dealing with these challenges

Modeling and Analyzing Engagement in Social Network Challenges

Participation to challenges within social networks is a very effective instrument for promoting a brand or event. In this paper,we take the challenge organizer’s perspective,and we study how to raise the engagement of players in challenges where the players are stimulated to create and evaluate content,thereby indirectly raising the awareness about the brand or event itself. We illustrate a comprehensive model of the actions and strategies that can be exploited for progressively boosting the social engagement during the challenge evolution. The model studies the organizer-driven management of interactions among players,and evaluates the effectiveness of each action in light of several other factors (time,repetition,third party actions,interplay between different social networks,and so on). We evaluate the model through a set of experiment upon a real case,the YourExpo2015 challenge. Overall,our experiments lasted 9 weeks and mobilized hundreds of thousands of users on two different social platforms; our quantitative analysis assesses the validity of the model

Programming incentives in information systems

Abstract. Information systems are becoming ever more reliant on different forms of social computing, employing individuals, crowds or assembled teams of professionals. With humans as first-class elements, the success of such systems depends heavily on how well we can motivate people to act in a planned fashion. Incentives are an important part of human resource management, manifesting selective and motivating effects. However, support for defining and executing incentives in today’s information systems is underdeveloped, often being limited to simple, per-task cash rewards. Furthermore, no systematic approach to program incentive functionalities for this type of platforms exists. In this paper we present fundamental elements of a framework for programmable incentive management in information systems. These elements form the basis necessary to support modeling, programming, and execution of various incentive mechanisms. They can be integrated with different underlying systems, promoting portability and reuse of proven incentive strategies. We carry out a functional design evaluation by illustrating modeling and composing capabilities of a prototype implementation on realistic incentive scenarios