This article focuses on the asymptotic and transient behavior of a food chain model with vigilance in the biparameter spaces. Firstly, the local asymptotic stability conditions of the positive ...equilibrium point are obtained. Then, the transient dynamical behavior of the positive equilibrium point is analyzed based on eight parameters. Using numerical simulation, the stable regions of the model with single and double parameters are plotted, as well as the value changes of resilience, reactivity, and amplification envelope within the stable regions. The results show that the coexistence equilibrium point is always reactive, and the corresponding parameter ranges for system stability are large, but the resilience values are small. The vigilance parameter of the middle- and lower-level organisms has the greatest impact on the system’s resilience and reactivity, and the lowest vigilance corresponds to the maximum resilience and reactivity. Our results provide important references for effective management and protection of wild animal populations by the potential for transient amplification, disturbance growth time, and amplitude.
To battle adverse internal and external conditions and maintain homeostasis, diploid organisms employ various cellular processes, such as proliferation and apoptosis. In some tissues, an alternative ...mechanism, endoreplication, is employed toward similar goals. Endoreplication is an evolutionarily conserved cell cycle program during which cells replicate their genomes without division, resulting in polyploid cells. Importantly, endoreplication is reported to be indispensable for normal development and organ formation across various organisms, from fungi to humans. In recent years, more attention has been drawn to delineating its connections to wound healing and tumorigenesis. In this Review, we discuss mechanisms of endoreplication and polyploidization, their essential and positive roles in normal development and tissue homeostasis, and the relationship between polyploidy and cancer.
As an alternative cell cycle program, endoreplication is crucial during development. Polyploid cells assume various pivotal functions in metazoans.
Besides its significant role in development, endoreplication is induced by various signaling pathways to maintain homeostasis and tissue integrity, and to assist the wound healing and tissue repair processes.
Polyploidy and aneuploidy are widespread across different types of cancer, contributing to cancer progression, surveillance escape, and relapse.
Polyploid giant cancer cells (PGCCs) possess stem cell characteristics, and can differentiate into three germ layers in vitro. PGCCs can form tumors through asymmetric budding or bursting.
Seismic instrumentation for earthquake early warnings (EEWs) has improved significantly in the last few years, considering the station coverage, data quality, and the related applications. The ...official EEW system in Taiwan is operated by the Central Weather Bureau (CWB) and is responsible for issuing the regional warning for moderate-to-large earthquakes occurring in and around Taiwan. The low-cost micro-electro-mechanical system (MEMS)-based P-Alert EEW system is operational in Taiwan for on-site warnings and for producing shakemaps. Since 2010, this P-Alert system, installed by the National Taiwan University (NTU), has shown its importance during various earthquakes that caused damage in Taiwan. Although the system is capable of acting as a regional as well as an on-site warning system, it is particularly useful for on-site warning. Using real-time seismic signals, each P-Alert system can provide a 2–8 s-long warning time for the locations situated in the blind zone of the CWB regional warning system. The shakemaps plotted using this instrumentation help to assess the damage pattern and rupture directivity, a key feature in the risk mitigation process. These shakemaps are delivered to the intended users, including the disaster mitigation authorities, for possible relief purposes. Earlier, the network provided only peak ground acceleration (PGA) shakemaps, but has now been updated to include peak ground velocity (PGV), spectral acceleration (Sa) at different periods, and CWB intensity maps. The PGA and PGV shakemaps plotted using this network have proven helpful in establishing the fact that PGV is a better indicator of damage detection than PGA. This instrumentation is also useful in structural health-monitoring and estimating co-seismic deformations. Encouraged by the performance of the P-Alert network, more instruments are installed in Asia-Pacific countries.
•Critical review on several aspects of microbiologically induced concrete corrosion.•Discussion of the important influencing factors associated with the mechanisms.•Summary of the phenomena observed ...on site investigations and laboratory studies.•Important knowledge gaps in current understanding on the subject highlighted.
