Reconstrucción paleoambiental de turberas del Norte de la Península Ibérica mediante análisis de macrofósiles vegetales y grado de humificación de la turba

Las turberas son ecosistemas con una distribución muy restringida en la Península Ibérica. Entre ellas las turberas ombrotróficas de cobertor constituyen un hábitat aún más escaso y en peligro grave de desaparición, a pesar de estar bajo la protección de diferentes normativas vigentes, tanto nacionales como internacionales. Además de su importancia ecológica, uno de sus mayores valores radica en su funcionamiento como archivos paleoambientales del pasado, principalmente del período Holoceno. La tesis está organizada en nueve capítulos; los tres primeros de carácter general, en el primero de los cuales se presenta una recopilación de información bibliográfica sobre turberas, haciendo hincapié en turberas de cobertor, sobre macrofósiles vegetales y sobre propiedades de la turba, particularmente el grado de humificación de la misma. El segundo capítulo contempla los objetivos de la tesis y el tercero la metodología utilizada. En el cuarto se presenta un estudio detallado de los distintos macrofósiles vegetales estudiados en tres turberas de cobertor y una elevada del norte de la Península Ibérica. De todos los taxones de macrofósiles identificados se realiza una descripción y se establecen las bases para su identificación, mediante claves dicotómicas con ilustraciones detalladas de los caracteres de mayor valor taxonómico. En los capítulos quinto y sexto se realizan las reconstrucciones paleoambientales durante el Holoceno, en la turbera vasca de Zalama en primer lugar y posteriormente en el caso de la turbera gallega de Borralleiras de Cal Grande; realizadas a partir de los macrofósiles vegetales extraídos de la turba y de los resultados de los análisis de la turba, especialmente los del grado de humificación, el contenido en elementos litogénicos, carbones y la tasa de crecimiento vertical. La comparación de diferentes registros bióticos y abióticos ha permitido reconstruir la dinámica de las condiciones hidrológicas, es decir, de la humedad superficial de la turbera e inferir, a partir de las mismas, características climáticas pasadas, además de detectar posibles cambios en la turbera de origen natural y/o antrópicos. El capítulo séptimo se dedica a la discusión general de los resultados obtenidos, el octavo a las conclusiones obtenidas a partir del trabajo realizado y por último, el noveno a las referencias bibliográficas citadas en esta memoria. A modo de síntesis global, con este trabajo de tesis se pretende por un lado, contribuir al conocimiento y estudio de los macrofósiles vegetales en turberas de cobertor de la Península Ibérica, desarrollando y profundizando en la estandarización de protocolos para estudios paleobotánicos y preparar colecciones de referencia para investigaciones futuras; por otro lado ofrecer un sólido análisis paleoambiental en dos turberas de cobertor del Norte de la Península Ibérica, para conocer los cambios en la cubierta vegetal a lo largo del tiempo, la propia evolución de la turbera, identificación de los factores ambientales (de origen natural y antrópico), registrados en la turba y su aplicación en la reconstrucción paleoambiental durante el Holoceno

Dressed tunneling approximation for electronic transport through molecular transistors

A theoretical approach for the non-equilibrium transport properties of nanoscale systems coupled to metallic electrodes with strong electron-phonon interactions is presented. It consists in a resummation of the dominant Feynman diagrams from the perturbative expansion in the coupling to the leads. We show that this scheme eliminates the main pathologies found in previous simple analytical approaches for the polaronic regime. The results for the spectral and transport properties are compared with those from several other approaches for a wide range of parameters. The method can be formulated in a simple way to obtain the full counting statistics. Results for the shot and thermal noise are presented.Comment: 11 pages, 11 figures. Accepted for publication in Physical Review

Distribution of testate amoebae in bryophyte communities in São Miguel Island (Azores Archipelago)

