Efectos de los temporales sobre las playas de la Bahía de Cádiz

[Resumen] En el presente trabajo se estudian los efectos que los temporales de Diciembre e 1995 y Enero de 1996 tuvieron sobre las playas de la Bahía de Cádiz. Del análisis del oleaje incidente se observa cómo sus efectos se multiplican cuando los picos de temporal coinciden con el máximo rango de mareas. Los cambios morfológicos registrados en las playas se estudian mediante el perfilamiento pre y post-temporal de playas tanto naturales como regeneradas artificialmente. La cuantificación de dichos cambios muestra cómo la forma inicial de los perfiles es determinante en el tipo de respuesta de las playas frente a olejaes de gran energía. También se manifiestan procesos de erosión en cordones dunares, mediante incisiones, desbordamientos, etc. La estimación final de los daños sufridos por las playas revela mayores pérdidas en aquellas zonas donde la presión antrópica es mayor[Abstract] The work deals with the effects that the storm surges of December-1995 and January-1996 made upon the beaches of Cádiz Bay (SW Spain). From the incidentwave analysis it can be deduced that the effects are much stronger when the surge peak coincides with maximum tidal ranges. The morphological changes recorded in the beaches are studied through pre- and post-surge profiling of both natural and artificially nourished beaches. The quantification of such morphological transformations shows that the initial beach profile is determinant in the kind of response of the beach to high wave-energy conditions. The erosive processes upon dune ridges are represented by gullying, overwashing, etc. The final estimation of losses in the beaches reveals higher damages in zones where anthropic preassure is higher

Gulf of Cadiz beaches: A comparative response to storm events

The aim of the present paper is to compare the profile response of two mesotidal beaches (Faro, 10 km long, Algarve; La Barrosa, 8 km long, Cadiz) within a single regional physiographic unit (the Gulf of Cadiz) to the same storm event (January, 1996). For this comparison, a series of beach surveys was used, including a total of 10 study sites, five at each study area. The two beaches belong to exposed, mesotidal, sandy shores, and have a similar coastal orientation. However, the response time-scale is different for each one. Faro showed a total amount of 130 000 m³ of erosion due to the storm, with a complete post-storm recovery after one tidal cycle. La Barrosa had a total sand loss of 80 000 m³ due to the storm, with a final recovery of 60 000 m³, 4-6 months after the event. These differences are due to the beaches' different morphodynamic behaviours. Whereas Faro is a reflective beach, with dominant plunging breakers, La Barrosa is mainly dissipative, having spilling breakers. The difference in beach slope and grain size could also be important in determining their response to storm events.El objetivo del presente trabajo es comparar la respuesta, ante un mismo episodio de tormenta (enero de 1996), de dos playas mesomareales de comportamiento distinto (Praia de Faro, de 10 km de longitud en el Algarve, y La Barrosa, de 8 km de longitud en Cádiz) pero pertenecientes a la misma unidad fisiográfica (el golfo de Cádiz). Para esta comparación se han estudiado una serie de levantamientos topográficos que incluyen un total de diez líneas de perfilamiento, cinco en cada área de estudio. Ambas playas se localizan en costas arenosas, expuestas, mesomareales y con una orientación similar. Sin embargo, el tiempo de respuesta es diferente en cada caso. Praia de Faro mostró una erosión total de 130 000 m³ debida a temporales y una recuperación completa tras un único ciclo mareal. La Barrosa presentó una pérdida total de arena de 80 000 m³ asociada a los temporales, con una recuperación final de 60 000 m³ después de 4 a 6 meses de los temporales. Estas diferencias son debidas al desigual comportamiento morfodinámico mostrado por ambas playas. Así, mientras Praia de Faro es una playa reflectiva con rotura dominante de tipo plunging, La Barrosa es predominantemente disipativa y con una rotura de tipo spilling. Del mismo modo, las diferencias en la pendiente y el tamaño de grano pueden ser también importantes a la hora de explicar la respuesta de ambas playas ante la llegada de temporales.Instituto Español de Oceanografí

Simulación de diferentes alternativas de gestión de los recursos hídricos del acuífero costero del río Verde (Almuñécar, España)

