Search

Copyright of Informador Técnico is the property of Servicio Nacional de Aprendizaje SENA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Praxis Filosófica is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Informador Técnico is the property of Servicio Nacional de Aprendizaje SENA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The state estimation in power electronic converters is an interesting alternative to obtain indirectly some variables that are difficult to measure, due to sensor costs or limitations imposed by measurement noise. Therefore, in this paper we design three linear and three nonlinear state estimators for a DC/DC boost converter model, in order to verify the convenience of using only nonlinear estimators as a solution to the converter current estimation problem. Additionally, the behavior of these estimators is tested by simulation in Matlab software. [ABSTRACT FROM AUTHOR]

It has been recognized that that the design and prescription of Energy Storing and Returning prosthetic running feet are not well understood and that further information on their performance would be beneficial to increase this understanding. Dynamic analysis of an amputee wearing a prosthetic foot is typically performed using reflective markers and motion-capture systems. High-speed cameras and force plates are used to collect data of a few strides. This requires specialized and expensive equipment in an unrepresentative environment within a large area. Inertial Measurement Units are also capable of being used as wearable sensors but suffer from drift issues. This paper presents the development of a wearable sensing system that records the action of an Energy Storing and Returning prosthetic running foot (sagittal plane displacement and ground contact position) which could have research and/or clinical applications. This is achieved using five standalone pieces of apparatus including foot-mounted pressure sensors and a rotary vario-resistive displacement transducer. It is demonstrated, through the collection of profiles for both foot deflection and ground contact point over the duration of a stride, that the system can be attached to an amputee's prosthesis and used in a non-laboratory environment. It was found from the system that the prosthetic ground contact point, for the amputee tested, progresses along the effective metatarsal portion of the prosthetic foot towards the distal end of the prosthesis over the duration of the stride. Further investigation of the effective stiffness changes of the foot due to the progression of the contact point is warranted. [ABSTRACT FROM AUTHOR]

This paper presents a novel phase-shift arctangent (PSA) interpolation method to improve the measurement accuracy of a planar capacitive incremental displacement sensor. Signals of planar capacitive micro-sensors acquire waveform errors, including sensitivity differences and phase-shift errors, because of static errors and dynamic disturbances. In the proposed PSA scheme, such errors are removed completely by loading a particular arctangent function. Moreover, measuring efficiency of the proposed planar capacitive sensors is improved by combining coarse measurement and fine estimation. Experiments show unanimous results to model-based fitting. When electrode length is four times the gap distance, applying the PSA interpolation method decreases waveform errors from more than 4% to 1.72%. [ABSTRACT FROM AUTHOR]

Currently smartphones technology results in small portable devices, highly sophisticated and with a wide range of integrated sensors, among which are the GPS/GNSS receivers. This were incorporated to smartphones to developed location based services, which allows access to personalized spatial information, by informatics networks. There is still some distrust on the value of these sensors for scientific research but a growing number of papers had validated their use. In the current review we present the position of the general scientific literature in ecology and environmental fields worldwide in relation to location sensors at smartphones. Besides assisted GPS system, modern models incorporate multi-constellation and double frequency receivers with spatial precision similar to other commercial GPS, around few meters. Several factors should be taken into account such as smartphone model, measurement places and the goal of the research. By following appropriated validation protocols and carefully selecting the app to gather data, it has been demonstrated that this sensors in modern smartphones can be reasonable alternatives with enough quality for most of the field work uses in Ecology. [ABSTRACT FROM AUTHOR]

