El Grial y sus castillos dentro y fuera de España.

Análisis de las diversas leyendas existentes sobre el Grial y su castillo, el Montsalvatsch, fundadas en la poesía épica medieval, y la evolución del mito hasta nuestros días. De los diferentes orígenes etimológicos posibles, la versión más extendida apoya la forma del vaso sagrado, resultando así tradiciones como la del Sacro Catino de la Catedral de Génova que se remonta al siglo XII, la de la escudilla de esmeralda de Almería del siglo XIII referenciado por Rodrigo de Toledo en su Historia gótica, la versión del Grial de Valencia de Ricardo Wagner presente en sus obras Parsifal y Lohengrin, o una más reciente de Angel del Castillo que sitúa la sagrada forma en Cerebro, provincia de Lugo y lugar de paso de la peregrinación a Santiago de Compostela. En lo concerniente al Castillo del Grial, también existen diferentes fábulas, desde su localización en San Juan de la Peña, a su ubicación en Montserrat, por la semejanza de los vocablos Montsalvatsch y Montsalvat utilizados en el Perceval del francés Chretien de Troyes y en el Parzival del alemán Wolfram von Eschenbach, otro mito más reciente es el de Montségur-Montsalvatsch de Otto Rahn en sus libros La cruzada contra el Grial y Los criados de corte de Lucifer, pero existen otras teorías que lo ubican en Monte Saint-Michel, o en Odenwald, Baviera. Todas estas versiones, sin pruebas científicas, ayudan a acrecentar la leyenda del Grial, que no puede concretar en realidad hasta la fecha.

Educación para la autonomía : una última entrevista con Adorno.

En esta entrevista radiofónica a Theodor Adorno, concedida unos días antes de morir, el filósofo conversa con el periodista sobre distintos aspectos de la educación para la autonomía: la necesidad del pensamiento independiente en una sociedad democrática y de un sistema educativo motivador del aprendizaje; la degradación del concepto de autonomía intelectual a nivel internacional; la relación autoridad-autonomía en el proceso de formación del niño como individuo y en la estructura del sistema escolar; las grandes dificultades para el desarrollo de la autonomía en las personas sometidas a la heterónoma organización social; la obligación de llevar a cabo una profunda reforma escolar con la abolición de la formación como un canon y la adopción de medidas de promoción de la autonomía o pensamiento independiente.

A new concept for museum training in Germany

To talk about a new concept for museum training seems perhaps, to be a little bit exaggerated. For long time you have all been talking about concepts and contents for museum training and as I figured out the debate on the topic in Germany is as old as the appearance of national museums in the 19th century. Men like Theodor Mommsen, Rudolph Virchow, Alfred Lichtwark, all well known historians and supporters of the museum idea, spoke and wrote not only about the importance of museums as cultural and educational institutions but also supported the idea of professionalisation of museums work. Some of the ideas of our ancestors are still part of an ongoing discussion. The topic of my talk today will be what king of personnel a museum of our time needs to cope with the growing demand for internal and external organization. I shall present to you a new training program for museum workers in Germany which aims not to produce a new group of researchers but to prepare students for the practical work in the museum field.

El esmeraldeño: ¿una lengua prehispánica en el siglo XIX?

El esmeraldeño fue una lengua que se habló en el curso medio e inferior del Esmeraldas hasta finales del siglo diecinueve, cuando fue registrada por J. M. Pallares para Theodor Wolf de boca de los últimos ancianos que aún la recordaban. Saber más sobre cuál fue el asiento original de esta lengua y quiénes fueron sus hablantes es una pieza clave rompecabezas etnolingüístico de la costa norte del Ecuador antes de la conquista castellana y de las relaciones interétnicas entre conquistadores, indígena y afrodescendientes desde mediados del siglo dieciséis. Aunque ha habido algunos intentos por describir y clasificar el esmeraldeño con criterios lingüísticos y a partir de fuentes etnohistóricas, sigue siendo una lengua no clasificada y poco o nada se sabe de sus hablantes. Esto se debe a la falta de una coteja exhaustiva entre los datos lingüísticos y etnohistóricos disponibles, pero sobre todo a un acercamiento clasificatorio tradicional que no toma en cuenta las consecuencias lingüísticas del contacto interétnico. Se pretende resolver ambas falencias con una interpretación sociolingüística de las fuentes etnohistóricas y un análisis lingüístico comparativo del corpus disponible, que incluye la evidencia toponímica, antroponímica, pero sobre todo de las palabras y oraciones glosadas que conforman el corpus Pallares-Wolf.

