Enseñanza agrícola

La enseñanza agrícola es esencial y hay tres tipos diferentes dependiendo de a quién va dirigida: a los jóvenes, a adultos y a mujeres. Para que los jóvenes puedan atender a los trabajos agrícolas más importantes e ir a la escuela se sugiere la creación de las escuelas de invierno (de Noviembre a Marzo) que de momento solamente existen en el extranjero. Pero a su vez también se necesita formar a técnicos especializados que luego enseñaran a los jóvenes y niños en la enseñanza agrícola primariaAgricultural teaching is essential and there are three different types of agricultural courses depending on who they have been conceived for: young people, adults and women. The establishment of winter schools (of November to March) is suggested so that young people may tend to the most important agricultural tasks and at the same time go to school. Such schools only exist abroad at present. But it is also necessary to train specialized technicians who can then train young people and children in primary agricultura

Lattice deformations and spin-orbit effects in two dimensional materials

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de lectura: 18-09-2014This thesis deals with the interplay between structural and electronic properties of two-dimensional materials such as graphene, and the novel and very interesting phenomena, both from the point of view of fundamental Physics and potential applications, which emerge when lattice distortions such as strains or superlattice modulations are combined with the dynamics of the electrons confined in two spatial dimensions. The main microscopic ingredient which is behind all these phenomena is the spin-orbit interaction. On the one hand, we analyze in detail how the spin-orbit interaction modifies the electronic structure of these materials, and on the other, how structural changes affect the spin-orbit interaction suffered by the electrons of the solid, then modifying its electronic response in a very peculiar manner due to the entanglement of the spin and orbital degrees of freedom. The contents of the thesis are divided in three blocks. The first part is devoted to study the effect of out-of-plane (flexural) vibration modes on the electronic properties of graphene. We examine in detail the influence of the electron-phonon coupling on the mobilities of suspended graphene samples, and we compare our findings with transport experiments, revealing that scattering by these phonon modes constitute the main intrinsic limitation to electron mobilities. Then, we study how flexural phonons contribute to enhance the spin-orbit coupling in graphene, which is in principle very weak due to the lightness of carbon. In the second part we analyze in detail different spin relaxation mechanisms mediated by the spin-orbit interaction. We focus on the standard Elliot-Yafet and D’yakonov- Perel’ mechanisms, and how such conventional theories are modified when spatially varying spin-orbit fields are considered due to the presence of impurities or curvature. In the last part we propose novel platforms for engineering topological states of matter based on the interplay between strain and superlattice perturbations in combination with the spin-orbit interaction. Our first proposal relies on the application of shear strain in monolayers of transition metal dichalcogenides in order to cretae spin-polarized pseudo-Landau levels. The resulting system resembles a time reversal invariant version of the quantum Hall effect. We also study a system consisting on graphene grown on iridium with some monolayers of lead intercalated between them. The experiments show that the local density of states develops a sequence of regularly spaced sharp resonances due to the presence of the lead. These resonances are attributed to the confinement due to spatially modulated spin-orbit fields created by lead, which mimic the effect of a magnetic field.Esta tesis trata de la interacción entre las propiedades estructurales y electrónicas de materiales bidimensionales como el grafeno, y los fenómenos que emergen cuando deformaciones de la red como las tensiones elásticas o las modulaciones producidas por super-redes se combinan con la dinámica de los electrones confinados en dos dimensiones espaciales, muy interesantes tanto desde el punto de vista de la Física fundamental como del de las aplicaciones. El ingrediente microscópico esencial que está detrás de esta fenomenología es la interacción espín-órbita. Por un lado, analizamos en detalle cómo la interacción espín-órbita modifica la estructura electrónica de estos materiales, y por otro, cómo los cambios estructurales afectan a la interacción espín-órbita experimentada por los electrones del sólido, modificando su respuesta electrónica de una manera muy peculiar debido al entrelazamiento de los grados de libertad orbitales y de espín. Los contenidos de esta tesis están divididos en tres bloques. El primero está dedicado al estudio del efecto de las vibraciones fuera del plano (flexurales) en las propiedas electrónicas del grafeno. Examinamos en detalle la influencia del acoplo electrónfonón en las movilidades de las muestras de grafeno suspendido, y comparamos nuestros hallazgos con experimentos de transporte que revelan que la dispersión debida a estos modos de fonones constituye la principal limitación intrínseca de las movilidades electrónicas. Estudiamos entonces cómo estos modos de fonones flexurales conribuyen al aumento del acoplo espín-órbita en grafeno, que es en principio muy débil debido al bajo número atómico del carbono. En la segunda parte analizamos en detalle diferentes mecanismos de relajación de espín mediados por la interacción espín-órbita. Nos centramos en los mecanismos convencionales de Elliot-Yafet y D’yakonov-Perel’, y cómo éstos se modifican cuando se incluye el efecto de campos espín-órbita que varían en el espacio debido a la presencia de impurezas o curvatura. En la última parte proponemos nuevas plataformas para el diseño de estados topológicos de la materia basados en la combinación de tensiones y perturbaciones debido a super-redes con la interacción espín-órbita. Nuestra primera propuesta se basa en la aplicación de tensiones de cizalladura en monocapas de dicalcogenuros de metales de transición con el objeto de crear pseudo-niveles de Landau polarizados en espín. El sistema resultante recuerda a una versión invariante bajo inversión temporal del efecto Hall cuántico. También estudiamos el sistema formado por grafeno crecido sobre iridio con algunas monocapas de plomo intercaladas entre ambos. Los experimentos muestran que la densidad local de estados desarrolla una secuencia de resonancias muy nítidas y regularmente espaciadas debidas a la presencia del plomo. Estas resonancias se atribuyen al confinamiento debido a la modulación espacial de campos espín-órbita creados por el plomo que imitan el efecto de un campo magnético

