Sobre la distribución de Riella Helicophylla (Bory et Mont.) Mont en la Península Ibérica

Nueva localidad española de Riella helicophylla (Bory et Mont.) Mont. y mapa de distribución de la especie en la Peninsula Ibérica.A new record of Riella helicophylla from Spain and distributional map in the Iberian Peninsul

Electron beam induced electronic transport in alkyl amine-intercalated VOx nanotubes

The electron beam induced electronic transport in primary alkyl amine-intercalated V2O5 nanotubes is investigated where the organic amine molecules are employed as molecular conductive wires to an aminosilanized substrate surface and contacted to Au interdigitated electrode contacts. The results demonstrate that the high conductivity of the nanotubes is related to the non-resonant tunnelling through the amine molecules and a reduced polaron hopping conduction through the vanadium oxide itself. Both nanotube networks and individual nanotubes exhibit similarly high conductivities where the minority carrier transport is bias dependent and nanotube diameter invariant

Bead, Hoop, and Spring as a Classical Spontaneous Symmetry Breaking Problem

We describe a simple mechanical system that involves Spontaneous Symmetry Breaking. The system consists of two beads constrained to slide along a hoop and attached each other through a spring. When the hoop rotates about a fixed axis, the spring-beads system will change its equilibrium position as a function of the angular velocity. The system shows two different regions of symmetry separated by a critical point analogous to a second order transition. The competitive balance between the rotational diynamics and the interaction of the spring causes an Spontaneous Symmetry Breaking just as the balance between temperature and the spin interaction causes a transition in a ferromagnetic system. In addition, the gravitational potential act as an external force that causes explicit symmetry breaking and a feature of first-order transition. Near the transition point, the system exhibits a universal critical behavior where the changes of the parameter of order is described by the critical exponent beta =1/2 and the susceptibility by gamma =1. We also found a chaotic behavior near the critical point. Through a demostrative device we perform some qualitative observations that describe important features of the system.Comment: 7 pages, 2 tables, 30 figures, LaTeX2

Charged Annular Disks and Reissner-Nordstr\"{o}m Type Black Holes from Extremal Dust

We present the first analytical superposition of a charged black hole with an annular disk of extremal dust. In order to obtain the solutions, we first solve the Einstein-Maxwell field equations for sources that represent disk-like configurations of matter in confomastatic spacetimes by assuming a functional dependence among the metric function, the electric potential and an auxiliary function,which is taken as a solution of the Laplace equation. We then employ the Lord Kelvin Inversion Method applied to models of finite extension in order to obtain annular disks. The structures obtained extend to infinity, but their total masses are finite and all the energy conditions are satisfied. Finally, we observe that the extremal Reissner-Nordstr\"{o}m black hole can be embedded into the center of the disks by adding a boundary term in the inversion.Comment: 17 revtex pages, 8 eps figure

Differences and homologies of chromosomal alterations within and between breast cancer cell lines: A clustering analysis

BACKGROUND: The MCF7 (ER+/HER2-), T47D (ER+/HER2-), BT474 (ER+/HER2+) and SKBR3 (ER-/HER2+) breast cancer cell lines are widely used in breast cancer research as paradigms of the luminal and HER2 phenotypes. Although they have been subjected to cytogenetic analysis, their chromosomal abnormalities have not been carefully characterized, and their differential cytogenetic profiles have not yet been established. In addition, techniques such as comparative genomic hybridization (CGH), microarray-based CGH and multiplex ligation-dependent probe amplification (MLPA) have described specific regions of gains, losses and amplifications of these cell lines; however, these techniques cannot detect balanced chromosomal rearrangements (e.g., translocations or inversions) or low frequency mosaicism. RESULTS: A range of 19 to 26 metaphases of the MCF7, T47D, BT474 and SKBR3 cell lines was studied using conventional (G-banding) and molecular cytogenetic techniques (multi-color fluorescence in situ hybridization, M-FISH). We detected previously unreported chromosomal changes and determined the content and frequency of chromosomal markers. MCF7 and T47D (ER+/HER2-) cells showed a less complex chromosomal make up, with more numerical than structural alterations, compared to BT474 and SKBR3 (HER2+) cells, which harbored the highest frequency of numerical and structural aberrations. Karyotype heterogeneity and clonality were determined by comparing all metaphases within and between the four cell lines by hierarchical clustering. The latter analysis identified five main clusters. One of these clusters was characterized by numerical chromosomal abnormalities common to all cell lines, and the other four clusters encompassed cell-specific chromosomal abnormalities. T47D and BT474 cells shared the most chromosomal abnormalities, some of which were shared with SKBR3 cells. MCF7 cells showed a chromosomal pattern that was markedly different from those of the other cell lines. CONCLUSIONS: Our study provides a comprehensive and specific characterization of complex chromosomal aberrations of MCF7, T47D, BT474 and SKBR3 cell lines. The chromosomal pattern of ER+/HER2- cells is less complex than that of ER+/HER2+ and ER-/HER2+ cells. These chromosomal abnormalities could influence the biologic and pharmacologic response of cells. Finally, although gene expression profiling and aCGH studies have classified these four cell lines as luminal, our results suggest that they are heterogeneous at the cytogenetic level

