4,805 research outputs found
Interpretación del análisis paleopalinológico del yacimiento protocogotas de el Castillo (Rábano, Valladolid, España)
El presente artículo presenta los resultados del análisis palinológico del relleno de cuatro fosas en un campo de hoyos de atribución Protocogotas. A partir de los resultados paleopolínicos obtenidos, se propone una interpretación del paleopaisaje regional. Se detecta cerealicultura inmediata al poblado y una actividad pastoril en un paisaje dominado por las zonas de pradera, destacando los herbazales de tipo nitrófilo, y con un avanzado estadio de deforestación del bosque autóctono, formado por las encinas y la sabina albar.The aim of this paper is to give information about the dates obtained in the polinic anal ysis proceeding from four holes in a so named "campo de hoyos" of the Nord-Iberian upland, with a chronology of the Middle Bronze Age: El Castillo (Rábano, Valladolid). Palaeoecological indicators show a cereal agricultural economy near de site as well as a pastoral activity in a notable deforested context with nitrophilous communities
Paisaje y economía durante el Bronce Antiguo en la Meseta Norte desde una perspectiva paleoambiental: algunos casos de estudio
El objeto de este artículo es dar a conocer los datos aportados por los análisis polínicos procedentes de tres yacimientos de la Meseta Norte española, adscribibles al Bronce Antiguo: El Picuezo (Sotalvo, Ávila), El Parpantique (Balluncar, Soria) y Pico Romero (Santa Cruz de la Salceda, Burgos). Aunque el número de secuencias arqueopalinológicas es corto, al menos, sirve para comenzar a interpretar el paleoambiente y la paleoeconomía de este periodo en la Submeseta Norte. El trabajo es un ejemplo de la investigación inspirada en los principios de la arqueología del paisaje.The aim of this paper is to give information about the dates obtained in the polinic anal ysis proceeding from the excavations of three archaeological sites, of the Nord-Iberian upland, with a chronology of the Earlier Bronze Age: El Picuezo (Sotalvo, Ávila), El Parpantique (Balluncar, Soria) y Pico Romero (Santa Cruz de la Salceda, Burgos). Obviously the number of archaeopalinological sequences is short, but, almost, has permitted to begin to interpret the reconstruction of the palaeoenvironment and the palaeoeconomy of this period in Nord Upland. This paper is an example of the research inspired in the principles of landscape archaeology
An approach to visual cortex operation: optical neuron model
Several works have been published in the last years concerning the modelling and implementation of the visual cortex operation. Most of them present simple neurons with just two different responses, namely inhibitory and excitatory. Some of the different types of visual cortex cells are simulated in these configurations
Analysis of large-scale digital optical neural networks by Feynman diagrams
A new method to study large scale neural networks is presented in this paper. The basis is the use of Feynman- like diagrams. These diagrams allow the analysis of collective and cooperative phenomena with a similar methodology to the employed in the Many Body Problem. The proposed method is applied to a very simple structure composed by an string of neurons with interaction among them. It is shown that a new behavior appears at the end of the row. This behavior is different to the initial dynamics of a single cell. When a feedback is present, as in the case of the hippocampus, this situation becomes more complex with a whole set of new frequencies, different from the proper frequencies of the individual neurons. Application to an optical neural network is reported
Logic cells as basic structures to add/drop WDM information signals
Nowadays, in order to take advantage of fiber optic bandwidth, any optical communications system tends to be WDM. The way to extract a channel, characterized by a wavelength, from the optical fiber is to filter the specific wavelength. This gives the systems a low degree of freedom due to the fact of the static character of most of the employed devices. In this paper we will present a different way to extract channels from an optical fiber with WDM transmission. The employed method is based on an Optically Programmable Logic Cells (OPLC) previously published by us, for other applications as a chaotic
generator or as basic element for optical computing.
In this paper we will describe the configuration of the OPLC to be employed as a dropping device. It acts as a filter because it will extract the data carried by a concrete wavelength. It does depend, internally, on the wavelength. We will show how the intensity of the signal is able to select the chosen information from the line. It will be also demonstrated that a new idea of redundant information it is the way of selecting the concrete wavelength. As a matter of fact this idea is apparently the only way to use the OPLC as a dropping device. Moreover, based on these concepts, a similar way to route signals to different routes is reported. The basis is the use of photonic switching configurations, namely Batcher or Bayan
structures, where the unit switching cells are the above indicated OPLCs
Algunas consideraciones sobre la formación de titulados en tecnologías emergentes
Uno de los problemas más cruciales que se presenta en cualquier país cuando se pretende realizar una planificación más o menos ajustada a los objetivos que se desean alcanzar, es el de adecuar el número de profesionales en una determinada tecnología a las necesidades reales que en cada momento puedan presentarse. Este hecho, que ha llegado a tener repercusiones de carácter casi histórico en épocas pasadas, cuando se registraron saltos bruscos de un tipo de sociedad a otra, se está produciendo hoy de manera casi continua en la mayor parte de los países, tanto desarrollados como en vías de desarrollo como se verá en el presente artículo, las crisis de exceso de un tipo de profesionales en unas áreas y las de escasez de otras, está siendo un hecho habitual tanto en empresas, sean del tamaño que sean, como en entornos académicos e incluso en países y el bloques socioeconómicos como un todo
Some aspects of amacrine neuron simulation for motion detection
As it is known, there are five types of neurons in the mammalian retinal layer allowing the detection of several important characteristics of the visual image impinging onto the visual system, namely, photoreceptors, horizontal cells, amacrine, bipolar and ganglion cells. And it is a well known fact too, that the amacrine neuron architecture allows a first detection for objects motion, being the most important retinal cell to this function. We have already studied and simulated the Dowling retina model and we have verified that many complex processes in visual detection is performed with the basis of the amacrine cell synaptic connections. This work will show how this structure may be employed for motion detectio
Use of Feynman diagrams in large-scale neural networks with nonlinear behaviour
A new proposal to the study of large-scale neural networks is reported. It is based on the use of similar graphs to the Feynman diagrams. A first general theory is presented and some interpretations are given. A propagator, based on the Green's function of the neuron, is the basis of the method. Application to a simple case is reported
Quasi chaotic digital behaviour in an optically processing
Digital chaotic behavior in an optically processing element is reported. It is obtained as the result of processing two fixed train of bits. The process is performed with an Optically Programmable Logic Gate. Possible outputs for some specific conditions of the circuit are given. These outputs have some fractal characteristics, when input variations are considered. Digital chaotic behavior is obtained by using a feedback configuration. A random-like bit generator is presented
- …