Lattice deformations and spin-orbit effects in two dimensional materials

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de la Materia Condensada. Fecha de lectura: 18-09-2014This thesis deals with the interplay between structural and electronic properties of two-dimensional materials such as graphene, and the novel and very interesting phenomena, both from the point of view of fundamental Physics and potential applications, which emerge when lattice distortions such as strains or superlattice modulations are combined with the dynamics of the electrons confined in two spatial dimensions. The main microscopic ingredient which is behind all these phenomena is the spin-orbit interaction. On the one hand, we analyze in detail how the spin-orbit interaction modifies the electronic structure of these materials, and on the other, how structural changes affect the spin-orbit interaction suffered by the electrons of the solid, then modifying its electronic response in a very peculiar manner due to the entanglement of the spin and orbital degrees of freedom. The contents of the thesis are divided in three blocks. The first part is devoted to study the effect of out-of-plane (flexural) vibration modes on the electronic properties of graphene. We examine in detail the influence of the electron-phonon coupling on the mobilities of suspended graphene samples, and we compare our findings with transport experiments, revealing that scattering by these phonon modes constitute the main intrinsic limitation to electron mobilities. Then, we study how flexural phonons contribute to enhance the spin-orbit coupling in graphene, which is in principle very weak due to the lightness of carbon. In the second part we analyze in detail different spin relaxation mechanisms mediated by the spin-orbit interaction. We focus on the standard Elliot-Yafet and D’yakonov- Perel’ mechanisms, and how such conventional theories are modified when spatially varying spin-orbit fields are considered due to the presence of impurities or curvature. In the last part we propose novel platforms for engineering topological states of matter based on the interplay between strain and superlattice perturbations in combination with the spin-orbit interaction. Our first proposal relies on the application of shear strain in monolayers of transition metal dichalcogenides in order to cretae spin-polarized pseudo-Landau levels. The resulting system resembles a time reversal invariant version of the quantum Hall effect. We also study a system consisting on graphene grown on iridium with some monolayers of lead intercalated between them. The experiments show that the local density of states develops a sequence of regularly spaced sharp resonances due to the presence of the lead. These resonances are attributed to the confinement due to spatially modulated spin-orbit fields created by lead, which mimic the effect of a magnetic field.Esta tesis trata de la interacción entre las propiedades estructurales y electrónicas de materiales bidimensionales como el grafeno, y los fenómenos que emergen cuando deformaciones de la red como las tensiones elásticas o las modulaciones producidas por super-redes se combinan con la dinámica de los electrones confinados en dos dimensiones espaciales, muy interesantes tanto desde el punto de vista de la Física fundamental como del de las aplicaciones. El ingrediente microscópico esencial que está detrás de esta fenomenología es la interacción espín-órbita. Por un lado, analizamos en detalle cómo la interacción espín-órbita modifica la estructura electrónica de estos materiales, y por otro, cómo los cambios estructurales afectan a la interacción espín-órbita experimentada por los electrones del sólido, modificando su respuesta electrónica de una manera muy peculiar debido al entrelazamiento de los grados de libertad orbitales y de espín. Los contenidos de esta tesis están divididos en tres bloques. El primero está dedicado al estudio del efecto de las vibraciones fuera del plano (flexurales) en las propiedas electrónicas del grafeno. Examinamos en detalle la influencia del acoplo electrónfonón en las movilidades de las muestras de grafeno suspendido, y comparamos nuestros hallazgos con experimentos de transporte que revelan que la dispersión debida a estos modos de fonones constituye la principal limitación intrínseca de las movilidades electrónicas. Estudiamos entonces cómo estos modos de fonones flexurales conribuyen al aumento del acoplo espín-órbita en grafeno, que es en principio muy débil debido al bajo número atómico del carbono. En la segunda parte analizamos en detalle diferentes mecanismos de relajación de espín mediados por la interacción espín-órbita. Nos centramos en los mecanismos convencionales de Elliot-Yafet y D’yakonov-Perel’, y cómo éstos se modifican cuando se incluye el efecto de campos espín-órbita que varían en el espacio debido a la presencia de impurezas o curvatura. En la última parte proponemos nuevas plataformas para el diseño de estados topológicos de la materia basados en la combinación de tensiones y perturbaciones debido a super-redes con la interacción espín-órbita. Nuestra primera propuesta se basa en la aplicación de tensiones de cizalladura en monocapas de dicalcogenuros de metales de transición con el objeto de crear pseudo-niveles de Landau polarizados en espín. El sistema resultante recuerda a una versión invariante bajo inversión temporal del efecto Hall cuántico. También estudiamos el sistema formado por grafeno crecido sobre iridio con algunas monocapas de plomo intercaladas entre ambos. Los experimentos muestran que la densidad local de estados desarrolla una secuencia de resonancias muy nítidas y regularmente espaciadas debidas a la presencia del plomo. Estas resonancias se atribuyen al confinamiento debido a la modulación espacial de campos espín-órbita creados por el plomo que imitan el efecto de un campo magnético

