SUMMARY
In this paper, we report on the seismogram synthesis of Rayleigh and Love waves in horizontally double-layered elastic half-space. For purpose of analytically extracting surface wave ...components from full-wavefield, we first derive a compact expression of Green’s function in this medium, from which the excitation formulae of Rayleigh and Love waves are then obtained. Secondly, adopting a set of medium parameters close to those of the Earth, and with Rayleigh poles and Love poles solved in complex domain, we manage to compute synthetic seismograms of the two surface waves separately. Their phase-velocity dispersion and particle motion are also explored. For Rayleigh wave, the senior modes behave rather differently from the fundamental mode. While different Love modes share similar patterns, which are generally in conformity with the classic picture.
•A multi-objective optimization model is designed for multi-period dynamic emergency resource scheduling (ERS) problems.•MOEA/D-mdERSis proposed to solve the designed modelbased on the properties of ...multi-period dynamic ERS problems.•The experimental results show that MOEA/D-mdERS can find a set of better candidate solutions than NSGA-II.
The resource distribution in post-disaster is an important part of emergency resource scheduling. In this paper, we first design a multi-objective optimization model for multi-period dynamic emergency resource scheduling (ERS) problems. Then, using the framework of multi-objective evolutionary algorithm based on decomposition (MOEA/D), an MOEA is proposed to solve this model. In the proposed algorithm, new evolutionary operators are designed with the intrinsic properties of multi-period dynamic ERS problems in mind. The experimental results show that the proposed algorithm can get a set of better candidate solutions than the non-dominated sorting genetic algorithm II (NSGA-II).
The objective of this study is to assess the influence of staggered boards on corporate financialization and the role that incentive and supervision mechanisms play in this process.
We employ a total ...of 20,647 panel data samples of Chinese A-share listed companies over the period 2011-2020 to empirically test the impact of staggered boards on corporate financialization in the Chinese context.
The results indicate that implementing staggered boards significantly increases levels of corporate financialization. On the one hand, the implementation of a staggered board structure can exacerbate the speculative mindset and profit-driven behavior among board members, leading management to prioritize financial investments for personal gain. On the other hand, a staggered board system may also amplify managerial laziness, potentially incentivizing them to rely heavily on financial investments in order to swiftly achieve performance targets with minimal effort. Furthermore, both managerial ownership and audit supervision are found to be critical factors in mitigating this positive impact and preventing excessive financial investment behavior.
This paper offers guidance on comprehending the applicability of staggered board provisions and mitigating financial risks in enterprises.
The bone marrow microenvironment has a key role in regulating haematopoiesis, but its molecular complexity and response to stress are incompletely understood. Here we map the transcriptional ...landscape of mouse bone marrow vascular, perivascular and osteoblast cell populations at single-cell resolution, both at homeostasis and under conditions of stress-induced haematopoiesis. This analysis revealed previously unappreciated levels of cellular heterogeneity within the bone marrow niche and resolved cellular sources of pro-haematopoietic growth factors, chemokines and membrane-bound ligands. Our studies demonstrate a considerable transcriptional remodelling of niche elements under stress conditions, including an adipocytic skewing of perivascular cells. Among the stress-induced changes, we observed that vascular Notch delta-like ligands (encoded by Dll1 and Dll4) were downregulated. In the absence of vascular Dll4, haematopoietic stem cells prematurely induced a myeloid transcriptional program. These findings refine our understanding of the cellular architecture of the bone marrow niche, reveal a dynamic and heterogeneous molecular landscape that is highly sensitive to stress and illustrate the utility of single-cell transcriptomic data in evaluating the regulation of haematopoiesis by discrete niche populations.
The COVID-19 pandemic has caused negative impacts both on populations' health worldwide. COVID-19 vaccines are currently developed and tested in clinical trials. However, limited studies have ...investigated the willingness to get COVID-19 vaccines in populations. Therefore, the study aimed to determine the individual's willingness to accept and pay for COVID-19 vaccines, and knowledge, attitude, and perceptions (KAP) of COVID-19 vaccines, which hopefully will be available soon. Non-pregnant Chinese adults aged ≥18 years were asked to complete a self-administered KAP COVID-19 vaccine questionnaire distributed between March and May 2020. A total of 1179 participants (574 males and 605 females) were included and the mean age was 36.0 ± 11.5 years. Both the willingness to be vaccinated against COVID-19 and pay for COVID-19 vaccines were high (77.4% and 81.1%), respectively. Also, the most acceptable price range of COVID-19 vaccine was ¥501-1000 (US $ 75-149). Education and willingness to be vaccinated were significantly associated with some of the responses in KAP (P < .05). In conclusion, our study reported high willingness to be vaccinated against COVID-19 and pay for COVID-19 vaccines in Chinese population. Our findings also provided some important contributions for public health policy makers to formulate appropriate vaccination programs.
