1,220 research outputs found
HS-CAI: A Hybrid DCOP Algorithm via Combining Search with Context-based Inference
Search and inference are two main strategies for optimally solving
Distributed Constraint Optimization Problems (DCOPs). Recently, several
algorithms were proposed to combine their advantages. Unfortunately, such
algorithms only use an approximated inference as a one-shot preprocessing phase
to construct the initial lower bounds which lead to inefficient pruning under
the limited memory budget. On the other hand, iterative inference algorithms
(e.g., MB-DPOP) perform a context-based complete inference for all possible
contexts but suffer from tremendous traffic overheads. In this paper,
hybridizing search with context-based inference, we propose a complete
algorithm for DCOPs, named {HS-CAI} where the inference utilizes the contexts
derived from the search process to establish tight lower bounds while the
search uses such bounds for efficient pruning and thereby reduces contexts for
the inference. Furthermore, we introduce a context evaluation mechanism
to select the context patterns for the inference to further reduce the
overheads incurred by iterative inferences. Finally, we prove the
correctness of our algorithm and the experimental results demonstrate its
superiority over the state-of-the-art
Analytical Solution of Poisson's Equation with Application to VLSI Global Placement
Poisson's equation has been used in VLSI global placement for describing the
potential field caused by a given charge density distribution. Unlike previous
global placement methods that solve Poisson's equation numerically, in this
paper, we provide an analytical solution of the equation to calculate the
potential energy of an electrostatic system. The analytical solution is derived
based on the separation of variables method and an exact density function to
model the block distribution in the placement region, which is an infinite
series and converges absolutely. Using the analytical solution, we give a fast
computation scheme of Poisson's equation and develop an effective and efficient
global placement algorithm called Pplace. Experimental results show that our
Pplace achieves smaller placement wirelength than ePlace and NTUplace3. With
the pervasive applications of Poisson's equation in scientific fields, in
particular, our effective, efficient, and robust computation scheme for its
analytical solution can provide substantial impacts on these fields
High photo-excited carrier multiplication by charged InAs dots in AlAs/GaAs/AlAs resonant tunneling diode
We present an approach for the highly sensitive photon detection based on the
quantum dots (QDs) operating at temperature of 77K. The detection structure is
based on an AlAs/GaAs/AlAs double barrier resonant tunneling diode combined
with a layer of self-assembled InAs QDs (QD-RTD). A photon rate of 115 photons
per second had induced 10nA photocurrent in this structure, corresponding to
the photo-excited carrier multiplication factor of 10^7. This high
multiplication factor is achieved by the quantum dot induced memory effect and
the resonant tunneling tuning effect of QD-RTD structure.Comment: 10 pages,5 figures. Submitted to Applied Physics Letter
Individual and Combined Effects of Herbicide Tribenuron-Methyl and Fungicide Tebuconazole on Soil Earthworm \u3cem\u3eEisenia fetida\u3c/em\u3e
Earthworms are soil engineers that alter the soil bio-physical properties to favor plant growth whereas pesticides represent a significant threat to their abundance and soil health. Thus, we investigated the toxic effects of tribenuron-methyl (TBM) and tebuconazole (TEB) on the soil earthworm, Eisenia fetida. The TBM demonstrated low toxicity to E. fetida in the contact filter paper and artificial soil tests, with median lethal concentrations (LC50) of 135.6âÎŒgâcmâ2 at 48âh and 511âmgâkgâ1 on day 14, respectively. Similarly, TEB also showed low toxicity to E. fetida in the artificial soil test with LC50 of 287âmgâkgâ1 on day 14. However, TEB was highly toxic to earthworm in the contact filter paper test with LC50 of 5.7âÎŒgâcmâ2 at 48âh. The mixture of two pesticides had an antagonistic effect on the earthworm. Under 0.1 LC50 of TBM and TEB, either single or combined application of pesticides induced oxidative stress and inhibited cellulase activity in early days of the earthworm exposure. However, both pesticides did not damage the earthworm DNA. Our results suggest that pesticides can negatively affect soil earthworms and provide valuable information regarding the responses of soil biological engineers to the lethal agrochemicals
Jitter analysis of a superconducting nanowire single photon detector
Jitter is one of the key parameters for a superconducting nanowire single
photon detector (SNSPD). Using an optimized time-correlated single photon
counting system for jitter measurement, we extensively studied the dependence
of system jitter on the bias current and working temperature. The
signal-to-noise ratio of the single-photon-response pulse was proven to be an
important factor in system jitter. The final system jitter was reduced to 18 ps
