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Sihailongwan Maar Lake, located in Northeast China, is a candidate Global boundary Stratotype Section and Point (GSSP) for demarcation of the Anthropocene. The lake’s varved sediments are formed by alternating allogenic atmospheric inputs and authigenic lake processes and store a record of environmental and human impacts at a continental-global scale. Varve counting and radiometric dating provided a precise annual-resolution sediment chronology for the site. Time series records of radioactive (239,240Pu, 129I and soot 14C), chemical (spheroidal carbonaceous particles, polycyclic aromatic hydrocarbons, soot, heavy metals, δ13C, etc.), physical (magnetic susceptibility and grayscale) and biological (environmental DNA) indicators all show rapid changes in the mid-20th century, coincident with clear lithological changes of the sediments. Statistical analyses of these proxies show a tipping point in 1954 CE. 239,240Pu activities follow a typical unimodal globally-distributed profile, and are proposed as the primary marker for the Anthropocene. A rapid increase in 239,240Pu activities at 88 mm depth in core SHLW21-Fr-13 (1953 CE) is synchronous with rapid changes of other anthropogenic proxies and the Great Acceleration, marking the onset of the Anthropocene. The results indicate that Sihailongwan Maar Lake is an ideal site for the Anthropocene GSSP.

Background A large number of studies have confirmed that immunotherapy of tumor immune microenvironment is one of the important treatment methods. In pancreatic cancer, monocytes play an important role in poor prognosis, but the mechanism and prognosis prediction methods are unclear.Methods CIBERSORT was used to identify cellular immune score and evaluate the effect of each immune cell on prognosis. The gene modules related to monocytes were obtained by weighted correlation network analysis through WGCNA package. Consensus clustering was used to screen out prognostic genes. The regression signature was generated by LASSO Cox analysis, and its reliability was verified by univariate and multivariate Cox analysis. The ssGSEA and TIDE algorithms were used to predict immune status and sensitivity to immune checkpoint blockade (ICBs) in tumor microenvironment. Finally, the expression levels of each gene in the signature were verified at tissue level and single cell level.Results High infiltration of monocytes suggests poor prognosis of pancreatic cancer. After WGCNA analysis and cluster typing, 262 genes were significantly differentially expressed and prognostic. The 6 gene (MET, ITGB6, CEP55, NUSAP1, MYEOV, LY6D) prognostic signature was established by LASSO Cox analysis. It was verified to be an independent prognostic factor for pancreatic cancer. The high-risk group had high infiltration of monocytes in the immune microenvironment and was more sensitive to ICBs. At the tissue level, all 6 genes were highly expressed in cancer tissues. At the single-cell level, MET and MYEOV were significantly higher in malignant cells and lower in monocytes.Conclusions High infiltration of monocytes affects the poor prognosis of pancreatic cancer, suggesting that the immune microenvironment has a certain research prospect for the treatment of pancreatic cancer. The monocyte-related genes signature can accurately assess the prognostic risk of pancreatic cancer.

Cylindrical specimens are commonly used in Split Hopkinson pressure bar (SHPB) tests to study the uniaxial dynamic properties of concrete-like materials. In recent years, true tri-axial SHPB equipment has also been developed or is under development to investigate the material dynamic properties under tri-axial impact loads. For such tests, cubic specimens are needed. It is well understood that static material strength obtained from cylinder and cube specimens are different. Conversion factors are obtained and adopted in some guidelines to convert the material strength obtained from the two types of specimens. Previous uniaxial impact tests have also demonstrated that the failure mode and the strain rate effect of cubic specimens are very different from that of cylindrical ones. However, the mechanical background of these findings is unclear. As an extension of the previous laboratory study, this study performs numerical SHPB tests of cubic and cylindrical concrete specimens subjected to uniaxial impact load with the validated numerical model. The stress states of cubic specimens in relation to its failure mode under different strain rates is analyzed and compared with cylindrical specimens. The detailed analyses of the numerical simulation results show that the lateral inertial confinement of the cylindrical specimen is higher than that of the cubic specimen under the same strain rates. For cubic specimen, the corners are more severely damaged because of the lower lateral confinement and the occurrence of the tensile radial stress which is not observed in cylindrical specimens. These results explain why the dynamic material strengths obtained from the two types of specimens are different and are strain rate dependent. Based on the simulation results, an empirical formula of conversion factor as a function of strain rate is proposed, which supplements the traditional conversion factor for quasi-static material strength. It can be used for transforming the dynamic compressive strength from cylinders to cubes obtained from impact tests at different strain rates.

