1,479 research outputs found
In situ characterization of an optical cavity using atomic light shift
We report the precise characterization of the optical potential obtained by
injecting a distributed-feedback erbium-doped fiber laser (DFB EDFL) at 1560 nm
to the transversal modes of a folded optical cavity. The optical potential was
mapped in situ using cold rubidium atoms, whose potential energy was spectrally
resolved thanks to the strong differential light shift induced by the 1560 nm
laser on the two levels of the probe transition. The optical potential obtained
in the cavity is suitable for trapping rubidium atoms, and eventually to
achieve all-optical Bose-Einstein condensation directly in the resonator.Comment: 3 pages, 4 figure
Using a Case Study to Teach Leaders How to Enact Positive Organizational Change
https://digitalcommons.usmalibrary.org/books/1062/thumbnail.jp
Analysis of large-scale sequencing of small RNAs
The advent of large-scale sequencing has opened up new areas of research, such as the study of Piwi-interacting small RNAs (piRNAs). piRNAs are longer than miRNAs, close to 30 nucleotides in length, involved in various functions, such as the suppression of transposons in germline. Since a large number of them (many tens of thousands) are generated from a wide range of positions in the genome, large-scale sequencing is the only way to study them. The key to understanding their genesis and biological roles is efficient analysis, which is complicated by the large volumes of sequence data. Taking account of the underlying biology is also important. We describe here novel analyses techniques and tools applied to small RNAs from germ cells in D. melanogaster, that allowed us to infer mechanism and biological function
Dynamical Coupling between a Bose-Einstein Condensate and a Cavity Optical Lattice
A Bose-Einstein condensate is dispersively coupled to a single mode of an
ultra-high finesse optical cavity. The system is governed by strong
interactions between the atomic motion and the light field even at the level of
single quanta. While coherently pumping the cavity mode the condensate is
subject to the cavity optical lattice potential whose depth depends nonlinearly
on the atomic density distribution. We observe bistability already below the
single photon level and strong back-action dynamics which tunes the system
periodically out of resonance.Comment: 5 pages, 4 figure
An epigenetic role for maternally inherited piRNAs in transposon silencing
In plants and mammals, small RNAs indirectly mediate epigenetic inheritance by specifying cytosine methylation. We found that small RNAs themselves serve as vectors for epigenetic information. Crosses between Drosophila strains that differ in the presence of a particular transposon can produce sterile progeny, a phenomenon called hybrid dysgenesis. This phenotype manifests itself only if the transposon is paternally inherited, suggesting maternal transmission of a factor that maintains fertility. In both P- and I-element-mediated hybrid dysgenesis models, daughters show a markedly different content of Piwi-interacting RNAs (piRNAs) targeting each element, depending on their parents of origin. Such differences persist from fertilization through adulthood. This indicates that maternally deposited piRNAs are important for mounting an effective silencing response and that a lack of maternal piRNA inheritance underlies hybrid dysgenesis
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