1,407 research outputs found
Optimal Quantization in Energy-Constrained Sensor Networks under Imperfect Transmission
This paper addresses the optimization of quantization at local sensors under strict energy constraint and imperfect transmission to improve the reconstruction performance at the fusion center in the wireless sensor networks (WSNs). We present optimized quantization scheme including the optimal quantization bit rate and the optimal transmission power allocation among quantization bits for BPSK signal and binary orthogonal signal with envelope detection, respectively. The optimization of the quantization is formulated as a convex problem and the optimal solution is derived analytically in both cases. Simulation results demonstrate the effectiveness of our proposed quantization schemes
Six-month adherence to Statin use and subsequent risk of major adverse cardiovascular events (MACE) in patients discharged with acute coronary syndromes
Acknowledgements: The authors thank all participants who contributed to the study. Funding: CPACS-1 was funded by unrestricted educational grants from Guidant and Sanofi-Aventis, and grants from The Royal Australasian College of Physicians. AP is supported by an Australian National Heart Foundation Career Development Award. CPACS-2 was funded by an unrestricted grant from Sanofi-Aventis China. The George Institute for Global Health at Peking University Health Science Center sponsored the study and owns the data. Data analyses and reports were supported by Beijing Science and Technology Key Research Plan (D151100002215001). However, the authors are solely responsible for the design, analyses, the drafting and editing of the manuscript, and its final contents.Peer reviewedPublisher PD
Cardiac Biomarkers Predicting MACE in Patients Undergoing Noncardiac Surgery: A Meta-Analysis
Objective: The present meta-analysis was aimed to systematically evaluate the effectiveness and accuracy of brain natriuretic peptide (BNP), cardiac troponin (cTn), high sensitive C reactive protein (hs-CRP) and CRP for predicting postoperative major adverse cardiovascular events (MACE) in patients undergoing noncardiac surgery.Methods: A total of 26 relevant studies with 7,877 participants were collected from five databases, namely PubMed, Embase, China National Knowledge Infrastructure (CNKI), CQVIP and the Wanfang Database until August 10, 2018. And the Review Manager Version 5.3 and Stata/SE 12 software were used for data syntheses in the meta-analysis.Results: Strong relationships of BNP/NT-proBNP, cTnI/cTnT and hs-CRP with MACE were detected in patients undergoing noncardiac surgery, and the five biomarkers all increased the risk of MACE. Compared to normal levels, elevated BNP/NT-proBNP could increase the MACE risk by almost 4-fold [RR:3.92, 95%CI: 3.23–4.75, P < 0.001]; elevated BNP corresponded to a 4.5-fold risk [RR:4.57, 95%CI: 3.37–6.20, P < 0.001]; elevated NT-proBNP led to a 3-fold higher risk [RR:3.48, 95%CI: 2.71–4.46, P < 0.001]. Comparing with normal levels of cTnI/cTnT, increased cTnI/cTnT was associated with nearly 5-fold more higher risk of MACE [RR:5.52, 95%CI: 4.62–6.58, P < 0.001]; elevated cTnI faced a 5-fold risk [RR:5.21, 95%CI: 3.96–6.86, P < 0.001]; elevated cTnT resulted in nearly 6-fold higher risk [RR:5.73, 95%CI: 4.55–7.22, P < 0.001]. The elevation of hs-CRP was associated with nearly 4-fold higher risk of MACE in comparison with normal concentration [RR:3.73, 95%CI: 2.63–5.30, P < 0.001].Conclusion: According to the results of our meta-analysis, the elevations of BNP/NT-proBNP, cTnI/cTnT, and hs-CRP, pre-operation or post-operation immediately, can predict much higher risk of postoperative MACE in patients undergoing noncardiac surgery
Design of a small reverberation box based on BEM-SEA method
The reverberation chamber which was used to test sound absorption and insulation performance in the reverberation space had the following problems. Firstly, the construction cost of the reverberation chamber was high. Secondly, the test can’t be completed when the size of the specimen was too small. As a result, a small reverberation box with a relatively small size had significant meaning. The previous researchers designed the small reverberation box by using the traditional experience and theory formulas which had a long period and high cost. In order to solve this problem, simulation analysis on sound insulation performance of a compound structure through Statistical Energy Analysis (SEA) was proposed. And then the sound field distribution of the small reverberation box was simulated by Boundary Element Method (BEM). According to the simulation results, the model was optimized repeatedly. And finally a small reverberation box model with sufficient sound insulation performance and uniform sound field was obtained. The actual structure was made based on simulation model, and its sound characteristic was tested. The results showed that the small reverberation box had an excellent performance. BEM-SEA method was feasible to be used to design a small reverberation box
Thermal Properties of Liquid Iron at Conditions of Planetary Cores
Thermal properties of iron at high pressures (P) and temperatures (T) are essential for determining the internal structure and evolution of planetary cores. Compared to its solid counterpart, the liquid phase of iron is less studied and existing results exhibit large discrepancies, hindering a proper understanding of planetary cores. Here we use the formally exact urn:x-wiley:21699097:media:jgre21861:jgre21861-math-0019 thermodynamic integration approach to calculate thermal properties of liquid iron up to 3.0 TPa and 25000 K. Uncertainties associated with theory are compensated by introducing a T-independent pressure shift based on experimental data. The resulting thermal equation of state agrees well with the diamond anvil cell (DAC) data in the P-T range of measurements. At higher P-T it matches the reduced shock wave data yet deviates considerably from the extrapolations of DAC measurements, indicating the latter may require further examinations. Moreover, the calculated heat capacity and thermal expansivity are substantially lower than some recent reports, which have important ramifications for understanding thermal evolutions of planetary cores. Using Kepler-36b as a prototype, we examine how a completely molten core may affect the P-T profiles of massive exoplanets. By comparing the melting slope and the adiabatic slope along the iron melting line, we propose that crystallization of the cores of massive planets proceeds from the bottom-up rather than the top-down
On the Generation of Medical Question-Answer Pairs
Question answering (QA) has achieved promising progress recently. However,
answering a question in real-world scenarios like the medical domain is still
challenging, due to the requirement of external knowledge and the insufficient
quantity of high-quality training data. In the light of these challenges, we
study the task of generating medical QA pairs in this paper. With the insight
that each medical question can be considered as a sample from the latent
distribution of questions given answers, we propose an automated medical QA
pair generation framework, consisting of an unsupervised key phrase detector
that explores unstructured material for validity, and a generator that involves
a multi-pass decoder to integrate structural knowledge for diversity. A series
of experiments have been conducted on a real-world dataset collected from the
National Medical Licensing Examination of China. Both automatic evaluation and
human annotation demonstrate the effectiveness of the proposed method. Further
investigation shows that, by incorporating the generated QA pairs for training,
significant improvement in terms of accuracy can be achieved for the
examination QA system.Comment: AAAI 202
THE INFLUENCE OF BACKPACK CARRIAGE ON TRUNK POSTURE IN CHILDREN DURING UNPLANNED GAIT TERMINATION
This study aimed to examine the trunk posture in children with different backpack loads during unplanned gait termination. Twelve school boys aged 9–10 years completed unplanned and planned gait termination with a backpack load of 0%, 10%, and 15% of their body weight (BW) while level walking. Trunk inclination angle and trunk range of motion at sagittal plane and spinal angle at frontal plane were examined. In comparison
with 0% BW load condition, the spinal angle increased significantly at 10% and 15% BW load condition during gait termination (
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