Background Many researches have confirmed that immunotherapy of tumor immune microenvironment is necessary. In pancreatic cancer, monocytes play an important role in poor prognosis, but the mechanism and prognosis prediction methods are unclear. Methods CIBERSORT was used to identify cellular immune score and evaluate the effect of each immune cell on prognosis. The gene modules related to monocytes were obtained by weighted correlation network analysis through WGCNA package. Consensus clustering was used to sort prognostic genes. The regression signature was generated by LASSO Cox analysis and verified by Cox analysis. The ssGSEA and TIDE algorithms were used to predict immune status and sensitivity to ICB. Finally, the expression levels of each gene were verified at tissue level and single-cell level. Results High infiltration of monocytes suggests poor prognosis of pancreatic cancer. 262 genes were significantly differentially expressed and prognostic after WGCNA analysis and cluster typing. The related 6 genes prognostic signature established by LASSO Cox analysis was verified to be an independent prognostic factor. The high-risk group had high infiltration of monocytes in the immune microenvironment and was more sensitive to ICBs. At the tissue level, all genes were highly expressed in cancer tissues. At the single-cell level, MET and MYEOV were significantly higher in malignant cells and lower in monocytes. Conclusions High infiltration of monocytes affects poor prognosis of pancreatic cancer, suggesting that the immune microenvironment has a certain research prospect for treatment of pancreatic cancer. The monocyte-related genes signature can accurately assess the prognostic risk of pancreatic cancer.

Discrete short steel fibres were proposed to be mixed with concrete for arresting cracks and enhancing the post-cracking resistance. It has been proven in previous tests that spiral steel fibres possessed markedly higher bonding to concrete matrix, leading to significantly improved performance of steel fibre reinforced concrete (SFRC) in terms of crack controllability, impact resistance, deformability and energy absorption capability. However, at the initial stage of cracking, SFRC reinforced with spiral fibres has relatively lower resistance to crack opening as compared to that reinforced with other types of steel fibres because of spiral shape stretching. To overcome this shortcoming, in the present study, short hooked-end steel fibres that exhibit high pull-out resistance at the crack initiation stage were mixed with spiral steel fibres in the normal-strength concrete matrix. A total volume fraction of 1% of hybrid steel fibres was mixed to cast SFRC specimens. With various mix ratios between spiral and hooked-end fibres considered, five batches of SFRC specimens were tested. Uniaxial compressive tests and four-point bending tests were carried out to compare the mechanical properties of SFRC materials with hybrid fibres while three-point bending tests on SFRC structural beams under static, drop-weight impact and post-impact static loading tests were conducted to investigate the structural performances. An equal dosage of hooked-end and spiral fibres was found to outperform other blend proportions to provide synergetic reinforcement to concrete matrix in terms of post-cracking resistance, energy absorption capacity and post-impact performance.

Cooperation between upstream suppliers and downstream manufacturers in technology investment is a popular way to improve production technology for reducing suppliers' production costs of key components. Technology investments undertaken by manufacturers and wholesale price discount contract provided by suppliers have an important impact on their cooperation. This paper explores whether a supplier should cooperate with two downstream competing manufacturers to accept their technology investments to reduce the supplier's production cost of a key component. Specifically, we consider the following three cooperation strategies: the supplier does not accept manufacturers' technology investments, only accepts one manufacturer's technology investment and accepts both manufacturers' technology investments. Our results demonstrate that the wholesale price discount contract and the technology investment can enhance the profits of the supplier and two manufacturers when the discount degree is low. Further, we conclude that when the discount degree is relatively low or when the discount degree and the technology investment efficiency are relatively high, the supplier's optimal cooperation strategy with two manufacturers is to accept both manufacturers' technology investments for reducing the supplier's production cost of the key component and both manufacturers are also willing to invest simultaneously. At last, we extend the model to the asymmetric potential market size and show that our theoretical results are robust.

