2,640 research outputs found
Exploring the total Galactic extinction with SDSS BHB stars
Aims: We used 12,530 photometrically-selected blue horizontal branch (BHB)
stars from the Sloan Digital Sky Survey (SDSS) to estimate the total extinction
of the Milky Way at the high Galactic latitudes, and in each line
of sight. Methods: A Bayesian method was developed to estimate the reddening
values in the given lines of sight. Based on the most likely values of
reddening in multiple colors, we were able to derive the values of and
.
Results: We selected 94 zero-reddened BHB stars from seven globular clusters
as the template. The reddening in the four SDSS colors for the northern
Galactic cap were estimated by comparing the field BHB stars with the template
stars. The accuracy of this estimation is around 0.01\,mag for most lines of
sight. We also obtained to be around 2.40 and map within
an uncertainty of 0.1\,mag. The results, including reddening values in the four
SDSS colors, , and in each line of sight, are released on line. In
this work, we employ an up-to-date parallel technique on GPU card to overcome
time-consuming computations. We plan to release online the C++ CUDA code used
for this analysis.
Conclusions: The extinction map derived from BHB stars is highly consistent
with that from Schlegel, Finkbeiner & Davis(1998). The derived is around
2.40. The contamination probably makes the be larger.Comment: 16 pages, 13 figures, 4 tables, accepted for publication in A&
Expression of WRKY and MYB genes during infection with powdery mildew in cucumber (Cucumis sativus L)
The expression change pattern of three transcription genes (WRKY30, WRKY6 and MYB) in two cucumber lines with different powdery mildew resistance (resistant line ‘JIN5-508’ and susceptible line ‘D8’) were investigated during the infection process with powdery mildew using real-time quantitative polymerase chain reaction (RT-PCR). Gene expression analysis during different time points revealed that the expression ratio of WRKY30 was 10.08585 in D8 and 5.117667 in JIN5-508, respectively, and for WRKY6, the expression ratio was 5.396152 in D8 and 3.787322 in JIN5-508, respectively, and for MYB, the expression ratio was 14.17324 in D8 and 10.70195 in JIN5-508, respectively. Additionally, the time point of the highest relative expression ratio for the three genes was different in the two cucumber lines according to their resistance to powdery mildew, whereas the susceptible line D8 was earlier than the resistant line JIN5-508 in responding to the powdery mildew infection. We suggest that the three genes’ expressions induced by powdery mildew pathogen is related to the disease resistance, and the response of susceptible line is earlier and higher than the resistant line, which may have interactions between the three genes and other resistant genes.Key words: Cucumber, powdery mildew, gene expression pattern
Exact quantum dissipative dynamics under external time-dependent fields driving
Exact and nonperturbative quantum master equation can be constructed via the
calculus on path integral. It results in hierarchical equations of motion for
the reduced density operator. Involved are also a set of well--defined
auxiliary density operators that resolve not just system--bath coupling
strength but also memory. In this work, we scale these auxiliary operators
individually to achieve a uniform error tolerance, as set by the reduced
density operator. An efficient propagator is then proposed to the hierarchical
Liouville--space dynamics of quantum dissipation. Numerically exact studies are
carried out on the dephasing effect on population transfer in the simple
stimulated Raman adiabatic passage scheme. We also make assessments on several
perturbative theories for their applicabilities in the present system of study
Phase-controlled asymmetric optomechanical entanglement against optical backscattering
Quantum entanglement plays a key role in both understanding the fundamental
aspects of quantum physics and realizing various quantum devices for practical
applications. Here we propose how to achieve coherent switch of optomechanical
entanglement in an optical whispering-gallery-mode resonator, by tuning the
phase difference of the driving lasers. We find that the optomechanical
entanglement and the associated two-mode quantum squeezing can be well tuned in
a highly asymmetric way, providing an efficient way to protect and enhance
quantum entanglement against optical backscattering, in comparison with
conventional symmetric devices. Our findings shed a new light on improving the
performance of various quantum devices in practical noisy environment, which is
crucial in such a wide range of applications as noise-tolerant quantum
processing and the backscattering-immune quantum metrology.Comment: To be published in SCIENCE CHINA Physics, Mechanics & Astronom
VEGF attenuates development from cardiac hypertrophy to heart failure after aortic stenosis through mitochondrial mediated apoptosis and cardiomyocyte proliferation
<p>Abstract</p> <p>Background</p> <p>Aortic stenosis (AS) affects 3 percent of persons older than 65 years and leads to greater morbidity and mortality than other cardiac valve diseases. Surgery with aortic valve replacement (AVR) for severe symptomatic AS is currently the only treatment option. Unfortunately, in patients with poor ventricular function, the mortality and long-term outcome is unsatisfied, and only a minority of these patients could bear surgery. Our previous studies demonstrated that vascular endothelial growth factor (VEGF) protects cardiac function in myocardial infarction model through classic VEGF-PI3k-Akt and unclear mitochondrial anti-apoptosis pathways; promoting cardiomyocyte (CM) proliferation as well. The present study was designed to test whether pre-operative treatment with VEGF improves AS-induced cardiac dysfunction, to be better suitable for AVR, and its potential mechanism.</p> <p>Methods</p> <p>Adult male mice were subjected to AS or sham operation. Two weeks later, adenoviral VEGF (Ad-VEGF), enhanced green fluorescence protein (Ad-EGFP, as a parallel control) or saline was injected into left ventricle free wall. Two weeks after delivery, all mice were measured by echocardiography and harvested for further detection.</p> <p>Results</p> <p>AS for four weeks caused cardiac hypertrophy and left ventricular dysfunction. VEGF treatment increased capillary density, protected mitochondrial function, reduced CMs apoptosis, promoted CMs proliferation and eventually preserved cardiac function.</p> <p>Conclusions</p> <p>Our findings indicate that VEGF could repair AS-induced transition from compensatory cardiac hypertrophy to heart failure.</p
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