Smartphones have irrupted in every facets of modern life for most of the humankind, including professional and scientific activities. Many apps exist to help in guiding experimental protocols, literature management and wireless connection to other equipment. But the wide range of miniaturized integrated sensors, of high accuracy that act in hidden aspect of cellphone functioning, has not yet been fully explored. Modern smartphones contain powerful digital cameras, microphones, GPS/GNSS receivers, accelerometers, gyroscopes, magnetism sensor, light sensors, barometers, thermometers, moisture sensors, biometric sensors and many others with the potential of became important allied for researcher´s data collect during his work. Based on them, had emerge compasses, altimeters, scanners, barcode or QR readers, face, sounds or species identification apps, metal detectors, movement and vibration detectors, pedometers, colorimeter, spectrophotometer and many others. All this tools are producing a high impact in many scientific fields such as medicine, social sciences, environmental monitoring, transportation and industry. The advantages and possibilities of these sensors for biological investigations are still unknown. For this reason, the present paper is a review of the potentials associated to common modern smartphones sensors and its applications in biological researches. In conditions were technical equipment is limited, smartphones, its sensors and corresponding apps can be reasonably efficient alternatives to overcome the technological breach and to increase quality of researches. [ABSTRACT FROM AUTHOR]

Copyright of Ra Ximhai is the property of Universidad Autonoma Indigena de Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Entramado is the property of Universidad Libre Seccional Cali and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Entre Ciencia e Ingeniería is the property of Entre Ciencia e Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Gerencia Tecnologica Informatica is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tecnura is the property of Tecnura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Superficies y Vacío is the property of Sociedad Mexicana de Ciencia y Tecnologia de Superficies y Materiales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ciencia e Ingenieria Neogranadina is the property of Ciencia e Ingenieria Neogranadina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Energía y Computación is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ingeniería y Competitividad is the property of Universidad del Valle and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cognitive Radio is one of the most promising techniques for optimizing the use of spectrum. However, the large amount of spectral information that must be processed to identify and assign spectral components makes the channel assignment's times to be increased due to the previous processing of this data and therefore cannot provide service to the devices that require it. Meanwhile, the compressed sampling is a technique that allows the reconstruction of sparse or compressible signals using fewer samples than those required by the Nyquist criterion. This paper presents a new model that uses compressed multispectral sampling for radio-electric spectrum sensing in cognitive radio that improves sensing and channel assignment times, decreasing the number of data required for reconstructing the power spectral information in different bands. This model is based on architectures that use a compressed sample to analyze multispectral images. The operation of a centralized manager is presented to select the power data of different software defined radios (SDR) by binary patterns. These SDRs are in different geographical positions. The centralized manager reconstructs a data cube with the transmitted power and operation's frequency of all the users based on the samples taken and applying multispectral sensing techniques. The results show that this multispectral data cube can be built with only a 50% of the samples generated by the devices, and can be stored using only a 6.25% of the original data. [ABSTRACT FROM AUTHOR]

In this paper we will discuss the construction, use and operation of an electrostatic polarity detector that was designed with the purpose of making interesting and fun an introductory class about the existence of electric charges and their interactions. The polarity detector uses a simple circuit and a design that can be printed on a 3D printer. So the reader can easily build their own detector after buying and assembling some electronic components at low cost. The body of the detector has the form of a hammerhead shark whose eyes light up according to the sign of the charge of the object to be measured. This fun form of shark allows to build entertaining activities where students can investigate the fundamental properties of interactions between electrically charged objects. [ABSTRACT FROM AUTHOR]

This paper reports the main design elements of a programmable gain transimpedance amplifier (TIA) with a photodiode as sensor device. The photodiode and the TIA are part of the measurement system of a plate reader with two reading modes, absorbance and fluorescence. The photodiodes are one of the most used sensors in spectroscopy systems and TIA are fundamental for conditioning signals from such sensor block. An analysis of some aspects that must be considered in their design, such as bandwidth, gain, noise as well as the main sources of noise that affect their operation is done. An analysis of the stability of the system to ensure proper operation. Emphasis on the characteristics of the components used and detail some layout suggestions of printed circuit boards in order to minimize the leakage currents. The design presented is a novel and feasible alternative to maximize the dynamic range of measurement plate readers or other optical spectroscopy system designed and produced by the Cuban biopharmaceutical industry. [ABSTRACT FROM AUTHOR]

