Concepciones de la lógica

Se examinan las motivaciones teóricas, los lineamientos generales y las principales variantes de dos modos complementarios de entender la naturaleza de la lógica. El primero centrado en logros técnicos alcanzados desde fines del siglo XIX, y el segundo vinculado con la reflexión clásica sobre la naturaleza de los principios de la actividad de la razón. Se pone énfasis en la importancia del vínculo constitutivo entre las reglas y leyes lógicas y la estructura del lenguaje, en particular de aquél que subyace cuando el habla se orienta por pretensiones cognoscitivas

La unidad proposicional

Un problema fundamental de la reflexión filosófica sobre el lenguaje ha sido el de explicar la diferencia entre nombrar y predicar. Se sostendrá que hay una disolución del problema, en términos de la noción de interpretación, que parece obviar su solución tradicional basada en relaciones referenciales. Pero que, sin embargo, el marco general de esa disolución -las condiciones de una interpretación en general- o bien requiere ese tipo de fundamentación, o bien hace lugar a planteamientos trascendentales que la exceden.Fil: Moretti, Hector Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Analytic continuation of nucleon electromagnetic form factors in the time-like region

The possibility to compute nucleon electromagnetic form factors in the time-like region by analytic continuation of their space-like expressions has been explored in the framework of the Skyrme model. We have developed a procedure to solve analytically Fourier transforms of the nucleon electromagnetic current and hence to obtain form factors defined in all kinematical regions and fulfilling the first-principles requirements. The results are discussed and compared to data, both in space-like and time-like region.Comment: 34 pages, 15 figure

Subitizing as pattern recognition: evidence for automaticity when non-symbolic number stimuli are canonically arranged

Subitizing allows detecting the quantity of a small set of elements (up to four) with the accuracy of counting and the velocity of estimation. Recent studies have supported a theory which considers subitizing as a visual mechanism of pattern recognition, sensitive to spatial disposition of elements. These studies have found an increase in response rate and accuracy in the assessment of quantity when elements to be enumerated are arranged in an orderly fashion. Whether the numerosity of orderly arranged elements is accessed automatically, without the requirement of attentional resources, is a relevant issue not yet empirically investigated. The current study investigated the relation between subitizing and automaticity in a target detection task where distractors were non-symbolic number stimuli (dot patterns), with two different arrangements, random or canonical (like dice faces), having the same or different numerosity in the number target. We found that with canonical patterns, in the subitizing range, response times were faster in compatible trials, and slower in incompatible trials, compared to random patterns which did not influence response times in any condition. This result revealed that when elements in a visual display form easily recognizable patterns, their numerosity is accessed automatically

"Spoon-feeding" an AGN

Tidal disruption events (TDEs) occur when a star, passing too close to a massive black hole, is ripped apart by tidal forces. A less dramatic event occurs if the star orbits just outside the tidal radius, resulting in a mild stripping of mass. Thus, if a star orbits a central black hole on one of these bound eccentric orbits, weaker outbursts will occur recurring every orbital period. Thanks to five Swift observations, we observed a recent flare from the close by (92 Mpc) galaxy IC 3599, where a possible TDE was already observed in December 1990 during the Rosat All-Sky Survey. By light curve modeling and spectral fitting, we account for all these events as the non-disruptive tidal stripping of a single star into a 9.5 yr highly eccentric bound orbit. This is the first example of periodic partial tidal disruptions, possibly spoon-feeding the central black hole.Comment: 7 pages, 3 figures, to appear in "Swift:10 years of discovery", Proceedings of Scienc

Laboratory and on-site tests for rapid runway repair

The attention to rapid pavement repair has grown fast in recent decades: this topic is strategic for the airport management process for civil purposes and peacekeeping missions. This work presents the results of laboratory and on-site tests for rapid runway repair, in order to analyse and compare technical and mechanical performances of 12 different materials currently used in airport. The study focuses on site repairs, a technique adopted most frequently than repairs with modular elements. After describing mechanical and physical properties of the examined materials (2 bituminous emulsions, 5 cement mortars, 4 cold bituminous mixtures and 1 expanding resin), the study presents the results of carried out mechanical tests. The results demonstrate that the best performing material is a one-component fast setting and hardening cement mortar with graded aggregates. This material allows the runway reopening 6 h after the work. A cold bituminous mixture (bicomponent premixed cold asphalt with water as catalyst) and the ordinary cement concrete allow the reopening to traffic after 18 h, but both ensure a lower service life (1000 coverages) than the cement mortar (10,000 coverages). The obtained results include important information both laboratory level and field, and they could be used by airport management bodies and road agencies when scheduling and evaluating pavement repairs

Todo canon, El canon

Whenever expressions like "X is philosophical" appear in different questions and assorted statements, the reference to special kinds of actions, questions or demands are suggested by these uses. Rabossi propounds a way for characterizing the sense of our using such expressions and, based on it, he states that philosophy, as it is accomplished from the last two centuries up to now, pretends to be a professional discipline but she cannot to be as such because the nature of its precepts (the Canon). Rabossi's arguments are examined and it is maintained that although they do not seem to be sufficient for the pursued conclusion, there are reasons to modify them such a way to come to that conclusion.En la consideración de numerosos asuntos y respecto de muy variadas exposiciones, el uso de expresiones como "filosófica" sugiere que debemos remitirnos a procederes, preguntas o exigencias especiales. Rabossi propone un modo de caracterizar el sentido con que usamos esas expresiones y, sobre esa base, concluye que la filosofía tal como se la practica desde hace doscientos años pretende ser una disciplina profesional pero no puede serlo debido a la índole de la preceptiva que la constituye (el Canon). En este artículo se examinan sus argumentos y se sostiene que, aunque no parecen suficientes para la conclusión a la que apuntan, hay razones para modificarlos de cierto modo que conducen a ese resultado

Laudatio

Con esta ceremonia culminan los actos del otorgamiento del título de Doctor Honoris Causa de la Universidad de Buenos Aires al filósofo, maestro de maestros, Thomas Moro Simpson.De este modo nuestra Universidad, siguiendo una noble idea iniciada por los romanos mucho antes de que existieran las universidades, la idea de destacar la labor de aquellos ciudadanos que hubieran contribuido notablemente a mejorar la vida de la ciudad común, ha resuelto hacer público su reconocimiento de los excepcionales méritos intelectuales, éticos y académicos de nuestro querido Tomás Simpson. He sido encargado de recordar ahora, sumariamente, ante la comunidad universitaria y, con eso, ante nuestra comunidad simpliciter, algunos de los motivos que condujeron a esta resolución

Lógica y semántica

The fundamental link between logical and semantic inquiries is emphasized, and by relating some of Frege’s ideas on the concepts of logic and truth with others of Davidson’s on the Tarskian structure of interpretation, an attempt is made to clarify the Fregean point of view about the nature of the logical-semantic reflection