Américo Tristão Bernardes

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Scientific and other non-patent references (NPRs) in patents are important tools to analyze interactions between science and technology. are 165,762 patents with at least one reference to science and engineering (S&E) literature, from a total of 1,375,503 references. Through a lexical analysis, 71.1% of this S&E literature is classified by S&E fields. These(More)
Some time ago Jerne proposed a new theory to explain the basis of the immune system. He suggested the existence of a functional connected network, based on pattern recognition of the idiotypes carried by the lymphocytes, which is responsible for the self regulation of the immune system. Only 15-20% of the lymphocytes available in the immune repertoire will(More)
Physicists are increasingly interested in studying the behavior of financial markets; likewise, researchers have applied statistical physics tools to study economic development in - and interactions among - various countries. We recently introduced a model that creates an artificial world economy of countries, each of which has a population with scientific(More)
One of the most intriguing features of the immune system is regulation: a limited response when perturbed repeatedly. We propose a minimal network model for immune regulation in a lymphocyte network containing two types of elements: B lymphocytes and ligands that bind to their receptors. Effective interactions between B cells, mediated by other components(More)
The immune system can be thought as a complex network of different interacting elements. A cellular automaton, defined in shape-space, was recently shown to exhibit self-regulation and complex behavior and is, therefore, a good candidate to model the immune system. Using this model to simulate a real immune system we find good agreement with recent(More)
The study of complex networks and the mechanisms underlying their formation gave an important direction to the research on the diffusion of information. It has been suggested that the network created by scientific citations follow a well-established picture of a scale-free network. Thus, citations should obey the basic mechanisms of preferential attachment,(More)
In this paper, we introduce a model for fracture in fibrous materials that takes into account the rupture height of the fibers, in contrast with previous models. Thus, we obtain the profile of the fracture and calculate its roughness, defined as the variance around the mean height. We investigate the relationship between the fracture roughness and the(More)
In this Letter we report spontaneous pattern formation in dense granular assemblies confined to a Hele-Shaw cell and quasistatic regime. Varied unexpected patterns, ranging from rounded to fingered, are observed due to the displacement of one granular material by another. Computer simulations reproduce the major features observed in these experiments. Two(More)
This paper presents a new methodology to describe global innovations networks. Using 167,315 USPTO patents granted in 2009 and the papers they cited, this methodology shows “scientific footprints of technology” that cross national boundaries, and how multinational enterprises interact globally with universities and other firms. The data and the map of these(More)
A bit-string model for the evolution of a population of haploid organisms, subject to competition, reproduction with mutation, and selection, is studied, using mean-field theory and Monte Carlo simulations. We show that, depending on environmental flexibility and genetic variability, the model exhibits a phase transition between extinction due to random(More)