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Luc Simard - One of the best experts on this subject based on the ideXlab platform.
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a catalog of bulge disk decompositions and updated photometry for 1 12 million galaxies in the sloan digital sky survey
Astrophysical Journal Supplement Series, 2011Co-Authors: Luc Simard, Trevor J Mendel, David R Patton, Sara L Ellison, Alan McconnachieAbstract:We perform two-dimensional, point-spread-function-convolved, bulge+disk decompositions in the g and r bandpasses on a sample of 1,123,718 galaxies from the Legacy area of the Sloan Digital Sky Survey Data Release Seven. Four different decomposition procedures are investigated which make improvements to sky background determinations and object deblending over the standard SDSS procedures that lead to more robust structural parameters and integrated galaxy magnitudes and colors, especially in crowded environments. We use a set of science-based quality assurance metrics, namely, the disk luminosity-size relation, the galaxy color-magnitude diagram, and the galaxy Central (Fiber) colors to show the robustness of our structural parameters. The best procedure utilizes simultaneous, two-bandpass decompositions. Bulge and disk photometric errors remain below 0.1 mag down to bulge and disk magnitudes of g 19 and r 18.5. We also use and compare three different galaxy fitting models: a pure Sersic model, an nb = 4 bulge + disk model, and a Sersic (free nb ) bulge + disk model. The most appropriate model for a given galaxy is determined by the F-test probability. All three catalogs of measured structural parameters, rest-frame magnitudes, and colors are publicly released here. These catalogs should provide an extensive comparison set for a wide range of observational and theoretical studies of galaxies.
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a catalog of bulge disk decompositions and updated photometry for 1 12 million galaxies in the sloan digital sky survey
arXiv: Cosmology and Nongalactic Astrophysics, 2011Co-Authors: Luc Simard, Trevor J Mendel, David R Patton, Sara L Ellison, Alan McconnachieAbstract:We perform two-dimensional, Point-Spread-Function-convolved, bulge+disk decompositions in the $g$ and $r$ bandpasses on a sample of 1,123,718 galaxies from the Legacy area of the Sloan Digital Sky Survey Data Release Seven. Four different decomposition procedures are investigated which make improvements to sky background determinations and object deblending over the standard SDSS procedures that lead to more robust structural parameters and integrated galaxy magnitudes and colors, especially in crowded environments. We use a set of science-based quality assurance metrics namely the disk luminosity-size relation, the galaxy color-magnitude diagram and the galaxy Central (Fiber) colors to show the robustness of our structural parameters. The best procedure utilizes simultaneous, two-bandpass decompositions. Bulge and disk photometric errors remain below 0.1 mag down to bulge and disk magnitudes of $g \simeq 19$ and $r \simeq 18.5$. We also use and compare three different galaxy fitting models: a pure Sersic model, a $n_b=4$ bulge + disk model and a Sersic (free $n_b$) bulge + disk model. The most appropriate model for a given galaxy is determined by the $F$-test probability. All three catalogs of measured structural parameters, rest-frame magnitudes and colors are publicly released here. These catalogs should provide an extensive comparison set for a wide range of observational and theoretical studies of galaxies.
Alan Mcconnachie - One of the best experts on this subject based on the ideXlab platform.
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a catalog of bulge disk decompositions and updated photometry for 1 12 million galaxies in the sloan digital sky survey
Astrophysical Journal Supplement Series, 2011Co-Authors: Luc Simard, Trevor J Mendel, David R Patton, Sara L Ellison, Alan McconnachieAbstract:We perform two-dimensional, point-spread-function-convolved, bulge+disk decompositions in the g and r bandpasses on a sample of 1,123,718 galaxies from the Legacy area of the Sloan Digital Sky Survey Data Release Seven. Four different decomposition procedures are investigated which make improvements to sky background determinations and object deblending over the standard SDSS procedures that lead to more robust structural parameters and integrated galaxy magnitudes and colors, especially in crowded environments. We use a set of science-based quality assurance metrics, namely, the disk luminosity-size relation, the galaxy color-magnitude diagram, and the galaxy Central (Fiber) colors to show the robustness of our structural parameters. The best procedure utilizes simultaneous, two-bandpass decompositions. Bulge and disk photometric errors remain below 0.1 mag down to bulge and disk magnitudes of g 19 and r 18.5. We also use and compare three different galaxy fitting models: a pure Sersic model, an nb = 4 bulge + disk model, and a Sersic (free nb ) bulge + disk model. The most appropriate model for a given galaxy is determined by the F-test probability. All three catalogs of measured structural parameters, rest-frame magnitudes, and colors are publicly released here. These catalogs should provide an extensive comparison set for a wide range of observational and theoretical studies of galaxies.
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a catalog of bulge disk decompositions and updated photometry for 1 12 million galaxies in the sloan digital sky survey
arXiv: Cosmology and Nongalactic Astrophysics, 2011Co-Authors: Luc Simard, Trevor J Mendel, David R Patton, Sara L Ellison, Alan McconnachieAbstract:We perform two-dimensional, Point-Spread-Function-convolved, bulge+disk decompositions in the $g$ and $r$ bandpasses on a sample of 1,123,718 galaxies from the Legacy area of the Sloan Digital Sky Survey Data Release Seven. Four different decomposition procedures are investigated which make improvements to sky background determinations and object deblending over the standard SDSS procedures that lead to more robust structural parameters and integrated galaxy magnitudes and colors, especially in crowded environments. We use a set of science-based quality assurance metrics namely the disk luminosity-size relation, the galaxy color-magnitude diagram and the galaxy Central (Fiber) colors to show the robustness of our structural parameters. The best procedure utilizes simultaneous, two-bandpass decompositions. Bulge and disk photometric errors remain below 0.1 mag down to bulge and disk magnitudes of $g \simeq 19$ and $r \simeq 18.5$. We also use and compare three different galaxy fitting models: a pure Sersic model, a $n_b=4$ bulge + disk model and a Sersic (free $n_b$) bulge + disk model. The most appropriate model for a given galaxy is determined by the $F$-test probability. All three catalogs of measured structural parameters, rest-frame magnitudes and colors are publicly released here. These catalogs should provide an extensive comparison set for a wide range of observational and theoretical studies of galaxies.