by using a high-critical-current SNSPD, which showed an intrinsic SNSPD jitter
of 15 ps. A laser ranging experiment using a 15-ps SNSPD achieved a record
depth resolution of 3 mm at a wavelength of 1550 nm.Comment: 7 pages, 6 figure
Isobavachalcone Sensitizes Cells to E2-Induced Paclitaxel Resistance by Down-Regulating CD44 Expression in ER+ Breast Cancer Cells
Oestrogen receptor (ER) is expressed in approximately 60%â70% of human breast cancer. Clinical trials and retrospective analyses have shown that ERâpositive (ER+) tumours are more tolerant to chemotherapeutic drug resistance than ERânegative (ERâ) tumours. In addition, isobavachalcone (IBC) is known as a kind of phytoestrogen with antitumour effect. However, the underlying mechanism of IBC in ER+ breast cancer needs to be elucidated further. Our in vitro experiments showed that IBC could attenuate 17ÎČâestradiol (E2)âinduced paclitaxel resistance and that E2 could stimulate CD44 expression in ER+ breast cancer cells but not in ERâ cells. Meanwhile, E2 could promote ERα expression to render ER+ breast cancer cells resistant to paclitaxel. Furthermore, we established paclitaxelâresistant breast cancer cell lines and determined the function of ERα in the enhancement of paclitaxel resistance via the regulation of CD44 transcription. IBC downâregulated ERα and CD44 expression and thus inhibited tumour growth in paclitaxelâresistant xenograft models. Overall, our data demonstrated for the first time that IBC could decrease CD44 expression level via the ERα pathway and make ER+ breast cancer cells sensitive to paclitaxel treatment
Correlation and entanglement of two-component Bose-Einstein condensates in a double well
We consider a novel system of two-component atomic Bose-Einstein condensate
in a double-well potential. Based on the well-known two-mode approximation, we
demonstrate that there are obvious avoided level-crossings when both
interspecies and intraspecies interactions of two species are increased. The
quantum dynamics of the system exhibits revised oscillating behaviors compared
with a single component condensate. We also examine the entanglement of two
species. Our numerical calculations show the onset of entanglement can be
signed as a violation of Cauchy-Schwarz inequality of second-order cross
correlation function. Consequently, we use Von Neumann entropy to quantity the
degree of entanglement
Rapamycin Attenuates Endothelial Apoptosis Induced by Low Shear Stress via mTOR and Sestrin1 Related Redox Regulation
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In situ grown palladium nanoparticles on polyester fabric as easy-separable and recyclable catalyst for Suzuki-Miyaura reaction
Palladium nanoparticles supported on low-melting polyester (Pd/LMPET) fabric were prepared through a microwave irradiation assisted method. In this way, in situ growth of Pd nanoparticles onto an easy to handle material was initiated and proceeded. The results of the characterization revealed that the palladium nanoparticles were well-dispersed on the surfaces of the polyester fibers. The Pd/LMPET fabrics were then employed in the Suzuki-Miyaura coupling. They exhibited excellent catalytic activity in ethanol/water under air atmosphere at 50 °C. Importantly, the Pd/LMPET fabrics could be separated from reaction mixture conveniently and they can still maintain good activity after 8 cycles without Pd leaching. © 2021 The Author
Diurnal concentrations, sources, and cancer risk assessments of 1 PM 2.5 -bound PAHs, NPAHs, and OPAHs in urban, marine and 2 mountain environments
International audienceAmbient measurements of PM2.5-bounded polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and oxy-PAHs (OPAHs) were conducted during the summer in Jinan, China, an urban site, and at Tuoji island and Mt. Tai, two background locations. 3.5 h and 11.5 h sampling intervals in daytime and nighttime were utilized to research the diurnal variations of PAHs, NPAHs, and OPAHs. The concentrations of PAHs, NPAHs, and OPAHs were highest at the urban site and lowest at the marine site. The diurnal patterns of PAHs and NPAHs at the urban and marine sites were dissimilar to those observed at the mountain site partly due to the influence of the boundary layer. Vehicle emissions at the urban site made a large contribution to high molecular weight PAHs. 1N-PYR and 7N-BaA during morning and night sampling periods in JN were relatively high. Fossil fuel combustion and biomass burning were the main sources for all three sites during the sampling periods. The air masses at the marine and mountain sites were strongly impacted by photo-degradation, and the air masses at the marine site were the most aged. Secondary formation of NPAHs was mainly initiated by OH radicals at all the three sites and was strongest at the marine site. Secondary formation was most efficient during the daytime at the urban and mountain sites and during morning periods at the marine site. The average excess cancer risk from inhalation (ECR) for 70 years' life span at the urban site was much higher than those calculated for the background sites
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