Interaction flow bathymetry at tidal scale in the main sill of the Strait of Gibraltar

Data collected in the north and south channels of the main sill of the Strait of Gibraltar (Camarinal sill) are used to investigate processes connected to the internal hydraulics of the exchange through the Strait at tidal frequencies. Observations strongly suggest the setting up of hydraulic jumps at both the western and eastern flank of the sill, the latter associated with the reversal of the Mediterranean undercurrent during spring tides. The northern site is more sensitive to processes triggered by the formation and release of the jump formed east of the sill during intense enough ebb tide cycles, which is thus better traced at this location; the southern site detects more neatly the fluctuations and footprints associated with the hydraulic jump regularly formed to the west of the sill during flood tides. A detailed inspection of the high resolution bathymetry of the area reveals the existence of two enclosed depressions at either side of the sill, almost certainly carved by the bottom flow over the millennia, whose shape and morphology are suggestive of this spatial differentiation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Lagrangian particle tracking for the assessment of the flushing efficiency of harbor structures: the case of the Port of the Bay of Algeciras, Strait of Gibraltar

The Bay of Algeciras, an inlet of about 9 x 11 km located at the eastern margin of the Strait of Gibraltar, opens to the south, where the Atlantic jet leaves the Strait and starts spreading into the Alboran Sea. In its western side, the Bay hosts one of the main ports in Europe, neuralgic base of the major traffic load from Europe to Africa and from Europa to the rest of the oversea countries. The massive transport of liquid and solid bulk or bunkering activity, daily carried out in the Bay, combined with the harsh weather conditions that often lash the zone, give the ideal scenario for an incipient ecological disaster. This high environmental risk motivates the interest for a deeper understanding of the small scale dynamics of the Bay and the role played by the port structures in case of oil spill or other surface contaminations. A series of Lagrangian particles tracking (LPT) experiments were carried out to investigate the flushing patterns of the Bay and 8 different docks inside the local port, under a representative variety of external conditions, such as tide phase and strength, and winds. A 2D LPT algorithm has been adapted to fully exploit the outputs of a very high resolution (∼30m) three-domain-nested hydrodynamic model, with the aim of resolving the complex circulation within the structures of the harbor. Winds are a clearly dominant factor, with westerlies featuring e-folding times one order of magnitude lower than easterlies. Fortnightly tidal modulation presents a counter-intuitive effect, with spring tides that, despite promoting higher ventilation in a first instance, end up providing higher accumulation of particles inside the docks and higher e-folding times than neap tides. Tide phase affects the current direction at the entrance of the docks during the first few hours of simulation and its effect is progressively masked throughout the experiment. In the 45% of the experiments, a significant quantity of particles flow out to the Alboran Sea (55% in the whole Bay experiment), confirming the importance of the Bay on the exportation of pollutant/properties to the nearby basin.Universidad de Málaga. Campus de Excelencia Internacional del Mar, CEIMAR. Campus de Excelencia Internacional Andalucía Tec

Mediterranean outflow and its link with upstream conditions in Alboran Sea

The Western Alboran Gyre (WAG) at the eastern entrance of the Strait of Gibraltar can influence the Mediterranean outflow (MOW) by favoring or hampering the flow of Levantine and Western Mediterranean (LIW and WMDW) waters, the main constituents of the MOW. Observations collected at Camarinal sill in the Strait and AVISO data are used to investigate this issue.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The influence of tides on the exchange through the Strait of Gibraltar and on properties of the Mediterranean Sea

A. Ishlinsky Institute for Problems in Mechanics, Rusi

Effect of labour flexibility on productivity in the andalusian hotel industry

In this work, we analyze the effect of labour flexibility on productivity in the Andalusian hotel industry. For this purpose, we use the data obtained by the Quality, Productivity and Competitiveness in the Hospitality Industry for Andalusia project (PO7/SEJ-02889). Using a expanded version of the Cobb-Douglas production function, the model distinguishes two employment shares: full-time permanent (standard work) and temporary plus part-time employees (non-standard work). Our results indicate that productivity in Andalusian hotels is lower the higher the percentage of temporary and part-time workers. Furthermore, there are no statistically significant differences between the negative impact on productivity of both types of labour contract. However, since the costs associated with both temporary and part-time workers are lower than those of workers with full-time permanent contracts, future studies should analyze the differential impact of all the types of contracts discussed on the mean cost per employee in hotels.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Youtubers infantiles, los nuevos protagonistas de la comunicación comercial

