Seawater carbonate chemistry and calcification of two mediterranean cold-water coral species in a laboratory experiment

Deep-water ecosystems are characterized by relatively low carbonate concentration values and, due to ocean acidification (OA), these habitats might be among the first to be exposed to undersaturated conditions in the forthcoming years. However, until now, very few studies have been conducted to test how cold-water coral (CWC) species react to such changes in the seawater chemistry. The present work aims to investigate the mid-term effect of decreased pH on calcification of the two branching CWC species most widely distributed in the Mediterranean, Lophelia pertusa and Madrepora oculata. No significant effects were observed in the skeletal growth rate, microdensity and porosity of both species after 6 months of exposure. However, while the calcification rate of M. oculata was similar for all colony fragments, a heterogeneous skeletal growth pattern was observed in L. pertusa, the younger nubbins showing higher growth rates than the older ones. A higher energy demand is expected in these young, fast-growing fragments and, therefore, a reduction in calcification might be noticed earlier during long-term exposure to acidified conditions.

Data base on pelagic ciliates grazing and growth rate as a function of size, prey size and type compiled from the literature

Microzooplankton (the 20 to 200 µm size class of zooplankton) is recognised as an important part of marine pelagic ecosystems. In terms of biomass and abundance pelagic ciliates are one of the important groups of organism in microzooplankton. However, their rates - grazing and growth - , feeding behaviour and prey preferences are poorly known and understood. A set of data was assembled in order to derive a better understanding of pelagic ciliates rates, in response to parameters such as prey concentration, prey type (size and species), temperature and their own size. With these objectives, literature was searched for laboratory experiments with information on one or more of these parameters effect studied. The criteria for selection and inclusion in the database included: (i) controlled laboratory experiment with a known ciliates feeding on a known prey; (ii) presence of ancillary information about experimental conditions, used organisms - cell volume, cell dimensions, and carbon content. Rates and ancillary information were measured in units that meet the experimenter need, creating a need to harmonize the data units after collection. In addition different units can link to different mechanisms (carbon to nutritive quality of the prey, volume to size limits). As a result, grazing rates are thus available as pg C/(ciliate*h), µm**3/(ciliate*h) and prey cell/(ciliate*h); clearance rate was calculated if not given and growth rate is expressed as the growth rate per day.

Project-based learning experience on Data Structures course

This paper presents the innovations in the practical work of the Data Structures subject carried out in the last five years, including a transition period and a first year of implantation of the European Higher Education Area. The practical coursework is inspired by a project-based methodology and from 2008/2009 additional laboratory sessions are included in the subject schedule. We will present the academic results and ratios of the mentioned time period which imply a significant improvement on students' performance.

Physical data acquisition and PWM signal generation using a microcontroller allowing control for DC motor rotation speed

El objetivo de este proyecto es diseñar un sistema capaz de controlar la velocidad de rotación de un motor DC en función del valor de temperatura obtenido de un sensor. Para ello se generará con un microcontrolador una señal PWM, cuyo ciclo de trabajo estará en función de la temperatura medida. En lo que respecta a la fase de diseño, hay dos partes claramente diferenciadas, relativas al hardware y al software. En cuanto al diseño del hardware puede hacerse a su vez una división en dos partes. En primer lugar, hubo que diseñar la circuitería necesaria para adaptar los niveles de tensión entregados por el sensor de temperatura a los niveles requeridos por ADC, requerido para digitalizar la información para su posterior procesamiento por parte del microcontrolador. Por tanto hubo que diseñar capaz de corregir el offset y la pendiente de la función tensión-temperatura del sensor, a fin de adaptarlo al rango de tensión requerido por el ADC. Por otro lado, hubo que diseñar el circuito encargado de controlar la velocidad de rotación del motor. Este circuito estará basado en un transistor MOSFET en conmutación, controlado mediante una señal PWM como se mencionó anteriormente. De esta manera, al variar el ciclo de trabajo de la señal PWM, variará de manera proporcional la tensión que cae en el motor, y por tanto su velocidad de rotación. En cuanto al diseño del software, se programó el microcontrolador para que generase una señal PWM en uno de sus pines en función del valor entregado por el ADC, a cuya entrada está conectada la tensión obtenida del circuito creado para adaptar la tensión generada por el sensor. Así mismo, se utiliza el microcontrolador para representar el valor de temperatura obtenido en una pantalla LCD. Para este proyecto se eligió una placa de desarrollo mbed, que incluye el microcontrolador integrado, debido a que facilita la tarea del prototipado. Posteriormente se procedió a la integración de ambas partes, y testeado del sistema para comprobar su correcto funcionamiento. Puesto que el resultado depende de la temperatura medida, fue necesario simular variaciones en ésta, para así comprobar los resultados obtenidos a distintas temperaturas. Para este propósito se empleó una bomba de aire caliente. Una vez comprobado el funcionamiento, como último paso se diseñó la placa de circuito impreso. Como conclusión, se consiguió desarrollar un sistema con un nivel de exactitud y precisión aceptable, en base a las limitaciones del sistema. SUMMARY: It is obvious that day by day people’s daily life depends more on technology and science. Tasks tend to be done automatically, making them simpler and as a result, user life is more comfortable. Every single task that can be controlled has an electronic system behind. In this project, a control system based on a microcontroller was designed for a fan, allowing it to go faster when temperature rises or slowing down as the environment gets colder. For this purpose, a microcontroller was programmed to generate a signal, to control the rotation speed of the fan depending on the data acquired from a temperature sensor. After testing the whole design developed in the laboratory, the next step taken was to build a prototype, which allows future improvements in the system that are discussed in the corresponding section of the thesis.