Barbora Antosova - One of the best experts on this subject based on the ideXlab platform.
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ectopic activation of wnt β catenin signaling in lens Fiber cells results in cataract formation and aberrant Fiber cell differentiation
PLOS ONE, 2013Co-Authors: Barbora Antosova, Jana Smolikova, Romana Borkovcova, Hynek Strnad, Jitka Lachova, Ondrej Machon, Zbynek KozmikAbstract:The Wnt/β-catenin signaling pathway controls many processes during development, including cell proliferation, cell differentiation and tissue homeostasis, and its aberrant regulation has been linked to various pathologies. In this study we investigated the effect of ectopic activation of Wnt/β-catenin signaling during lens Fiber cell differentiation. To activate Wnt/β-catenin signaling in lens Fiber cells, the transgenic mouse referred to as αA-CLEF was generated, in which the transactivation domain of β-catenin was fused to the DNA-binding protein LEF1, and expression of the transgene was controlled by αA-crystallin promoter. Constitutive activation of Wnt/β-catenin signaling in lens Fiber cells of αA-CLEF mice resulted in abnormal and delayed Fiber cell differentiation. Moreover, adult αA-CLEF mice developed cataract, microphthalmia and manifested downregulated levels of γ-crystallins in lenses. We provide evidence of aberrant expression of cell cycle regulators in embryonic lenses of αA-CLEF transgenic mice resulting in the delay in cell cycle exit and in the shift of Fiber cell differentiation to the Central Fiber cell compartment. Our results indicate that precise regulation of the Wnt/β-catenin signaling activity during later stages of lens development is essential for proper lens Fiber cell differentiation and lens transparency.
Zbynek Kozmik - One of the best experts on this subject based on the ideXlab platform.
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ectopic activation of wnt β catenin signaling in lens Fiber cells results in cataract formation and aberrant Fiber cell differentiation
PLOS ONE, 2013Co-Authors: Barbora Antosova, Jana Smolikova, Romana Borkovcova, Hynek Strnad, Jitka Lachova, Ondrej Machon, Zbynek KozmikAbstract:The Wnt/β-catenin signaling pathway controls many processes during development, including cell proliferation, cell differentiation and tissue homeostasis, and its aberrant regulation has been linked to various pathologies. In this study we investigated the effect of ectopic activation of Wnt/β-catenin signaling during lens Fiber cell differentiation. To activate Wnt/β-catenin signaling in lens Fiber cells, the transgenic mouse referred to as αA-CLEF was generated, in which the transactivation domain of β-catenin was fused to the DNA-binding protein LEF1, and expression of the transgene was controlled by αA-crystallin promoter. Constitutive activation of Wnt/β-catenin signaling in lens Fiber cells of αA-CLEF mice resulted in abnormal and delayed Fiber cell differentiation. Moreover, adult αA-CLEF mice developed cataract, microphthalmia and manifested downregulated levels of γ-crystallins in lenses. We provide evidence of aberrant expression of cell cycle regulators in embryonic lenses of αA-CLEF transgenic mice resulting in the delay in cell cycle exit and in the shift of Fiber cell differentiation to the Central Fiber cell compartment. Our results indicate that precise regulation of the Wnt/β-catenin signaling activity during later stages of lens development is essential for proper lens Fiber cell differentiation and lens transparency.
David C Beebe - One of the best experts on this subject based on the ideXlab platform.
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coincident loss of mitochondria and nuclei during lens Fiber cell differentiation
Developmental Dynamics, 1992Co-Authors: Steven Bassnett, David C BeebeAbstract:During normal differentiation, lens Fiber cells lose their nuclei, mitochondria, and other membrane-bound organelles. In the present study, a slice preparation of the embryonic chicken lens was used with laser scanning confocal microscopy to study the spatial and temporal patterns of organelle breakdown during embryonic development. At all stages examined, mitochondria in lens epithelial cells were present in perinuclear clusters. In contrast, early in development, lens Fiber cells contained extremely elongated mitochondria (>100 μm) that were distributed throughout the cytoplasm and oriented along the long axis of the cells. By the 8th day of embryonic development (E8), the mitochondria in the Central Fiber cells began to fragment. At the same time, the nuclei in these cells became smaller and more spherical. By E10, mitochondrial staining in the Central Fibers became punctate. Electron microscopy of this region revealed swollen mitochondria with disrupted cristae. By E12, cells in the Central region of the lens lacked mitochondria and nuclei. The loss of nuclei and mitochondria from a given cell was coincident and abrupt (2–4 hr), occurring in a previously unsuspected domain situated about 300 μm from the anterior surface of the lens. A cytoskeletal component, actin, persisted in the Central cells indicating that organelle degradation represents a selective process and not simply the global degradation of supramolecular structures. Throughout embryonic development, the organelle-free region grew at approximately the same rate as the lens and, by the time of hatching, had expanded to match the diameter of the pupil. The present results suggest that the embryonic lens will be a useful model system with which to study mechanisms of organelle degradation. © 1992 Wiley-Liss, Inc.