Estudio de las masas mixtas de Pinus Pinea L. en la Meseta Norte : crecimiento y dinámica en un contexto de cambio global

En un contexto de cambio global las masas mixtas mediterráneas han cobrado gran relevancia dado que la mezcla de especies arbóreas puede hacerlas más resistentes, estables y/o productivas que las masas puras. Pese a esto existen muy pocos modelos de gestión específicos para este tipo de masas. Entre las hipótesis que pueden explicar una mayor estabilidad, crecimiento o productividad en masas mixtas frente a puras están la hipótesis de la complementariedad de nichos y la hipótesis del gradiente de estrés. En esta Tesis Doctoral se han analizado las interacciones entre Pinus pinea, Quercus ilex subsp. ballota y Juniperus thurifera, especies que cohabitan en las masas mixtas de Pinus Pinea L. de los páramos calizos de la Meseta Norte de la Península Ibérica. Estas interacciones modulan la respuesta al clima en términos de crecimiento y supervivencia. Se ha hecho una aproximación mediante modelos de crecimiento lineales y no lineales y modelos de supervivencia que han permitido integrar estas interacciones con los principales factores climáticos que afectan a estos dos procesos a distintas escalas temporales. Se ha estimado el crecimiento radial mediante canutillos de crecimiento, se ha medido el crecimiento en circunferencia mediante dendrómetros de banda en arbolado adulto de las 3 especies y se ha evaluado la supervivencia de estas tres especies en una plantación a lo largo de un gradiente de disponibilidad de recursos simulando un escenario de reducción de precipitación. De estos modelos se infiere que a igualdad de densidad de masa el efecto de la competencia sobre el crecimiento de P. pinea es menor en masas mixtas que en puras, efecto que se ve acentuado en años secos. La competencia intraespecífica en P. pinea y en J. thurifera inhibe más el crecimiento que la interespecífica en masas mixtas. En rodales de masas puras de P. pinea más vulnerables se plantea promover la mezcla abriendo espacios para el regenerado avanzado de especies complementarias que ya esté instalado de forma natural y que presente una mayor plasticidad en respuesta a las condiciones climáticas, como Q. ilex subsp. ballota, Quercus faginea o J. thurifera. En el caso de que estas especies no estén instaladas se plantea recurrir a la siembra directa. Las masas mixtas objeto de estudio se transformarán a largo plazo en un monte bajo de Q. ilex, con pies aislados de P. pinea y una mayor abundancia de J. thurifera. La regeneración de Q. ilex quedará ligada a sus rebrotes de cepa, viéndose la supervivencia de sus plántulas procedentes de bellota seriamente comprometida. J. thurifera continuará colonizando estas masas mixtas viéndose menos afectada por factores climáticos extremos en todos los niveles de luz que se han evaluado

Población y poblamiento en la Ribera del Duero: Una comarca dinámica en el conjunto de Castilla y León

El presente estudio se dedica a conocer la realidad de la población y el poblamiento en la Ribera del Duero, una comarca cuya dinámica destaca dentro del marco de atonía que caracteriza a la mayor parte del territorio de Castilla y León, sirviéndose para ello de algunos de los principales métodos demográficos aplicables al estudio de poblaciones reducidas pero siempre desde una óptica más amplia, integrando los diferentes elementos que configuran el territorio.Departamento de GeografíaGrado en Geografía y Ordenación del Territori

A Cholinergic Synaptically Triggered Event Participates in the Generation of Persistent Activity Necessary for Eye Fixation

