Possible polarisation and spin dependent aspects of quantum gravity

We argue that quantum gravity theories that carry a Lie algebraic modification of the Poincare' and Heisenberg algebras inevitably provide inhomogeneities that may serve as seeds for cosmological structure formation. Furthermore, in this class of theories one must expect a strong polarisation and spin dependence of various quantum-gravity effects.Comment: Awarded an "honourable mention" in the 2007 Gravity Research Foundation Essay Competitio

Hydra tropomyosin TROP1 is expressed in head-specific epithelial cells and is a major component of the cytoskeletal structure that anchors nematocytes

A cDNA clone encoding a 253 amino acid tropomyosin was isolated from Hydra in a differential screen for headspecific genes. The Hydra tropomyosin gene, designated trop1, is a single copy gene, lacks introns and is strongly expressed in tentacle-specific epithelial cells. Analysis of protein synthesis in head and gastric tissue indicated a high rate of tropomyosin synthesis in head tissue. Immunolocalization of tropomyosin in tentacle tissue revealed a cushion-like tropomyosin-containing structure within battery cells at the base of nematocytes. The structure appears to form part of the cytoskeletal anchor for nematocytes. Tropomyosin cushions were also observed in epithelial cells along the body column, which contain mounted stenotele nematocytes

TransPlanckian Particles and the Quantization of Time

Trans-Planckian particles are elementary particles accelerated such that their energies surpass the Planck value. There are several reasons to believe that trans-Planckian particles do not represent independent degrees of freedom in Hilbert space, but they are controlled by the cis-Planckian particles. A way to learn more about the mechanisms at work here, is to study black hole horizons, starting from the scattering matrix Ansatz. By compactifying one of the three physical spacial dimensions, the scattering matrix Ansatz can be exploited more efficiently than before. The algebra of operators on a black hole horizon allows for a few distinct representations. It is found that this horizon can be seen as being built up from string bits with unit lengths, each of which being described by a representation of the SO(2,1) Lorentz group. We then demonstrate how the holographic principle works for this case, by constructing the operators corresponding to a field in space-time. The parameter t turns out to be quantized in Planckian units, divided by the period R of the compactified dimension.Comment: 12 pages plain tex, 1 figur

On Geometric Variational Models for Inpainting Surface Holes

Geometric approaches for filling-in surface holes are introduced and studied in this paper. The basic idea is to represent the surface of interest in implicit form, and fill-in the holes with a scalar, or systems of, geometric partial differential equations, often derived from optimization principles. These equations include a system for the joint interpolation of scalar and vector fields, a Laplacian-based minimization, a mean curvature diffusion flow, and an absolutely minimizing Lipschitz extension. The theoretical and computational framework, as well as examples with synthetic and real data, are presented in this paper

Caracterización y Tipificación De La Cadena Agroproductiva Del Cultivo De Maracuyá (passiflora edulis L) Pedernales, Manabí, Ecuador/Characterization and Typification of the Agroproductive Chain of Maracuya Cultivation (passiflora edulis L) Pedernales, M

La cadena agroproductiva de maracuyá (passiflora edulis L), se desarrolla en la costa ecuatoriana, destacando la calidad de producto en sus dos variedades amarilla y roja. El objetivo de esta investigación es realizar la caracterización y tipificación, analizando aspectos agroproductivos, socioeconómicos y comercio en las parroquias 10 de Agosto, Atahualpa y Cojimíes pertenecientes al cantón Pedernales, en cual cuenta con 266 productores de Maracuyá, abarcando una extensión de 532 hectáreas, la muestra constituye 20 fincas productoras, aplicando la metodología exploratoria, descriptiva y analítica, de evaluación insitú, obteniendo que el género masculino es el predominante en el manejo y responsabilidad de finca (100%), (90%) residen en la finca, cuentan con un nivel de estudios mayormente de escolaridad (75%), nivel sociorganizativo (15%) pertenecen alguna organización constituida legalmente, la tenencia de tierra representa un (25%) 1 - 5 ha, (25%) más de 26 ha, (20%) 6 - 10 ha, (15%) 11 - 15 ha y (15%) 16 - 25 ha, utilizan mano de obra adicional (40%), el tipo agricultura (90%) convencional, (10%) manejo orgánico, (55%), posee más de 3 cultivos en producción, ocupando el (75%) agua de rio, un (50%) realizan riego por surcos, la producción anual en Cojimíes representa (19 ha), con 27000 kg/ano, 10 de agosto (14 ha), con 24200 kg/año, Atahualpa (6 ha), con 5900 kg/año, el (74%) cultiva la variedad amarillo, (26%) variedad rojo morado, (100%) realizan actividades de pos cosecha el (85%) los ingresos mensuales provienen de agricultura (75%), (20%) crianza de animales; y (5%) del comercio. The agro-productive chain of passion fruit (passiflora edulis L), is developed on the Ecuadorian coast, highlighting the quality of the product in its two yellow and red varieties. The objective of this research is to characterize and typify, analyzing agroproductive, socioeconomic and trade aspects in the parishes 10 de Agosto, Atahualpa and Cojimíes belonging to the canton Pedernales, which has 266 Maracuyá producers, covering an area of 532 hectares, the sample constitutes 20 producing farms, applying the exploratory, descriptive and analytical methodology, of insitu evaluation, obtaining that the masculine gender is the predominant one in the management and responsibility of the farm (100%), (90%) they reside in the farm, they count With a level of education mostly of schooling (75%), socio-organizational level (15%) belong some legally constituted organization, land ownership represents one (25%) 1 - 5 ha, (25%) more than 26 ha, (20%) 6 - 10 ha, (15%) 11 - 15 ha and (15%) 16 - 25 ha, use additional labor (40%), the agriculture type (90%) conventional, (10%) management organic, (55%), owns more than 3 crops in production, occupying (75%) river water, one (50%) irrigate by furrows, the annual production in Cojimies represents (19 ha), with 27000 kg / year, August 10 (14 ha), with 24200 kg / year, Atahualpa (6 ha), with 5900 kg / year, (74%) cultivates the yellow variety, (26%) purple red variety, (100%) carry out post-harvest activities (85%) the monthly income comes from agriculture (75%), (20%) raising animals; and (5%) of commerce. Palabras clave: Caracterización, Tipificación, Cadena, Agro productiva, Maracuyá. Keywords: Characterization, Typification, chain, agro productive, passion fruit

Boundary description of Planckian scattering in curved spacetimes

We show that for an eikonal limit of gravity in a space-time of any dimension with a non-vanishing cosmological constant, the Einstein -- Hilbert action reduces to a boundary action. This boundary action describes the interaction of shock-waves up to the point of evolution at which the forward light-cone of a collision meets the boundary of the space-time. The conclusions are quite general and in particular generalize the previous work of E. and H. Verlinde. The role of the off-diagonal Einstein action in removing the bulk part of the action is emphasised. We discuss the sense in which our result is a particular example of holography and also the relation of our solutions in $AdS$ to those of Horowitz and Itzhaki

Anatomías inefables

Ante estas obras de Victoria Diehl es fácil pensar en conocidos modelos anatómicos en cera o en la iconografía de Venus y Evas de las que un vistazo rápido a cualquier libro de historia del arte nos mostraría múltiples variantes. Algo de todo ello hay aquí. Pero también hay algo que hace que los espectadores se detengan a pensar. Algo más allá de lo reconocible que hace que las lenguas del pasado se muevan a un ritmo actual. Hermes, al trasladar sus mensajes los interpreta, los adapta al interlocutor y al medio; los transforma, los traduce, los recrea. Y logra ponernos en movimiento. [...