505 research outputs found

    The Phase Angle Method For Electrical Resistivity Applied To The Hollow Circular Cylinder Geometry

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    The phase-angle method to measure electrical resistivity in nonmagnetic metals is calculated for samples presenting the hollow circular geometry. The phase angle versus the operating frequency for a general hollow circular cylinder geometry shows a similar qualitative behavior when compared with the massive cylinder geometry. A discussion of a procedure for a desirable experimental condition related to the geometrical parameters and exciting signal is presented. UFaipxr.6731167116

    Abundance of Anchovy eggs by CUFES: Inter-annual fluctuations and spatial patterns.

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    Data on the abundance of Anchovy eggs in the Gulf of Cadiz as collected by CUFES are explored in the present work in relation to their spatial pattern and inter-annual fluctuations. These data were gathered in 12 summer surveys, both acoustic (ECOCADIZ series) and DEPM (BOCADEVA series) ones, since 2004 to date (no survey in 2012). A total of 1499 CUFES stations were sampled, which distributed from the strait of Gibraltar, in Spain, to Cape San Vicente, in Portugal (in 2010 to Cape Sta. Maria only). The sampling scheme consisted in a grid of 21 parallel transects, normal to the shoreline and inter-spaced 8 nm, with the samples being collected every 3 nm at a c.a. 600 l/min flow with a 335 μm mesh size net and at a sampling depth of 5 m from the surface. A continuous record of SST and SSS at 5 m (termosalinometer) was coupled to the CUFES sampling. The surveys were carried out in June, July or August depending on the year. Oceanographic variables such as temperature, salinity and chlorophyll, and even the bottom topography of the shelf as well, they all showed significantly different in two regions: to the East and West of the Cape S. Mª. The density of Anchovy eggs presents a high variability between stations showing a very patched distribution. The stations with most eggs are located to the East of Cape Sta. Mª. Egg abundance also showed a very high between-year variability, ranging from 2955 eggs in 2005 to 41941 eggs collected in 2014. Regarding the spatial pattern of egg distribution, the 84.9% of the total egg density (all the surveys pooled) was collected in the area east of the Cape Sta. Mª (37.4 % in 2016), and the 89.8 % of total egg density in stations bellow 100 m depth (47.9 % in 2016). What happened in 2016? The mean temperature registered in 2016 in the Western stratum (22.0ºC) was practically the same that the mean temperature registered from 2004 to 2015 in the Eastern stratum (21.7ºC). The analysis of the centers of gravity of the eggs densities vs longitude and depth show significant trends, but not for latitude, which indicate a displacement towards the West in 2016. However, no trends were found in the centers of gravity of the acoustic energy (NASC) as a proxy of adults. Is then the westward displacement of the spawning in 2016 caused by an advective transport (currents and/or winds) or by other causes? What will be the further effect on recruitment? It would be good to obtain a statistical model in order to explain how the different variables affect the abundance of eggs, including other variables like the wind, tide... The presence of deep canyons crossing the shelf in the East of Cape Sta. Mª indicates that distance to the coast would be a better variable than depth

    Decoherence in a Josephson junction qubit

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    The zero-voltage state of a Josephson junction biased with constant current consists of a set of metastable quantum energy levels. We probe the spacings of these levels by using microwave spectroscopy to enhance the escape rate to the voltage state. The widths of the resonances give a measurement of the coherence time of the two states involved in the transitions. We observe a decoherence time shorter than that expected from dissipation alone in resonantly isolated 20 um x 5 um Al/AlOx/Al junctions at 60 mK. The data is well fit by a model including dephasing effects of both low-frequency current noise and the escape rate to the continuum voltage states. We discuss implications for quantum computation using current-biased Josephson junction qubits, including the minimum number of levels needed in the well to obtain an acceptable error limit per gate.Comment: 4 pages, 6 figure

    Toward an Object-Oriented Process Control Software Design Environment

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    The design of a control software design environment, namely the Integrated Design Notation (IDN) is presented. IDN supports the design, development and implementation of decentralised distributed control systems. A cable extrusion process is targeted as a demonstrator application, where object-orientation technology is expected to facilitate the improvement of extruder control in a distributed environment. The IDN is based on the Unified Modelling Language (UML). A CASE toll supporting UML is integrated with the IDN. The translation to integrate a control software tool (Simulink) and options to generate automatic Java code are described