Background: Testate amoebae are a polyphyletic group of protists living preferentially in soils, freshwaters and wetlands. These Protozoa have a worldwide distribution, but their presence and diversity in the Azores (a remote oceanic archipelago) is poorly known, with only twelve taxa recorded so far. The published information reflects occasional collections from sporadic field visits from naturalists to São Miguel Island, mainly in the nineteenth century. To overcome this limitation, a standardised survey was carried out on the Island, sampling different types of habitats from several localities to provide the distribution and information on species ecology of testate amoebae. New information: In this study, 43 species of testate amoebae were recorded (within a total of 499 occurrences), belonging to two orders of Protista (26 Arcellinida and 17 Euglyphida). The most frequently occurring testate amoebae were Euglypha strigosa, Trinema lineare, Euglypha rotunda, Assulina muscorum and Cyclopyxis eurystoma. The most diverse genus was Euglypha (six species). A total of 38 species are new records for the Azores Archipelago. These data help to improve knowledge of the geographical distribution of testate amoebae in the northern hemisphere and their diversity in the Azores ArchipelagoThis work was funded by FCT – Foundation for Science and Technology, the European Union, QREN, FEDER, COMPETE programmes (PMR - DL57/2016/ICETA/EEC2018/25; MSS - ICETA/EEC2018/25; DiscoverAzores Project - PTDC/CTA-AMB/28511/2017; UID/BIA/50027/2020 and POCI-01-0145-FEDER-006821), AZORESBIOPORTAL – PORBIOTA (ACORES-01-0145-FEDER-000072) and Consolidation and Structuring Project 2018 GRC-ED431C 2018/32 of Xunta de Galicia governmentS

The introduction of real numbers in secondary education. An institutional analysis of textbooks

In this paper we analyse the introduction of irrational and real numbers in secondary textbooks, and specifically the propositions on how these should be taught, in a sample of Brazilian textbooks used in state schools and approved by the Ministry of Education. The analyses discussed in this paper follow an institutional perspective (using Chevallard's Anthropological Theory of Didactics). Our results indicate that the notion of irrational number is generally introduced on the basis of the decimal representation of numbers, and that the mathematical need for the construction of the field of real numbers remains unclear in the textbooks. It seems that textbooks used in secondary teaching institutions develop mathematical organisations which focus on the practical block

Contribution of GIS and Geochemical Proxies to Improving Habitat Identification and Delimitation for the Natura 2000 Network: The Case of Coastal Lagoons in Galicia (NW Iberian Peninsula)

The Natura 2000 network is an ambitious European project aimed at nature conservation. Nevertheless, the identification and delimitation of habitats is a complex task and simultaneously essential for correct ecosystem management. In this study we compared the current habitat delimitation and designation and the results produced by Geographic Information Systems (GIS) and geochemical proxies for the categorization of four coastal lakes in Galicia (NW Iberian Peninsula). The findings reveal important errors in the delimitation/designation. The first error is the designation of all four lakes as Coastal lagoons (habitat 1150), when geochemical data indicate that two of these lakes were always freshwater lakes and should consequently be classified as Natural eutrophic lakes (habitat 3150). Another error is of conceptual origin, because the lakes comprise a unique functional system composing of different environmental units (e.g., open water or aquatic vegetation). Subdivision into different habitats is therefore meaningless for units of negligible surface area. In addition, the designation of some habitats is very dubious according to the available data. Finally, notable changes in relation to the temporal changes of wetlands were observed. Thus, the area occupied by aquatic macrophytes increased greatly at the expense of open waters, and the increase was also reflected in the alluvial forest. This last finding indicates the importance of updating the state of Natura 2000 network in Galicia to improve habitat managementThis work is part of a research project entitled “Monitorización de los procesos biogeoquímicos en las lagunas litorales en relación con su calidad ambiental y respuesta al cambio climático” (Xunta de Galicia, PGIDIT08MDS036000PR), the program for consolidation of competitive research groups (Axudas á consolidación e estruturación de unidades de investigación competitivas do SUG del Plan Galego IDT, Ambiosol Group ref. 2018-PG036), and Cross-Research in Environmental Technologies, CRETUS (Xunta de Galicia GRUP2015/02, ref. 2018-PG100). A.G.-P. is supported by an FPU predoctoral contract by the Spanish government (Ministerio de Educación, Cultura y Deporte). Grant Number: FPU16/03050S