Microbiologically induced corrosion (MIC) is a century old problem facing global concrete sewer structures. Despite the substantial efforts that have been made, MIC of concrete sewers remains a highly debated subject. To further advances our understanding on the problem, we need to know the existing knowledge. In light of this, we intend to provide a state-of-the-art review on the subject. By acknowledging the complexity and broadness of the concerned problem and in order to discuss relevant aspects in depth, the scope of the current work is limited to the key elements of the mechanisms and phenomena observed on site investigations and laboratory studies for MIC of concrete sewers. In general, four main events have been considered accounting for the MIC process, i.e. formation of hydrogen sulfide in the waste steam, radiation and buildup of gaseous hydrogen sulfide, generation of sulfuric acid and deterioration of the concrete materials. Fundamentals associated with the main events, especially the important influencing factors, are reviewed and discussed. Based on site investigations and laboratory studies, several aspects of the MIC phenomena are summarized, including corrosion areas, corrosion rates, impact of cement and aggregate types. It is worth mentioning that the corrosion rates obtained on site and laboratory studies generally vary a lot, which may be attributed to different testing conditions and procedures. The fact that standard testing or evaluation methods are missing also complicates the issue. In addition, it seems difficult to establish quantitative relations between the corrosion behavior observed on site and that obtained in laboratory studies, at least based on the existing knowledge. This highlights the need for further research to advance our understanding on different aspects related to MIC of concrete sewers.
The rapidly emerging requirement for device miniaturization and structural flexibility make 2D semiconductors and their van der Waals (vdWs) heterostructures extremely attractive for nonvolatile ...optoelectronic memory (NOM) applications. Although several concepts for 2D NOM have been demonstrated, multi‐heterojunction devices capable of further improving storage performance have received little attention. This work reports a concept for MoS2/black phosphorus (BP)/MoS2 multi‐heterojunction NOM with artificial trap sites through the BP oxidation, in which the trapped holes at BP/POx interface intrigue a persistent photoconductivity that hardly recovers within the experimental time scales (exceeding 104 s). As a result of the interfacial trap‐controlled charge injection, the device exhibits excellent photoresponsive memory characteristics, including a record high detectivity of ≈1.2 × 1016 Jones, a large light‐to‐dark switching ratio of ≈1.5 × 107, an ultralow off‐state current of ≈1.2 pA, and an outstanding multi‐bit storage capacity (11 storage states, 546 nC state–1). In addition, the middle BP layer in the multi‐heterojunction enables broadband spectrum distinction (375–1064 nm), together with a high polarization ratio of 8.4. The obtained results represent the significant step toward the high‐density integration of optoelectronic memories with 2D vdWs heterostructures.
Here, the polarization‐resolved broadband MoS2/black phosphorus/MoS2 optoelectronic memory is prepared by exploiting oxidation induced defects in black phosphorus layer. As a result of interfacial trap‐controlled charge injection, the device exhibits an ultrahigh responsivity of 1.3 × 107 A W−1, an ultralong retention time exceeding 6 × 104 s, together with an excellent multi‐bit storage capacity.
A convenient and rapid detection method for methanol in ethanol remains a major challenge due to their indistinguishable physical properties. Herein, a novel fluorescence probe based on perovskite ...was successfully designed to overcome this bottleneck. We report a new zero‐dimensional (0D) hybrid perovskite of MP2InxSb1−xCl7 ⋅ 6 H2O (MP=2‐methylpiperazine) displaying an unusual green light emission with near‐unity photoluminescence quantum yield. Remarkably, this 0D perovskite exhibits reversible methanol‐response luminescence switching between green and yellow color but fail in any other organic vapors. Even for blended alcohol solutions, the luminescent probe exhibits excellent sensing performance with multiple superiorities of rapid response time (30 s) and ultra‐low detection limit (40 ppm), etc. Therefore, this 0D perovskite can be utilized as a perfect fluorescence probe to detect traces of methanol from ethanol with ultrahigh sensitivity, selectivity and repeatability. To the best of our knowledge, this work represents the first perovskite as fluorescence probe for methanol with wide potential in environmental monitoring and methanol detection, etc.