In this paper, a control architecture based on the reactive paradigm to solve the problem of autonomous navigation of mobile robots with limited computational capabilities and sensor system is presented. Stand out as the most significant contributions to this work, the encapsulation of a behavior-based control architecture in a programmable embedded system with limited processing capabilities and the use of fuzzy control theory in the implementation of a wall following behavior. Experimental tests were performed on a robotic platform equipped with three ultrasonic sensors and a wireless communication module. This module supports the 802.15.4 protocol in the ISM (Industrial, Scientific and Medical) band, through it sensory measures are transferred to a PC where computational representations of the explored environment are made. [ABSTRACT FROM AUTHOR]

The common way of assessing structural parts of machines, buildings, vehicles, aircraft and other structures is based on the calculation of the strength of materials to external forces. A property representing the resistance of the solid is the mechanical deformation. The recording and analysis of this property to characterize solid materials are very important. This paper exposes the design made of hardware and firmware implementation of a prototype system that aims to measure the mechanical deformation on the surface of a steel beam in bending using metallic strain gauges. In order to reduce measurement errors a new compensation method was implemented via DSSP (Digital Sensor Signal Processor). A mechanical system which is modeled mathematically to tune the designed system was also carried out. From evaluation of prototype performance an error of about 1% over the span of measurement was obtained. [ABSTRACT FROM AUTHOR]

The actual development of electronics and computers has allowed developing methods for measuring corrosion in real time and at very short periods. The generation of new knowledge has allowed using physicochemical methods to determine corrosion very fast and store the data obtained. The information contained in patent documents claiming these new advanced technologies is of great value to generate knowledge that respond to the problems and needs of the R + D + i related to the continuous measurement of corrosion in transport vehicles and other instruments and equipment. Distance monitoring is important in these cases where the vehicle is moving. It is very important for operation and maintenance and for the evaluation of the protective products against corrosion. The aim of this paper is to generate new knowledge from the application of the methodology Generation and Knowledge Management (MGGC), from which the search strategy that inventions claiming keywords recovered was determined: corrosion sensor and monitoring, patent databases freely available on internet. The results obtained from the processing of the information contained in these patent documents identified the strategic objectives of an R + D + i related corrosion monitoring by sensors. [ABSTRACT FROM AUTHOR]

This paper summarizes the general features of the trend of using mechanical nanoresonators based on carbon nanotubes for mass spectrometry. It discusses the advantages and obstacles that stand in the way towards its application in mass spectrometry and finally, possible impacts in different fields of research and technology were considered. [ABSTRACT FROM AUTHOR]

Copyright of Revista Tecno Lógicas is the property of Instituto Tecnologico Metropolitano and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ciencia e Ingenieria Neogranadina is the property of Ciencia e Ingenieria Neogranadina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A model for collision detection based on double hierarchical spherical representation is proposed in this paper: an outer spherical representation for detecting no-intersections and an inner spherical representation in order to improve the performance of the collision detector. The algorithm has been implemented. Several tests were conducted with convex polyhedral and the performance of the algorithm was evaluated in terms of the collision between inner spheres. The experimental results show that outer spheres have been useful to determine lack of intersection, whereas inner spheres are more efficient for detecting existence of intersection and for speeding up the process of detecting collision. Using inner spheres improve the general performance because it reduces the number of intersection tests between the faces of the polyhedral. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper shows the results from the application of mathematical simulation to study the quantum efficiency of a microstrips crystalline silicon detector, intended for medical imaging and the development of other applications such as authentication and dating of cultural heritage. The effects on the quantum efficiency of some parameters of the system, such as the detector-source geometry, X rays energy and detector dead zone thickness, were evaluated. The simulation results were compared with the theoretical prediction and experimental available data, resulting in a proper correspondence. It was concluded that the use of frontal configuration for incident energies lower than 17 keV is more efficient, however the use of the edge-on configuration for applications requiring the detection of energy above this value is recommended. It was also found that the reduction of the detector dead zone led to a considerable increase in quantum efficiency for any energy value in the interval from 5 to 100 keV. [ABSTRACT FROM AUTHOR]