Cell-free systems can effectively eliminate the inter-cell interference by enabling multiple base stations (BSs) to cooperatively serve users without cell boundaries at the expense of high costs of ...hardware and power sources due to the large-scale deployment of BSs. To tackle this issue, the low-cost reconfigurable intelligent surface (RIS) can serve as a promising technique to improve the energy efficiency of cell-free systems. In this article, we consider an RIS aided cell-free MIMO system where multiple RISs are deployed around BSs and users to create favorable propagation conditions via reconfigurable reflections in a low-cost way, thereby enhancing cell-free MIMO communications. To maximize the energy efficiency, a hybrid beamforming (HBF) scheme consisting of the digital beamforming at BSs and the RIS-based analog beamforming is proposed. The energy efficiency maximization problem is formulated and an iterative algorithm is designed to solve this problem. The impact of the transmit power, the number of RIS, and the RIS size on energy efficiency are investigated. Both theoretical analysis and simulation results reveal that the optimal energy efficiency depends on the numbers of RISs and the RIS size. Numerical evaluations also show that the proposed system can achieve a higher energy efficiency than conventional ones.
The synthesis of a macrocyclic Ru carbene catalyst for selective cross alkene metathesis is reported. The new catalyst showed different reactivity for various type 1 alkenes in homodimerization which ...correlated with the aggregrate size of the allylic substituent. The altered reactivity profile allowed for selective product formation in competition cross alkene metathesis between two different type 1 alkenes and tert-butyl acrylate. Selectivity in these reactions is attributed to the ability of the macrocyclic catalyst to differentiate alkenes based on their size. Two preparative examples of cross metathesis with the macrocyclic catalyst are also provided.
How small and medium-sized (SMS) rural banks, as the main banks offering rural financial services, serve all-round rural revitalization is a vital realistic and policy issue for the time being. Now, ...SMS rural banks are confronted with many shortcomings in serving rural revitalization due to dull financial service supply chain circulation and lack of coordination with the rural industry supply chain. The research based on survey data and typical cases shows that the key to solving these problems is to realize a double chain linkage of the financial service supply chain and the rural industry supply chain: The financial service supply chain and the rural industry supply chain should make use of their common infrastructure, share the digital technology capacity and data handling capacity and promote the linkage of customers, channels and scenarios in all links of the two supply chains in a bid to realize mutual promotion and improve the quality and efficiency of the two chains and hence fuel the all-round rural revitalization through industrial revitalization. Double chain linkage can be achieved through five major effective means: in terms of data, collaborating with digital rural governance and strengthening data collection and utilization; in terms of industry, collaborating with core entity enterprises and strengthening the supply chain financial service capacity; in terms of ecology, collaborating with internet technology companies and enhancing ecological, scenario and technological enabling; in terms of channels, collaborating with rural service and focusing on channel linkage, offline network, mobile services and village financial officers, etc.; and in terms of cooperation, constructing the common infrastructure of SMS rural banks and boosting the efficiency of digital enabling innovation.
Urban agglomerations have become a new geographical unit in China, breaking the administrative fortresses between cities, which means that the population and economic activities between cities will ...become more intensive in the future. Constructing and optimizing the ecological security pattern of urban agglomerations is important for promoting harmonious social-economic development and ecological protection. Using the Harbin-Changchun urban agglomeration as a case study, we have identified ecological sources based on the evaluation of ecosystem functions. Based on the resistance surface modified by nighttime light (NTL) data, the potential ecological corridors were identified using the least-cost path method, and key ecological corridors were extracted using the gravity model. By combining 15 ecological sources, 119 corridors, 3 buffer zones, and 77 ecological nodes, the ecological security pattern (ESP) was constructed. The main land-use types composed of ecological sources and corridors are forest land, cultivated land, grassland, and water areas. Some ecological sources are occupied by construction, while unused land has the potential for ecological development. The ecological corridors in the central region are distributed circularly and extend to southeast side in the form of tree branches with the Songhua River as the central axis. Finally, this study proposes an optimizing pattern with "four belts, four zones, one axis, nine corridors, ten clusters and multi-centers" to provide decision makers with spatial strategies with respect to the conflicts between urban development and ecological protection during rapid urbanization.
Joint detection and embedding (JDE) methods usually fuse the target motion information and appearance information as the data association matrix, which could fail when the target is briefly lost or ...blocked in multi-object tracking (MOT). In this paper, we aim to solve this problem by proposing a novel association matrix, the Embedding and GioU (EG) matrix, which combines the embedding cosine distance and GioU distance of objects. To improve the performance of data association, we develop a simple, effective, bottom-up fusion tracker for re-identity features, named SimpleTrack, and propose a new tracking strategy which can mitigate the loss of detection targets. To show the effectiveness of the proposed method, experiments are carried out using five different state-of-the-art JDE-based methods. The results show that by simply replacing the original association matrix with our EG matrix, we can achieve significant improvements in IDF1, HOTA and IDsw metrics, and increase the tracking speed of these methods by around 20%. In addition, our SimpleTrack has the best data association capability among the JDE-based methods, e.g., 61.6 HOTA and 76.3 IDF1, on the test set of MOT17 with 23 FPS running speed on a single GTX2080Ti GPU.
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