Estudio de los mecanismo de acción de compuestos que modifican la fermentación ruminal en pequeños rumiantes

Se han llevado a cabo cuatro experimentos in vitro y cuatro in vivo para estudiar el efecto de aditivos, derivados de plantas o sintéticos, sobre la fermentación ruminal, la producción de metano y distintos grupos microbianos del rumen. El estudio de aditivos in vivo, tras conocer sus efectos in vitro, está sujeto a una serie de limitaciones. Igualmente el uso de aditivos en condiciones prácticas tiene una serie de limitaciones. Entre esas limitaciones destacan la variación en el efecto de los aditivos dependiendo del tipo de compuesto activo y su concentración así como de la dieta que recibe el animal; las diferencias entre los resultados obtenidos in vitro e in vivo; la falta de estudios acerca de la persistencia temporal de los efectos de los aditivos y; el desconocimiento de los mecanismos de acción de la mayoría de los compuestos antimetanogénicos estudiados recientemente. En la presente tesis se pretende responder a los interrogantes que existen acerca del uso de aditivos en alimentación de rumiantes, tratando de conocer los posibles mecanismos de acción de los compuestos que presentan un efecto antimetanogénico más claro sin comprometer la fermentación ruminal. La Publicación 1 recoge los resultados obtenidos en dos experimentos in vitro en los que se estudiaron los efectos de una serie de aceites esenciales y compuestos organosulfurados sobre la fermentación ruminal, la producción de metano y las poblaciones microbianas. Esta publicación también recoge los resultados de un experimento in vivo, de corta duración (9 días) realizado en caprino, en el que se estudió el efecto del compuesto que se mostró más prometedor en los experimentos in vitro, en cuanto a su potencial para reducir la producción de metano. El primer...Four in vitro and four in vivo experiments have been conducted to study the effect of additives, synthetic or plants extract compounds, on rumen fermentation, methane production and microbial ecosystem. The development of an additive to its application in practical conditions normally is supported by in vitro and in vivo studies. Such studies face challenges that constraint the interpretation of results: the variation in the effects due to the type of active compound and its concentration; the diet fed to animals; the differences between the results obtained in vitro and in vivo; the lack of studies about the temporal persistence of the effects and; the lack of knowledge of the mechanisms of action of most of the compounds recently investigated. In the present thesis we aim to provide more insight into these issues by trying to understand the possible mechanisms of action of the antimethanogenic compounds without compromising rumen fermentation. Publication 1 shows the results obtained from two in vitro experiments conducted to investigate the effects of different essential oils and organosulphur compounds on rumen fermentation, methane production and microbial concentration. This publication also shows the results of a short-term in vivo trial (9 days) conducted with goats, which studied the effect of the most promising antimethanogenic compound selected from in vitro experiments. The first experiment consisted of 24 hours in vitro batch cultures incubations using rumen fluid from goats as inoculum. The compounds tested were carvacrol (CAR), cinnamaldehyde (CIN), eugenol (EUG), propyl propane thiosulfinate (PTS), propyl propane thiosulfonate (PTSO), diallyl disulfide (DDS), a mixture..

Presentación: Teoría arqueológica en español

El origen de la publicación de este volumen monográfico sobre teoría arqueológica surgió, como ocurre en muchas otras circunstancias de la vida, de una casualidad. Cierto día llegó a la revista un artículo bastante “raro” que el consejo de redacción consideró que, ni por el tema ni por el contexto, encajaba con la línea actual de Complutum. Es decir, el trabajo no se parecía en nada a lo que veníamos publicando en los últimos años. Por otro lado, determinados hechos recientes aconsejaban a los más atrevidos dentro de la Redacción tener un cuidado especial con lo que finalmente veía la luz en sus páginas. Ahora mismo ya no recordamos a quién se le ocurrió que una forma de aprovechar el trabajo, que por supuesto a los tres nos parecía interesante, podría ser publicarlo junto con otros de su misma o parecida cuerda.Peer Reviewe

La Concha de la Plateria en la catedral de Santiago de Compostela: la estereotomía de las bóvedas cónicas

Título del trabajo presentado: La Concha de la Platería en la Catedral de Santiago de Compostela: la estereotomía de las bóvedas cónicas Entidad organizadora: Sociedad Española de Historia de la Construcción Congreso : Tercer Congreso Nacional de Historia de la Construcció

Population dynamics of a fragmented subtidal Zostera marina population affected by shell fishing