0D hybrid lead‐free halide displays highly efficient broadband green light emission with a near‐unity photoluminescence quantum yield, and acts as a unique fluorescence sensor for methanol in ethanol with ultrahigh selectivity, sensitivity and repeatability as well as fast response time.
Abstract
Driven by the rapid development of the information age, information technology has been widely used in various fields, especially in the accounting work of enterprises. From the perspective ...of information risk, the improvement of computer technology and the degree of informationization not only bring the informationization and high efficiency of enterprise accounting treatment, but also bring many risks. In the face of increasingly fierce market competition, in order to achieve better development, we must attach importance to internal control audit, continuously improve work quality and efficiency, and win a longer-term development prospect for enterprises. In the face of increasingly fierce market competition, in order to obtain better development, we must attach importance to internal control audit, constantly improve the quality and efficiency of work, so as to win a more long-term development prospect for enterprises. This paper discusses the internal control audit of enterprises under the condition of accounting computerization, and puts forward the corresponding countermeasures to improve the internal control and audit of computer accounting in Chinese enterprises.
The self-assembly and pH- and thermo-sensitivities properties of hydroxypropyl cellulose-graft-poly( N,N -dimethyl aminoethyl methacrylate) (HPC-g-PDMAEMA) copolymers in aqueous solutions were ...investigated by transmittance, dynamic light scattering (DLS), and 1H NMR spectroscopy. Micelles with different structure can be formed by varying either pH value or temperature. At low pH, e.g., 3.0, the HPC backbone of the copolymer collapse to form the core of micelles stabilized with protonated PDMAEMA side chains on the surface of the micelles upon heating. At the medium pH, e.g., 8.1, both HPC backbone and PDMAEMA side chains collapse upon heating to form unstable aggregates. At high pH, e.g., 12.3, PDMAEMA side chains collapse first to form the core of micelles stabilized with HPC chains upon heating. Further heating the copolymer solution at this pH leads to the aggregation of the micelles due to the collapse of the shell HPC chains. The thermal sensitivity of the HPC-g-PDMAEMA copolymers is reversible.
Microplastic pollution has become emerging environmental concern around world. The wastewater treatment plants (WWTPs) are attributed to a major pathway for microplastics (MPs) to enter into aquatic ...environment. To understand the fate and control strategies of MPs in WWTPs, we investigated MPs at a full-scale WWTP, Eastern China, with two parallel wastewater treatment systems, i.e. oxidation ditch (OD) and membrane bioreactor (MBR) for case study. The influent MPs consisted of polyethylene terephthalate (PET, 47%), polystyrene (PS, 20%), polyethylene (PE, 18%) and polypropylene (PP, 15%). MP morphotypes dominated in fragments (65%) and fibers (21%), which mainly were PET, with limited films (12%) and foams (2%). Typical plastic microbeads were not observed. The dominant size of MPs was >500 μm (40%) and 62.5–125 μm (29%). MP concentrations increased across the treatment systems depends on facility of treatment process. Influent MPs were removed by 99.5% in MBR system versus 97% in OD system on the basis of plastic mass while 82.1% versus 53.6% on MP number. The removed MPs accumulated in sludge phase. MBR system has much higher MP removal efficiency than OD system, likely due to membrane filtration. The results suggest that the source control of MPs by eliminating MP fibers from laundry facilities, banning use of plastic microbeads, Styrofoam products and plastic bags and properly selecting WWTP treatment unit could significantly reduce the mass and number of MPs from WWTPs.
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•Microplastics (MP) numbers increased cross oxidation ditch and MBR systems.•MPs belonging to PET, PS, PE and PP dominated in morphotypes of fragments and fibers.•MPs removed from water phase by >97% and accumulated in sludge phase.•MBR was superior in MP removal due to micromembrane filtration.•Strategies for MP source reduction and enhancement of WWTP management are proposed.
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