54 research outputs found
Merger rates of dark matter haloes: a comparison between EPS and N-body results
We calculate merger rates of dark matter haloes using the Extended
Press-Schechter approximation (EPS) for the Spherical Collapse (SC) and the
Ellipsoidal Collapse (EC) models.
Merger rates have been calculated for masses in the range
to and for
redshifts in the range 0 to 3 and they have been compared with merger rates
that have been proposed by other authors as fits to the results of N-body
simulations. The detailed comparison presented here shows that the agreement
between the analytical models and N-body simulations depends crucially on the
mass of the descendant halo. For some range of masses and redshifts either SC
or EC models approximate satisfactory the results of N-body simulations but for
other cases both models are less satisfactory or even bad approximations. We
showed, by studying the parameters of the problem that a disagreement --if it
appears-- does not depend on the values of the parameters but on the kind of
the particular solution used for the distribution of progenitors or on the
nature of EPS methods.
Further studies could help to improve our understanding about the physical
processes during the formation of dark matter haloes.Comment: 29 pages, 9 figure
Help-Seeking Patterns Among LGBTQ Young Adults Exposed to Intimate Partner Violence Victimization
Localization of Cacna1s to ON Bipolar Dendritic Tips Requires mGluR6-Related Cascade Elements
Citation: Tummala SR, Neinstein A, Fina ME, Dhingra A, Vardi N. Localization of Cacna1s to ON bipolar dendritic tips requires mGluR6-related cascade elements. Invest Ophthalmol Vis Sci. 2014;55:148355: -149255: . DOI:10.1167 PURPOSE. L-type voltage gated calcium channels in retina localize primarily at the presynaptic active zones of photoreceptors and bipolar cells where they modulate glutamate release. However, the pore forming subunit Cacna1s of certain L-type channels is also expressed postsynaptically at the tips of ON bipolar cell dendrites where it colocalizes with mGluR6, but has an unknown function. At these dendritic tips, the components of the mGluR6 signaling cascade cluster together in a macromolecular complex, and each one's localization often depends on that of the others. Thus, we explored if Cacna1s is part of the mGluR6 complex. METHODS. We determined Cacna1s expression by PCR using an ON bipolar library, by Western blotting, and by standard immunohistochemistry. RESULTS. The PCR amplification confirmed expression of the transcript in ON bipolar cells, and Western blotting showed the expected bands. Immunostaining for Cacna1s was stronger in the dendritic tips of rod bipolar cells than in those of ON cone bipolar cells. This staining severely decreased in mice missing various mGluR6 cascade elements (Grm6 À/À , Gnao1 À/À , Gnb3 À/À , Gng13 À/À , and Trpm1 À/À ). During development, the ratio of the number of Cacna1s puncta to the number of presynaptic ribbons followed a sigmoidal pattern, rising rapidly from P13 to P17. The mGluR6 expression preceded that of Cacna1s and RGS11. CONCLUSIONS. Our results show that the localization and stability of Cacna1s depend on the expression of mGluR6 and its cascade components, and they suggest that Cacna1s is part of the mGluR6 complex. We hypothesize that Cacna1s contributes to light adaptation by permeating calcium
Localization of Cacna1s to ON Bipolar Dendritic Tips Requires mGluR6-Related Cascade Elements
PURPOSE. L-type voltage gated calcium channels in retina localize primarily at the presynaptic active zones of photoreceptors and bipolar cells where they modulate glutamate release. However, the pore forming subunit Cacna1s of certain L-type channels is also expressed postsynaptically at the tips of ON bipolar cell dendrites where it colocalizes with mGluR6, but has an unknown function. At these dendritic tips, the components of the mGluR6 signaling cascade cluster together in a macromolecular complex, and each one's localization often depends on that of the others. Thus, we explored if Cacna1s is part of the mGluR6 complex. METHODS. We determined Cacna1s expression by PCR using an ON bipolar library, by Western blotting, and by standard immunohistochemistry. RESULTS. The PCR amplification confirmed expression of the transcript in ON bipolar cells, and Western blotting showed the expected bands. Immunostaining for Cacna1s was stronger in the dendritic tips of rod bipolar cells than in those of ON cone bipolar cells. This staining severely decreased in mice missing various mGluR6 cascade elements (Grm6(−/−), Gnao1(−/−), Gnb3(−/−), Gng13(−/−), and Trpm1(−/−)). During development, the ratio of the number of Cacna1s puncta to the number of presynaptic ribbons followed a sigmoidal pattern, rising rapidly from P13 to P17. The mGluR6 expression preceded that of Cacna1s and RGS11. CONCLUSIONS. Our results show that the localization and stability of Cacna1s depend on the expression of mGluR6 and its cascade components, and they suggest that Cacna1s is part of the mGluR6 complex. We hypothesize that Cacna1s contributes to light adaptation by permeating calcium
Relação da ginecomastia puberal com o Ãndice de massa corporal em amostra de adolescentes atendidos em Unidade de Pacientes Externos de Hospital Universitário
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