9,400 research outputs found
Analyses of celestial pole offsets with VLBI, LLR, and optical observations
This work aims to explore the possibilities of determining the long-period
part of the precession-nutation of the Earth with techniques other than very
long baseline interferometry (VLBI). Lunar laser ranging (LLR) is chosen for
its relatively high accuracy and long period. Results of previous studies could
be updated using the latest data with generally higher quality, which would
also add ten years to the total time span. Historical optical data are also
analyzed for their rather long time-coverage to determine whether it is
possible to improve the current Earth precession-nutation model
Characterization of the activation and allosteric regulation of photoreceptor phosphodiesterase (PDE6)
Photoreceptor phosphodiesterase (PDE6) amplifies visual signals in rod and cone photoreceptors. We developed an assay to quantify binding of radiolabeled PDE inhibitors to the catalytic sites of PDE6 to explore the activation and regulation of PDE6. We determined that both catalytic domains on the PDE6 heterodimer are catalytically active and equivalent. Only one catalytic subunit on PDE6 readily binds to and becomes activated by the G-protein, transducin. The other PDE6 catalytic site requires a large excess of activated transducin to fully activate PDE6. We conclude that transducin activates the two catalytic subunits of rod PDE6 differently. We also demonstrate direct allosteric communication between the regulatory GAF domain and catalytic domain of PDE6: binding of a fragment of the inhibitory gamma subunit to the GAF domain stabilizes radiolabeled PDE inhibitor binding to the catalytic sites; conversely, occupancy of the catalytic site by PDE inhibitors alters cGMP binding to the GAF domain
Release of virtual photon and phonon pairs from qubit-plasmon-phonon ultrastrong coupling system
The most important difference between ultrastrong and non-ultrastrong
coupling regimes is that the ground state contains excitations. We consider a
qubit-plasmon-phonon ultrastrong coupling (USC) system with a three-level atom
coupled to the photon and phonon via its upper two energy levels and show that
spontaneous emission of the atom from its intermediate to its ground state
produces photon and phonon pairs. It is shown that the current system can
produce a strong photon/phonon stream and the atom-phonon coupling plays the
active role, which ensures the experimental detection. The emission spectrum
and various high-order correlation functions confirm the generation of the
pairs of photons and phonons. Our study has important implications for future
research on virtual photon and phonon pairs creation in the ground state of the
USC regime.Comment: 9 pages, 7 figure
Quantum heat valve and diode of strongly coupled defects in amorphous material
The mechanical strain can control the frequency of two-level atoms in
amorphous material. In this work, we would like to employ two coupled two-level
atoms to manipulate the magnitude and direction of heat transport by
controlling mechanical strain to realize the function of a thermal switch and
valve. It is found that a high-performance heat diode can be realized in the
wide Piezo voltage range at different temperatures. We also discuss the
dependence of the rectification factor on temperatures and couplings of heat
reservoirs. We find that the higher temperature differences correspond to the
larger rectification effect. The asymmetry system-reservoir coupling strength
can enhance the magnitude of heat transfer, and the impact of asymmetric and
symmetric coupling strength on the performance of the heat diode is
complementary. It may provide an efficient way to modulate and control heat
transport's magnitude and flow preference. This work may give insight into
designing and tuning quantum heat machines.Comment: 10 pages, 9 figures;Accepted for publication in Physical Review
On the Translation of Chinese Webcomics: A Case Study of My Dear Highness
This paper discusses how to translate Chinese webcomic strips using My Dear Highness as an example. In our translation practice, such methods as variation translation, omission, and shift were adopted to deal with address forms or lengthy sentences, while free translation was used to deal with four-character structures and culture-loaded words or phrases in the original text to the effect that the intended meaning of the source text can be accurately conveyed to target readers under a multimodal context. We believe that whatever methods are used, the ultimate purpose of translation remains the same, and that is, the reading experience provided by the original text can be restored to the greatest possible extent
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