A ferrofluid-based sensor to measure bottom shear stresses under currents and waves

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Hydraulic Research on 2018, available online at: http://www.tandfonline.com/10.1080/00221686.2017.1397779The measurement of the near-bottom flow characteristics is crucial to correctly understand coastal processes. To overcome some of the limits of present state-of-the-art measuring instruments, we propose a novel approach to measure bottom shear stress under currents and waves based on the exploitation of magneto-rheological fluids, named ferrofluids. In particular, the deformation of a magnetically controlled ferrofluid drop O(0.01 ml) is transformed by a conditioning circuit into an output voltage which is proportional to the bottom shear stress. Calibration curves are presented for both steady-current and regular wave conditions, over fixed and weakly mobile beds, showing that the behaviour of the proposed measuring system can be assumed linear. In the range of the investigated parameters, it is shown that the working range is comprised between 0.08 N m-2 and an upper limit which is a function of the controlling magnetic field and the flow type.Peer ReviewedPostprint (author's final draft

La experiencia constitucional gaditana y la Constitución portuguesa de 1822

Very soon, the 1812 Constitution of Cádiz became an archetype, the pattern to be followed by the liberalism, not only European but also Hispano-American. Consequently, when the liberal revolution took over in Portugal, there is little wonder that the text from Cádiz was taken in careful consideration in order to draft theConstitution. However, the Portuguese Constitution of 1822 introduced new and very important concepts with respect to the Spanish one, ten years older. In order to explain these changes it has been argued that the intention of the Portuguese constituents was to produce a more liberal draft than the 1812 Spanish Constitution. The present work deals with the hypotheses that the amendments introduced by authors of the 1822 Constitution were mainly due to their sound knowledge of the day-by-day political life of the Liberal Trienium, with the political and legal problems that the application of 1812 Spanish Constitution was bringing in the daily practice.La Constitución de Cádiz de 1812 se convirtió muy pronto en el arquetipo o modelo a seguir no sólo por el liberalismo europeo, sino también por el hispanoamericano. No es de extrañar, en consecuencia, que cuando triunfó la revolución liberal en Portugal, el Texto gaditano fuera muy tenido en cuenta a la hora de redactar la Constitución. Sin embargo, la Constitución portuguesa de 1822 introdujo importantes novedades con respecto a la Gaditana de 1812. Estos cambios se han intentando explicar desde la idea de que los constituyentes portugueses quisieron hacer una Constitución más liberal que la española. En este trabajo se parte de la hipótesis de que las modificaciones introducidas por los autores de la Constitución de 1822 obedecieron principalmente al buen conocimiento de la realidad política del Trienio Liberal y a los problemas político jurídicos que la aplicación de la Constitución de 1812 estaba ocasionando en la práctica

JUAN MANZANO Y MANZANO (1911-2004)

Sin resume

Symbiosis numerical - hydraulic models

Peer Reviewe

Ten Principles for Bird-Friendly Forestry: Conservation Approaches in Natural Forests Used for Timber Production

Bird–forestry relationships have been the subject of research and conservation initiatives for decades, but there are few reviews of resulting recommendations for use by forest managers. We define “bird-friendly forestry” as forest management that applies recommendations from research seeking to reconcile logging with bird conservation in natural forests used for timber production. We reviewed relevant studies to synthesize 10 principles of bird-friendly forestry: (1) protect and enhance vertical structure through uneven-aged silviculture; (2) leave abundant dead wood in different decay stages; (3) maintain residual large green trees; (4) create and maintain sufficient amounts of uncut reserves and corridors; (5) maximize forest interior by retaining large contiguous forest tracts in landscapes with sufficient functional connectivity; (6) maintain buffers along streams, rivers, and wetlands cultural and urban landscapes; (7) maintain horizontal stand structure and enhance vegetation diversity by creating canopy gaps; (8) extend the temporal scale of logging cycles; (9) minimize post-logging disturbance to forests, particularly during the bird breeding season; and (10) manage for focal species and guilds. These principles may serve as guidelines in developing bird-friendly management plans customized for regional priority species, with a clearly articulated vision and quantitative objectives through which success can be measured

Comparison between nested grids and unstructured grids for a high-resolution wave forecasting system in the western Mediterranean sea

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Operational Oceanography on 2017, available online at: http://www.tandfonline.com/10.1080/1755876X.2016.1260389Traditionally wave modelling uses a downscaling process by means of successive nested grids to obtain high-resolution wave fields near the coast. This supposes an uncertain error due to internal boundary conditions and a long computational time. Unstructured grids avoid multiple meshes and thus the problem of internal boundary conditions. In the present study high resolution wave simulations are analysed for a full year where high-resolution meteorological models were available in the Catalan coast. This coastal case presents sharp gradients in bathymetry and orography and therefore correspondingly sharp variations in the wind and wave fields. Simulations with SWAN v.4091A using a traditional nested sequence and a regional unstructured grid have been compared. Also a local unstructured grid nested in an operational forecast system is included in the analysis. The obtained simulations are compared to wave observations from buoys near the coast; almost no differences are found between the unstructured grids and the regular grids. Simultaneously, tests have been carried out in order to analyse the computational time required for each of the alternatives, showing a decrease to less than half the time when working with regional unstructured grids and maintaining the forecast accuracy and coastal resolution with respect to the downscaling system.Peer ReviewedPostprint (author's final draft

NEW BREEDING RECORD AND LOCATION FOR WILSON’S PHALAROPE (PHALAROPUS TRICOLOR) IN THE NEBRASKA GREAT PLAINS, USA

Wilson’s phalarope (Phalaropus tricolor; Scolopacidae) is a migratory shorebird that relies on interior wetlands for foraging and breeding (Colwell and Jehl 1994, van Gils et al. 2018). Its global population status is unclear (Colwell and Jehl 1994, Lesterhuis and Clay 2010), and is variously listed as declining (Morrison et al. 2006, van Gils et al. 2018), increasing (Andres 2009, BirdLife International 2018), and exhibiting a long-term decline but recent stability (Sauer et al. 2011, Andres et al. 2012). Its global population estimate of 1.5 million birds has not been updated for 30 years, since 1988 (Colwell and Jehl 1994, Lesterhuis and Clay 2010, Andres 2012). In Nebraska, analysis of Breeding Bird Survey data indicate a population decline in Wilson’s phalarope by ~1.5% between 1966 and 2014 (Sauer et al. 2017). Published maps of the breeding range Wilson’s phalarope vary but typically include north-central and northwestern Nebraska as its easternmost extent (Sauer et al. 2017, Silcock and Jorgensen 2018, van Gils et al. 2018, but see also Colwell and Jehl 1994). Their historic breeding range has contracted due to the conversion of native grasslands and wetlands to agriculture (Lesterhuis and Clay 2010), but in recent decades their breeding range has also expanded, particularly eastward (van Gils et al. 2018), presumably as birds search for suitable new habitat. In contrast to most other shorebirds, Wilson’s phalaropes forage mainly while swimming and thus require close proximity to wetlands at all stages of their life cycle (Lesterhuis and Clay 2010). They are considered highly vulnerable to drought and other climate variables (Lesterhuis and Clay 2010, Galbraith et al. 2014), and recent climate modeling predicts a 100% loss of their current breeding range by 2080 due to global warming (National Audubon Society 2015)