Wildfires play an important role in earth climate systems, with influences on the atmosphere, vegetation distributions, and human survival. Considerable debate persists with regard to the relationship between wildfire occurrence and climate. Some records indicate relatively fewer wildfires during glacial times as compared to the Holocene, while others support the opposite view. These contradictory views need to be resolved to fully understand the relationship and controlling mechanisms that relate biomass burning to climate. In this study, black carbon (BC), including both char and soot, is used to reconstruct wildfire history over the past 32 ka from Qinghai Lake. BC, especially as micrometer-size soot, is mainly transported via the atmosphere, and can carry evidence of wildfires over long distances. Qinghai Lake's position on the northeastern edge of the Tibet Plateau is especially well-suited to such long-distance transport, with a potentially global climatic impact. We observed a significantly positive relationship between char and soot fluxes that suggest that the Qinghai Lake BC record is dominated by material transported through the atmosphere in large-scale wildfires. We find that relatively more wildfires occurred during cold-dry late glacial time (32.8–11.7 ka), and fewer wildfires during the warm-humid Holocene. Our study demonstrates that drought is the key factor that determines wildfire occurrences on an orbital time-scale. These fundamental and persistent patterns can assist in our understanding of climate-wildfire interactions and in the assessment of feedbacks on the global climate system, for example, through the well-known relationship between soluble iron and atmospheric CO2.

With the development of online retailing, traditional online platforms have begun to offer a novel online marketplace format that brings many advantages but also gives rise to problems such as oper...

Complex oxide heterointerfaces and van der Waals heterostructures present two versatile but intrinsically different platforms for exploring emergent quantum phenomena and designing new functionalities. The rich opportunity offered by the synergy between these two classes of materials, however, is yet to be charted. Here, we report an unconventional nonlinear optical filtering effect resulting from the interfacial polar alignment between monolayer MoS$_2$ and a neighboring ferroelectric oxide thin film. The second harmonic generation response at the heterointerface is either substantially enhanced or almost entirely quenched by an underlying ferroelectric domain wall depending on its chirality, and can be further tailored by the polar domains. Unlike the extensively studied coupling mechanisms driven by charge, spin, and lattice, the interfacial tailoring effect is solely mediated by the polar symmetry, as well explained via our density functional theory calculations, pointing to a new material strategy for the functional design of nanoscale reconfigurable optical applications., 22 pages, 4 figures

Despite its efficiency in reducing the impact of pandemics (e.g., the COVID-19), whether to introduce telemedicine as an additional way to serve chronically ill patients remains controversial for hospitals in many countries. This paper builds a stylized model to investigate a hospital's telemedicine strategy and the corresponding impacts on its operations regarding outpatient management of chronic diseases. We implement our analysis from three key concerns of the hospital in the presence of a pandemic: the differences in medical consumption and reimbursement between in-person and telemedicine modalities and the effort cost of infection reduction resulting from the pandemic. We find that in the absence of the pandemic, the hospital prefers to introduce telemedicine when the differences in medical consumption and reimbursement are both small. In the presence of the pandemic, we find that the introduction of telemedicine does not always benefit the hospital and that it is better not to introduce telemedicine in some cases since it may exacerbate the negative influence of the pandemic on the hospital's total costs. Furthermore, we surprisingly find that the hospital may set greater in-person capacity but less telemedicine capacity in response to the outbreak of the pandemic under certain conditions, which contradicts public beliefs. Finally, we show that social welfare can be improved by introducing telemedicine when the effort cost of infection reduction and the difference in reimbursement are both of moderate size. The condition under which social welfare is improved tightens with a greater difference in medical consumption.

We report the effect of remote surface optical (RSO) phonon scattering on carrier mobility in monolayer graphene gated by ferroelectric oxide. We fabricate monolayer graphene transistors back-gated by epitaxial (001) Ba0.6Sr0.4TiO3 films, with field effect mobility up to 23 000 cm2 V−1 s−1 achieved. Switching ferroelectric polarization induces nonvolatile modulation of resistance and quantum Hall effect in graphene at low temperatures. Ellipsometry spectroscopy studies reveal four pairs of optical phonon modes in Ba0.6Sr0.4TiO3, from which we extract RSO phonon frequencies. The temperature dependence of resistivity in graphene can be well accounted for by considering the scattering from the intrinsic longitudinal acoustic phonon and the RSO phonon, with the latter dominated by the mode at 35.8 meV. Our study reveals the room temperature mobility limit of ferroelectric-gated graphene transistors imposed by RSO phonon scattering.

