Land is a complex system of production, ecology, economy, and ecology, which constitutes the basis of human survival and development. In the current land environment, most of China’s land development ...and utilization are focused on economic interests, while ignoring the environmental impact, which leads to the increase of land use intensity and the increasing pressure on the land environment. In recent years, the research on land ecological security evaluation is deepening, and many land ecological security evaluation methods and genetic network algorithms are proposed. However, due to the complexity and diversity of soil environmental security, the theoretical research of land environmental security evaluation is still the central topic of researchers in related fields. This paper makes an in-depth study of resource situation analysis based on cloud computing monitoring platform, and analyzes the related research needs, including advanced cloud computing monitoring technology, cloud resource trend prediction model, data collection technology, correlation analysis technology, and basic big data estimation algorithm. This paper designs a situation analysis system on cloud computing real-time data monitoring platform, including the module for analyzing resource situation, the module for recording resource data, and the external display module. This paper proposes a new method to estimate the performance of big data stream. Based on this method, we can create a performance calculator to calculate the target source and IP address of each node more efficiently, real time, and accurately in cloud monitoring. In this paper, the land ecological security evaluation method and genetic network algorithm are proposed, which are applied to the cloud computing real-time data monitoring platform, and promote the vigorous development of cloud computing monitoring platform.
Alzheimer's disease (AD) is the most progressive form of neurodegenerative disease, which severely impairs cognitive function. Oxidative stress is identified to contribute to the mechanisms ...responsible for the pathogenesis of such neurodegenerative diseases. Aluminum is a potent neurotoxin for inducing oxidative stress associated with neurodegenerative diseases. The treatment for AD is limited; hence more treatment options are the need of the day. Betalain is known for its multitude of medicinal assets, including anti-inflammatory activity. Hence, this study was intended to investigate the possible protective effect of betalain against aluminum chloride (AlCl3) induced AD on Sprague Dawley (SD) rats. AlCl3 (100 mg/kg) was administrated orally to induce the AD in SD rats. The rats were supplemented with low and high betalain doses (10 mg/kg and 20 mg/kg) for four weeks. At the end of the experiment, the rats were subjected to behavioral examination and sacrificed to study the biochemical and histological parameters. The results showed attenuation of memory and learning capacity, suppression of lipid oxidation (MDA) through regulation of antioxidant content (SOD, CAT, and GSH) and inhibition of lactate dehydrogenase (LDH), nitric oxide (NO), acetylcholinesterase (AChE), and transmembrane protein (Na+K+ATPase) activity. In addition, the NF-ƙB associated mRNA expression (TNF-α IL-6, Il-1β, iNOS, COX-2) was decreased, as evidenced in histopathological results. The present investigation established that the betalain treatment ameliorated the AlCl3 induced AD by modulating NF-κB pathway activation.
Whispering gallery mode (WGM) resonators are shown to hold great promise to achieve high‐performance lasing using colloidal semiconductor nanocrystals (NCs) in solution phase. However, the low ...packing density of such colloidal gain media in the solution phase results in increased lasing thresholds and poor lasing stability in these WGM lasers. To address these issues, here optical gain in colloidal quantum wells (CQWs) is proposed and shown in the form of high‐density close‐packed solid films constructed around a coreless fiber incorporating the resulting whispering gallery modes to induce gain and waveguiding modes of the fiber to funnel and collect light. In this work, a practical method is presented to produce the first CQW‐WGM laser using an optical fiber as the WGM cavity platform operating at low thresholds of ≈188 µJ cm−2 and ≈1.39 mJ cm−2 under one‐ and two‐photon absorption pumped, respectively, accompanied with a record low waveguide loss coefficient of ≈7 cm−1 and a high net modal gain coefficient of ≈485 cm−1. The spectral characteristics of the proposed CQW‐WGM resonator are supported with a numerical model of full electromagnetic solution. This unique CQW‐WGM cavity architecture offers new opportunities to achieve simple high‐performance optical resonators for colloidal lasers.
A novel whispering‐gallery‐mode (WGM) assisted optical resonator is demonstrated for lasing of colloidal quantum wells (CQW). The CQW‐WGM resonator benefits from a high net modal gain coefficient of core/crown@gradually alloyed shell (C/C@GAS) CQWs solids. WGM‐assisted laser of close‐packed films of C/C@GAS nanoplatelets addresses the previous issues of in solution WGM lasers by performing highly stable laser emission.
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•The North China Craton (NCC) has undergone six major tectonic-metallogenic events from Neoarchean to Mesozoic.•Nature and mineralization style of metallogeny change as the continent ...evolves.•The metallogenic systems formed by different events have distinct characteristics and show variations through time.•The non-repeatability of the metallogeny was controlled by irreversible continental tectonic evolution.
