Tratamiento del experimento de Rutherford en libros de texto de bachillerato

En el presente trabajo de investigación se han evaluado los textos y las figuras contenidas en trece libros de texto de ambos cursos de bachillerato de las asignaturas de Física y Química. Estos libros fueron publicados en el marco de las distintas reformas educativas españolas de los últimos treinta años. Han sido analizados con el objetivo de identificar si contienen los elementos necesarios para que los alumnos sean capaces de forjarse un experimento mental acerca de la experiencia del bombardeo de la lámina de oro con partículas alfa llevado a cabo a principios del siglo XX por parte de Rutherford y sus colaboradores. Para realizar tal análisis se han descrito una serie de categorías, tanto para los textos como para las figuras contenidos en los libros. Tras su evaluación se ha observado que solamente un 46% de la muestra sometida a estudio poseen los elementos que se han considerado importantes para que los alumnos puedan forjarse el experimento mental. Un 67% de los libros propuestos como válidos fueron publicados en el marco de la LOGSE, frente un 33% para las leyes sucesivas. Además, se ha podido concluir que los textos de bachillerato no son capaces de realizar una contextualización histórica adecuada, limitando los acontecimientos a una mera secuencia cronológica

Validación de datos altimétricos en la Bahía de Algeciras y Estrecho de Gibraltar

Las aplicaciones en Oceanografía costera empleando el sensor radar altimétrico se han convertido en un reto para la comunidad científica dedicada al uso de este instrumento. Próximas a costa, las medidas altimétricas pueden presentar menor calidad por dos motivos fundamentales: mala calidad de las correcciones aplicadas a la medida y la contaminación de tierra sobre la propia medida altimétrica. En este trabajo, se ha validado los datos altimétricos del satélite ENVISAT, usando medidas de tres mareógrafos situados en la Bahía de Algeciras y en los puertos de Tarifa y de Ceuta. Se ha analizado siete años y ocho meses (2002-2010) de datos altimétricos de una traza descendente del satélite, que cruza la zona de estudio. Se ha realizado un análisis de las correcciones aplicadas a las señales radar: dos correcciones de marea (GOT00.2b y FES2004), dos correcciones troposféricas húmedas (MWR y ECMWF) y dos correcciones ionosféricas (DORIS e instrumento). Dos de los puntos de la traza se localizan en la Bahía de Algeciras y otros dos en el Estrecho de Gibraltar. El primer punto, situado más al norte de la Bahía presenta un 5.71% de valores válidos de Rango, mientras que en el segundo el porcentaje asciende hasta un 52.86%. El tercer y cuarto punto, muestran porcentaje de 81.43 y 95.71% respectivamente. Debido al bajo porcentaje obtenido en el punto 1, este ha sido eliminado del estudio. Los coeficientes de correlación obtenidos indican un buen ajuste entre las series altimétricas AINM (altura instantánea del nivel del mar) y las medidas in-situ, en los tres puntos analizados. Las correlaciones más altas se dan en el punto 3, en torno a 0.9. Al comparar las medidas altimétricas y los datos in-situ, una vez eliminado el efecto de la marea, se obtienen coeficientes de correlación inferiores (0.6). Además, de los tres puntos altimétricos analizados, sólo en el punto 3 se obtienen resultados estadísticamente significativos. Esto indica la necesidad de aplicar un modelo de marea loca a los datos altimétricos en la zona de estudio

Modelling the effect of the tidal cycle on the high phytoplankton biomass area of Cape Trafalgar (SW Iberian Peninsula)

Physical–biological interactions in the ocean are known to be crucial for understanding ecosystem processes. In this study, we examine the influence of the tide-topography interaction on the high productivity area of Cape Trafalgar using a high-resolution ocean circulation model coupled to an ecosystem model. The obtained results highlight the relevance of the tidal cycle explaining the high phytoplankton biomass that characterises this region through an active and periodic forcing, resulting in a pulsating upwelling system. Our model shows that the interaction of the westward zonal component of the tidal current (uvel) with the submarine ridge that characterises this region, which is perpendicular to the coast, results in the pumping of deep, cold, salty, and nutrient-rich waters to the well-illuminated subsurface waters, fuelling phytoplankton growth. At the same time, the interaction of the westward tidal current with the ridge leads to the development of a cyclonic eddy, which enables the redistribution of the upwelled waters over and to the east of Barbate High. The fortnightly tidal period has been identified as the most influential because (an effective) tidal-pumping process only takes place when the westward uvel is ∼ 0.42 m s−1, a condition attained between ∼ 3 days before and after the moment of maximum tidal flow during spring tides. Simultaneously, the energy and the associated horizontal and vertical mixing of the cyclonic gyre also vary with the tidal cycle, being stronger during spring tides. Both tidally driven processes, i.e., the cyclical upslope advection of deep nutrient-rich water and the influence of the cyclonic gyre, are the main mechanisms that lead to the development of a persistent phytoplankton-rich tongue over Barbate High. Consequently, Cape Trafalgar acts as a source of nutrient- and phytoplankton-rich waters to the surrounding waters