This investigation illustrates the spatial and temporal dynamics of a Zostera marina seagrass meadow affected by clam harvesting. Photointerpretation of satellite imagery corresponding to years 2007, 2013, 2017 and 2018, combined with field monitoring in 2019 allowed assessing the spatial coverage, population dynamics and genetic characterization of the Z. marina population in areas impacted and non-impacted by the shellfishing activity. The impacted meadow displayed a highly fragmented and discontinuous seagrass matrix anthropogenically induced by the periodical disturbance associated with bottom raking. A continuous colonization process characterized the seagrass landscape, where the area occupied by the meadow varied by a two-fold factor, with changes even exceeding 86% in some years. Only 740 m2 (ca. 15%) of the seagrass matrix remained vegetated in the four years monitored in this investigation. The number of patches showed a large interannual variability, exceeding 100% in the four years studied, ranging from 58 to 199, while the border effect perimeter/area indicator showed a two-fold variation ranging between 1 and 2. Clearly differentiated patterns were observed in shoot density, biomass, and flowering density between shellfishing-induced patches of different sizes and the long-term non-impacted areas. A significant pattern of genetic differentiation among impacted and control populations were also found. Our results showed that population dynamics varied as a function of Z. marina patch-sizes, thus reinforcing the need for a combined approach involving seascape structure and patch dynamics with population dynamics and genetic structure to assess the impact of disturbances on seagrass ecosystems

Utilización de la realidad aumentada en el trabajo de campo geográfico: posibilidades y dificultades para su uso docente

La comunicación pretende evaluar las potencialidades de la realidad aumentada para el trabajo de campo de los alumnos en procesos de aprendizaje autónomo. En primer lugar, se hace una breve introducción acerca del concepto y la tecnología actual de la realidad aumentada, para, a continuación, presentar un estudio de caso referido al uso de esta tecnología dentro de un trabajo práctico realizado por alumnos del Grado de Geografía y Ordenación del Territorio. Finalmente, el trabajo reflexiona acerca de las posibilidades y limitaciones de la realidad aumentada en la geografía y plantea líneas de investigación

New Perspectives Related to the Bioluminescent System in Dinoflagellates: Pyrocystis lunula, a Case Study

Pyrocystis lunula is considered a model organism due to its bioluminescence capacity linked to circadian rhythms. The mechanisms underlying the bioluminescent phenomenon have been well characterized in dinoflagellates; however, there are still some aspects that remain an enigma. Such is the case of the presence and diversity of the luciferin-binding protein (LBP), as well as the synthesis process of luciferin. Here we carry out a review of the literature in relation to the molecular players responsible for bioluminescence in dinoflagellates, with particular interest in P. lunula. We also carried out a phylogenetic analysis of the conservation of protein sequence, structure and evolutionary pattern of these key players. The basic structure of the luciferase (LCF) is quite conserved among the sequences reported to date for dinoflagellate species, but not in the case of the LBP, which has proven to be more variable in terms of sequence and structure. In the case of luciferin, its synthesis has been shown to be complex process with more than one metabolic pathway involved. The glutathione S-transferase (GST) and the P630 or blue compound, seem to be involved in this process. In the same way, various hypotheses regarding the role of bioluminescence in dinoflagellates are exposed

Evaluation of negentropy-based cluster validation techniques in problems with increasing dimensionality

The aim of a crisp cluster validity index is to quantify the quality of a given data partition. It allows to select the best partition out of a set of potential ones, and to determine the number of clusters. Recently, negentropy-based cluster validation has been introduced. This new approach seems to perform better than other state of the art techniques, and its computation is quite simple. However, like many other cluster validation approaches, it presents problems when some partition regions have a small number of points. Different heuristics have been proposed to cope with this problem. In this article we systematically analyze the performance of different negentropy-based validation approaches, including a new heuristic, in clustering problems of increasing dimensionality, and compare them to reference criteria such as AIC and BIC. Our results on synthetic data suggest that the newly proposed negentropy-based validation strategy can outperform AIC and BIC when the ratio of the number of points to the dimension is not high, which is a very common situation in most real applications.The authors thank the financial support from DGUI-CAM/UAM (Project CCG10-UAM/TIC-5864

A comparison of techniques for robust gender recognition

Reprinted, with permission, from [Rojas Bello, R.N., Lago Fernández, L.F., Martínez Muñoz, G., y Sánchez Montañés, M.A., A comparision of techniques for robust gender recognition, IEEE International Conference on Image Processing, ICIP 2011]. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the Universidad Autónoma de Madrid's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.Proceedings of 2011 18th IEEE International Conference on Image Processing (ICIP), 11-14 Sept. 2011, BrusselsAutomatic gender classification of face images is an area of growing interest with multiple applications. Appropriate classifiers should be robust against variations such as illumination, scale and orientation that occur in real world applications. This can be achieved by normalizing the images in order to reduce those variations (alignment, re-scaling, histogram-equalization, etc.), or by extracting features from the original images which are invariant respect to those variations. In this work we perform a robust comparison of eight different classifiers across 100 random partitions of a set of frontal face images. Four of them are state-of-the-art methods in automatic gender classification that use image normalization (SVMs, Neural Networks, ADABOOST and PCA+LDA). The other four strategies use invariant features extracted by SIFT (BOW, Evidence Random Trees, NBNN and Voted Nearest-Neighbor). The best strategies are SVM using normalized images and NBNN, the latter having the advantage that no strong image pre-processing is needed.This work has been supported by CDTI (project INTEGRA) and DGUICAM/UAM (project CCG10-UAM/TIC-5864