951 research outputs found

    The Euler Equations on Thin Domains

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    For the Euler equations in a thin domain Q_ε = Ω×(0, ε), Ω a rectangle in R^2, with initial data in (W^(2,q)(Qε))^3, q > 3, bounded uniformly in ε, the classical solution is shown to exist on a time interval (0, T(ε)), where T(є) → +∞ as є → 0. We compare this solution with that of a system of limiting equations on Ω

    Interpolating spatial language evolution in South America

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    Mapping language richness is essential not only for a better understanding of the lan- guages themselves, but also to gain new insights into related cultural phenomena such as migration or expansion. However, spatial language distribution data can be sparse to non-existent, depending on the time and location. In the framework of this thesis, a probabilistic method is developed to interpolate spatial language distributions over time in the case of South America, where overall information on the distribution of Indigenous languages families and Indo-European languages is provided at only two points in time: around the time of contact and around 1990. The newly developed algorithm, that allows to interpolate between given points in time, is composed of a cellular automaton as core underlying mechanism and Bayesian inference as statistical method. Follow-up research is suggested to further test the transferability of this model, thereby building a solid foundation for a globally applicable model allowing to conduct linguistic research in various regions across the globe

    New Histone Incorporation Marks Sites of UV Repair in Human Cells

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    SummaryChromatin organization is compromised during the repair of DNA damage. It remains unknown how and to what extent epigenetic information is preserved in vivo. A central question is whether chromatin reorganization involves recycling of parental histones or new histone incorporation. Here, we devise an approach to follow new histone deposition upon UV irradiation in human cells. We show that new H3.1 histones get incorporated in vivo at repair sites. Remarkably we find that H3.1, which is deposited during S phase, is also incorporated outside of S phase. Histone deposition is dependent on nucleotide excision repair (NER), indicating that it occurs at a postrepair stage. The histone chaperone chromatin assembly factor 1 (CAF-1) is directly involved in the histone deposition process in vivo. We conclude that chromatin restoration after damage cannot rely simply on histone recycling. New histone incorporation at repair sites both challenges epigenetic stability and possibly contributes to damage memory

    Phonon dispersion and low energy anomaly in CaC6_6

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    We report measurements of phonon dispersion in CaC6_6 using inelastic X-ray and neutron scattering. We find good overall agreement, particularly in the 50 meV energy region, between experimental data and first-principles density-functional-theory calculations. However, on the longitudinal dispersion along the (111)(1 1 1) axis of the rhombohedral representation, we find an unexpected anti-crossing with an additional longitudinal mode, at about 11 meV. At a comparable energy, we observe also unexpected intensity on the in-plane direction. These results resolve the previous incorrect assignment of a longitudinal phonon mode to a transverse mode in the same energy range. By calculating the electron susceptibility from first principles we show that this longitudinal excitation is unlikely to be due to a plasmon and consequently can probably be due to defects or vacancies present in the sample.Comment: Accepted for publication in Physical Review
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