Los estudios de audiencias infantiles nos muestran datos que revelan el importante papel que juega Internet y las redes sociales en la vida diaria de este público. El AIMC Niñ@s 2018 sitúa el consumo de vídeos en Internet de niños entre 6 y 13 años de edad en un 89%, e indica que 7 de cada 10 niños y niñas, de entre 12 y 13 años, utiliza las redes sociales. Cifras que convierten a Internet en el medio elegido por los más pequeños de la casa, quienes desde edades muy tempranas dominan ya las nuevas tecnologías. Uno de los contenidos más consumidos por el público infantil en este nuevo escenario son los espacios creados por los youtubers, influencers de un segmento de población especialmente vulnerable que se presentan como auténticas oportunidades en la gestión comunicacional de las marcas comerciales. El estudio que a continuación presentamos pretende, mediante el análisis de contenido de los principales canales de youtubers infantiles españoles, identificar la estructura que adoptan dichos espacios, los aspectos formales que describen sus publicaciones (frecuencia de aparición, duración…), así como la aparición de marcas comerciales y el uso de productos en los vídeos, valorando aspectos cuantitativos y cualitativos.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Blackspot seabream early life stages dispersal by hydrodynamic modelling (Strait of Gibraltar - Alboran Sea)

The Blackspot seabream (Pagellus bogaraveo) is a commercially appreciated demersal fish, widespread in the north-eastern Atlantic and middle-western Mediterranean. The Strait of Gibraltar (SoG) is an important fishing area where artisanal fleets from Spain and Morocco target this species using special longline gears known as “voracera”. Different studies on the health status of this species claim an overexploitation of the resource without any kind of objective management measures implemented yet by the associated countries. Improving the knowledge of the population dynamics, and particularly during the spawning window, is crucial for a better management of the fishing effort for this species. There is an agreement in literature in considering the SoG as an especially energetic and dispersive spawning zone for this species. Once spawned, eggs and larvae (ELS) are assumed to be scattered by the currents towards both sides of the SoG, mostly to the eastwards Alboran basin, where high concentrations of juveniles occur. A high resolution hydrodynamic model coupled to a Lagrangian particle tracking system is employed to assess the potential dispersal pathways of blackspot seabream ELS spawned in the SoG. Recursive releases of passive tracers in different virtual spawning spots and depths within the SoG region are tracked under different tidal conditions in order to obtain an overall characterization of the spatial dispersion patterns of the studied species. Semidiurnal tidal currents emerge as the primary factor in determining the horizontal dispersion and pathway of the spawning products, although the spring-neap tidal cycle and the spawning depth can be also important variables depending on the region considered as well as the arrival zone for the ELS dispersal paths over the Alboran SeaUniversidad de Málaga. Campus de Excelencia Internacional CEIMA

A Decision Tree and S-Transform Based Approach for Power Quality Disturbances Classification

In this paper, it is presented an automated classification based on S-transform as feature extraction tool and Decision Tree as algorithm classifier. The signals generated according to mathematical models, including complex disturbances, have been used to design and test this approach, where noise is added to the signals from 40dB to 20dB. Finally, several disturbances, simple and complex, have been considered to test the implemented system. Evaluation results verifying the accuracy of the proposed method are presented.IEE

Some properties of bornological convergences

We study some basic properties of the so-called bornological convergences in the realm of quasi-uniform spaces. In particular, we revisit the results about when these convergences are topological by means of the use of pretopologies. This yields a presentation of the bornological convergences as a certain kind of hit-and-miss pretopologies. Furthermore, we characterize the precompactness and total boundedness of the natural quasi-uniformities associated to these convergences. We also obtain an extension of the classical result of Künzi and Ryser about the compactness of the topology generated by the Hausdorff quasi-uniformity to this framework. © 2010 Elsevier B.V.The authors acknowledge the support of the Spanish Ministry of Science and Innovation grant MTM2009 12872 C02 01Rodríguez López, J.; Sanchez Granero, MA. (2011). Some properties of bornological convergences. Topology and its Applications. 158(1):101-117. https://doi.org/10.1016/j.topol.2010.10.009S101117158