Modelling the effect of the tidal cycle on the high phytoplankton biomass area of Cape Trafalgar (SW Iberian Peninsula)

Physical-biological interactions in the ocean are known to be crucial for understanding ecosystem processes. This is particularly relevant in the highly dynamic coastal regions, where the biogeochemical processes associated with higher-frequency perturbations such as tidal waves play a key role in primary production. In this study, we examine the influence of the tide-topography interaction on the high productivity area of Cape Trafalgar (NW limit of the Strait of Gibraltar, Iberian Peninsula) using a high-resolution ocean circulation model coupled to an ecosystem model. The obtained results highlight the relevance of the tidal cycle explaining the high phytoplankton biomass that characterises this region through an active and periodic forcing, resulting in a pulsating upwelling system. Our model shows that the interaction of the westward zonal component of the tidal current (uvel) with the submarine ridge (i.e., Barbate High) that characterises this region, which is perpendicular to the coast, results in the pumping of deep, cold, salty, and nutrient-rich waters to the well-illuminated subsurface waters, fuelling phytoplankton growth. At the same time, the interaction of the westward tidal current with the ridge leads to the development of a cyclonic eddy, which enables the redistribution of the upwelled waters over and to the east of Barbate High. The fortnightly tidal period has been identified as the most influential because (an effective) tidal-pumping process only takes place when the westward uvel is ∼0.42 m s−1, a condition attained between ∼3 days before and after the moment of maximum tidal flow during spring tides. Simultaneously, the energy and the associated horizontal and vertical mixing of the cyclonic gyre also vary with the tidal cycle, being stronger during spring tides. Both tidally driven processes, i.e., the cyclical upslope advection of deep nutrient-rich water and the influence of the cyclonic gyre, are the main mechanisms that lead to the development of a persistent phytoplankton-rich tongue over Barbate High. Consequently, Cape Trafalgar acts as a source of nutrient- and phytoplankton-rich waters to the surrounding waters

Revising the Effects of Local and Remote Atmospheric Forcing on the Atlantic Jet and Western Alboran Gyre Dynamics

The main objective of the present study is to gain insight into the response of the Atlantic Jet (AJ) to the atmospheric forcing, in order to understand the hydrodynamic processes behind its disconnection from the Western Alboran Gyre (WAG) and the eastward displacement of the latter. An analysis was carried out based on observations of high frequency radar (HFR) derived currents and sea level, numerical model simulations and satellite imagery, with particular focus on the events of intense and endured easterlies. Among the main factors that characterize the atmospheric forcing linked to intense and persistent easterly wind events, the conjugation of the direct local wind forcing effect on the Atlantic Inflow (AI) on the eastern side of the Strait of Gibraltar and the response of the coastal waters in the northwestern (NW) corner of the Alboran Sea to the wind forcing over the Alboran Sea are of particular interest. In addition, the effect of the elevation surges in the Strait coming from the western Mediterranean Sea on reducing the AI intensity must be taken into account. These surges appear in coincidence with the establishment of persistent and intense easterlies over the Alboran Sea. The alteration of the AJ-WAG system in response to this forcing causes important changes in the phytoplankton distributions in the Alboran Sea. After the events of persistent and intense easterlies the phytoplankton accumulations in the NW Alboran Sea are displaced offshore and the phytoplankton transported with the AJ is injected toward the central zone of the WAG.33 página

Types and Distribution of Bioactive Polyunsaturated Aldehydes in a Gradient from Mesotrophic to OligotrophicWaters in the Alborán Sea (Western Mediterranean)