In this work, we exploit the ferroelectric-dielectric layer thickness ratio r as an effective tuning parameter to control the ferroelectric polarization and transient negative capacitance (NC) state in epitaxial ${\mathrm{Pb}\mathrm{Zr}}_{0.2}{\mathrm{Ti}}_{0.8}{\mathrm{O}}_{3}/{\mathrm{Sr}\mathrm{Ti}\mathrm{O}}_{3}$ bilayer heterostructures. The remnant polarization decreases monotonically with decreasing r, with the system exhibiting an abrupt transition from ferroelectric to dielectric dominated behavior at a critical ratio ${r}_{c}$ of 8 to 7, which is consistent with the evolution of the free-energy profile modeled via Landau theory. For samples with large r, the polarization switching dynamics during the transient NC regime can be well described by the nucleation and growth model, with the narrow distribution of the characteristic switching time (${t}_{0}$) pointing to a domain-wall-motion-limited behavior. Right below ${r}_{c}$, we observe a significantly broadened distribution of ${t}_{0}$, which can be attributed to the emergence of a multidomain state. The transient NC mode is quenched in samples with r 6, confirming that the ferroelectric order is suppressed. Our study provides critical information for optimizing the materials design for complex oxide-based NC transistors, paving the path for their application in low-power nanoelectronics.

Basalt fiber is more cost-effective than carbon fiber and has superior mechanical and chemical properties than glass fiber. Most existing studies considered the use of micro basalt fibers in concrete matrix to reduce shrinkage and control micro cracks. However, macro fibers are often required to reinforce concrete material when large deformation and macro cracks in structural elements are of concern. Very few studies have been reported for macro Basalt Fiber Reinforced Polymer (BFRP) fibers to improve mechanical properties of concrete. The geometric characteristics of macro fibers are critical for concrete reinforcement. It is known that macro fibers with smooth surface possess poor bond strength. To enhance the bonding properties between macro BFRP fibers and concrete, in this experimental study, pullout tests on macro BFRP fibers with various geometric forms from different grades of mortar matrix were carried out. Smooth fiber, etched fiber and double-helix fiber were manufactured and evaluated. The effects of embedded length and matrix strength are also investigated through pullout behavior of single BFRP fiber. The variation of etched intervals of etched fibers on bond strength was also taken into account. It was found that the double-helix fiber outperformed other types of fibers in terms of strength utilization ratio and energy absorption capability. An empirical model for interfacial bond-slip relation was proposed based on the test results. Based on results of pullout tests, the outstanding performance of double-helix BFRP fiber was further verified by examining the mechanical properties of normal-strength concrete specimens reinforced with different types of macro BFRP fibers.

We report the competing effects of disorder pinning and thermal roughening on ferroelectric domain walls as a function of temperature in epitaxial $\mathrm{Pb}{\mathrm{Zr}}_{0.2}{\mathrm{Ti}}_{0.8}{\mathrm{O}}_{3}$ thin films deposited on (001) $\mathrm{SrTi}{\mathrm{O}}_{3}$ substrates buffered by three types of correlated oxide electrodes, ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}\mathrm{Mn}{\mathrm{O}}_{3}$, $\mathrm{LaNi}{\mathrm{O}}_{3}$, and $\mathrm{SrIr}{\mathrm{O}}_{3}$. Piezoresponse force microscopy studies show that the 50-nm $\mathrm{Pb}{\mathrm{Zr}}_{0.2}{\mathrm{Ti}}_{0.8}{\mathrm{O}}_{3}$ films are uniformly polarized in the as-grown states, with the patterned domain structures persisting above 700 \ifmmode^\circ\else\textdegree\fi{}C. For all three types of films, the domain wall roughness is dominated by two-dimensional (2D) random bond disorder at room temperature, and transitions to 1D thermal roughening upon heating. The roughness exponent $\ensuremath{\zeta}$ increases progressively from 0.3 to 0.5 within a temperature window that depends on the bottom conducting oxide type, from which we extracted the distribution of disorder pinning energy. We discuss the possible origins of the disorder pinning and the effect of the correlated oxide electrodes on the energy landscape of DW motion.