    CMOS x-rays detector array based on scintillating light guides

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    This paper describes a pixel imaging array consisting in 400µm x 400µm photodiodes fabricated in CMOS technology. An array of scintillating CsI:Tl crystals is placed above the photodiodes. These crystals are encapsulated in aluminum walls, forming a light path that guides the visible light produced by the scintillating crystal into the photodiodes. In This way, the x-ray energy is first converted into visible light which is then detected by the photodiode at the end of each light guide. The scintillator is 800 µm thick, absorbing almost all 20keV x-ray photons. Usually, the spatial resolution of the scintillating x-ray detectors is identical to the scintillator thickness. By using the light guides, the scintillator thickness can be increased without decreasing the spatial resolution. The increase of the scintillator thickness is desirable in order to increase the x-rays absorption efficiency. Tests carried out on the system show very promising results near 20keV

    Spatio-temporal variability of mid-size pelagic fishes in the Gulf of Cadiz shelf waters in relation to climatic and environmental drivers

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    Understanding spatio-temporal distribution patterns of mid-size pelagic fish species (MSPF) is of great interest from the standpoint of both their management and conservation. MSPF inhabiting in the Gulf of Cadiz (SW Iberian Peninsula, Atlantic Ocean) are relevant because they contribute to a large number of individuals captured by the different fishing métiers operating in the area. So far, information on their spatial distribution and temporal changes remain scarce in the study area despite their implications in their stock discrimination and management. Herein, temporal changes of the distribution patterns of abundance and their response to environmental drivers of five MSPF (Scomber colias, Scomber scombrus, Trachurus trachurus, Trachurus mediterraneus and Trachurus picturatus) off the Gulf of Cadiz (GoC) are analyzed from acoustic surveys data for the period 2007-2017. In particular, we evaluated intra- and inter-specific overlapping over time and space using four spatial indices. The species’ abundance and distribution were estimated and mapped by applying geostatistical techniques taking into account autocorrelation between observations. Furthermore, analyses including environmental variables were tested to explain such spatial fluctuations. The main findings showed a progressive reduction of their distribution area in all species over time except for T. trachurus. The only species overlapping in space and time wasbetween T. picturatus and S. colias. The distribution areas of S. colias and T. mediterraneus were notably reduced and showed northern/southern preferences over the years. The main environmental variables shaping the abundance and distribution of each species were found to be chlorophyll and temperature. Climatic indices such as NAO and AMO affected MSPF by reducing or increasing their spatial distribution. Finally, we discuss implications of our findings to contribute to the implementation of the Marine Strategy Framework Directive in the frame of implementing an effective ecosystem approach to fisheries management in the region

    BOCADEVA 0714 Gulf of Cadiz Anchovy Egg Survey and 2014 SSB preliminary estimates

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    This working document provides a brief description of the survey, laboratory analysis and estimation procedures used to obtain the Gulf of Cadiz anchovy SSB by DEPM for 2014 in the South-Atlantic Iberian Stock. Results are preliminary, because the estimation of the spawning fraction is not available yet

    Anchovy Spawning Stock Biomass of the Gulf of Cadiz in 2020 by the DEPM

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    The Daily Egg Production Method (DEPM) to estimate the Anchovy Spawning Stock Biomass (SSB) in the Gulf of Cádiz (ICES, Subdivision 9a South) is conducted by Spain (Centro Nacional Instituto Español de Oceanografía, CSIC) every three years, since 2005. BOCADEVA 0720 is the sixth survey of the historical DEPM series for anchovy in the Gulf of Cádiz and was delivered on board R/V Ramón Margalef (CNIEO) from the 9th to the 17th of July 2020. The surveyed area extended from Strait of Gibraltar to Cape San Vicente (Spanish and Portuguese waters in the Gulf of Cadiz). Plankton samples, along a grid of 21 transects perpendicular to the coast were obtained for the spawning area delimitation and density estimation of the daily egg production. The survey objectives also included the characterization of the oceanographic and meteorological conditions in the study area. The samples to estimate adult parameters (sex ratio, female mean weight, batch fecundity and spawning fraction) were obtained in the acoustic survey “ECOCADIZ 2020-07”, carried out during the same period. This working document provides a d escription of the survey, laboratory analysis and estimation procedures used to obtain the Gulf of Cadiz Anchovy SSB by DEPM for 2020 in the South-Atlantic Iberian Stock

    BOCADEVA 0720. Anchovy DEPM survey in the Gulf of Cadiz

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    The Daily Egg Production Method (DEPM) to estimate the Anchovy Spawning Stock Biomass (SSB) in the Gulf of Cádiz (ICES, Subdivision 9.a South) is conducted by Spain (Instituto Español de Oceanografía, IEO) every three years, since 2005. BOCADEVA 0720 is the sixth survey of the historical DEPM series for anchovy in the Gulf of Cádiz and was delivered on board R/V Ramón Margalef (IEO) from the 9th to the 17th of July 2020.This working document provides a brief description of the survey and the progress status of t h e laboratory analysis c a r ri e d o u t to obtain the Anchovy SSB by the a ppl i c at i o n o f th e DEPM in the South-Atlantic Iberian Stock
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