Polyunsaturated aldehydes (PUAs) are bioactive molecules suggested as chemical defenses and infochemicals. In marine coastal habitats, diatoms reach high PUA production levels during bloom episodes. Two fractions of PUA can usually be analyzed: pPUA obtained via artificial breakage of collected phytoplankton cells and dissolved PUA already released to the environment (dPUA). In nature, resource supply arises as a main environmental controlling factor of PUA production. In this work, we monitored the vertical distribution and daily variation of pPUA associated with large-size phytoplankton and dPUA, at three sites located in the Alboran Sea from mesotrophic to oligotrophic waters. The results corroborate the presence of large-size PUA producers in oligotrophic and mesotrophic waters with a significant (58%-85%) diatom biomass. In addition to diatoms, significant correlations between pPUA production and dinoflagellate and silicoflagellate abundance were observed. 2E,4E/Z-Heptadienal was the most abundant aldehyde at the three sites with higher values (17.1 fg center dot cell(-1)) at the most oligotrophic site. 2E,4E/Z-Decadienal was the least abundant aldehyde, decreasing toward the oligotrophic site. For the first time, we describe the daily fluctuation of pPUA attributable to cellular physiological state and not exclusively to taxonomical composition. Our results demonstrate the persistence of threshold levels of dPUA deep in the water column, as well as the different chromatographic profiles of dPUA compared with pPUA. We propose different isomerization processes that alter the chemical structure of the released PUAs with unknown effects on their stability, biological function, and potential bioactivity

A numerical simulation study of the hydrodynamic effects caused by morphological changes in the Guadalquivir River Estuary

This study presents an analysis of the impacts of the changes in bottom depth along the Guadalquivir Estuary on tidal dynamics. A realistic non-linear 1D numerical model, incorporating changes in both breadth and bottom depth, was employed to investigate the involved effects. The findings reveal a significant amplification of the M2 tidal wave towards the upper region of the Estuary, resulting from the gradual deepening caused by multiple dredging operations. The Estuary exhibits a pronounced tendency towards resonance, which is further enhanced by its deepening, resulting in reduced bottom friction and a smaller decrease in tidal wave amplitude as it propagates through the Estuary. The alterations in depth, particularly in breadth, along the Estuary play a crucial role in determining the magnitude of the resonant response of the M2 tidal wave.12 página

Analysis of internal soliton signals and their eastward propagation in the Alboran Sea : exploring the effect of subinertial forcing and fortnightly variability

Internal waves are commonly observed in oceans and lakes where high stratification exists. In the present study in the Strait of Gibraltar, we analyse internal soliton signals recorded in different locations in their eastward propagation from their release point (Camarinal Sill) to the continental slope of the northwestern Alboran Sea. Moreover, the effect of subinertial forcing on the release of solitons is also explored. The internal soliton activity was assessed from different approaches: (i) in-situ data (i.e., current and temperature measurements or High-Frequency Radar), (ii) numerical modelling, and (iii) an analytical approach. The arrival of solitons over the continental slope of the north-western Alboran Sea showed fortnightly variability in both number (occurrence) and amplitude during spring tides when compared with during neap tides. The observed arrival times of the solitons oscillated between 14 (spring tides) and 20 h (neap tides). Nevertheless, to provide a comprehensive explanation for the fluctuations in travel times, it is necessary to consider the subinertial variability driven by atmospheric forcing, which impacts both the flow in the Strait of Gibraltar and the mesoscale patterns in the Alboran Sea (e.g., the Coastal Cyclonic Gyre)

The fate of Guadalquivir River discharges in the coastal strip of the Gulf of Cadiz. A study based on the linking of watershed catchment and hydrodynamic models.

