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Reseña de la obra: Ley y ser: Derecho y ontología crítica en Foucault (1978-1984). Marco Díaz Marsá. Madrid, Escolar y Mayo, 2016.

Laser-induced breakdown spectroscopy (LIBS) is a powerful optical emission analytical tool capable of sampling solids, liquids and gases for research and industrial applications[1]. A pulsed high-power laser is used to ablate a piece of the sample and excite it till plasma state. The optical emission from the relaxation of excited species within the plasma yields information regarding the composition of the material under test. Moreover, LIBS enables the study of some parameters regarding the fundamental point of view: electron temperature Te and number density Ne. This is feasible since some assumptions can be made, such as the existence of local thermodynamic equilibrium (LTE) conditions and optically thin plasma. Even though the plasma parameters rapidly change during the measurement time due to its expansion, the plasmas fulfil LTE conditions. In this communication we report some results on wavelength and time resolved measurements of the optical emissions in a plasma induced by both, Nd-Yag and CO2 pulsed-laser on the target surface of an aluminium 2024 alloy. The composition of this alloy allows the analysis of emission lines from atomic and ionic species of Al, Mg, Cu and Mn. This study was made in both medium vacuum conditions and atmospheric pressure of air. In these conditions, vibrational bands sequence of AlO is observed. The time dependence and velocity distributions of space-integrated emission of some excited species are registered thanks to time-resolved optical emission spectroscopy and imaging techniques. Intensities of some species were used for determining electron temperature and their Stark-broadened profiles were employed to calculate electron density as described in previous papers[2-3]. Some important differences in the obtained spectra are observed because of different characteristics between Nd-Yag and CO2 pulsed laser. The plasma spectrum obtained using CO2 laser shows more lines, due to ionic species, than the plasma spectrum obtained using Nd-Yag laser. On the other hand, the imaging and time-resolved combined techniques allow the identification of some low-intensity lines, which are hidden in the integrated spectrum.

For finite-ranged potentials the behavior of the total correlation function h (r) at large distances can be of two different types. In three-dimensional systems at low densities the function r h (r) presents exponential decay whereas at high densities it presents exponentially damped oscillatory decay. The locus of points on the phase diagram where a transition from exponential to oscillatory decay occurs is denoted as the Fisher-Widom line after the work of these authors [M. E. Fisher and B. Widom, J. Chem. Phys. 50, 3756 {1969)]. These authors exactly computed the Fisher-Widom line for several one-dimensional systems and conjectured that the same behavior could occur in three dimensions. In this work the Fisher-VA'dom line is computed for a three-dimensional finite-range potential by using the structural information obtained from the reference hypernetted chain theory which is probably the most successful theory of liquid structure available now. By combining these results with computer simulations of the vapor-liquid equilibria of the considered model the Fisher-Widom line is located within the phase diagram of the model. For the considered model the Fisher-VA'dom line cuts the liquid branch of the vapor liquid equilibria at a reduced temperature of T/T, =0.88 and a reduced density of p/p, =2.07. The effect of the range of the potential on the location of the Fisher-%'idom line is also considered. Increasing the range of the potential reduces the region of the phase diagram where oscillatory behavior of the function r h (r ) occurs. The long-range decay of a Lennard Jones Quid is also considered. Decay of h (r) to zero at large distances is difFerent for a Lennard-Jones potential and for a finite-ranged potential. Although the Lennard Jones potential does not present a true Fisher-Widom line when the ultimate decay of h (r} is considered it is shown that it exhibits a Fisher-Widom —like transition when an intermediate range of distances is considered.

In this note the reference hypernetted chain equation is solved for a finite ranged potential. For the model considered no solution to the integral equation is found in a certain region of the phase diagram. To determine the presence of criticality in the no-solution line, the behaviour of the total correlation function h(r) at large distances is investigated. For finite ranged potentials, the decay of the function rh(r) at large distances can be either exponential (at low and intermediate densities) or exponentially damped oscillatory (at high densities). For the model considered, the no-solution line falls within the region where the function rh(r) shows exponential decay. The correlation length in the region where the decay of rh(r) is exponential is given by the inverse of the purely imaginary pole of the structure factor. The purely imaginary pole is analysed in the proximities of the no-solution line. It is shown that the correlation length remains finite when approaching the no-solution line. There...

We used a large-scale data-driven approach to investigate the role of word form in accessing semantics. By using distributional semantic methods and taking advantage of an ERP lexical decision mega-study, we investigated the exact time dynamic of semantic ac-cess from printed words as driven by orthography-semantics consistency (OSC) and phonology-semantics consistency (PSC). Generalized Additive Models revealed very early and late OSC-by-PSC interactions, visible at 100 and 400 msec, respectively. This pattern suggests that, during visual word recognition: a) meaning is accessed by means of two distinct and interactive paths -the orthography-to-meaning and the orthography-to -phonology-to-meaning path-, which mutually contribute to recognition since early stages; b) the system may exploit a dual mechanism for semantic access, with early and late effects associated to a fast-coarse and a slow-fine grained semantic analysis, respec-tively. The results also highlight the high sensitivity of the visual word recognition system to arbitrary form-meaning relations.(c) 2022 Elsevier Ltd. All rights reserved.