La presencia del otro en los procesos de formación humana

En este libro se vincula la mirada a la semiótica como alternativa para formar docentes a partir de su propuesta sobre didáctica clínica. Seguidamente, se pueden reconocer los aportes de la lingüística a la educación. Además se enuncia al trabajo autobiográfico como estrategia de la investigación cualitativa y otra, como estrategia de formación humana. Finalmente, se presenta un marco de referencia sobre la virtualidad y sus implicaciones en los procesos de formación

Proteínas morfogenéticas óseas (BMPs): Efecto de la proteína osteogénica-1 (OP-l/BMP-7) en la condrogénesis y osteogenesis

En la actualidad, los estudios sobre biología molecular han facilitado el análisis de ciertos factores de transformación del crecimiento tipo ß(TGF-ß)I, entre los que destaca una familia de proteínas morfogenéticas óseas (BMPs). Las técnicas de ingeniería genética han permitido replicar alguno de estos factores y localizar los genes que codifican dichas proteínas. La proteína osteogenics-1 (OP-1) ha sido caracterizada y sintetizada in vitro y muestra un elevado potencial osteogénico y condrogénico tanto in vivo como in vitro. Se presenta una revisión de los últimos avances en la aplicación experimental de las BMPs, y especialmente de la OP-1, en el área de la Cirugía Ortopédica y la TraumatologíaNowadays, molecular biology studies have promoted the bone morphogenetic proteins (BMPs) analysis. These multifunctional proteins are structurally related to transforming growth factor-6 (TGF-6). Genetic engineering techniques have allowed to sequence some of these BMPs. It has been characterized the expression and processing of osteogenic protein-1 (OP-1), a bone morphogenetic protein of the TGF-6 family. The OP-1 shows a high osteogenic and chondrogenic potential. The aim of this paper is to review some updated advances of the BMPs experimental applications, particularly OP-1, in relation to Orthopaedic Surgery and Traumatolog

A Bacia do Algarve: estratigrafia, paleogeografia e tectónica

A “Bacia do Algarve” corresponde, segundo a literatura científica tradicional, aos terrenos mesocenozóicos que orlam o Sul de Portugal, desde o Cabo de São Vicente ao rio Guadiana (~140km), penetrando irregularmente para o interior entre 3 km a 25 km, sobre terrenos de idade carbónica da Zona Sul Portuguesa. O hiato, de aproximadamente 70 milhões de anos, materializado pela discordância angular entre as rochas sedimentares de tipo flysch do Carbónico, metamorfizadas e deformadas durante a orogenia varisca, e as rochas sedimentares continentais do Triásico inferior provável, separa dois ciclos de Wilson. Os sedimentos carbónicos metamorfizados resultam do empilhamento orogénico de um possível prisma de acrecção associado à orogenia varisca e ao fecho de um oceano paleozóico e formação da Pangeia, enquanto que os sedimentos continentais triásicos resultam do fim do colapso e do arrasamento do orógeno varisco e início do estiramento continental que viriam a culminar com a separação das placas litosféricas África, Eurásia e América.Os sedimentos mais recentes do Mesozóico e os mais antigos bem datados do Cenozóico encontram-se separados por um outro hiato que ultrapassa ligeiramente os 70 milhões de anos na área emersa. Este hiato resulta duma alteração tectónica radical no contexto onde nessa época geológica se inseria a Bacia do Algarve. Esta mudança, que ocorreu no fim do Cenomaniano, resultou da rotação do vector de deslocamento da trajectória de África em relação à Eurásia, de aproximadamente NW-SE para SW-NE (segundo as coordenadas actuais, e.g. Dewey et al, 1989), poria termo ao regime distensivo e de bacia de tipo rifte na Bacia do Algarve, com o fim do regime transtensivo entre a região noroeste da placa África e sudoeste da placa Eurásia e início da colisão