0000000000502457
AUTHOR
Rosario Nunzio Mantegna
Networks in biological systems: An investigation of the Gene Ontology as an evolving network
Many biological systems can be described as networks where diFFerent elements interact, in order to perform biological processes. We introduce a network associated with the Gene Ontology. Specifically, we construct a correlation-based network where the vertices are the terms of the Gene Ontology and the link between each two terms is weighted on the basis of the number of genes that they have in common. We analyze a filtered network obtained from the correlation-based network and we characterize its evolution over different releases of the Gene Ontology.
Comment on the scientific paper no. 10
Modeling the dynamics os a financial index after a crash
The Tenth Article of Ettore Majorana
This year is the centenary of the birth of Ettore Majorana, one of the major Italian physicists of all times. In this note we briefly sketch a few biographical details about Ettore Majorana and introduce and discuss the main points of Majorana's 10th article. In his article Majorana explicitly considers quantum mechanics as an irreducible statistical theory because the theory is not able to describe the time evolution of a single particle or atom in a precise environment at a deterministic level. This lack of determinism at the level of an elementary physical system motivated him to suggest a formal analogy between statistical laws observed in physics and in the social sciences. We hope the…
Generation of hierarchically correlated multivariate symbolic sequences: With an application to the assessment of bootstrap confidence in phylogenetic analysis.
We introduce a method to generate multivariate series of symbols from a finite alphabet with a given hierarchical structure of similarities based on the Hamming distance. The target hierarchical structure of similarities is arbitrary, for instance the one obtained by some hierarchical clustering method applied to an empirical matrix of similarities. The method that we present here is based on a generating mechanism that does not make use of mutation rate, which is widely used in phylogenetic analysis. Here we use the proposed simulation method to investigate the relationship between the bootstrap value associated with a node of a phylogeny and the probability of finding that node in the tru…
Majorana's article on "The value of statistical laws in physics and social sciences"
Dall’analisi del genoma al vocabolario biologico dell’autismo
Econofisica: il contributo dei fisici allo studio dei sistemi economici
Hierarchical structures in Complex Systems: from DNA to financial markets
In this paper we discuss the concepts of short-range and long-range correlated stochastic processes and we investigate the presence of such variables in two model complex systems. The selected model systems are DNA sequences of complete genomes and financial time series of equities traded in a stock market. Specifically, by starting from our research results, we discuss the statistical properties of (i) coding and non-coding regions of DNA and (ii) equity returns and volatility in financial markets. The stylized facts about these variables are presented and discussed with a focus on the statistical tools already used and/or still needed to better characterize these model complex systems.
Exploratory analysis of safety data and their interrelation with flight trajectories and network metrics
This paper presents an exploratory analysis of the correlation between different network metrics and safety events. The objective is to develop analysis methods and indicators that relate the network structure with safety events. In particular by using data gathered with an automatic tool developed by EUROCONTROL and a database of traffic data, we measured the correlations between the classical metrics of the airspace network, especially the network of navigation points, and the occurrence of Short Term Conflicts Alerts (STCA). The results obtained are not univocal; correlation between STCA occurrences and classical network metrics are present but the correlation coefficient is around 0.7. …
Value-at-risk and Tsallis statistics: risk analysis of the aerospace sector
Autism Spectrum Disorders: From Candidate Genes to Candidate Ontology Terms
Genetic heterogeneity for a multifactorial disease such as autism would imply that any two patients are unlikely to share the same susceptibility loci. Since different susceptibility loci may affect the same function and since functions may be considered at different levels of analysis, the following question arises: at what phenotypic levels is convergence attained by different genes in autism ? This is an important question to answer in order to shed light on subcellular, cellular or multicellular structures and functions possibly involved in the pathogenesis of autism. Among the various attempts made to answer this question it is worth mentioning the use of the best available genetic inf…