An exciting topic regarding integrative properties of the nervous system is how transient motor commands or brief sensory stimuli are able to evoke persistent neuronal changes, mainly as a sustained, tonic action potential firing. A persisting firing seems to be necessary for postural maintenance after a previous movement. We have studied in vitro and in vivo the generation of the persistent neuronal activity responsible for eye fixation after spontaneous eye movements. Rat sagittal brainstem slices were used for the intracellular recording of prepositus hypoglossi (PH) neurons and their synaptic activation from nearby paramedian pontine reticular formation (PPRF) neurons. Single electrical pulses applied to the PPRF showed a monosynaptic glutamatergic projection on PH neurons, acting on AMPA-kainate receptors. Train stimulation of the PPRF area evoked a sustained depolarization of PH neurons exceeding (by hundreds of milliseconds) stimulus duration. Both duration and amplitude of this sustained depolarization were linearly related to train frequency. The train-evoked sustained depolarization was the result of interaction between glutamatergic excitatory burst neurons and cholinergic mesopontine reticular fibers projecting onto PH neurons, because it was prevented by slice superfusion with cholinergic antagonists and mimicked by cholinergic agonists. As expected, microinjections of cholinergic antagonists in the PH nucleus of alert behaving cats evoked a gaze-holding deficit consisting of a re-centering drift of the eye after each saccade. These findings suggest that a slow, cholinergic, synaptically triggered event participates in the generation of persistent activity characteristic of PH neurons carrying eye position signals.Unión Europea Grants BI04-CT98-0546España, Ministerio de Ciencia PB98-0011, BFI2000-00936, BFI2000-1190, y BFI2002-0137

Linking climate, annual growth and competition in a Mediterranean forest: Pinus pinea in the Spanish Northern Plateau

Climate, competition and site conditions are the main drivers controlling annual secondary growth in tree species. These factors do no act independently on tree growth, but by means of interactions, resulting in mediated interactive effects. For example, the stress gradient hypothesis postulates alleviated interspecific competition under limiting spatial (site) or temporal (climate) resources. According to this, models predicting annual growth and yield for a given forest should consider these issues in their formulation. In this study, we present a modelling approach based on using data from permanent plots and dendrochronological analysis in order to describe annual tree growth in pure, even-aged stands of Pinus pinea L. in the Spanish Northern Plateau, a highly limiting environment due to its Mediterranean continental climate. Our method is based on identifying the different sources of variability by means of a multilevel linear mixed model, and thereby identifying the potential covariates explaining observed variability at the different spatiotemporal scales. Our results indicate that site related factors such as site index or dominant height exert a greater influence on annual secondary growth than size-symmetric competition. In addition, we found that the controlling influence of water stress is greater than that of temperatures on tree growth. Furthermore, our results allow evidence to be identified for the stress gradient hypothesis in temporal intraspecific interactions, since trees exposed to a higher degree of competition tend to grow more than expected in dry periods. In contrast, the effect of competition on growth, on average, tends to be aggravated at very poor sites. Finally, our modelling approach allows us to conduct growth and yield simulations under different climate scenarios at different spatial scales, providing results which point to significant decreases in timber and cone production under the more severe scenarios, which can be alleviated through more intensive silviculture.This work has been carried out under the financial and functional framework of the National Projects RTA-2013-00011.C2.1, PCIN-2014-138 INFORMED, AGL-2017-83828-C2.1 and the PROPINEA agreement between INIA, ITACYL and Deputation of Valladolid. Authors wish to thank Forest Service of Valladolid for their permanent support with the inventory and maintenance of the experimental trials

Quartzite procurement in conglomerates and deposits:Geoarchaeological characterization of potential catchmentareas in the central part of the Cantabrian Region, Spain

Raw material characterization in Paleolithic archaeology has widened our knowledge of Middle Paleolithic societies. Procurement of raw material, specifically flint, has allowed the tracing of the mobility of both stones and people, as well as selective processes to obtain specific types or even extraction activities. The analysis of quartzite has also developed in recent years, providing an opportunity to better understand prehistoric societies. This study characterizes the procurement strategies implemented by Middle Paleolithic people in the mountainous region of the Picos de Europa. To this end, we present a comprehensive characterization of potential catchment areas: massive outcrops, conglomerates, and river deposits. The exploitation of quartzite at the sites of El Habario and El Arteu allows us to understand the territorial management of this mountainous area through the combination of selective processes and mobility mechanisms in lower and middle altitudes. These perspectives enable us to view the mountainous region not as a barrier but as an environmental mosaic managed by Middle Paleolithic groups. This study shows strategies that bring together direct and embedded procurement based on both intensive and extensive searches. These discourses are more closely related to the daily life of people than those only considering the mobility of people and objects.Education Department of the Government of the Basque Country, Grant/Award Number: POS_2018_1_002; The Spanish Ministry of Science Project, Grant/Award Number: HAR2017-82493-C3-1-P; The Consolidated Research Group in Prehistory of the Basque Country University, Grant/Award Number: IT-1223-1

