Portus, New Contributions to its Research: Construction Systems and Dating of the East-West Docks

The archaeological site of Portus (Ostia Antica), is a most important ports of the ancient world. Since 2017, the University of Huelva, in collaboration with the Archaeological Park of Ostia Antica, has been developing a research project on one of its interior piers, the socalled lantern. Said east-west structure or pier is the best example of its category in the port complex. With a length of about 150 m. the latest research has provided numerous and interesting data on its architecture and diachrony, highlighting significant phases in its evolution from its construction to its final abandonment in the beginnings of the Middle Ages. Therefore, the results presented here represent a significant novelty in the general knowledge of Portus and in that of its docks in particular.Funding for open access publishing: Universidad de Huelva / CBUA. The study and analysis of the east-west dock are part of a research agreement signed between University of Huelva and the Parco Archeologico di Ostia Antica. It was also carried out in the context of the Research Project Del Atlántico al Tirreno: Investigaciones en las infraestructuras de Portus- Ostia Antica, el muelle de la Lanterna (From the Atlantic to the Tyrrhenian: Investigations in the infrastructures of Portus-Ostia Antica, the Lanterna dock), of the Call for Archaeological Projects Abroad of the Ministry of Education of Spain

A Geometrical Study on the Roof Tile-Shaped Modes in AlN-Based Piezoelectric Microcantilevers as Viscosity–Density Sensors

Cantilever resonators based on the roof tile-shaped modes have recently demonstrated their suitability for liquid media monitoring applications. The early studies have shown that certain combinations of dimensions and order of the mode can maximize the Q-factor, what might suggest a competition between two mechanisms of losses with different geometrical dependence. To provide more insight, a comprehensive study of the Q-factor and the resonant frequency of these modes in microcantilever resonators with lengths and widths between 250 and 3000 µm and thicknesses between 10 and 60 µm is presented. These modes can be efficiently excited by a thin piezoelectric AlN film and a properly designed top electrode layout. The electrical and optical characterization of the resonators are performed in liquid media and then their performance is evaluated in terms of quality factor and resonant frequency. A quality factor as high as 140 was measured in isopropanol for a 1000 × 900 × 10 µm3 cantilever oscillating in the 11th order roof tile-shaped mode at 4 MHz; density and viscosity resolutions of 10−6 g/mL and 10−4 mPa·s, respectively are estimated for a geometrically optimized cantilever resonating below 1 MH

El Centro de Investigación y Documentación del Eucalipto (CIDEU): una herramienta al servicio de la Investigación Universitaria

El CIDEU es el primer Centro de sus caracteristicas en Europa. Se ha concebido combinando las siguientes particularidades: ser un Centro de Investigacion y Documentacion, tener vocacion de servicio social, establecerse a traves de Internet y ubicarse en el marco de la Universidad de Huelva. Todo ello le convierte en un Centro de Investigacion forestal de primer orden que permitira tanto a estudiantes como a docentes y personal investigador de la Universidad de Huelva, disponer de un conjunto de herramientas y servicios que facilitaran, incrementaran y enriqueceran notablemente su labor investigadora. En la presente comunicacion se detallan los objetivos, lineas de trabajo y caracteristicas de funcionamiento que definen al CIDEU

Piezoelectric MEMS Linear Motor for Nanopositioning Applications

This paper reports the design, fabrication, and performance of piezoelectric bidirectional conveyors based on microelectromechanical systems (MEMS) and featuring 3D-printed legs in bridge resonators. The structures consisted of aluminum-nitride (AlN) piezoelectric film on top of millimeter-sized rectangular thin silicon bridges and two electrode patches. The position and size of the patches were analytically optimized for travelling or standing wave generation, while the addition of 3D-printed legs allowed for a controlled contact and amplified displacement, a further step into the manufacturing of efficient linear motors. Such hybrid devices have recently demonstrated the conveyance of sliders of several times the motor weight, with speeds of 1.7 mm/s by travelling waves generated at 6 V and 19.3 kHz. In this paper both travelling and standing wave motors are compared. By the optimization of various aspects of the device such as the vibrational modes, leg collocation and excitation signals, speeds as high as 35 mm/s, and payloads above 10 times the motor weight were demonstrated. The devices exhibited a promising positional resolution while actuated with only a few sinusoidal cycles in an open-loop configuration. Discrete steps as low as 70 nm were measured in the conveyance of 2-mg sliders

Bidirectional Linear Motion by Travelling Waves on Legged Piezoelectric Microfabricated Plates

This paper reports the design, fabrication and performance of MEMS-based piezoelectric bidirectional conveyors featuring 3D printed legs, driven by linear travelling waves (TW). The structures consisted of an aluminium–nitride (AlN) piezoelectric film on top of millimetre-sized rectangular thin silicon bridges and two electrode patches. The position and size of the patches were analytically optimised for TW generation in three frequency ranges: 19, 112 and 420 kHz, by the proper combination of two contiguous flexural modes. After fabrication, the generated TW were characterized by means of Laser–Doppler vibrometry to obtain the relevant tables of merit, such as the standing wave ratio and the average amplitude. The experimental results agreed with the simulation, showing the generation of a TW with an amplitude as high as 6 nm/V and a standing wave ratio as low as 1.46 for a device working at 19.3 kHz. The applicability of the fabricated linear actuator device as a conveyor was investigated. Its kinetic performance was studied with sliders of different mass, being able to carry a 35 mg silicon slider, 18 times its weight, with 6 V of continuous sinusoidal excitation and a speed of 0.65 mm/s. A lighter slider, weighting only 3 mg, reached a mean speed of 1.7 mm/s at 6 V. In addition, by applying a burst sinusoidal excitation comprising 10 cycles, the TW generated in the bridge surface was able to move a 23 mg slider in discrete steps of 70 nm, in both directions, which is a promising result for a TW piezoelectric actuator of this size

