4,222 research outputs found
Hindgut specification and cell-adhesion functions of Sphox11/13b in the endoderm of the sea urchin embryo
Sphox11/13b is one of the two hox genes of Strongylocentrotus purpuratus expressed in the embryo. Its
dynamic pattern of expression begins during gastrulation, when the transcripts are transiently located in a
ring of cells at the edge of the blastopore. After gastrulation, expression is restricted to the anus–hindgut
region at the boundary between the ectoderm and the endoderm. The phenotype that results when translation
of Sphox11/13b mRNA is knocked down by treatment with morpholino antisense oligonucleotides (MASO)
suggests that this gene may be indirectly involved in cell adhesion functions as well as in the proper
differentiation of the midgut–hindgut and midgut–foregut sphincters. The MASO experiments also reveal that
Sphox11/13b negatively regulates several downstream endomesoderm genes. For some of these genes,
Sphox11/13b function is required to restrict expression to the midgut by preventing ectopic expression in the
hindgut. The evolutionary conservation of these functions indicates the general roles of posterior Hox genes
in regulating cell-adhesion, as well as in spatial control of gene regulatory network subcircuits in the
regionalizing gut
Spatial expression of Hox cluster genes in the ontogeny of a sea urchin
The Hox cluster of the sea urchin Strongylocentrous purpuratus contains ten genes in a 500 kb span of the genome. Only two of these genes are expressed during embryogenesis, while all of eight genes tested are expressed during development of the adult body plan in the larval stage. We report the spatial expression during larval development of the five 'posterior' genes of the cluster: SpHox7, SpHox8, SpHox9/10, SpHox11/13a and SpHox11/13b. The five genes exhibit a dynamic, largely mesodermal program of expression. Only SpHox7 displays extensive expression within the pentameral rudiment itself. A spatially sequential and colinear arrangement of expression domains is found in the somatocoels, the paired posterior mesodermal structures that will become the adult perivisceral coeloms. No such sequential expression pattern is observed in endodermal, epidermal or neural tissues of either the larva or the presumptive juvenile sea urchin. The spatial expression patterns of the Hox genes illuminate the evolutionary process by which the pentameral echinoderm body plan emerged from a bilateral ancestor
Biases on cosmological parameters by general relativity effects
General relativistic corrections to the galaxy power spectrum appearing at
the horizon scale, if neglected, may induce biases on the measured values of
the cosmological parameters. In this paper, we study the impact of general
relativistic effects on non standard cosmologies such as scenarios with a time
dependent dark energy equation of state, with a coupling between the dark
energy and the dark matter fluids or with non-Gaussianities. We then explore
whether general relativistic corrections affect future constraints on
cosmological parameters in the case of a constant dark energy equation of state
and of non-Gaussianities. We find that relativistic corrections on the power
spectrum are not expected to affect the foreseen errors on the cosmological
parameters nor to induce large biases on them.Comment: 17 pages, 5 figures, one added figure, results of Tab. I revised,
version accepted for publication in PR
El ascetismo pentecostal gitano y la gestión corporal. Una aproximación desde la antropología del cuerpo Gipsy pentecostal ascetism and body management
Las creencias y prácticas religiosas pentecostales constituyen un conjunto elaborado de estrategias de transformación y renacimiento personal. Tanto la reforma corporal como diferentes aspectos de la experiencia vital y biográfica se convierten en factores decisivos de la construcción social de la realidad de los gitanos pertenecientes a la Iglesia de Filadelfia. El trabajo que presentamos se detiene en aspectos como: el cuerpo como objeto y sujeto de prácticas biopolíticas y religiosas; las relaciones entre experiencia religiosa y gestión corporal; las nuevas interacciones sociales y dinámicas comunitarias; los discursos autobiográficos como vehículos ideológicos de la conversión y transformación personal. Todos estos procesos reflejan el modo como las prácticas sociales reelaboran y canalizan los comportamientos y significados del cuerpo. Por otro lado, los dones carismáticos pentecostales canalizan y expresan las demandas individuales y comunitarias de los conversos de la Iglesia de Filadelfia y suponen elementos centrales de la gestión corporal y vital pentecostal. El objetivo es, pues, analizar las prácticas corporales que permiten la transformación de los creyentes y configuran los rituales e interacciones comunitarias de las congregaciones.Pentecostal religious beliefs and practices consist of a complex set of strategies of transformation and personal renewal. Among other aspects of their experiences in the Church of Philadelphia, the social construction of Gypsy reality turns on the reform of the body. The present paper lies on aspects such as the body as object and subject of biopolitical and religious practices; the relationships between religious experience and body management; new social and community interactions; and autobiographical discourse as the ideological vehicle of personal conversion and transformation. All these processes reveal how social practices remake and shape bodily behaviour and its meaning. Pentecostal charismatic practices channel and express the community and individual demands of Church of Philadelphia converts, and represent central issues in the Pentecostal management of body and spirit. Our aim in this paper is to analyze the bodily practices which provide for believers' transformation, and which shape community rituals and the congregation's interactions
El ascetismo pentecostal gitano y la gestión corporal. Una aproximación desde la antropología del cuerpo
Pentecostal religious beliefs and practices consist of a complex set of strategies of transformation and personal renewal. Among other aspects of their experiences in the Church of Philadelphia, the social construction of Gypsy reality turns on the reform of the body. The present paper lies on aspects such as the body as object and subject of biopolitical and religious practices; the relationships between religious experience and body management; new social and community interactions; and autobiographical discourse as the ideological vehicle of personal conversion and transformation. All these processes reveal how social practices remake and shape bodily behaviour and its meaning. Pentecostal charismatic practices channel and express the community and individual demands of Church of Philadelphia converts, and represent central issues in the Pentecostal management of body and spirit. Our aim in this paper is to analyze the bodily practices which provide for believers´ transformation, and which shape community rituals and the congregation's interactions.Las creencias y prácticas religiosas pentecostales constituyen un conjunto elaborado de estrategias de transformación y renacimiento personal. Tanto la reforma corporal como diferentes aspectos de la experiencia vital y biográfica se convierten en factores decisivos de la construcción social de la realidad de los gitanos pertenecientes a la Iglesia de Filadelfia. El trabajo que presentamos se detiene en aspectos como: el cuerpo como objeto y sujeto de prácticas biopolíticas y religiosas; las relaciones entre experiencia religiosa y gestión corporal; las nuevas interacciones sociales y dinámicas comunitarias; los discursos autobiográficos como vehículos ideológicos de la conversión y transformación personal. Todos estos procesos reflejan el modo como las prácticas sociales reelaboran y canalizan los comportamientos y significados del cuerpo. Por otro lado, los dones carismáticos pentecostales canalizan y expresan las demandas individuales y comunitarias de los conversos de la Iglesia de Filadelfia y suponen elementos centrales de la gestión corporal y vital pentecostal. El objetivo es, pues, analizar las prácticas corporales que permiten la transformación de los creyentes y configuran los rituales e interacciones comunitarias de las congregaciones
Matching of spatially homogeneous non-stationary space--times to vacuum in cylindrical symmetry
We study the matching of LRS spatially homogeneous collapsing dust
space-times with non-stationary vacuum exteriors in cylindrical symmetry. Given
an interior with diagonal metric we prove existence and uniqueness results for
the exterior. The matched solutions contain trapped surfaces, singularities and
Cauchy horizons. The solutions cannot be asymptotically flat and we present
evidence that they are singular on the Cauchy horizons.Comment: LaTeX, 15 pages, 1 figure, submitted for publicatio
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