La circulación del darwinismo en el Ecuador (1870-1874) (Debates)

En 1871, el jesuita alemán Theodor Wolf comenzó a difundir el darwinismo en el Ecuador a través de las clases de geología y paleontología que impartía en la Escuela Politécnica. Expuso una posición conciliadora del evolucionismo con el catolicismo, en el contexto de un Estado que promovía la cohesión y la identidad nacional a través de la moral católica y las ciencias como vehículo para el progreso. En este estudio se discuten algunos apuntes que atribuyeron estas enseñanzas como la razón por la cual Wolf se separó de la Politécnica y de la Orden Jesuita en 1874, en el marco de una controversia mayor, en la cual el darwinismo fue determinante.

The role of Wnt signalling in the development of somites and neural crest

The Wnt family of secreted signalling molecules controls a wide range of developmental processes in all metazoans. In this investigation we concentrate on the role that members of this family play during the development of (1) the somites and (2) the neural crest. (3) We also isolate a novel component of the Wnt signalling pathway called Naked cuticle and investigate the role that this protein may play in both of the previously mentioned developmental processes. (1) In higher vertebrates the paraxial mesoderm undergoes a mesenchymal-to-epithelial transformation to form segmentally organised structures called somites. Experiments have shown that signals originating from the ectoderm overlying the somites or from midline structures are required for the formation of the somites, but their identity has yet to be determined. Wnt6 is a good candidate as a somite epithelialisation factor from the ectoderm since it is expressed in this tissue. In this study we show that injection of Wnt6-producing cells beneath the ectoderm at the level of the segmental plate or lateral to the segmental plate leads to the formation of numerous small epithelial somites. We show that Wnts are indeed responsible for the epithelialisation of somites by applying Wnt antagonists which result in the segmental plate being unable to form somites. These results show that Wnt6, the only member of this family to be localised to the chick paraxial ectoderm, is able to regulate the development of epithelial somites and that cellular organisation is pivotal in the execution of the differentiation programmes. (2) The neural crest is a population of multipotent progenitor cells that arise from the neural ectoderm in all vertebrate embryos and form a multitude of derivatives including the peripheral sensory neurons, the enteric nervous system, Schwann cells, pigment cells and parts of the craniofacial skeleton. The induction of the neural crest relies on an ectodermally derived signal, but the identity of the molecule performing this role in amniotes is not known. Here we show that Wnt6, a protein expressed in the ectoderm, induces neural crest production. (3) The intracellular response to Wnt signalling depends on the choice of signalling cascade activated in the responding cell. Cells can activate either the canonical pathway that modulates gene expression to control cellular differentiation and proliferation, or the non-canonical pathway that controls cell polarity and movement (Pandur et al. 2002b). Recent work has identified the protein Naked cuticle as an intracellular switch promoting the non-canonical pathway at the expense of the canonical pathway. We have cloned chick Naked cuticle-1 (cNkd1) and demonstrate that it is expressed in a dynamic manner during early embryogenesis. We show that it is expressed in the somites and in particular regions where cells are undergoing movement. Lastly our study shows that the expression of cNkd1 is regulated by Wnt expression originating from the neural tube. This study provides evidence that non-canonical Wnt signalling plays a part in somite development.

The evolution of maximum body size of terrestrial mammals

The extinction of dinosaurs at the Cretaceous/Paleogene (K/Pg) boundary was the seminal event that opened the door for the subsequent diversification of terrestrial mammals. Our compilation of maximum body size at the ordinal level by sub-epoch shows a near-exponential increase after the K/Pg. On each continent, the maximum size of mammals leveled off after 40 million years ago and thereafter remained approximately constant. There was remarkable congruence in the rate, trajectory, and upper limit across continents, orders, and trophic guilds, despite differences in geological and climatic history, turnover of lineages, and ecological variation. Our analysis suggests that although the primary driver for the evolution of giant mammals was diversification to fill ecological niches, environmental temperature and land area may have ultimately constrained the maximum size achieved.

The maximum rate of mammal evolution

How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000- fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous–Paleogene (K–Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. Keywords: haldanes, biological time, scaling, pedomorphosis

Effects of allometry, productivity and lifestyle on rates and limits of body size evolution

Body size affects nearly all aspects of organismal biology, so it is important to understand the constraints and dynamics of body size evolution. Despite empirical work on the macroevolution and macroecology of minimum and maximum size, there is little general quantitative theory on rates and limits of body size evolution. We present a general theory that integrates individual productivity, the lifestyle component of the slow–fast life-history continuum, and the allometric scaling of generation time to predict a clade's evolutionary rate and asymptotic maximum body size, and the shape of macroevolutionary trajectories during diversifying phases of size evolution. We evaluate this theory using data on the evolution of clade maximum body sizes in mammals during the Cenozoic. As predicted, clade evolutionary rates and asymptotic maximum sizes are larger in more productive clades (e.g. baleen whales), which represent the fast end of the slow–fast lifestyle continuum, and smaller in less productive clades (e.g. primates). The allometric scaling exponent for generation time fundamentally alters the shape of evolutionary trajectories, so allometric effects should be accounted for in models of phenotypic evolution and interpretations of macroevolutionary body size patterns. This work highlights the intimate interplay between the macroecological and macroevolutionary dynamics underlying the generation and maintenance of morphological diversity.