The generation and evolution of continent crust have long been matters of debates. There is evidence to support the view that the first formation of TTGs of continent was possibly before 4.4 Ga, followed by the sizable continent crust associated with BIF-bearing supra-crustal rocks at ca. 3.8 Ga. Multiple stages of continental growth include continental nuclei at ~3.1 Ga, enormous crustal growth at 2.9–2.7 Ga and stabilization and cratonization at ~2.5 Ga. Subsequently a stable super-continent was formed and the Earth was evolved into the Proterozoic eon. In the Proterozoic eon, major geological events include the great oxygen event (GOE), global rift and mobile belt event, and the Earth’s middle age event with a 1.0 billion years long period of Earth’s adjustment or silence. After that, the Rodinian super-continental break up event (the Nanhua rift) and subsequent Gondwana amalgamation have been suggested to be involved with mantle-plume and the modern style-like plate tectonics, both of which are still under debates. Recent studies suggest that the continental metallogeny has secular changes with the evolving Earth, showing synchronous evolution with the continental crust through time. The North China Craton (NCC) is one of the oldest cratons in the world, and has undergone six major tectono-metallogenic cycles: (1) the Neoarchean crustal growth and Algoman-type BIFs-greenstone belt and gold metallogenic system, (2) Paleoproterozoic GOE associated with global (Huronian) rifting- Glaciation and Superior-type BIFs-Mg-B metallogenic system, (3) Paleoproterozoic rifting-subduction-accretion-collision event (mobile belt) and Cu-Pb-Zn metallogenic system; (4) Late Paleoproterozoic – Neoproterozoic multi-stage rifting and REE-Fe-Pb-Zn metallogenic system; (5) Paleozoic orogenesis at the margins of the craton and porphyry Cu-Mo metallogenic system; and (6) Mesozoic extensional tectonics associated with lithosphere thinning and intracontinental Au metallogenic systems. Ore deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities. Changes of metallogenic styles with time, from the dominant BIFs in Archean to polymetallic deposits in Proterozoic and Phanerozoic, demonstrate that the nature and style of metallogeny through time change with different stages of the Earth’s evolution and are the expression of variable materials at the different stages. The changes of metallogeny through time are controlled by the irreversible continental tectonic evolution. The connotation and signification of synchronous evolution of continental crust and mineral deposit systems through time are beyond the study of mineral resources but would provide new insights into the geodynamics of the generation and evolution of the continent. The NCC provides an excellent venue to address the linkage between metallogenic processes and secular changes in the Earth System, including mantle dynamics and crust-mantle interaction on a global perspective.
•NPP in the Shule River Basin was relatively small.•Impacts of landscape metrics on NPP varied with spatial scales and land use.•Landscape configuration explained 68% of the variation in NPP at the ...landscape level.•Different landscape metrics played different roles in explaining NPP at the class level.
Human activities and environmental degradation have resulted in landscape pattern changes and can eventually profoundly affect net primary productivity (NPP) at different scales worldwide. A comprehensive understanding of how the relationship between landscape patterns (composition and configuration) and NPP changes across scales, is helpful for landscape planning and ecological protection and restoration. However, relevant research is currently understudied. Therefore, this study selected 39 landscape metrics and 5 types of land use in the Shule River Basin (SRB), and analysed their correlation under eight different scales via multiple linear regression models, aiming to determine the core landscape metrics to assess the NPP. Results indicate obvious spatial variations in the landscape metrics. At the same time, NPP in SRB was relatively small and showed obvious spatial heterogeneity. Landscape metrics and NPP showed different degrees of positive or negative correlation at different grid scales, and there were higher correlation at the 30 km scale. The increase in patch fragmentation and diversity promoted an increase in NPP. The correlation between landscape metrics and NPP was higher and more significant at the class level than at the landscape level, except in the case of unused land. Configuration metric (patch density and patch richness) explained 68% of the variation in NPP at the landscape level. At the class level, composition metrics (class area and percentage of landscape) played an important role in farmland, forestland, and grassland, while edge density (configuration metric) played an absolute role in the built-up land and unused land; overall, the effectiveness of the model was stronger at the class level than at the landscape level. The generated regression model allows us to quantitatively understand how to characterize changes in NPP through changes in landscape patterns. Appropriate landscape pattern and optimal scale should be considered in landscape planning and land use management to reduce the expected ecological impact.
