Neural Information Processing: between synchrony and chaos

The brain is characterized by performing many different processing tasks ranging from elaborate processes such as pattern recognition, memory or decision-making to more simple functionalities such as linear filtering in image processing. Understanding the mechanisms by which the brain is able to produce such a different range of cortical operations remains a fundamental problem in neuroscience. Some recent empirical and theoretical results support the notion that the brain is naturally poised between ordered and chaotic states. As the largest number of metastable states exists at a point near the transition, the brain therefore has access to a larger repertoire of behaviours. Consequently, it is of high interest to know which type of processing can be associated with both ordered and disordered states. Here we show an explanation of which processes are related to chaotic and synchronized states based on the study of in-silico implementation of biologically plausible neural systems. The measurements obtained reveal that synchronized cells (that can be understood as ordered states of the brain) are related to non-linear computations, while uncorrelated neural ensembles are excellent information transmission systems that are able to implement linear transformations (as the realization of convolution products) and to parallelize neural processes. From these results we propose a plausible meaning for Hebbian and non-Hebbian learning rules as those biophysical mechanisms by which the brain creates ordered or chaotic ensembles depending on the desired functionality. The measurements that we obtain from the hardware implementation of different neural systems endorse the fact that the brain is working with two different states, ordered and chaotic, with complementary functionalities that imply non-linear processing (synchronized states) and information transmission and convolution (chaotic states)

The radio jets of SS 433 at millimetre wavelengths

Context. SS 433 is historically a well-known microquasar in the Galaxy that has been deeply studied during the four decades elapsed since its discovery. However, observations at very high radio frequencies with good angular resolution are still very scarce in the literature. The present paper tries to partially fill this gap using archival data of the source obtained with the Atacama Large Millimeter Array (ALMA). Aims. We aim to study the SS 433 jet properties at radio frequencies corresponding to millimetre wavelengths where the synchrotron emitting particles are expected to lose their energy much faster than at lower frequencies of centimetre wavelengths. Results. A resolved view of the SS 433 radio core and jets is presented. In addition to spectral index and magnetic field measurements, we are able to estimate the age of the oldest visible ejecta still radiating significantly at millimetre wavelengths. By combining our findings with those of previous authors at lower frequencies, we confirm that the energy loss of the radiating electrons is dominated by adiabatic expansion instead of synchrotron radiative losses. In addition, we find suggestive evidence for the previously proposed period of slowed expansion within the first months of the ejecta flow, needed to simultaneously match the radiative lifetime observed in the centimetre domain. Our results argue for the need for future coordinated millimetre and centimetre interferometric observations with good time sampling throughout the SS 433 precessional cycle to better understand energetic processes in stellar relativistic jets.Comment: 14 pages, 7 figures, Accepted for publication in Astronomy & Astrophysic

Peculiar objects towards 3FGL J0133.3+5930: an eclipsing Be star and an active galactic nucleus

Aims. We aim to contribute to the identification of unassociated gamma-ray sources in the galactic plane in order to enlarge the currently known population of gamma-ray binaries and related systems, such as radio emitting X-ray binaries and microquasars. These objects are currently regarded as excellent test beds for the understanding of high energy phenomena in stellar systems. Methods. Potential targets of study are selected based on cross-identification of the 3rd Fermi Large Area Telescope catalogue with historical catalogues of luminous stars often found as optical counterparts in known cases. Follow-up observations and analysis of multi-wavelength archival data are later used to seek further proofs of association beyond the simple positional agreement. Results. Current results enable us to present here the case of the Fermi source 3FGL J0133.3+5930 where two peculiar objects have been discovered inside its region of uncertainty. One of them is the star TYC 3683-985-1 (LS I +59 79) whose eclipsing binary nature is reported in this work. The other one is the X-ray source SWIFT J0132.9+5932, that we found to be a likely low-power Active Galactic Nucleus at z = 0:1143 \pm 0:0002. If this second object is of blazar type, it could easily account for the observed gamma-ray photon flux. However, this is not confirmed at present, thus rendering still open the star system TYC 3683-985-1 as an alternative counterpart candidate to the Fermi source.Comment: 8 pages; 10 figures; accepted for publication in Astronomy & Astrophysic

Hardy's inequalities for monotone functions on partially ordered measure spaces

We characterize the weighted Hardy's inequalities for monotone functions in ${\mathbb R^n_+}.$ In dimension $n=1$, this recovers the classical theory of $B_p$ weights. For $n>1$, the result was only known for the case $p=1$. In fact, our main theorem is proved in the more general setting of partially ordered measure spaces.Comment: 14 page

Incompatibilismo y necesidad contrafáctica

Algunos piensan que este conflicto entre la imagen determinista del mundo y la libertad de decisión es irresoluble, y ello les define como incompatibilistas; mientras que otros consideran que hay modos de integrar ambas intuiciones y merecen, pues, el nombre de compatibilistas. El presente artículo pretende mediar en el debate entre estas dos posiciones. Para ello, reflexionaremos acerca de la naturaleza de los vínculos contrafácticos implicados en las relaciones causales que se presuponen tanto en la imagen determinista del mundo como en nuestras intuiciones acerca de la libertad de decisión. En concreto, nuestra propuesta vendrá a subrayar la debilidad de las estrategias compatibilistas clásicas, al tiempo que se sugiere una estrategia alternativa que apunta igualmente a una disolución de la tensión inicial

El conexionismo y su impacto en la filosofía de la mente

Discusión del impacto del surgimiento del conexionismo en la filosofía de la ment

Physicalism and the mental: the dominant view

The main purpose of this book is to elaborate a number of reductio arguments that are meant to challenge causal physicalism, as well as the dominant view, in its attempt to show the compatibility between the causal efficacy of the mental and causal physicalism. As a result, we will provide an alternative analysis of our intuitions about the primacy of the physical that fits with the casual autonomy of mental properties. The present chapter is meant to characterize and motivate the dominant view

Stochastic-Based Pattern Recognition Analysis

In this work we review the basic principles of stochastic logic and propose its application to probabilistic-based pattern-recognition analysis. The proposed technique is intrinsically a parallel comparison of input data to various pre-stored categories using Bayesian techniques. We design smart pulse-based stochastic-logic blocks to provide an efficient pattern recognition analysis. The proposed rchitecture is applied to a specific navigation problem. The resulting system is orders of magnitude faster than processor-based solutions

Moral Emotions, Principles, and the Locus of Moral Perception

I vindicate the thrust of the particularist position in moral deliberation. to this purpose, I focus on some elements that seem to play a crucial role in first-person moral deliberation and argue that they cannot be incorporated into a more sophisticated system of moral principles. More specifically, I emphasize some peculiarities of moral perception in the light of which I defend the irreducible deliberative relevance of a certain phenomenon, namely: the phenomenon of an agent morally coming across a particular situation. Following on from Bernard Williams, I talk of an agent's character as a factor that con- tributes to fixing what situations an agent comes morally across. A crucial point, in the debate, will be how an agent confronts the normatively loaded features of his own character when he is engaged in first-person deliberation