Microplastics have become global emerging issue and received widespread attention in recent years. Due to their chemical persistence, plastic particles can be broken into smaller items but accumulated for long time in the environment like sediment. However, limited by current detection technologies, the distribution and characteristics of small-sized microplastics in coastal sediment remain uncertain. In this study, we established a new method based on micro-Raman spectroscopy for detecting small-sized microplastics, namely multipoint confocal micro-Raman spectrum scanning (MCmRSS). The MCmRSS was first applied in detecting microplastics in the sediment samples collected from three bays of the East China Sea. The minimum size of microplastics was 4 μm and average microplastics concentration was 91 ± 55 items /g dry weight sediment, with fragment and polyethylene as the most common shape and polymer type, respectively. The spatial variation of microplastics was in accordance with the strength of coastal human activities and marine dynamics. In all the microplastic items, the small-sized ones (<10 μm) accounted for 67%; and the relationship between microplastic concentration and its size followed a power-exponential equation. Compared with previous studies, the number of microplastics in coastal sediments detected by the MCmRSS increased by 2 orders of magnitude, which was benefited from the advantages of multipoint scanning in the fixed identification areas and high resolution of micro-Raman spectrum. Our findings would summon the re-evaluation of the potential risks of small-sized microplastics in the coastal environment.
Here, we present a protocol to characterize the antiviral ability of a protein of interest to SARS-CoV-2 infection in cultured cells, using MUC1 as an example. We use SARS-CoV-2 ΔN trVLP system, which utilizes transcription and replication-competent SARS-CoV-2 virus-like particles lacking nucleocapsid gene. We describe the optimized procedure to analyze protein interference of viral attachment and entry into cells, and RT-qPCR-based quantification of viral infection. The protocol can be applied to characterize more antiviral candidates and clarify their functioning stage.
Y Utilizing in situ oxygen isotope analysis, we demonstrate the potential of cassiterite as a robust recorder of fluid source and evolution. Cassiterite is an ore mineral, and its mineral-water oxygen isotope fractionation factor is only weakly temperature-dependent. Unlike most explored gangue minerals such as quartz, cassiterite can provide a direct and robust archive of ore-forming fluids, e.g., fluid oxygen isotope composition (delta O-18 values). Core and rim domains of a representative cassiterite crystal from the Piaotang tin-tungsten (Sn-W) deposit, China, are characterized by contrasting delta O-18 values. Cassiterite delta O-18 values are -2.14 +/- 0.41 parts per thousand for the core and 2.36 +/- 0.36 parts per thousand for the rim, which equate to fluid delta O-18 values of similar to 4.1 parts per thousand (core) and similar to 8.6 parts per thousand (rim). Additionally, the cassiterite rim is enriched in niobium (Nb) and tantalum (Ta) compared to the mineral core. The delta O-18, and Nb and Ta data are interpreted to reflect core to rim crystallization from distinct pulses of magmatic-hydrothermal fluids that possessed a discrete oxygen isotopic, and Nb and Ta composition. Such a pulsed process could be a common feature for Sn-W deposits, and is critical to the formation of giant deposits with high metal grades. Involvement of meteoric water associated with the first mineralization stage reaches similar to 33%, but is limited (similar to 7%) in the second (main) mineralization stage. Therefore, cooling induced by fluid mixing may not be necessary for tin deposition, and our new findings invite a reassessment of the role of meteoric water in other Sn-W deposits. Our petrologic modelling shows that fluids exsolved from a 10 - 15 km(3) parental granitic magma can yield the Sn-W endowments recorded at Piaotang. Further, during magma fractionation, Sn and W are preferentially transferred into fluids compared to Nb and Ta. As a consequence, fluid chemistry is the primary factor controlling metal endowment and zoning in W-Sn deposits, as observed at Piaotang, and explains the predominant magmatic origin of Nb-Ta deposits.
How does China’s growing financial power reshape the structure of world politics? Does the expansion of China’s global influence come at the expense of the United States? A growing body of research in International Relations (IR) finds that China is increasingly using its economic power to gain leverage in international politics and engage countries to support its foreign policy. This paper addresses the question of whether “the rise of the Renminbi" – China’s entry into global monetary affairs through its BSA network – boosts its political influence and diminishes US political power on the global stage. To tackle the identification problem, we employ a Bayesian causal inference method devel-oped by Pang et al. (2021): bpCausal. Our analysis reveals intriguing results. First, we find that on average China’s BSAs have statistically a significant short-run causal effect of on governments’ expressed preferences over global issues. That is, BSAs bring the foreign policy ideal points of China and its partner states closer together in the year after a BSA is signed. Interestingly, while BSAs shift signatories closer to China’s ideal point in the UNGA, we find no evidence that BSAs pull countries away from the positions of the United States. On the contrary, weak evidence suggests that governments are moving closer to the United States in the median run, holding all other things constant, though the impact is much smaller compared to moving closer toChina.