A catchmentmodel for river basins and a hydrodynamicmodelwere combined in order to simulate the spreading of the turbidity plume produced by sediment discharges from the Guadalquivir River basin within the Gulf of Cádiz under different meteorological conditions. The current fields provided by the hydrodynamic model and a transport-diffusion scheme based on tracking virtual particles tracking released at the river mouth have enabled us to simulate turbidity plumes that show great similarity with the plumes observed in satellite images. The most relevant results of the study show that in the absence of winds, the plume tends to spread very slowly, gradually progressing northwards; this is because of the symmetry between the filling and draining flows at the mouth of the Guadalquivir and low intensity of the tidal currents beyond the mouth. In addition, the transport of the plume towards the Strait of Gibraltar requires wind conditions with a northerly, north-westerly or westerly component. Westwards transport, however, requires winds with an easterly, southerly, or south-easterly component. The periods of heaviest rainfall in the Guadalquivir River basin coincide with winds mainly from the west; therefore, the times ofmaximum discharge at the mouth of the river occurwhen there are wind conditions that favour the transport of the matter suspended in the plume, southwards along the coast, towards the Strait of Gibraltar and the Alboran Sea. Linking the watershed catchment and hydrodynamic models has proved its suitability to predict the evolution and reaching of the sediment plumes fromthe Guadalquivir River discharges and the experience encourages the use of that methodology to be applied in a future prediction systemfor the creation and evolution of those sediment plumes.We would like to thank the Regional Government of Andalusia ( P11-RNM-7722 project), the Spanish Government (TRUCO project RTI2018-100865-B-C22 ), the SUDOE INTERREG AGUAMOD and OCASO projects for supporting this work financially. We are also grateful to NASA for distributing the MODIS data used in this study, and to the AERONET project for the MODIS AQUA RGB True Color Images, especially those from the Malaga-San Jose and Huelva stations

I Congreso Jóvenes Investigadores del Mar. Libro de Resúmenes.

El primer Congreso de Jóvenes Investigadores (JIs) del Mar surge con el fin de crear un espacio de encuentro donde dar a conocer los trabajos de investigación que se están desarrollando en los distintos organismos y centros I+D+i marinos. Entre los objetivos planteados se propuso: • Fomentar y dinamizar la presentación de trabajos científicos realizados por las nuevas generaciones de investigadores en el ámbito del mar. • Promover la interdisciplinariedad entre los JIs que llevan a cabo su trabajo en diferentes centros de investigación tanto públicos como del sector privado. • Establecer cooperaciones entre los JIs: conocer y potenciar sinergias en investigación marina. El I Congreso JIs del Mar cuenta con la participación de un total de 160 Jóvenes Investigadores, en su mayoría pertenecientes a universidades y centros de investigación con sede en Andalucía, así como de universidades y centros de investigación nacionales e internacionales. El Congreso se ha dividido en las 5 grandes áreas temáticas que coinciden con las establecidas por el Campus de Excelencia Internacional del Mar (CEI·MAR), y en las cuales se ha estructurado el presente libro de resúmenes: El conocimiento del mar, La gestión integrada del mar, El mar como fuente de recursos, Las ingenierías y el mar, El valor cultural el mar. También se ha potenciado la nueva gran área que es La salud y el mar. Se presentan en este libro de resúmenes todas las Flash-Talk y comunicaciones en formato póster presentadas en el Congreso. También las charlas inaugurales y de cierre ofrecidas por el Dr. Andrés Cozar y el Dr. Ricardo Sánchez Leal; a los cuales queremos agradecer su disposición para este fin. De la misma manera, se han incorporado las “charlas JIs”, que serán presentadas por jóvenes doctores en el ámbito marino. Gracias por vuestra participación. Por otra parte, cabe destacar la realización de dos mesas transversales en las que se abordarán aspectos relacionados con el trabajo en el medio marino desde otros puntos de vista y más allá del carácter científico. La transferencia de conocimiento a través de la participación de empresas (Ctaqua, Naturix, LifeBioencapsulation, 1d3milhistorias) y cátedras universitarias (cátedra Verinsur y Veterinaria), o el papel de la mujer en la Ciencia, con la participación de científicas en distintas etapas de la carrera investigadora, serán final de este I Congreso de JIs del mar. Gracias a todos. Sin alargar más esta pequeña contextualización inicial, os queremos trasladar desde el comité organizador nuestra más sincera bienvenida al I Congreso JIs del mar y desearos que disfrutéis desde el punto de vista científico y social. Agradecer a las instituciones que han respaldado la organización de este Congreso: El Instituto Universitario de Investigación Marina (INMAR), CEI·MAR y la Universidad de Cádiz de la mano de D. Ignacio González-Gordillo, Dña. Carmen Garrido y D. Juan José Vergara. También a todos los patrocinadores que han ayudado al desarrollo del Congreso. Por último, destacar que este Congreso ha nacido de la iniciativa de jóvenes investigadores pertenecientes a distintas ramas de conocimiento en el ámbito, con el fin de unificar todas ellas y converger en futuros proyectos. Por ello, esperamos que sea una actividad interesante y a la vez productiva para todo aquel que quiera saber más de nuestro océano, el gran desconocido