The relationship of network structure and dynamics is one of most extensively investigated problems in the theory of complex systems of the last years. Understanding this relationship is of relevance to a range of disciplines -from Neuroscience to Geomorphology. A major strategy of investigating this relationship is the quantitative comparison of a representation of network architecture (structural connectivity) with a (network) representation of the dynamics (functional connectivity). Analysing such SC/FC relationships has over the past years contributed substantially to our understanding of the functional role of network properties, such as modularity, hierarchical organization, hubs and cycles.Here, we show that one can distinguish two classes of functional connectivity -one based on simultaneous activity (co-activity) of nodes the other based on sequential activity of nodes. We delineate these two classes in different categories of dynamical processesexcitations, regular and chaotic oscillators -and provide examples for SC/FC correlations of both classes in each of these models. We expand the theoretical view of the SC/FC relationships, with conceptual instances of the SC and the two classes of FC for various application scenarios in Geomorphology, Freshwater Ecology, Systems Biology, Neuroscience and Social-Ecological Systems.Seeing the organization of a dynamical processes in a network either as governed by coactivity or by sequential activity allows us to bring some order in the myriad of observations relating structure and function of complex networks.

Resumo:A equação que relaciona a intensidade e duração da precipitação com a ocorrência de escorregamentos é uma ferramenta simples para antecipar e prevenir os desastres hidrológicos. O objetivo do presente trabalho foi elaborar uma curva de intensidade-duração para o município de Porto Alegre. Para isso, foram analisados dados pluviométricos e registros de escorregamentos ocorridos em Porto Alegre no período de 2006 a 2013. A análise foi feita por geoprocessamento no software ArcGIS seguida do uso de Excel. Duas equações de intensidade-duração foram ajustadas de acordo com o raio do ponto de escorregamento analisado -uma equação para pontos de 10 m de raio e outra para 25 m de raio. A equação ID para 10 m de raio obteve um ajuste melhor, indicando um detalhamento maior dos eventos e das condições do terreno. Porém, a análise tem incertezas, o que dificulta definição de um limiar para deflagração de escorregamentos. Os objetivos do trabalho foram satisfeitos e as equações ID propostas podem servir como ferramenta para a gestão do risco de desastre. Palavras-chave:Escorregamento, relação intensidade-duração da precipitação, Porto Alegre INTRODUÇÃO E OBJETIVOFenômenos naturais que ocorrem em locais ocupados pelo homem e que causam danos humanos, materiais e prejuízos socioeconômicos são denominados desastres naturais (UNDP, 2004). Os desastres hidrológicos são de difícil previsão e grande potencial destrutivo, a citar os escorregamentos e as inundações. No Brasil, a maioria dos escorregamentos ocorre durante períodos chuvosos, motivo pelo qual devem ser considerados desastres hidrológicos conforme classificação do Emergency Disaster Data Base (EMDAT) do Centre for Research

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The relationship between network structure and dynamics is one of the most extensively investigated problems in the theory of complex systems of recent years. Understanding this relationship is of relevance to a range of disciplines—from neuroscience to geomorphology. A major strategy of investigating this relationship is the quantitative comparison of a representation of network architecture (structural connectivity, SC) with a (network) representation of the dynamics (functional connectivity, FC). Here, we show that one can distinguish two classes of functional connectivity—one based on simultaneous activity (co-activity) of nodes, the other based on sequential activity of nodes. We delineate these two classes in different categories of dynamical processes—excitations, regular and chaotic oscillators—and provide examples for SC/FC correlations of both classes in each of these models. We expand the theoretical view of the SC/FC relationships, with conceptual instances of the SC and the two classes of FC for various application scenarios in geomorphology, ecology, systems biology, neuroscience and socio-ecological systems. Seeing the organisation of dynamical processes in a network either as governed by co-activity or by sequential activity allows us to bring some order in the myriad of observations relating structure and function of complex networks.

<p>Sediment transport in rivers depends on interactions between sediment supply, topography, and flow characteristics. Erosion in bedrock rivers controls topography and is paramount in landscape evolution models. The riverbed cover indicates sediment transport processes: alluvial cover indicates low transport capacity or high sediment supply, and bedrock cover demonstrates high transport capacity or low sediment supply. This study aims to evaluate controls on the spatial distributions of bedrock and alluvial covers, by analysing scaling geometric relations between bedrock and alluvial channels. A Principal Component Analysis (PCA) was conducted to evaluate correlations between river slope, depth, width, and sediment size. The two principal components were used to implement a clustering analysis in order to identify differences in alluvial and bedrock sections. Spatial distributions of mixed bedrock-alluvial sections were investigated from two datasets - Scottish Highlands (Whitbread 2015) and the San Gabriel Mountains in the USA (Dibiase 2011)-, representing different environmental conditions, such as erosion rates, lithology, tectonics, and climate. The rock strength of both areas is high, and therefore it is excluded as a factor that explains the difference between the areas. The results of the cluster analysis were different in each environment. The main sources of variation among river sections identified by PCA were slope and width for the San Gabriel Mountains, and drainage area and depth for the Scottish Highlands. The rivers in the Scottish Highlands formed clusters that differentiate bedrock and alluvial patches, showing a clear geometric distinction between channels. However, the river analysis from the San Gabriel Mountains showed no clusters. Bedrock rivers are typically described as narrower and steeper than alluvial rivers, as demonstrated by rivers in the Scottish Highlands (e.g. slope was around 0.1 m/m for bedrock sections and 0.01 m/m for alluvial sections). However, this may not be always the case: both bedrock and alluvial sections in San Gabriel Mountains presented similar slope around 0.1 m/m. The inability to demonstrate significant geometry differences in bedrock and alluvial sections in the San Gabriel Mountains may be due to the frequency and magnitude of sediment supply of that region, which are influenced by tectonics and climate. A major difference in the supply of sediment in rivers of the San Gabriel Mountains is the frequent occurrence of debris flow. Non-linear interactions between hydraulic and sediment processes may constantly modify the geometry of bedrock-alluvial channels, increasing the complexity of analysis at larger temporal and spatial scales. This study is part of the i-CONN project, which links connectivity in different scientific disciplines. A sediment connectivity assessment in different environments and scales may be useful to evaluate the controls on the spatial distribution of bedrock and alluvial rivers.</p><p> </p><p>Dibiase, R.A. 2011. Tectonic Geomorphology of the San Gabriel Mountains, CA. PhD Thesis. Arizona State University, Phoenix, 247pp.</p><p>Whitbread, K. 2015. Channel geometry data set for the northwest Scottish Highlands. British Geological Survey Open Report, OR/15/040. 12pp.</p>