Based on relational exchange theory and transaction cost theory, a conceptual model for the relationships among supply chain partnership, inter-organizational knowledge trading and enterprise innovation performance is proposed and empirically tested using the data collected from 256 Chinese manufacturing enterprises in project-based supply chain with the structural equation model. The dimension of supply chain partnership in this model is described from shared goal, trust and relationship commitment. Inter-organizational knowledge trading is categorized into explicit knowledge trading and tacit knowledge trading. The results showed that: (1) there are significant and positive effects of shared goal and trust on explicit knowledge trading, tacit knowledge trading and enterprise innovation performance, while trust has a stronger positive effect on tacit knowledge trading than explicit knowledge trading; (2) although relationship commitment has significant and positive effects on tacit knowledge trading and enterprise innovation performance, it does not affect explicit knowledge trading significantly; (3) it is also proved that inter-organizational knowledge trading (explicit knowledge trading and tacit knowledge trading) has significant and positive effects on enterprise innovation performance; (4) the mediating effects of inter-organizational knowledge trading (explicit knowledge trading and tacit knowledge trading) are proved on the relationships between supply chain partnership (shared goal, trust and relationship commitment) and enterprise innovation performance, excluding the mediating effect of explicit knowledge trading between relationship commitment and enterprise innovation performance. The findings provide a theoretical basis for inter-organizational knowledge trading participants selecting an appropriate relational mechanism to promote knowledge trading, and these also guide the inter-organizational knowledge trading among members of project-based supply chain in practice.

A new fence type blast wall consisting of steel poles was recently proposed based on the idea that the blast wave-obstacle interaction could generate wave reflection, diffraction and out-of-phase interference to reduce the wave energy. The effectiveness of this kind of new blast wall in mitigating blast loading was investigated through 2D numerical simulations and field blasting tests. In this study, 3D numerical simulations are carried out as an extension of the previous studies for a more comprehensive understanding of the effectiveness of fence blast wall. The simulations are performed by using an explicit dynamic finite element analysis software AUTODYN 3D with validated material models. Responses of a reinforced concrete (RC) wall under blast load are also calculated for comparison. Influences of different parameters of the fence wall, including the cross-sectional shape of the steel poles, spacing between poles, number of fence layers and spacing between layers, on its effectiveness in mitigating the blast loadings are investigated. The peak overpressure, impulse and overpressure-time histories behind the fence and RC blast wall are compared with those in free field for evaluation. It is found that the fence blast wall, if properly arranged, could perform equally or even better than the RC wall in mitigating overpressure and impulse of blast wave. Moreover, fence blast wall is less likely to generate the secondary debris hazards associated with the RC and other solid walls when close-in explosion occurs. Therefore, it is an excellent alternative blast barrier in protecting critical structures in urban areas.

Although marked advancements have been achieved to improve the computer power, progressive collapse analysis of large-scale reinforced concrete structures is still time-consuming or even impractical. In this study, a numerical model is proposed for efficient progressive collapse analysis of reinforced concrete structures. Recent advancements that can accurately and efficiently model the mechanical behavior of structural components are incorporated in the numerical model of reinforced concrete structure. The beams/columns, joint regions, and slabs are modeled by enhanced fiber beam element, macrojoint model, and layered shell element, respectively. In this way, the shear failure of beams/columns, failure of joints, and resistance contribution from floor slab can be taken into account for progressive collapse analysis of reinforced concrete structures. A six-story reinforced concrete frame structure is modeled using the approach proposed in this study. The progressive collapse of the structure is analyzed under column removal and direct blast loading scenarios. For comparison purpose, other popularly used finite element models are also adopted to carry out numerical simulations. The proposed model is proven to yield accurate simulation results with the least cost of time among all models. Based on the proposed model, parametric simulations are performed to investigate effective measures to improve the structural resistance to progressive collapse. It is found that increasing longitudinal reinforcement ratio in beams and columns can increase the catenary action capacity, but hardly increases the compressive arch action capacity. Moreover, the steel mesh reinforcement at top layer of slabs plays a significant role in resisting progressive collapse of reinforced concrete structures, which should be considered in design to resist progressive collapse.

It is understood that the lateral inertia confinement, end-friction confinement, and aggregates influence the uniaxial dynamic compressive properties of concrete material. For particular circumstan...

In view of the importance of flexible job-shop scheduling problem (FJSP) in actual production, this paper constructs a mathematical model of fuzzy FJSP and then proposes a mixed quantum algorithm based on local optimization strategy and improved optimization rotation angle. For improving the production process, a double chain coding method was designed with two gene chains, which respectively represent the machine selection and the process sequencing. Next, the hybrid quantum particle swarm optimization (QPSO) was introduced to ensure the scheduling efficiency. Finally, the prototype system of the proposed strategy was simulated by using some actual examples. The results show that the proposed algorithm can quickly form an adjusted plan that has minimal difference from the original plan.