1,737 research outputs found
Spontaneously generated atomic entanglement in free space: reinforced by incoherent pumping
We study spontaneously generated entanglement (SGE) between two identical
multilevel atoms in free space via vacuum-induced radiative coupling. We show
that the SGE in two-atom systems may initially increase with time but
eventually vanishes in the time scale determined by the excited state lifetime
and radiative coupling strength between the two atoms. We demonstrate that a
steady-state SGE can be established by incoherently pumping the excited states
of the two-atom system. We have shown that an appropriate rate of incoherent
pump can help producing optimal SGE. The multilevel systems offer us more
chanel to establish entanglement. The system under consideration could be
realized in a tight trap or atoms/ions doped in a solid substrate.Comment: have some difference with published version (please see PRA
Responses of mRNA expression of PepT1 in small intestine to graded duodenal soybean small peptides infusion in lactating goats
To study the effect of circulation small peptides concentration on mRNA expression in small intestine, graded amount of soybean small peptides (SSP) were infused into lactating goats through duodenal fistulas. Peptide-bound amino acid (PBAA) concentration in arterial plasma and the mRNA expression of PepT1 was detected in the current study. The results showed that concentrations of all peptidebound amino acids (PBAA) increased and the activity of PepT1 in duodenum tissue was enhanced by SSP infusion. The PepT1expression in duodenum tissue was significantly increased with the increment of amounts of SSP infusion (
Scale-invariance of human EEG signals in sleep
We investigate the dynamical properties of electroencephalogram (EEG) signals
of human in sleep. By using a modified random walk method, We demonstrate that
the scale-invariance is embedded in EEG signals after a detrending procedure.
Further more, we study the dynamical evolution of probability density function
(PDF) of the detrended EEG signals by nonextensive statistical modeling. It
displays scale-independent property, which is markedly different from the
turbulent-like scale-dependent PDF evolution.Comment: 4 pages and 6 figure
Control of Formation-Flying Multi-Element Space Interferometers with Direct Interferometer-Output Feedback
The long-baseline space interferometer concept involving formation flying of multiple spacecrafts holds great promise as future space missions for high-resolution imagery. A major challenge of obtaining high-quality interferometric synthesized images from long-baseline space interferometers is to accurately control these spacecraft and their optics payloads in the specified configuration. Our research focuses on the determination of the optical errors to achieve fine control of long-baseline space interferometers without resorting to additional sensing equipment. We present a suite of estimation tools that can effectively extract from the raw interferometric image relative x/y, piston translational and tip/tilt deviations at the exit pupil aperture. The use of these error estimates in achieving control of the interferometer elements is demonstrated using simulated as well as laboratory-collected interferometric stellar images
Geometry and optics calibration of WFCTA prototype telescopes using star light
The Large High Altitude Air Shower Observatory project is proposed to study
high energy gamma ray astronomy ( 40 GeV-1 PeV ) and cosmic ray physics ( 20
TeV-1 EeV ). The wide field of view Cherenkov telescope array, as a component
of the LHAASO project, will be used to study energy spectrum and compositions
of cosmic ray by measuring the total Cherenkov light generated by air showers
and shower maximum depth. Two prototype telescopes have been in operation since
2008. The pointing accuracy of each telescope is crucial to the direction
reconstruction of the primary particles. On the other hand the primary energy
reconstruction relies on the shape of the Cherenkov image on the camera and the
unrecorded photons due to the imperfect connections between photomultiplier
tubes. UV bright stars are used as point-like objects to calibrate the pointing
and to study the optical properties of the camera, the spot size and the
fractions of unrecorded photons in the insensitive areas of the camera.Comment: 5 pages, 6 figures, submitted to Chinese Physics
Control of Formation-Flying Multi-Element Space Interferometers with Direct Interferometer-Output Feedback
The long-baseline space interferometer concept involving formation flying of multiple spacecraft holds great promise as future space missions for high-resolution imagery. A major challenge of obtaining high-quality interferometric synthesized images from long-baseline space interferometers is to accurately control these spacecraft and their optics payloads in the specified configuration. Our research focuses on the determination of the optical errors to achieve fine control of long-baseline space interferometers without resorting to additional sensing equipment. We present a suite of estimation tools that can effectively extract from the raw interferometric image relative x/y, piston translational and tip/tilt deviations at the exit pupil aperture. The use of these error estimates in achieving control of the interferometer elements is demonstrated using simulated as well as laboratory-collected interferometric stellar images
Comparison of the Geometrical Characters Inside Quark- and Gluon-jet Produced by Different Flavor Quarks
The characters of the angular distributions of quark jets and gluon jets with
different flavors are carefully studied after introducing the cone angle of
jets. The quark jets and gluon jets are identified from the 3-jet events which
are produced by Monte Carlo simulation Jetset7.4 in e+e- collisions at =91.2GeV. It turns out that the ranges of angular distributions of gluon jets
are obviously wider than that of quark jets at the same energies. The average
cone angles of gluon jets are much larger than that of quark jets. As the
multiplicity or the transverse momentum increases, the cone-angle distribution
without momentum weight of both the quark jet and gluon jet all increases, i.e
the positive linear correlation are present, but the cone-angle distribution
with momentum weight decreases at first, then increases when n > 4 or p_t > 2
GeV. The characters of cone angular distributions of gluon jets produced by
quarks with different flavors are the same, while there are obvious differences
for that of the quark jets with different flavors.Comment: 13 pages, 6 figures, to be published on the International Journal of
Modern Physics
Fucosyltransferase 1 and 2 play pivotal roles in breast cancer cells.
