Seismic Waveform Inversion Using the Finite-Difference Contrast Source Inversion Method

This paper extends the finite-difference contrast source inversion method to reconstruct the mass density for two-dimensional elastic wave inversion in the framework of the full-waveform inversion. The contrast source inversion method is a nonlinear iterative method that alternatively reconstructs contrast sources and contrast function. One of the most outstanding advantages of this inversion method is the highly computational efficiency, since it does not need to simulate a full forward problem for each inversion iteration. Another attractive feature of the inversion method is that it is of strong capability in dealing with nonlinear inverse problems in an inhomogeneous background medium, because a finite-difference operator is used to represent the differential operator governing the two-dimensional elastic wave propagation. Additionally, the techniques of a multiplicative regularization and a sequential multifrequency inversion are employed to enhance the quality of reconstructions for this inversion method. Numerical reconstruction results show that the inversion method has an excellent performance for reconstructing the objects embedded inside a homogeneous or an inhomogeneous background medium

COVID-19 causes record decline in global CO2 emissions

The considerable cessation of human activities during the COVID-19 pandemic has affected global energy use and CO2 emissions. Here we show the unprecedented decrease in global fossil CO2 emissions from January to April 2020 was of 7.8% (938 Mt CO2 with a +6.8% of 2-{\sigma} uncertainty) when compared with the period last year. In addition other emerging estimates of COVID impacts based on monthly energy supply or estimated parameters, this study contributes to another step that constructed the near-real-time daily CO2 emission inventories based on activity from power generation (for 29 countries), industry (for 73 countries), road transportation (for 406 cities), aviation and maritime transportation and commercial and residential sectors emissions (for 206 countries). The estimates distinguished the decline of CO2 due to COVID-19 from the daily, weekly and seasonal variations as well as the holiday events. The COVID-related decreases in CO2 emissions in road transportation (340.4 Mt CO2, -15.5%), power (292.5 Mt CO2, -6.4% compared to 2019), industry (136.2 Mt CO2, -4.4%), aviation (92.8 Mt CO2, -28.9%), residential (43.4 Mt CO2, -2.7%), and international shipping (35.9Mt CO2, -15%). Regionally, decreases in China were the largest and earliest (234.5 Mt CO2,-6.9%), followed by Europe (EU-27 & UK) (138.3 Mt CO2, -12.0%) and the U.S. (162.4 Mt CO2, -9.5%). The declines of CO2 are consistent with regional nitrogen oxides concentrations observed by satellites and ground-based networks, but the calculated signal of emissions decreases (about 1Gt CO2) will have little impacts (less than 0.13ppm by April 30, 2020) on the overserved global CO2 concertation. However, with observed fast CO2 recovery in China and partial re-opening globally, our findings suggest the longer-term effects on CO2 emissions are unknown and should be carefully monitored using multiple measures

Near-real-time monitoring of global CO₂ emissions reveals the effects of the COVID-19 pandemic

The COVID-19 pandemic is impacting human activities, and in turn energy use and carbon dioxide (CO₂) emissions. Here we present daily estimates of country-level CO2 emissions for different sectors based on near-real-time activity data. The key result is an abrupt 8.8% decrease in global CO₂ emissions (−1551 Mt CO₂) in the first half of 2020 compared to the same period in 2019. The magnitude of this decrease is larger than during previous economic downturns or World War II. The timing of emissions decreases corresponds to lockdown measures in each country. By July 1st, the pandemic’s effects on global emissions diminished as lockdown restrictions relaxed and some economic activities restarted, especially in China and several European countries, but substantial differences persist between countries, with continuing emission declines in the U.S. where coronavirus cases are still increasing substantially

Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic

The COVID-19 pandemic is impacting human activities, and in turn energy use and carbon dioxide (CO2) emissions. Here we present daily estimates of country-level CO2 emissions for different sectors based on near-real-time activity data. The key result is an abrupt 8.8% decrease in global CO2 emissions (−1551 Mt CO2) in the first half of 2020 compared to the same period in 2019. The magnitude of this decrease is larger than during previous economic downturns or World War II. The timing of emissions decreases corresponds to lockdown measures in each country. By July 1st, the pandemic’s effects on global emissions diminished as lockdown restrictions relaxed and some economic activities restarted, especially in China and several European countries, but substantial differences persist between countries, with continuing emission declines in the U.S. where coronavirus cases are still increasing substantially

