6,078 research outputs found
Democedes de Crotona : biografía de un médico de finales del siglo VI a.C.
La biografía de Democedes presente en la Historia de Herodotus constituye un documento
esencial para conocer la situación de la medicina griega de finales del siglo VI a.C., así como
el papel que los médicos desempeñaban en el seno de la sociedad. Aunque Heródoto no
proporciona una datación cronológica precisa, se puede establecer una correlación cronológica
aproximada de la vida de Democedes.The biography of Democedes, present in the History of Herodotus, constitutes an essential
document to know the situation of the Greek medicine of final of the century VI B.C., as well
as for the paper that the doctors carried out in the breast of the society. Although Herodotus
doesn’t provide a precise chronology, an approximate chronological correlation of the life of
Democedes can settle establish
El debate sobre la esfericidad de la Tierra en época clásica
El debate sobre la esfericidad, cuya solución encontramos reflejada por primera vez en los textos de Aristóteles, ocupó un papel importante en los ambientes intelectuales de los siglos VI y V a.C. Si bien se conserva poco del pensamiento de los llamados filósofos presocráticos, otros autores como historiadores, médicos, comediógrafos y filósofos de finales del siglo V y principios del IV proporcionan una importante información para comprender la realidad de dichos planteamientos.The debate on the esfericidad, whose demonstration we are reflected for the first time in the texts of Aristóteles, occupied an important role in the intellectual ambiences of the VIth and Vth centuries B.C. Although little survives of the thought of the so-called preSocratic philosophers, other authors as historians, doctors, comediógrafos and philosophers of the ends of the Vth century and beginning of the IVth provide important information to understand the reality of the above mentioned expositions
La circunnavegación de "Libia" : entre mito y realidad
En los inicios de la corriente de pensamiento y experiencias que abren el camino para
llegar a la geografía científica, junto al desarrollo teórico elaborado por los llamados “físicos
jonios”, encontramos una serie de empresas oceánicas que venían a confirmar en parte tales
planteamientos. El caso de la circunnavegación de África que nos presenta Heródoto constituye
un ejemplo paradigmático de este tipo de expedicionesIn the beginnings of the current of thought and experiences that open the way to come
to the scientific geography, along with the theoretical development prepared by the so-called
“ionic physicists”, we find a series of oceanic companies that were coming to confirm partly
such expositions. The case of the circumnavigation of Africa that Herodotus presents to us
constitutes a paradigmatic example of this type of expedition
Dieta y salud en época Clásica
La dietética constituía una de las principales bases de la medicina griega, tanto a nivel explicativo como terapéutico. El concepto de dieta hay que entenderlo no sólo como un régimen alimenticio, sino más bien como el modo de vida y la propia realidad del individuo en toda su complejidad.The dietetics constituted one of the principal bases of the Greek medicine, both at explanatory and therapeutic level. The concept of diet is necessary to understand it not only as a nutritive regime, but rather as the way of life and the proper reality of the individual in all his complexity
Estimation of specific cutting energy in an S235 alloy for multi-directional ultrasonic vibration-assisted machining using the Finite Element Method
The objective of this work is to analyze the influence of the vibration-assisted turning process on the machinability of S235 carbon steel. During the experiments using this vibrational machining process, the vibrational amplitude and frequency of the cutting tool were adjusted to drive the tool tip in an elliptical or linear motion in the feed direction. Furthermore, a finite element analysis was deployed to investigate the mechanical response for different vibration-assisted cutting conditions. The results show how the specific cutting energy and the material’s machinability behave when using different operational cutting parameters, such as vibration frequency and tool tip motion in the x-axis, y-axis, and elliptical (x-y plane) motion. Then, the specific cutting energy and material’s machinability are compared with a conventional turning process, which helps to validate the finite element method (FEM) for the vibration-assisted process. As a result of the operating parameters used, the vibration-assisted machining process leads to a machinability improvement of up to 18% in S235 carbon steel. In particular, higher vibration frequencies were shown to increase the material’s machinability due to the specific cutting energy decrease. Therefore, the finite element method can be used to predict the vibration-assisted cutting and the specific cutting energy, based on predefined cutting parameters.Peer ReviewedPostprint (published version
Output-feedback anti-disturbance predictor-based control for discrete-time systems with time-varying input delays
[EN] This paper investigates the robust stabilization of discrete-time systems with time-varying input delays and model uncertainties by predictor-based anti-disturbance output-feedback control strategies. Here, a novel predictor-feedback control combined with an extended state observer is proposed. The objective is to counteract the negative effects of input delays while actively rejecting disturbance signals typically encountered in engineering practice, such as steps or harmonics. Differently from previous approaches, unknown but bounded time-varying delays are taken into consideration. Moreover, the complexity of the algorithm for control synthesis is notably reduced. Finally, an illustrative example from the literature is provided to show that better robust performance can be achieved with the proposed method.This work was partially supported by projects TIN201786520C31R, Ministerio de Economia y Competitividad (Spain) , and PGC2018098719BI00, MCIU/AEI/FEDER, UE, and Group DGA T4517R, Spain. The material in this paper was not presented at any conference. This paper was recommended for publication in revised form by Associate Editor Bin Zhou under the direction of Editor Ian R. Petersen.González Sorribes, A.; García Gil, PJ. (2021). Output-feedback anti-disturbance predictor-based control for discrete-time systems with time-varying input delays. Automatica. 129:1-8. https://doi.org/10.1016/j.automatica.2021.109627S1812
Industrial synthesis of cysteine derivatives
Comunicación presentada en European Research Conference: "Organic Electrochemistry: Moving Towards Clean and Selective Synthesis", Agelonde-La Londe Les Maures, April 15-19, 1998
Scalable Inference of Gene Regulatory Networks with the Spark Distributed Computing Platform Cristo
Inference of Gene Regulatory Networks (GRNs) remains an important open challenge in computational biology. The goal of bio-model inference is to, based on time-series of gene expression data, obtain the sparse topological structure and the parameters that quantitatively understand and reproduce the dynamics of biological system. Nevertheless, the inference of a GRN is a complex optimization problem that involve processing S-System models, which include large amount of gene expression data from hundreds (even thousands) of genes in multiple time-series (essays). This complexity, along with the amount of data managed, make the inference of GRNs to be a computationally expensive task. Therefore, the genera- tion of parallel algorithmic proposals that operate efficiently on distributed processing platforms is a must in current reconstruction of GRNs. In this paper, a parallel multi-objective approach is proposed for the optimal inference of GRNs, since min- imizing the Mean Squared Error using S-System model and Topology Regularization value. A flexible and robust multi-objective cellular evolutionary algorithm is adapted to deploy parallel tasks, in form of Spark jobs. The proposed approach has been developed using the framework jMetal, so in order to perform parallel computation, we use Spark on a cluster of distributed nodes to evaluate candidate solutions modeling the interactions of genes in biological networks.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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