Estudio de la batería general de pruebas de aptitudes gatb en formación profesional de adolescentes: investigación realizada en el sena

El presente trabajo se ha realizado con el propósito de poseer un instrumento útil para la selección de los aspirantes a los cursos de aprendizaje, en el Servicio Nacional de Aprendizaje, SENA. A) Revisión histórica. Antes del perfeccionamiento de la GATB, el USES (United States Employment Service) construyo cerca de 100 pruebas con la finalidad de medir aptitudes diferentes que parecían tener relación con el éxito en diversas ocupaciones. Dichas pruebas incluían aspectos tales como aritmética, vocabulario, espacio bidimensional, etc. y algunas pruebas de ejecución (aparatus test)

Muscular and physical response to an agility and repeated sprint tests according to the level of competition in futsal players

© Copyright © 2020 García-Unanue, Felipe, Bishop, Colino, Ubago-Guisado, López-Fernández, Hernando, Gallardo and Sánchez-Sánchez. The aim of this study was to evaluate the neuromuscular response to an agility and repeated sprint ability (RSA) test according to the level of competition in futsal players. A total of 33 players from two elite teams and one amateur team participated in the study. The participants completed an agility t-test, a 30 m-speed test, and a RSA test. A countermovement jump (CMJ) test and a tensiomyography test of the rectus femoris (RF) and biceps femoris (BF) of both legs were carried out before and after the tests. RSA test revealed better sprint times in elite players compared to amateurs in the seven bouts, as well as in the 30 m sprint and in the agility test (p \u3c 0.05). Before the tests, elite players showed higher sustain time (Ts) in RF (+31.03 ms; ES: 0.76) and BF (+28.73 ms; ES: 0.73), higher half-relaxation time (Tr) in BF (+20.79 ms; ES: 0.94), and lower delay time (Td) in BF (−2 ms; ES: 1.19) compared to amateur players. However, post-test values did not present any significant differences (p \u3e 0.05). In conclusion, elite players showed greater performance in the RSA test, in the 30 m tests and in the agility test compared to amateur players. The contractile properties were not a key factor in the RSA performance of the futsal players

Estudio paleobotánico de estróbilos y maderas subfósiles holocenas en el yacimiento de Cevico Navero (Palencia, España)

This paper reports results of work at the Cevico Navero site in Palencia, Spain. Macro- and microscopic study of the subfossil cones and trunks found at the site has permitted their identification to the species Pinus nigra. Radiocarbon dating of the wood indicates that this pine species was present in the región 3,500 years ago. The results are discussed in the context of other relevant literature. The dynamics of vegetation cover in the study área and the paleochorology of P. nigra are considered.Se exponen en este artículo los resultados del trabajo llevado a cabo en el yacimiento de Cevico Navero (Palencia, España) en el que han sido hallados restos subfósiles de estróbilos y troncos. El estudio mediante anatomía comparada -macro y microscópica- de dichos materiales ha permitido asignarlos a la especie Pinus nigra. La datación radiocarbónica de la madera revela la presencia de esta especie de pino en esa zona de la provincia de Palencia hace unos 3.500 años. Con estos datos y otros bibliográficos se hace una discusión acerca de la posible dinámica de la cubierta vegetal en el ámbito geográfico considerado, así como de la paleocorología del propio P. nigr

Sensors for product characterization and quality of specialty crops—A review

This review covers developments in non-invasive techniques for quality analysis and inspection of specialty crops, mainly fresh fruits and vegetables, over the past decade up to the year 2010. Presented and discussed in this review are advanced sensing technologies including computer vision, spectroscopy, X-rays, magnetic resonance, mechanical contact, chemical sensing, wireless sensor networks and radiofrequency identification sensors. The current status of different sensing systems is described in the context of commercial application. The review also discusses future research needs and potentials of these sensing technologies. Emphases are placed on those technologies that have been proven effective or have shown great potential for agro-food applications. Despite significant progress in the development of non-invasive techniques for quality assessment of fruits and vegetables, the pace for adoption of these technologies by the specialty crop industry has been slow

Yo-Yo intermittent recovery test level 2: Cardiorespiratory response and performance in professional soccer players, comparison between under 20 and over 20 years old players

Purpose: The aim of this study was to compare the older players (O20) and the younger ones (U20) of the Colombian Professional National League 2015 champion team in cardiopulmonary responses and performance, using the Yo-Yo Intermittent Recovery Test level 2 (YYIR2). Methods: Nine O20 and nineteen U20 were voluntarily evaluated. All subjects were monitored for heart rate, and a continuous breath-to-breath recording was carried out while they performed the YYIR2. The Student T test and the Pearson correlation were used for the statistical analysis. Results: A significant difference in distance covered and speed in the ventilatory threshold between U20 players (280 ± 85,3 m) (16,6 ± 0,3 km.h-1) and O20 players (373 ± 113,1 m) (17 ± 0,3 km.h-1) was observed. Only in the U20 group, a significant correlation between the variables oxygen uptake in the ventilatory threshold (V̇O2atVT) and performance in the test (Dmax), V̇O2 at VT and maximum speed (Smax), peak oxygen uptake (V̇O2peak) and Smax and V̇O2peak and Dmax was observed. Conclusion: The only variables that differentiated the performance in the population was the analysis of the distance and the speed at the time of the ventilatory threshold