arXiv subjects

Alexandre de Castro

Publications and source records attributed to Alexandre de Castro.

7 recordsLinked to original sources

arXiv2017

A network model for clonal differentiation and immune memory

A model of bit-strings, that uses the technique of multi-spin coding, was previously used to study the time evolution of B-cell clone repertoire, in a paper by Lagreca, Almeida and Santos. In this work we extend that simplified model to include independently the role of the populations of antibodies, in the control of the immune response, producing mechanisms of differentiation and regulation in a more complete way. Although the antibodies have the same molecular shape of the B-cells receptors (BCR), they should present a different time evolution and thus should be treated separately. We have also studied a possible model for the network immune memory, suggesting a random memory regeneration, which is self-perpetuating.

q-bio.PE↗

arXiv2017

A dynamical modeling to study the adaptive immune system and the influence of antibodies in the immune memory

Immunological systems have been an abundant inspiration to contemporary computer scientists. Problem solving strategies, stemming from known immune system phenomena, have been successfully applied to challenging problems of modern computing (MONROY, SAAB, GODINEZ, 2004). Simulation systems and mathematical modeling are also beginning use to answer more complex immunological questions as immune memory process and duration of vaccines, where the regulation mechanisms are not still known sufficiently (LundegaarD, Lund, Kesmir, Brunak, Nielsen, 2007).In this article we studied in machina a approach to simulate the process of antigenic mutation and its implications for the process of memory. Our results have suggested that the durability of the immune memory is affected by the process of antigenic mutation and by populations of soluble antibodies in the blood. The results also strongly suggest that the decrease of the production of antibodies favors the global maintenance of immune memory.

q-bio.CB↗

arXiv2016

Quantum one-way permutation over the finite field of two elements

In quantum cryptography, a one-way permutation is a bounded unitary operator $U:\mathcal{H} \to \mathcal{H}$ on a Hilbert space $\mathcal{H}$ that is easy to compute on every input, but hard to invert given the image of a random input. Levin [Probl. Inf. Transm., vol. 39 (1): 92-103 (2003)] has conjectured that the unitary transformation $g(a,x)=(a,f(x)+ax)$, where $f$ is any length-preserving function and $a,x \in GF_{{2}^{\|x\|}}$, is an information-theoretically secure operator within a polynomial factor. Here, we show that Levin's one-way permutation is provably secure because its output values are four maximally entangled two-qubit states, and whose probability of factoring them approaches zero faster than the multiplicative inverse of any positive polynomial $poly(x)$ over the Boolean ring of all subsets of $x$. Our results demonstrate through well-known theorems that existence of classical one-way functions implies existence of a universal quantum one-way permutation that cannot be inverted in subexponential time in the worst ca

cs.CC↗

arXiv2016

On the quantum principles of cognitive learning

Pothos & Busemeyer's (P&B's) query about whether quantum probability can provide a foundation for the cognitive modeling embodies so many underlying implications that the subject is far from exhausted. In this brief commentary, however, I suggest that the conceptual thresholds of the meaningful learning give rise to a typical Boltzmann's weighting measure, which indicates a statistical verisimilitude of quantum behavior in the human cognitive ensemble.

q-bio.NC↗

arXiv2013

The thermodynamic cost of fast thought

After more than sixty years, Shannon's research [1-3] continues to raise fundamental questions, such as the one formulated by Luce [4,5], which is still unanswered: "Why is information theory not very applicable to psychological problems, despite apparent similarities of concepts?" On this topic, Pinker [6], one of the foremost defenders of the computational theory of mind [6], has argued that thought is simply a type of computation, and that the gap between human cognition and computational models may be illusory. In this context, in his latest book, titled Thinking Fast and Slow [8], Kahneman [7,8] provides further theoretical interpretation by differentiating the two assumed systems of the cognitive functioning of the human mind. He calls them intuition (system 1) determined to be an associative (automatic, fast and perceptual) machine, and reasoning (system 2) required to be voluntary and to operate logical- deductively. In this paper, we propose an ansatz inspired by Ausubel's learning theory for investigating, from the constructivist perspective [9-12], information processing in the working memory of cognizers. Specifically, a thought experiment is performed utilizing the mind of a dual-natured creature known as Maxwell's demon: a tiny "man-machine" solely equipped with the characteristics of system 1, which prevents it from reasoning. The calculation presented here shows that [...]. This result indicates that when the system 2 is shut down, both an intelligent being, as well as a binary machine, incur the same energy cost per unit of information processed, which mathematically proves the computational attribute of the system 1, as Kahneman [7,8] theorized. This finding links information theory to human psychological features and opens a new path toward the conception of a multi-bit reasoning machine.

cs.AI↗

arXiv2013

The Thinking machine: a psychological view of Mawxwell's demon mind

Recently, in a letter to Nature, del Rio et al.8 exploited the quantum viewpoint of the old but well-known thought experiment of Maxwell's demon, a tiny "man-machine" that processes only a single unit of information. In their work, they showed that the thermodynamic cost for Maxwell's demon to erase quantum information decreases as the amount it "knows" increases. Indeed, as the authors themselves concluded, that finding has the ability to strengthen the link between information theory and statistical physics. However, the factual link between information theory and psychology remains unknown. There may be no better way to investigate to this issue than to subject this dual natured creature to psychological treatment! In this work, we propose an Ausubel-inspired ansatz to map the thermodynamic mind of Maxwell's demon, addressing information processing from a cognitive perspective9-12. The main calculation presented in this short report shows that the Ausubelian assimilation theory13-15 leads to a Shannon-Hartley-like model1,2 that, in turn, converges exactly to the Landauer limit16-18 when one single information is discarded from the demon's memory. This result indicates that both a thermodynamic device and an intelligent being "think" in the same way when one bit of information is processed. Consequently, this finding links information theory to the "psychological features" of the thermodynamic engine through the Landauer limit, which opens a new path towards the conception of a multi-bit reasoning machine.

cs.IT↗

arXiv2013

Ag-dependent (in silico) approach implies a deterministic kinetics for homeostatic memory cell turnover

Verhulst-like mathematical modeling has been used to investigate several complex biological issues, such as immune memory equilibrium and cell-mediated immunity in mammals. The regulation mechanisms of both these processes are still not sufficiently understood. In a recent paper, Choo et al. [J. Immunol., v. 185, pp. 3436-44, 2010], used an Ag-independent approach to quantitatively analyze memory cell turnover from some empirical data, and concluded that immune homeostasis behaves stochastically, rather than deterministically. In the paper here presented, we use an in silico Ag-dependent approach to simulate the process of antigenic mutation and study its implications for memory dynamics. Our results have suggested a deterministic kinetics for homeostatic equilibrium, what contradicts the Choo et al. findings. Accordingly, our calculations are an indication that a more extensive empirical protocol for studying the homeostatic turnover should be considered.

q-bio.CB↗