This paper presents a novel feedback technique for fluxgate magnetometers based on second harmonic detection method. This new technique mainly consists of the injection of a sample output current in the excitation coil, thus the resultant magnetic field will be in opposition to the external magnetic field object of measurement. This kind of compensation has been conceived for its implementation on integrated fluxgate microsensors. They are used for systems of gyroscopes and electronic compasses in the inertial control of autonomous agricultural vehicles in Precision Agriculture. [ABSTRACT FROM AUTHOR]

This paper reports the characterization of a set of Neodymium magnets with different sizes and geometries, which is devoted to determine the influence of the former parameters both in the magnitude as direction of the magnetic field produced in: a) points near but not on an symmetry axis of the magnet and b) points placed along the symmetry axis of the magnet to different distances from it. Characterization was performed with a Hall Effect sensor, which was accompanied of a conditioning signal circuit, which allows obtaining an output voltage proportional to the magnetic flux density present in the sensing region. The signal given by the sensor allows to measure not only the magnitude of the magnetic field present in the sensing region but the orientation of the magnetic field lines in that region through the sign of the induced Hall voltage. The results of the measurements suggest some criteria for choosing the most convenient type of magnet for application in sensing of the position of magnetized objects, or objects which contain that type of magnets inside, as well as give tracks to prevent overlapping errors in the determination of the position of multiple neighboring magnets or objects which contain that type of magnets [ABSTRACT FROM AUTHOR]

Copyright of Anáhuac Journal is the property of Universidad Anahuac del Sur S.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Circuits that carry out the signal acquisition and processing by multiple channels are required in digital radiography. These circuits should be tested in order to characterize their performance. This paper describes an automated system to control (by a software, from a personal computer) the characterization of a system based on RX64DTH specific integrated circuits with microstrip detectors. The results are shown. [ABSTRACT FROM AUTHOR]

The properties of optical fibers allow innovative approaches to the design of optical sensors; the main features of the optical fiber sensor are its immunity from electromagnetic noise, very good sensitivity and compactness, since optical fibers are very sensitive to strain and bending losses, a variety of intensity modulated sensors can be used to carry out in situ studies. In this paper a simple, effective and inexpensive fiber optic proximity sensor using a bifurcated fiber bundle is described, the experimental setup is very simple and straightforward and this can be installed at the work site with no sophisticated instruments for measurements. [ABSTRACT FROM AUTHOR]

In this paper we present the design and construction of an interferometer that it uses optic mono-mode fiber; this sensor type differ on those based on multimode fibers because besides observing modifications in the intensity of transmitted light it allow to detect changes in phase that which guarantee high sensibility and good resolution in the measurement of the parameter to observe. Results are shown when the designed device is used to measure changes of temperature and pres-sure. [ABSTRACT FROM AUTHOR]

The control of forces that intervene in the development of the deep drawing process, as well as in the generation of the friction force it is a way to achieve the decrease of defects in spares, and to minimize friction. The present paper deals with the process of design and selection of components of the regulation and control system for a die designed and build for the analysis of the principal forces in the deep drawing process. Different types of sensors or collectors have been used in order to allow the control and the measurement of parameters. [ABSTRACT FROM AUTHOR]

In the production of thermal laser radiation detectors, like the thermopiles and the pyroelectric detector, the absorption coefficient of the incident radiation plays an important role in the detector characteristics. The detector surface exposed to the laser radiation possesses a coating that elevates this coefficient and decreases the dependence with the wavelength. In this paper different products in order to improve the absorption radiation in thermal detectors of He-Ne and CO2 lasers of the thermopiles type are evaluated. The studied compounds exposed to the laser radiation are deposited on the metallic laminates. The sensitivity and response time of the detector are presented. [ABSTRACT FROM AUTHOR]