FUT1 and FUT2 encode alpha 1, 2-fucosyltransferases which catalyze the addition of alpha 1, 2-linked fucose to glycans. Glycan products of FUT1 and FUT2, such as Globo H and Lewis Y, are highly expressed on malignant tissues, including breast cancer. Herein, we investigated the roles of FUT1 and FUT2 in breast cancer. Silencing of FUT1 or FUT2 by shRNAs inhibited cell proliferation in vitro and tumorigenicity in mice. This was associated with diminished properties of cancer stem cell (CSC), including mammosphere formation and CSC marker both in vitro and in xenografts. Silencing of FUT2, but not FUT1, significantly changed the cuboidal morphology to dense clusters of small and round cells with reduced adhesion to polystyrene and extracellular matrix, including laminin, fibronectin and collagen. Silencing of FUT1 or FUT2 suppressed cell migration in wound healing assay, whereas FUT1 and FUT2 overexpression increased cell migration and invasion in vitro and metastasis of breast cancer in vivo. A decrease in mesenchymal like markers such as fibronectin, vimentin, and twist, along with increased epithelial like marker, E-cadherin, was observed upon FUT1/2 knockdown, while the opposite was noted by overexpression of FUT1 or FUT2. As expected, FUT1 or FUT2 knockdown reduced Globo H, whereas FUT1 or FUT2 overexpression showed contrary effects. Exogenous addition of Globo H-ceramide reversed the suppression of cell migration by FUT1 knockdown but not the inhibition of cell adhesion by FUT2 silencing, suggesting that at least part of the effects of FUT1/2 knockdown were mediated by Globo H. Our results imply that FUT1 and FUT2 play important roles in regulating growth, adhesion, migration and CSC properties of breast cancer, and may serve as therapeutic targets for breast cancer
Is clopidogrel better than aspirin following breakthrough strokes while on aspirin? A retrospective cohort study.
ObjectiveThere is insufficient evidence on which to base a recommendation for optimal antiplatelet therapy following a stroke while on aspirin. The objective was to compare clopidogrel initiation vs aspirin reinitiation for vascular risk reduction among patients with ischaemic stroke on aspirin at the time of their index stroke.DesignRetrospective.SettingWe conducted a nationwide cohort study by retrieving all hospitalised patients (≥18 years) with a primary diagnosis of ischaemic stroke between 2003 and 2009 from Taiwan National Health Insurance Research Database.ParticipantsAmong 3862 patients receiving aspirin before the index ischaemic stroke and receiving either aspirin or clopidogrel after index stroke during follow-up period, 1623 were excluded due to a medication possession ratio <80%. Also, 355 were excluded due to history of atrial fibrillation, valvular heart disease or coagulopathy. Therefore, 1884 patients were included in our final analysis.InterventionsPatients were categorised into two groups based on whether clopidogrel or aspirin was prescribed during the follow-up period. Follow-up was from time of the index stroke to admission for recurrent stroke or myocardial infarction, death or the end of 2010.Primary and secondary outcome measuresThe primary end point was hospitalisation due to a new-onset major adverse cardiovascular event (MACE: composite of any stroke or myocardial infarction). The leading secondary end point was any recurrent stroke.ResultsCompared to aspirin, clopidogrel was associated with a lower occurrence of future MACE (HR=0.54, 95% CI 0.43 to 0.68, p<0.001, number needed to treat: 8) and recurrent stroke (HR=0.54, 95% CI 0.42 to 0.69, p<0.001, number needed to treat: 9) after adjustment of relevant covariates.ConclusionsAmong patients with an ischaemic stroke while taking aspirin, clopidogrel initiation was associated with fewer recurrent vascular events than aspirin reinitiation
Nematicide influence on cotton yield and plant-parasitic nematodes in conventional and sod-based crop rotation
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