Patterns of maximum body size evolution in Cenozoic land mammals: eco-evolutionary processes and abiotic forcing

There is accumulating evidence that macroevolutionary patterns of mammal evolution during the Cenozoic follow similar trajectories on different continents. This would suggest that such patterns are strongly determined by global abiotic factors, such as climate, or by basic eco-evolutionary processes such as filling of niches by specialization. The similarity of pattern would be expected to extend to the history of individual clades. Here, we investigate the temporal distribution of maximum size observed within individual orders globally and on separate continents. While the maximum size of individual orders of large land mammals show differences and comprise several families, the times at which orders reach their maximum size over time show strong congruence, peaking in the Middle Eocene, the Oligocene and the Plio-Pleistocene. The Eocene peak occurs when global temperature and land mammal diversity are high and is best explained as a result of niche expansion rather than abiotic forcing. Since the Eocene, there is a significant correlation between maximum size frequency and global temperature proxy. The Oligocene peak is not statistically significant and may in part be due to sampling issues. The peak in the Plio-Pleistocene occurs when global temperature and land mammal diversity are low, it is statistically the most robust one and it is best explained by global cooling. We conclude that the macroevolutionary patterns observed are a result of the interplay between eco-evolutionary processes and abiotic forcing

Isolation of novel multipotent neural crest-derived stem cells from adult human inferior turbinate

Adult human neural crest-derived stem cells (NCSCs) are of extraordinary high plasticity and promising candidates for the use in regenerative medicine. Here we describe for the first time a novel neural crest-derived stem cell population within the respiratory epithelium of human adult inferior turbinate. In contrast to superior and middle turbinates, high amounts of source material could be isolated from human inferior turbinates. Using minimally-invasive surgery methods isolation is efficient even in older patients. Within their endogenous niche, inferior turbinate stem cells (ITSCs) expressed high levels of nestin, p75(NTR), and S100. Immunoelectron microscopy using anti-p75 antibodies displayed that ITSCs are of glial origin and closely related to nonmyelinating Schwann cells. Cultivated ITSCs were positive for nestin and S100 and the neural crest markers Slug and SOX10. Whole genome microarray analysis showed pronounced differences to human ES cells in respect to pluripotency markers OCT4, SOX2, LIN28, and NANOG, whereas expression of WDR5, KLF4, and c-MYC was nearly similar. ITSCs were able to differentiate into cells with neuro-ectodermal and mesodermal phenotype. Additionally ITSCs are able to survive and perform neural crest typical chain migration in vivo when transplanted into chicken embryos. However ITSCs do not form teratomas in severe combined immunodeficient mice. Finally, we developed a separation strategy based on magnetic cell sorting of p75(NTR) positive ITSCs that formed larger neurospheres and proliferated faster than p75(NTR) negative ITSCs. Taken together our study describes a novel, readily accessible source of multipotent human NCSCs for potential cell-replacement therapy.

Adult craniofacial stem cells: sources and relation to the neural crest

During the process of development, neural crest cells migrate out from their niche between the newly formed ectoderm and the neural tube. Thereafter, they give rise not only to ectodermal cell types, but also to mesodermal cell types. Cell types with neural crest ancestry consequently comprise a number of specialized varieties, such as ectodermal neurons, melanocytes and Schwann cells, as well as mesodermal osteoblasts, adipocytes and smooth muscle cells. Numerous recent studies suggest that stem cells with a neural crest origin persist into adulthood, especially within the mammalian craniofacial compartment. This review discusses the sources of adult neural crest-derived stem cells (NCSCs) derived from the cranium, as well as their differentiation potential and expression of key stem cell markers. Furthermore, the expression of marker genes associated with embryonic stem cells and the issue of multi- versus pluripotency of adult NCSCs is reviewed. Stringent tests are proposed, which, if performed, are anticipated to clarify the issue of adult NCSC potency. Finally, current pre-clinical and clinical data are discussed in light of the clinical impact of adult NCSCs.

Origin and regenerative potential of vertebrate mechanoreceptor-associated stem cells

Meissner corpuscles and Merkel cell neurite complexes are highly specialized mechanoreceptors present in the hairy and glabrous skin, as well as in different types of mucosa. Several reports suggest that after injury, such as after nerve crush, freeze injury, or dissection of the nerve, they are able to regenerate, particularly including reinnervation and repopulation of the mechanoreceptors by Schwann cells. However, little is known about mammalian cells responsible for these regenerative processes. Here we review cellular origin of this plasticity in the light of newly described adult neural crest-derived stem cell populations. We also discuss further potential multipotent stem cell populations with the ability to regenerate disrupted innervation and to functionally recover the mechanoreceptors. These capabilities are discussed as in context to cellularly reprogrammed Schwann cells and tissue resident adult mesenchymal stem cells.