The effects of various alternatives in managing the water from a coastal aquifer with sea-water intrusion problems (the river Verde alluvial aquifer, Almuñecar, Granada, Spain) have been analyzed by means of a finite element approximation. The differential equation which describes the horizontal flow of groundwater and the movement of a sharp interface between the fresh and salt water is solved in a steady state regimen for boundaries with flow and open boundary conditions. This stationary solution has shown very accurate results in calculating freshwater potentials, thicknesses of fresh and salt water, discharges of fresh water and the intrusion of salt water along the coast. Various alternatives were simulated in the aquifer which included: the operation of the planned Otivar reservoir at the head of the catchment basin, changes in the location of extractions from the aquifer, and artificial recharge by urban waste water in the proximity of the coast. These simulations revealed that a considerable advance in the interface is to be expected if the current pumping exploitation continues and a significant part of the surface flow of the river Verde is channeled from the planned Otivar reservoir to irrigate the Almuñécar plain. On the other hand, the injection of urban waste water in the proximity of the coast would contribute to limiting the advance of the interface in the aquifer. However, the replacement of exploitation by pumping wells, currently spread aH over the aquifer's surface area, by a comparatively shallower extraction close to the coast, would seem to constitute the most effective way of containing the advance of the interface. e, even for small flows discharging into the sea as a consequence of intensive exploitation.Mediante una aproximación por elementos finitos se analizan los efectos de diferentes alternativas de gestión del agua de un acuífero costero con problemas de intrusión marina (acuífero aluvial del río Verde, Almuñécar, Granada). La ecuación diferencial que describe el flujo horizontal del agua subterránea y el movimiento de una interfase neta entre el agua dulce y salada se resuelve en régimen permanente para límites con condiciones de flujo y para límites abiertos. Esta solución estacionaria ha mostrado una gran precisión para el cálculo de los potenciales de agua dulce, los espesores de agua dulce y salada, la descarga de agua dulce al mar y la entrada de agua salada a lo largo de la costa. Se han simulado distintas alternativas de actuación sobre el acuífero, que incluyen: la entrada en funcionamiento del proyectado embalse de Otívar en la cabecera de la cuenca, la modificación en la ubicación de las extracciones en el acuífero y la recarga artificial con aguas residuales urbanas en la proximidad de la línea de costa. Las simulaciones muestran que cabe esperar un avance considerable de la interfase si continúan los actuales bombeos de explotación y una parte significativa de la escorrentía superficial del río Verde es canalizada desde el proyectado embalse de Otívar para el regadío en la vega de Almuñécar. Por otra parte, la inyección de aguas residuales urbanas en la proximidad de la línea de costa contribuiría a limitar el avance de la interfase en el acuífero; sin embargo, la sustitución de la actual explotación, mediante bombeo en pozos dispersos en toda la superficie del acuífero, por extracciones en captaciones poco penetrantes próximas a la costa parece constituir la opción más efectiva para contener el avance de la interfase, incluso para caudales muy pequeños de descarga al mar como consecuencia de una explotación intensiva

Changes of data sampling procedure to avoid energy and data losses during microclimates monitoring with wireless sensor networks.

Wireless sensor networks are gaining importance in agricultural applications, such as monitoring crops microclimates. Precision agriculture is one of the areas that can most benefit from this technology in the sense that wireless sensors networks allow data collection with high resolution, enabling better decision making. Such networks have restrictions on their deployment in a real environment, for example, on energy. Thus, several studies have been conducted in order to optimize the use of this technology. Depending on the application, it is desirable that the available energy on sensor nodes batteries allows operation for months or even years. One proposed solution to extend the lifetime of sensor nodes, so as to avoid unnecessary data collection, is the implementation of a routing protocol that allows a differentiated data sampling. An application that can benefit from this approach is vineyard microclimates monitoring, which is very important to monitor temperature and reIative humidity, and can apply precision agriculture techniques to the crop. Thus, in the program to be installed into sensor nodes, rules for data collection are defined, so that the value collected by the sensor at a given time is in the rule that defines normal conditions, the rate of sampling data used will be higher; however, when the value collected by the sensor is out ofthis rule, the sampling rate will automatically be reprogrammed to a higher value. This differentiated data collection allows savings in power consumption under normal conditions, and generates less data to be analyzed. Keywords: Wireless sensor network, microclimates monitoring, vineyards differentiated data samplin

Accurate determination of the milk protein allergen β-lactoglobulin by on-line aptamer affinity solid-phase extraction capillary electrophoresis-mass spectrometry