Numerical analysis of emissions from marine engines using alternative fuels

The current restrictions on emissions from marine engines, particularly sulphur oxides (SOx ), nitrogen oxides (NOx ) and carbon dioxide (CO2 ), are compelling the shipping industry to a change of tendency. In the recent years, many primary and secondary reduction techniques have been proposed and employed in marine engines. Nevertheless, the increasingly restrictive legislation makes it very difficult to continue developing efficient eduction procedures at competitive prices. According to this, the paper presents the possibility to employ alternative fuels. A numerical model was developed to analyze the combustion process and emissions using oil fuel, natural gas and hydrogen. A commercial marine engine was studied, the Wärtsilä 6L 46. It was found, that hydrogen is the cleanest fuel regarding CO2 , hydrocarbons (HC) and carbon monoxide (CO). Nevertheless, it is very expensive for marine applications. Natural gas is cheaper and cleaner than fuel oil regarding CO2 and CO emissions. Still, natural gas emits more NOx and HC than oil fuel. SOx depends basically on the sulphur content of each particular fuel.S

Photonic heterodyne pixel for imaging arrays at microwave and MM-Wave frequencies

The use of photonic heterodyne receivers based on semiconductor optical amplifiers to be used in imaging arrays at several GHz frequencies is evaluated. With this objective, a 3×3 imaging array based on such photonic pixels has been fabricated and characterized. Each of the receiving optoelectronic pixels is composed of an antipodal linear tapered slot antenna (LTSA) that sends the received RF signal directly to the electrical port of a semiconductor opticalamplifier (SOA) acting as the optoelectronic mixer. Both the local oscillator (LO) and the intermediate frequency (IF) signals are directly distributed to/from the array pixels using fiber optics, that allows for remote LO generation and IF processing to recover the image. The results shown in this work demonstrate that the performances of the optoelectronic imaging array are similar to a reference all-electronic array, revealing the possibility of using this photonic architecture in future high-density, scalable, compact imaging arrays in microwave and millimeter wave ranges.Publicad

The Value of Music Therapy in the Expression of Emotions in Children with Cancer

Background. Children with cancer are subjected to aggressive tests and treatments that can affect their emotional states. Studies available in the academic literature analyse the effect of music therapy on the emotions of these patients are scarce. Objectives. The objective of this study was to explore and transform the emotional responses that may arise with the application of music therapy (MT) in children with oncological pathology. Methods. The methodology of this study was based on the participatory action research approach. Semistructured interviews were conducted with 27 children with cancer who participated in 65MT sessions. Interviews were also conducted with their families. Results. We conducted a thematic analysis using MAXQDA software. Three main categories emerged from this process as follows: (1) expression: children with cancer stated that MT made it easier for them to express their emotions, with indirect benefits to families; (2) participation: patients showed interest in the sessions; and (3) experiences: MT was valued and created a positive environment. The results of this research demonstrate the positive transformative power MT had on children with cancer in terms of their emotions. Conclusions. Positive results were achieved through MT that encouraged the expression of emotions by children with cancer and favoured and improved their moods. In addition, it also encouraged social interactions in the hospital and helped the children to better cope with their illness through self-awareness. Their families also benefited. Therefore, we encourage healthcare professionals to support the use of MT in paediatric oncology settings

A fast feedback controlled magnetic drive for the ASDEX Upgrade fast-ion loss detectors

A magnetically driven fast-ion loss detector system for the ASDEX Upgrade tokamak has been designed and will be presented here. The device is feedback controlled to adapt the detector head position to the heat load and physics requirements. Dynamic simulations have been performed taking into account effects such as friction, coil self-induction, and eddy currents. A real time positioning control algorithm to maximize the detector operational window has been developed. This algorithm considers dynamical behavior and mechanical resistance as well as measured and predicted thermal loads. The mechanical design and real time predictive algorithm presented here may be used for other reciprocating systems.EURATOM 63305

Manuel Vázquez Montalbán. Guías didácticas y de lectura para ESO y Bachillerato

Podeu consultar la versió en català a: http://hdl.handle.net/2445/11088