The immuneregulator role of neprilysin (NEP) in invertebrates

Neprilysin (NEP) represents an important enzyme in both vertebrates and invertebrates. In the present report we have focused our attention to invertebrates. In particular, a structure related to CD10/NEP as well as its activity in different tissues, such as immunocytes, nervous tissue and muscle of various species were detected. Moreover, the role played by the enzyme in the interactions between host and parasite has also been reported. The findings indicate that NEP immunoregulation is a well-balanced process that, with appropriate physiological and homeostatic responses to challenges, allows the survival and well-being of the species

Zaratustra en "La montaña mágica": confluencias transhumanistas

Este trabajo se centra en realizar una interpretación transhumanista de La montaña mágica (1924) del escritor alemán Thomas Mann ya que encontramos en esta novela numerosas características que pueden relacionarse con esta novedosa corriente filosófica. Además, aunque Mann no escribiese esta obra pensando en el transhumanismo; que se gestó muy posteriormente, sí que se vio fuertemente influenciado por la filosofía vitalista de Nietzsche; sobre quien se debate si podría ser denominado precursor de la posterior filosofía transhumanista. Por todo ello, el trabajo se dividirá en cuatro capítulos que atienden a algunas de las características que engloban el transhumanismo, puestas en relación con la novela de Mann: una nueva definición de ser humano, un cambio en la relación con la naturaleza, una nueva concepción del tiempo y, finalmente, la búsqueda de un nuevo sentido existencial en esta corriente tan compleja como fascinante a nivel filosófico

Amyloid and allorecognition in the colonial ascidian Botryllus schlosseri.

Allorecognition, i.e., the ability of intraspecific nonself recognition is widely distributed among colonial, sessile marine organisms in the form of colony specificity. In the cosmopolitan compound ascidian Botryllus schlosseri, colony specificity is controlled by a highly polymorphic Fu/HC locus: two colonies sharing at least one alleleat the Fu/HC locus can fuse into a chimeric colony; if no alleles are shared, a typical inflammatory reaction occurs, with the recruitment of a specific hemocyte type, the cytotoxic morula cells (MCs), inside the tips of the ampullae (the blind termini ofthe tunic vasculature) extending towards the alien colony, their extravasation in the tunic and their final degranulation. As a consequence of allorecognition, necrotic, melanic spots (points of rejection; PORs) form along the contact border, due to the release, by MCs, of their granular content, mainly represented by quinones, polyphenols and the enzyme phenoloxidase (PO), upon the perception of the allogeneic humoral factors diffusing from the alien colony through the partially fused tunics. It is remarkable that the deposition of melanin and the cell death is confined to the immediate outside of the ampullar tips, suggesting that the diffusion of PO and the products of its activity are, in some way, prevented in order to limit cytotoxicity to the immediate neighbourhood of the contact region. In this context, we looked for factors released by MCs that could limit the spreading of cytotoxicity and melanisation. We found that MCs share with vertebrate melanocytes similar packaging of melanin precursors, entrapped in a 3Dscaffold of amyloid fibrils. They contribute to form the electron dense content of MC granules that, after stimulation, flake off and is released in the surrounding medium. Released amyloid fibrils limit the diffusion of the produced melanin. The search for genes and factor controlling both melanogenesis and amyloidogenesis, revealed an evolutionary conserved machinery involved in the processes and an unexpected cross talk between the two Botryllus immunocyte types, i.e., phagocytes and MCs. Furthermore, this work confirms the physiological role of amyloid in tunicate immunity