An on-line aptamer affinity solid-phase extraction capillary electrophoresis-mass spectrometry (AA-SPE-CE-MS) method was developed to purify, preconcentrate, separate, and characterize the milk allergenic protein β-lactoglobulin (β-LG) in food samples. The sorbent to pack into the SPE microcartidges was prepared by immobilizing an aptamer against β-LG onto magnetic bead particles. After optimizing the SPE-CE-MS method, the sample (ca. 75 µL) was loaded in separation background electrolyte (BGE, 2 M acetic acid pH 2.2), while a solution of 100 mM NH4OH (pH 11.2) (ca. 100 nL) was used for the protein elution. The linearity of the method ranged between 0.1 and 20 µg·mL-1 and the limit of detection (LOD) was 0.05 µg·mL-1, which was 200 times lower than by CE-MS. The method was repeatable in terms of relative standard deviation (RSD) for migration times and peak areas (< 0.5 % and 2.4 %, respectively) and microcartridge lifetime was more than 25 analyses. The applicability of the method for the determination of low levels of β-LG was shown by analyzing milk-free foods (i.e. a 100 % cocoa dark chocolate, a hypoallergenic formula for infants, and a dairy-free white bread) and milk-containing white breads. Results were satisfactory in all cases, thus demonstrating the great potential of the developed method for accurate food safety and quality control

Determination of a lectin protein allergen in food by on-line aptamer affinity solid-phase extraction capillary electrophoresis-mass spectrometry

An aptamer affinity sorbent was prepared for clean-up, preconcentration, separation and characterization of a food allergen protein by on-line aptamer affinity solid-phase extraction capillary electrophoresis-mass spectrometry (AA-SPE-CE-MS). SPE microcartridges were packed with a sorbent based on magnetic bead particles modified with an aptamer against the target lectin protein concanavalin A (Con A). After optimization of several parameters of the SPE-CE-MS method, the sample (ca. 30 µL) was loaded in separation background electrolyte (BGE, 2 M acetic acid pH 2.2), while the retained protein was eluted with 100 mM NH4OH (pH 11.2) (ca. 100 nL). The developed method was linear between 0.5 and 20 mg·L-1 and the limit of detection (LOD) was 0.25 mg·L-1, which was 100 times lower than by CE-MS. The repeatability of the method was satisfactory, with relative standard deviations (RSD) for migration times and peak areas below 1.9 and 8.1%, respectively. In addition, the microcartridges could be reused more than 25 analyses without significant loss of extraction efficiency. Finally, the applicability and versatility of the developed method were demonstrated by analyzing low levels of Con A in different food matrices (i.e. white beans, as well as chickpea, lentils, and wheat flours), leading to satisfactory results, with recoveries between 87 and 115%

Experimental results and modelling of humidity control strategies for greenhouses in continental and coastal settings in the Mediterranean region. II: Modelling of strategies

Strategies for humidity control —with and without heating— were evaluated via simulations performed with apreviously developed model (see accompanying paper, this issue, part I). With heating, the best strategy combined theuse of a humidity setpoint with step control of the roof window, increasing the ventilation in line with the outsidetemperature. Without heating, the best strategy again combined the use of a humidity setpoint with step control of theroof window, but required ventilation to be increased in line with the inside air temperatur

The Differentiation and Promotion of Students’ Rights in Portugal

This investigation includes a differential study (Study 1) and a quasi-experimental research (Study 2). In Study 1, the objective was to establish to what extent students’ rights existed and analyse the differentiation between students’ rights with Portuguese and immigrant mothers, throughout school years. The sample consisted of 537 students with Portuguese and immigrant mothers, distributed by different school years (7th, 9th and 11th grades). The Children’s Rights Scale (Hart et al., 1996; Veiga, 2001) was used. In Study 2, the purpose was to analyse the effects on students’ rights of the use by teachers of a communicational intervention program, supervised by school psychologists. The sample involved 7th and 9th grade students, in a total of four classes, two forming the experimental groups (n = 36) and two the control groups (n = 43); as in Study 1, the Children’s Rights Scale was used. The results indicated the effectiveness of the communicational intervention program on students’ rights and are consistent with previous studies. An implication is that psychologists and teachers, working together and taking a human rights perspective, may develop an important role in projects to promote the students’ rights