Chiral lanthanide cages with circularly polarized luminescence (CPL) properties have found potential application in enantioselective guest recognition and sensing. However, it still remains a big ...challenge to develop a simple and robust method for the diastereoselective assembly of homochiral lanthanide cages in view of the large lability of the Ln(III) ions. Herein, we report the first example of the formation of a enantiopure lanthanide tetrahedral cage via a chiral ancillary ligand induction strategy. One such cage, (Eu4L4)(R/S-BINAPO)4, is assembled by four achiral C 3-symmeric tris(β-diketones) (4,4′,4″-tris(4,4,4-trifluoro-1,3-dioxobutyl)triphenylamine, L) as faces, four Eu(III) ions as vertices and four chiral R-/S-bis(diphenylphosphoryl)-1,1′-binaphthyl (R/S-BINAPO) as ancillary ligands. X-ray crystallography and NMR and CD spectra confirm the formation of a pair of enantiopure chiral topological tetrahedral cages, (Eu4L4)(R-BINAPO)4 and (Eu4L4)(S-BINAPO)4 (ΔΔΔΔ-1 and ΛΛΛΛ-1). As expected, the tetrahedral cages present strong CPL with |g lum| values up to 0.20, while they unexpectedly give ultrahigh luminescent quantum yields (QYs) of up to 81%, the highest value reported in chiral Ln(III) complexes. More impressively, the chiral memory effect for a lanthanide-based assembly is observed for the first time. The chirality of the original cage 1 framework is retained after R/S-BINAPO is replaced by the achiral bis2-(diphenylphosphino)phenyl ether oxide (DPEPO), and thus another pair of enantiopure Eu(III) tetrahedral cages, ΔΔΔΔ- and ΛΛΛΛ-(Eu4L4)(DPEPO)4 (ΔΔΔΔ-2 and ΛΛΛΛ-2), have been isolated. Encouragingly, cage 2 also presents an impressive luminescence quantum yield (QY = 68%) and intense CPL (|g lum| = 0.11). This study offers a simple and low-cost synthesis strategy for the preparation of lanthanide cages with CPL properties.
Aging poses a significant challenge worldwide, with China's aging status becoming particularly severe. What is the impact of Internet use on the health of the elderly? Existing studies have drawn ...conflicting conclusions that Internet use improves or harms health. The purpose of this study was to explore how Internet use affects the health of older adults, and the mechanisms and heterogeneity of these effects.
Based on Grossman's theory, this paper constructs a health production function model. Using the data of China Family Panel Studies (CFPS) from 2014 to 2020, we investigated the impact of Internet use on the health of older adults using fixed effect model and instrumental variable method. We also examined the mediating role of health information acquisition, lifestyle, and social interaction in these associations.
Internet use is positively associated with self-rated health and negatively associated with psychological sub-health level. Internet use promotes the health of older adults by facilitating access to health information, healthy lifestyles, and enhancing social interaction. And the impacts are heterogeneous at the individual and regional levels.
We should progressively enhance the level of internet accessibility for older adults, while concurrently addressing and narrowing the 'digital divide'. By generating an abundance of superior health-related information, we can significantly improve health education tailored for the elderly. Additionally, it is crucial to offer extensive training opportunities designed to equip older adults with the necessary skills to proficiently navigate the internet.
•The Ruyang Group in the southern North China Craton formed after 1744±22Ma.•The Ruyang Group was deposited in a passive continental margin basin.•The detritus was derived from a Paleoproterozoic ...silicic-intermediate source.•Detrital zircons have age peaks at ∼2.10 and ∼1.86Ga.•Hf isotopic data reveal the crustal growth occurred during late Archean.
Late Paleoproterozoic rifting and accompanying magmatism and sedimentation, which occurred widely in the North China Craton, are interpreted to be related to the breakup of the supercontinent Columbia. The Ruyang Group, overlying the Xiong’er Group in the southern margin of the craton, is a typical fluvial-marine sedimentary sequence mainly composed of sandstone with minor shale and dolostone. Sandstones from the Ruyang Group exhibit high contents of SiO2 (86.8–98.7wt.%) but relatively low contents of Al2O3, K2O, Na2O, TiO2 and MgO, typical of mature siliceous clastic rocks. Trace elements of these rocks indicate that the sequence was deposited in a passive continental margin environment and that the sedimentary detritus was derived from a Paleoproterozoic silicic-intermediate source, similar to other Paleo-Mesoproterozoic sedimentary sequences in the region.
Detrital zircons from three sandstone samples of the Ruyang Group yield 207Pb/206Pb ages ranging from 1.70Ga to 2.70Ga with two pronounced peaks at ca. 2.10Ga and 1.86Ga. A weighted mean age at 1744±22Ma from nine young zircon ages between 1.80Ga and 1.70Ga can constrain the maximum depositional age of the Ruyang Group. Most detrital zircons exhibit negative ɛHf(t) values ranging from −15.6 to 0 and old TDMC ages ranging from 2.50Ga to 3.60Ga, implying reworking of Archean crust. A close match between the U–Pb ages and TDMC(Hf) ages, as well as the positive ɛHf(t) values for some detrital zircons, indicate a contribution of juvenile materials. The detrital zircon grains have TDMC(Hf) ages clustering between 3.00Ga and 2.60Ga with a peak at around 2.80–2.70Ga, indicating a major period of crustal growth at this time.
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