New data on the Pleistocene of Trani (Adriatic Coast, Southern Italy)

Along the Apulian Adriatic coast, in a cliff south of Trani, a succession of three units (superimposed on one another) of marine and/or paralic environments has been recognised. The lowest unit I is characterised by calcareous/siliciclastic sands (css), micritic limestones (ml), stromatolitic and characean boundstones (scb), characean calcarenites (cc). The sedimentary environment merges from shallow marine, with low energy and temporary episodes of subaerial exposure, to lagoonal with a few exchanges with the sea. The lagoonal stromatolites (scb subunit) grew during a long period of relative stability of a high sea level in tropical climate. The unit I is truncated at the top by an erosion surface on which the unit II overlies; this consists of a basal pebble lag (bpl), silicicla - stic sands (ss), calcareous sands (cs), characean boundstones (cb), brown paleosol (bp). The sedimentary environment varies from beach to lagoon with salinity variations. Although there are indications of seismic events within the subunits cs, unit II deposition took place in a context of relative stability. The unit II is referable to a sea level highstand. Unit III, trangressive on the preceding, consists of white calcareous sands (wcs), calcareous sands and calcarenites (csc), phytoclastic calcirudite and phytohermal travertine (pcpt), mixed deposits (csl, m, k, c), sands (s) and red/brown paleosols (rbp). The sedimentation of this unit was affected by synsedimentary tectonic, attested by seismites found at several heights. Also the unit III is referable to a sea level highstand. The scientific literature has so far generally attributed to the Tyrrhenian (auct.) the deposits of Trani cliff. As part of this work some datings were performed on 10 samples, using the amino acid racemization method (AAR) applied to ostracod carapaces. Four of these samples have been rejected because they have shown in laboratory recent contamination. The numerical ages indicate that the deposits of the Trani cliff are older than MIS 5. The upper part of the unit I has been dated to 355±85 ka BP, thus allowing to assign the lowest stromatolitic subunit (scb) at the MIS 11 peak and the top of the unit I at the MIS 11-MIS 10 interval. The base of the unit II has been dated to 333±118 ka BP, thus attributing the erosion surface that bounds the units I and II to the MIS 10 lowstand and the lower part of the unit II to MIS 9.3. The upper part of the unit II has been dated to 234±35 ka BP, while three other numerical ages come from unit III: 303±35, 267±51, 247±61 ka BP. At present, the numerical ages cannot distinguish the sedimentation ages of units II and III, which are both related to the MIS 9.3- MIS 7.1 time range. However, the position of the units, superimposed one another, and their respective age, allows us to recognise a subsidence phase between MIS 11 and MIS 7, followed by an uplift phase between the MIS 7 and the present day, which led the deposits in their current position. This tectonic pattern is not in full agreement with what is described in the literature for the Apulian foreland.