Speaker
Cristina Masoller

Description Climate networks are located at the cross roads of three interdisciplinary research fields: climate dynamics, networks, and time-series analysis. During the talk I will try to convince you that there is added value when we apply networks and nonlinear analysis tools to climate data. Specifically, I will discuss global climate networks constructed from surface air temperature anomalies. To infer interdependencies, we use the mutual information computed from data values and from the symbolic, ordinal representation of time-series. The latter allows defining networks in different time-scales: from intra-season (e.g., of a few months) to inter-annual (e.g., of a few years). I will show that ordinal analysis uncovers the regional patterns of climate variability in the shorter time-scales, and the global circulation system in the longer time-scales. The analysis uncovers correlations among different regions, some of them very well limited geographically and in time scale. I will also discuss the methods used to infer link directionality and to estimate link significance. I will try to integrate “the results” (the inferred networks) and the “causes” (known atmospheric and oceanic phenomena); in this sense I will show that the uncovered links are fully consistent with the present understanding of climate phenomena. Finally, I will discuss some open issues, for example, if the multi-layer network paradigm could be useful for uncovering relations among networks constructed from different climate variables, or among networks constructed in different time-scales.

Speaker
Jordi Bascompte

Description The mutualistic interactions between plants and the animals that pollinate them or disperse their seeds can form complex networks involving hundreds of species. These coevolutionary networks are highly heterogeneous, nested, and built upon weak and asymmetric links among species. Such general architectural patterns maximize the number of coexisting species and increase the range of variability that these mutualistic networks can withstand before one or more species goes extinct. Therefore, mutualistic networks can be viewed as the architecture of biodiversity. However, because pylogenetically similar species tend to play similar roles in the network, extinction events trigger non-random coextinction cascades. This implies that taxonomic diversity is lost faster than expected if there was no relationship between phylogeny and network structure.

Speaker
José Remesal Rodríguez, Albert Díaz-Guilera, Xavier Rubio Campillo, Alessandro Mosca

Description EPNet (www.roman-ep.net) is an ERC Advanced Grant research project (03/2014 - 02/2019) that aims at studying the political and economic dynamics of the Roman Empire food production and trade system by exploring different historical hypotheses through computer modeling and simulations. For this reason, the project is coordinated by the CEIPAC (Classical Antiquity Studies on Provincial Interdependence Centre) and involves scholars from Ancient and Economic History, Physics and Computer Science. The project counts with one of the richest database for roman amphorae and epigraphy, one of the most precise archaeological and historical semantic markers available from the Roman Empire market. This large dataset, created by the CEIPAC in the last 20 years, provides information on different products, geographical origin and economic transactions, as well as on the social positions and relationships between those involved in trade. Furthermore, the possibility of dating the information with great precision makes it possible to undertake fine-resolution studies of the dynamics of trading networks over time and scale, from regional case studies to the entire Mediterranean basin. In the presentation we will present the general idea of the project and a first approximation in the use of big data in historical research, from a pilot case study considering the oil trade network from the Betica province (ancient Andalusia).

Description

Complex networks are an emerging and powerful computational tool in the physical, biological and social sciences. They aim is to capture the structural properties of data represented as graphs or networks, providing ways of characterising both the static and dynamic facets of network structure. The topic draws on ideas from graph theory, statistical physics and dynamic systems theory. Applications include communication networks, epidemiology, transportation, social networks and ecology. The aim in the Summer School is to provide an overview of both the foundations and state of the art in the field. Lectures will be presented by intellectual leaders in the field, and there will be an opportunity to interact closely with them during the school. The school will be held in the Bertinoro Residential Centre of the University of Bologna, which is situated in beautiful hills between Ravenna and Bologna. The summer school is aimed at PhD students, and younger postdocs or RA’s working in the complex networks area. It will run for 5 days with lectures in the mornings and afternoons, and the school fee includes residential accommodation and meals at the residential centre. List of Lecturers Michele Benzi, Emory University, USA Luciano Costa, University of São Paulo, Brasil Ernesto Estrada, University of Strathclyde, UK Jesus Gomez Gardenes, University of Zaragoza, Spain Ferenc Jordan, The Microsoft Research – COSBI, Italy Yamir Moreno, University of Zaragoza, Spain Mirco Musolesi, University of Birmingham, UK Simone Severini, University College London, UK Organizers Andrea Torsello, Università Ca’ Foscari Venezia, Italy Edwin Hancock, University of York, UK Richard Wilson, University of York, UK Ernesto Estrada, University of Strathclyde, UK Registration Fees Registration will include Accommodation for 5 nights (13/7 to 17/7), and meals. Accommodation can be in single or double rooms (subject to availability). Single room Double room PhD student EUR 700 EUR 650 Postdoc EUR 800 EUR 750 Other EUR 900 EUR 850 We hope to be able to provide scholarships to PhD students to reduce the registration Fees. Student applicants will be automatically considered for scholarships. Application is now open through the schools's website. Deadline for application is April 15th. After that time we will let all applicants know whether their application was successful, whether they are entitled for scholarship, and, in that case, the amount of financial aid we can offer. Applicants must send an expression of interest along with their Curriculum vitae. PhD students must also send a letter from the supervisor in support to the request to be considered for the scholarship. Contact: Andrea Torsello<torsello@dsi.unive.it>

Speaker
H. Auradou

Description It is usually believe that at a low concentration of bacteria (here we will focus on the situation where the volume fraction of bacteria f is less than 1%) has negligible influence on the rheological properties of the fluid so that they can be viewed as passive tracers. As we will see, the presence of bacteria can tremendously reduce the viscosity until a zero viscosity regime. To do so, we have measured using a couette rheometer the viscosity of suspensions of E-Coli. For shear rate above 1.5 s-1, the viscosity is found constant and slightly above the viscosity in absence of bacteria (as expected for a fluid containing particles). For lower shear rate, the fluid is found to display non newtonian properties: the viscosity decreases and finally reaches a second newtonian plateau. For f<0.2%, the value of this plateau decreases linearly with the concentration as predicted by recent theoretical modelling. But, for f>0.2% the viscosity becomes null and independent of the concentration.