The sampling points for the range devices, and in general for the 3D sensors, in the acquisition process, they are always affected by the noise due to the inherent limitations of the physical process of measure. The noise happens in form of atypical values, or in form of small deviations of the sampling points from the true surface. For this reason, some pre-processing type is required to obtain a model of valid surface from the group of physical measures. In this paper, three explored techniques are exposed to define a strategy of selection of representative points of a range image (random selection, SOM, k-means), with the purpose of reducing the noise of the data and later, to trace a triangular mesh to obtain an approximate fitting of the surface to model. [ABSTRACT FROM AUTHOR]

This paper is focused on the extraction of myocardial borders (septum, endocardium and epicardium) on M-mode echocardiograms. The proposed method combines two algorithms, each developed specially to extract certain borders. The extraction of the epicardium is done by means of a basic maximum tracking algorithm [8]. For the extraction of the endocardium and the left wall of the interventricular septum, a 2 stages discontinuity detector [6] is used. In the first stage the local mean of the image is calculated, and for the second stage the local variance is used. The output of this detector represents the discontinuities in the M-mode echocardographic image. Additionally, the method allows for manually correction of errors in the detection. Experimental examples are presented to test the performance of the methodology. [ABSTRACT FROM AUTHOR]

In the present paper the step response method for system time constant calculations is described, revealing the connections between auto-regression coefficients and transient functions for a given system. The general calculational results obtained through this method (ARSTEP algorithm) for thermocouples, ionization chambers, and self-powered detectors used in nuclear power plants are given. The typical transfer function for these detectors and for the physical system described by means of a third order differential equation, as well as transfer function for dynamical processes of reactor core is found. On these basis, and with the aim to made it useful also for the neutronical sensors, a new algorithm for improving the ARSTEP code system is proposed. [ABSTRACT FROM AUTHOR]

Optical low-coherence reflectometry is a non-destructive interferometric techique, that has several applications such as the characterization of optical components, stress measuring in civil structures and is the basis of optical coherence tomogra-phy (OCT), among others. This paper gives a comprehensive description of a partially coherent interferometer to characterize induced stress and strain in an optical fiber. The work is complemented with computational simulations for getting ready the interferometrer. Finally, are written a series of correct procedures to be applied to reproduce mounting and obtain reliable measurements. [ABSTRACT FROM AUTHOR]

This paper develops the calibration of a system of data acquisition to monitoring the relative humidity in real time using the saturated solutions method, which produce constant relative humidity bath to a given temperature. Relative humidity sensor HIH3610 is introduced in that bath and finally it compared the experimental values of the sensor output voltage with the referenced values by the data sheet. [ABSTRACT FROM AUTHOR]

Copyright of Gestión y Ambiente is the property of Universidad Nacional de Colombia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The attenuation of neutrons emitted by an 106n/s Am-Be source, in concretes elaborated with diffetent aggregates is discussed in this paper. Two measurement methods were used: an dosimetric system with Bonnet spheres and 6Lil(Eu) detector, and LAVSAN -dielectric nuclear track detectors- with 238U converts. The concretes elaborated with magnetite is reported as the best for neutron shielding while the bauxite is not advisable for this purpose. [ABSTRACT FROM AUTHOR]

The design of a multichannel analyzer of pulse height based on a 8080-microprocessor is presented in this paper. This multichannel analyzer examines pulses by their height amplitude, coming from different types of ionizing particles detectors. Equipment modules and the main solutions that allowed to obtain characteristics similar to those of commercial analyzers of the same type are described. [ABSTRACT FROM AUTHOR]

In this paper, a method for determining the optimal height with the objective of decreasing the error in low-activity gamma measurements of different samples is combined with the use of liquid standards to measure the efficiency of semiconductor detectors. The procedure was applied to find the optimal height of measurement in the 1,460 MeV line of K40 in zeolites. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Filosofía (00348236) is the property of Universidad de Chile, Facultad de Filosofia y Humanidades and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)