Anti-inflammatory and anti-arthritic activities of glycosylated flavonoids from syzygium jambos in edematogenic agent-induced paw edema in mice

Two glycosylated flavonoids, the quercetin-3-O-β-D-xylofuranosyl-(1 → 2)-α-l-rhamnopyranoside and myricetin-3-O-β-d-xylofuranosyl-(1 → 2)-α-l-rhamnopyranoside, were isolated from the CH2Cl2/MeOH fraction of Syzygium jambos (L.) Alston, Myrtaceae. The structures of these compounds were elucidated by spectroscopic means. The cytotoxicity of the compounds was evaluated against the RAW 264.7 cell lines by the lactate dehydrogenase assay. All analyzed compounds were less cytotoxic than the positive control (actinomycin D, CC50 = 0.008 μM). The anti-inflammatory and anti-arthritic activities were evaluated by measuring inflammatory parameters in murine models. The two glycosylated flavonoids inhibited the production of tumor necrosis factor-α in RAW 264.7 cell line with IC50 of 1.68 and 1.11 μM, respectively. In addition, all flavonoids decreased the levels of tumor necrosis factor-α, C-reactive protein, and fibrinogen at a dose of 5 mg/kg in murine modelsThis work was supported by the National Herbarium of Bolivia and the Fundación de la Universidad Autónoma de Madrid (FUAM

Rings, Hexagons, Petals, and Dipolar Moment Sink-Sources: The Fanciful Behavior of Water around Cyclodextrin Complexes

The basket-like geometry of cyclodextrins (CDs), with a cavity able to host hydrophobic groups, makes these molecules well suited for a large number of fundamental and industrial applications. Most of the established CD-based applications rely on trial and error studies, often ignoring key information at the atomic level that could be employed to design new products and to optimize their use. Computational simulations are well suited to fill this gap, especially in the case of CD systems due to their low number of degrees of freedom compared with typical macromolecular systems. Thus, the design and validation of solid and efficient methods to simulate and analyze CD-based systems is key to contribute to this field. The behavior of supramolecular complexes critically depends on the media where they are embedded, so the detailed characterization of the solvent is required to fully understand these systems. In the present work, we use the inclusion complex formed by two α-CDs and one sodium dodecyl sulfate molecule to test eight different parameterizations of the GROMOS and AMBER force fields, including several methods aimed to increase the conformational sampling in computational molecular dynamics simulation trajectories. The system proved to be extremely sensitive to the employed force field, as well as to the presence of a water/air interface. In agreement with previous experiments and in contrast to the results obtained with AMBER, the analysis of the simulations using GROMOS showed a quick adsorption of the complex to the interface as well as an extremely exotic behavior of the water molecules surrounding the structure both in the bulk aqueous solution and at the water surface. The chirality of the CD molecule seems to play an important role in this behavior. All together, these results are expected to be useful to better understand the behavior of CD-based supramolecular complexes such as adsorption or aggregation driving forces, as well as to introduce new methods able to speed up general MD simulationsThis work was supported by the Spanish Agencia Estatal de Investigación (AEI) and the ERDF (RTI2018-098795-A-I00), and by the Xunta de Galicia and the ERDF (ED431C 2017/25 and Centro singular de investigación de Galicia accreditation 2016-2019, ED431G/09). P.F.G. is funded by a predoctoral research grant (BES-2016-076761) from the Spanish Ministry of Economy and Competitiveness and the European Social Fund. M.C. is funded by a predoctoral fellowship from Xunta de Galicia. R.G.-F. is a “Ramón y Cajal” fellowship (RYC-2016-20335) from the Ministerio de Ciencia, Innovación y UniversidadesS