The bacteria in the water column and surface sediments are inherently intertwined and inseparable in aquatic ecosystems, yet little is known about the integrated spatiotemporal dynamics and driving mechanisms of both planktonic and sedimentary bacterial communities in reservoirs. By investigating the planktonic and sedimentary bacteria during four seasons from 88 samples of 11 representative sites across the Danjiangkou reservoir, we depicted an integrated biogeographic pattern of bacterial communities in the water source of the world's largest water diversion project. Our study revealed both planktonic (mantel r = 0.502, P = 0.001) and sedimentary (mantel r = 0.131, P = 0.009) bacterial communities were significantly correlated with environmental heterogeneity, but a weak disparity along spatial heterogeneity, and the significant seasonal dynamics of planktonic (mantel r = 0.499, P = 0.001) rather than sedimentary bacteria. Particularly, rare biosphere played a main role in determining the community succession in the reservoir. It not only exhibited a more striking environmental separation than abundant taxa but also was an essential part in mediating spatiotemporal shifts of planktonic bacteria and maintaining the stability of bacterial community. These rare bacteria were respectively mediated by stochastic (62.68%) and selective (79.60%) processes in water and sediments despite abundant taxa being largely determined by stochastic processes (86.88-93.96%). Overall, our study not only fills a gap in understanding the bacterial community dynamics and underlying drivers in source water reservoirs, but also highlights the particular importance of rare bacteria in mediating biogeochemical cycles in world's large reservoir ecosystems.
Summary A growing number of governments are pledging to achieve net-zero greenhouse gas emissions by mid-century. Despite such ambitions, realized emissions reductions continue to fall alarmingly short of modeled energy transition pathways for achieving net-zero. This gap is largely a result of the difficulty of realistically modeling all the techno-economic and sociopolitical capabilities that are required to deliver actual emissions reductions. This limitation of models suggests the need for an energy-systems analytical framework that goes well beyond energy-system modeling in order to close the gap between ambition and reality. Toward that end, we propose the Emissions-Sustainability-Governance-Operation (ESGO) framework for structured assessment and transparent communication of national capabilities and realization. We illustrate the critical role of energy modeling in ESGO using recent net-zero modeling studies for the world's two largest emitters, China and the United States. This illustration leads to recommendations for improvements to energy-system modeling to enable more productive ESGO implementation.
Abstract We present OH observations made in Amazonas, Brazil during the Green Ocean Amazon campaign (GoAmazon2014/5) from February to March of 2014. The average diurnal variation of OH peaked with a midday (10:00?15:00) average of 1.0 ? 106 (±0.6 ? 106) molecules cm?3. This was substantially lower than previously reported in other tropical forest photochemical environments (2?5 ? 106 molecules cm?3) while the simulated OH reactivity was lower. The observational data set was used to constrain a box model to examine how well current photochemical reaction mechanisms can simulate observed OH. We used one near-explicit mechanism (MCM v3.3.1) and four condensed mechanisms (i.e., RACM2, MOZART-T1, CB05, CB6r2) to simulate OH. A total of 14 days of analysis shows that all five chemical mechanisms were able to explain the measured OH within instrumental uncertainty of 40% during the campaign in the Amazonian rainforest environment. Future studies are required using more reliable NOx and VOC measurements to further investigate discrepancies in our understanding of the radical chemistry in the tropical rainforest.
Conventional digital cameras typically accumulate all the photons within an exposure period to form a snapshot image. It requires the scene to be quite still during the imaging time, otherwise it would result in blurry image for the moving objects. Recently, a retina-inspired spike camera has been proposed and shown great potential for recording high-speed motion scenes. Instead of capturing the visual scene by a single snapshot, the spike camera records the dynamic light intensity variation continuously. Each pixel on spike camera sensor accumulates the incoming photons independently and persistently, which fires a spike and restarts the photon accumulation immediately once the dispatch threshold is reached, producing a continuous stream of spikes recorded at very high temporal resolution. To recover the dynamic scene from captured spike stream, this paper presents an image reconstruction approach for spike camera. In order to generate high-quality reconstruction, we investigate the temporal correlation along motion trajectories and exploit it via adaptive temporal filtering. In particular, we present a hierarchical motion-aligned temporal filtering scheme, combining short-term filtering with long-term filtering to take advantage of long-term temporal correlation with low model complexity. Experimental results demonstrate that the proposed scheme outperforms the existing schemes significantly, producing much better objective and subjective qualities for spike camera image reconstruction.