Ras activation in Hirudo medicinalis angiogenic process

In some leeches like Hirudo medicinalis, any kind of stimulation (surgical wound or growth factor injection) provokes the botryoidal tissue response. This peculiar tissue, localized in the loose connective tissue between gut and body wall, is formed by granular botryoidal cells and flattened endothelial-like cells. Under stimulation, the botryoidal tissue changes its shape to form new capillaries. In mammals, the molecular regulation of the angiogenic phenotype requires coordinated input from a number of signalling molecules: among them the GTPase Ras is one of the major actor. In our current study, we determine whether Ras activation alone would be sufficient to drive vessels formation from leech botryoidal tissue. Our findings indicate that assembly and disassembly of actin filaments regulated by Ras protein is involved in morphological modification of botryoidal tissue cells during leech angiogenic process

Amyloidogenesis and Responses to Stress

Amyloidogenesis is a primitive, physiological response that seems to be an ancient process widely distributed in different cell types of evolutionary distant organisms. The amyloid fibril synthesis is part of a more general inflammatory response to stressful conditions all entailing overproduction of reactive oxygen species (ROS). Interestingly, this event has been integrated into additional physiological functions: (i) the formation of a scaffold promoting the activation and packaging of melanin; (ii) the formation of a scaffold to compartmentalize hormones in the cytoplasm; (iii) the ability to reversibly link different types of molecules to drive close to the nonself; (iv) the construction of a framework to close body lesions. Amyloid fibril formation is a cellular response harmonically integrated with the stress response but for a deregulation in assembling/dismantling, dangerous depots, as in a lot of pathologies, can occur

Ariketa fisikoa iktusaren sintoma motore eta psikologikoen arintzean: literaturaren errebisio kritikoa.

60 p. -- Bibliogr.: p. 26-28Iktusa, mundu mailan heriotza eta desgaitasun kausa nagusienetariko bat suposatzen duen gaixotasun kardiobaskular bat da. Istripu zerebrobaskular (IZB) terminoarekin ere ezaguna, bizipen estresagarria da paziente, senide zein zaintzailentzat. Izan ere, asaldura sentsorialak, motoreak, komunikazio asaldurak, asaldura kognitibo eta psikotikoak eta portaera asaldurak eragin ditzake. Aipatutako klinikaz gain, iktusaren intzidentzia, prebalentzia, kostu, heriotza eta desgaitasun-tasa altuek IZB osasun eta gizarte-arazo bilakatzen dute. Badaude zenbait gida eta errebisio sistematiko ere, ariketa fisikoaren onurak aztertzen dituztenak errehabilitazio prozesuan zehar iktusa pairatu duten pertsonen sintoma motore eta psikologikoen arintzean. Hori buruan izanik, eta erizainaren rola aztertuz, ikus daiteke erizaintzaren konpetentziaren barruan sartzen dela ariketa fisiko eta iktusaren arteko onura erlazio hori ezagutzea, pazienteen eguneroko bizitzako zainketetan aplikatu ahal izateko. Are gehiago, errebisio kritiko hau baliagarria izan daiteke erizainentzat iktusa pairatu duten pazienteen arreta integrala bermatzeko, hezkuntzaren bidez bizi-estilo osasuntsuak sustatuz, pertsonen osasun emaitzak eta bizi-kalitatea hobetuz eta iktus kasuen errekurrentziak ekidituz

Hirudo medicinalis as alternative model for in vivo and in vitro studies on nanomaterials toxicity.

Due to the steady increase of production and use of engineered nanomaterials (NMs), intentional or unintentional discharges into the environment may occur. Since it is critical to develop new methods to fully understand NMs bioaccumulation and cytotoxicity, a reliable model in which analyze NMs effects both in vivo and in vitro is more than ever necessary. Here we propose the leech, Hirudo medicinalis, as alternative animal model to study multi-walled carbon nanotubes (MWCNTs) effects by means of an extended study that includes in vivo and in vitro treatments. First, MWCNTs were dispersed in leeches\u2019 water to mimic a possible environmental exposure. In a second assay, a MWCNTs-supplemented biomatrix was injected in leeches\u2019 body wall. Thirdly, leeches macrophages were isolated and cultured to analyze their responses after MWCNTs in vitro treatment. Our results show that water dispersed MWCNTs evoke in the leech body wall a strong inflammatory response, involving mainly monocyte-macrophages cells. Ultrastructural analysis of MWCNTs-supplemented biomatrix revealed that in leech macrophages MWCNTs are internalized both in an active (phagocytosis) and a passive manner (membrane piercing). Finally, MWCNTs in vitro treatment cause the decrease of cell proliferation rate and the increase of ROS production and of the apoptotic rate. Our combined experimental approaches, not only attest the ability of MWCNTs in inducing a potent inflammatory response, but also confirm Hirudo medicinalis as a good alternative model that can be successfully used to study, both in vivo and in vitro, the possible harmful effects of any nanomaterial