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Quantum correlation of path-entangled two-photon states in waveguide arrays with defects

We study the quantum correlation of path-entangled states of two photons in coupled one-dimensional waveguide arrays with lattice defects. Both off-diagonal and diagonal defects are considered, which show different effects on the quantum correlation of path-entangled two-photon states. Two-photon bunching or anti-bunching effects can be observed and controlled. The two photons are found to have a tendency to bunch at the side lobes with a repulsive off-diagonal defect, and the path-entanglement of the input two-photon state can be preserved during the propagation. We also found that defect modes may play an important role on the two-photon correlation of path-entangled states in the waveguide arrays. Due to the quantum interference effect, intriguing evolution dynamics of the two-photon correlation matrix elements with oscillation frequencies being either twice of or the same as that of a classical light wave, depending on the position of the correlation matrix element, is observed. Our results show that it is possible to manipulate the two-photon correlation properties of path-entangled states in waveguide arrays with lattice defects

The exploration of Ti/SnO2-Sb anode/air diffusion cathode/UV dual photoelectric catalytic coupling system for the biological harmless treatment of real antibiotic industrial wastewater

The real antibiotic industrial wastewater with the characteristics of complex compositions, biological toxic, and degradation-resistant, is still biologically toxic to the ecosystem and human health even if the discharge standards have been met after treatment by traditional methods. Therefore, the biological harmless treatment of real antibiotic industrial wastewater is a valuable and meaningful research field. For the first time, a novel Ti/SnO2-Sb anode/air diffusion cathode/UV dual photo-electro catalysis coupling system (T-A-PE) for real antibiotic industrial wastewater treatment was investigated. Non-significant degradation was found in raw wastewater with high TOC = 2.61 × 103 mg·L−1. However, the increasing TOC removal with more dilution times indicated adaptability of T-A-PE system with lower organic matter loading. The highest 95.6% removal of TOC was obtained at 120 min, with 7.06 mA·cm−2 of current density and 200 dilution times. The high mineralization efficiency of T-A-PE system surpassed those of pure photo and electro catalysis combined, suggesting a significant synergistic effect between photo and electro catalysis. Neutral condition and current density = 7.06 mA·cm−2 are prior for pollutants mineralization, while acidic/alkaline conditions and unproper current density may cause faster side reactions. The GC–MS results demonstrated that the number of pollutant category dropped from 26 to 6 after treatment, with the concentrations of remained ones also remarkably decreased. The acute toxicity analysis using a luminescent bacteria method indicated that the treated wastewater by T-A-PE system was biological harmless

A trio of tumor suppressor miRNA downregulates CREB5 dependent transcription to modulate neoadjuvant hormonal therapy sensitivity

Neoadjuvant hormonal therapy (NHT) prior to radical prostatectomy (RP) is an approach that can potentially maximize survival outcomes in prostate cancer (PCa) patients with high-risk disease. Unfortunately, subsets of patients do not respond well to such hormonal therapy. We previously identified several pathological parameters in predicting differences in response to NHT of PCa. However, little is known about the potential role and mechanism of miRNAs mediated NHT resistance (NHT-R) in PCa. Here we demonstrate that miR-l42-3p, miR-150-5p and miR-342-3p are the top downregulated miRNAs in PCa tissues with NHT-R. Functional analysis reveals that the three miRNAs inhibit cell proliferation in vitro. Transfection of miRNAs mimics strengthens the inhibitory effects of bicalutamide and enzalutamide to PCa cells. Luciferase reporter assay reveals that CREB5 is the common target of these three miRNAs. Clinically, high expression level of CREB5 correlates with high Gleason score, advanced tumor stage and NHT-R in PCa tissues. CREB5 expression promotes antiandrogen therapy resistance in LNCaP cells and IL6 signaling pathway may be involved in this process. In all, our findings highlight an important role of miR-142-3p, miR-150-5p, and miR-342-3p in contributing NHT-R by targeting CREB5 in PCa