9 research outputs found

    CMB quadrupole suppression: II. The early fast roll stage

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    Within the effective field theory of inflation, an initialization of the classical dynamics of the inflaton with approximate equipartition between the kinetic and potential energy of the inflaton leads to a brief fast roll stage that precedes the slow roll regime. The fast roll stage leads to an attractive potential in the wave equations for the mode functions of curvature and tensor perturbations. The evolution of the inflationary perturbations is equivalent to the scattering by this potential and a useful dictionary between the scattering data and observables is established.Implementing methods from scattering theory we prove that this attractive potential leads to a suppression of the quadrupole moment for CMB and B-mode angular power spectra. The scale of the potential is determined by the Hubble parameter during slow roll. Within the effective field theory of inflation at the grand unification (GUT) energy scale we find that if inflation lasts a total number of efolds N_{tot} ~ 59, there is a 10-20% suppression of the CMB quadrupole and about 2-4% suppression of the tensor quadrupole. The suppression of higher multipoles is smaller, falling off as 1/l^2. The suppression is much smaller for N_{tot} > 59, therefore if the observable suppression originates in the fast roll stage, there is the upper bound N_{tot} ~ 59.Comment: Some comments and references adde

    The influence of clan structure on the genetic variation in a single Ghanaian village

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    Genomics, epigenetics, population genetics and bioinformatic

    The Y chromosome as the most popular marker in genetic genealogy benefits interdisciplinary research

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    The Y chromosome is currently by far the most popular marker in genetic genealogy that combines genetic data and family history. This popularity is based on its haploid character and its close association with the patrilineage and paternal inherited surname. Other markers have not been found (yet) to overrule this status due to the low sensitivity and precision of autosomal DNA for genetic genealogical applications, given the vagaries of recombination, and the lower capacities of mitochondrial DNA combined with an in general much lower interest in maternal lineages. The current knowledge about the Y chromosome and the availability of markers with divergent mutation rates make it possible to answer questions on relatedness levels which differ in time depth; from the individual and familial level to the surnames, clan and population level. The use of the Y chromosome in genetic genealogy has led to applications in several well-established research disciplines; namely in, e.g., family history, demography, anthropology, forensic sciences, population genetics and sex chromosome evolution. The information obtained from analysing this chromosome is not only interesting for academic scientists but also for the huge and lively community of amateur genealogists and citizen-scientists, fascinated in analysing their own genealogy or surname. This popularity, however, has also some drawbacks, mainly for privacy reasons related to the DNA donor, his close family and far-related namesakes. In this review paper we argue why Y-chromosomal analysis and its genetic genealogical applications will still perform an important role in future interdisciplinary research
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