17 research outputs found
Earthworms increase forest litter mass loss irrespective of deposited compounds – A field manipulation experiment in subtropical forests
No full textEarthworms modulate carbon and nitrogen cycling in terrestrial ecosystems, but their effect may be compromised by the deposition of pollutants from industrial emissions. However, studies investigating how deposited compounds affect the role of earthworms in carbon cycling such as litter decomposition are lacking, although the interactions of earthworms and deposited compounds are important for understanding the impact of pollutants on ecosystems and the potential of earthworms in bioremediation. We performed a 365-day in situ litterbag decomposition experiment in a deciduous (Quercus variabilis) and coniferous (Pinus massoniana) forest in southeast China. We manipulated nitrogen (N), sodium (Na), and polycyclic aromatic hydrocarbons (PAHs) as model compounds during litter decomposition with and without earthworms (Eisenia fetida). After one year, N, Na, and PAH all slowed down litter mass loss, with the effects of Na being the strongest. By contrast, E. fetida generally increased litter mass loss, and the positive effects were uniformly maintained irrespective of the type of compounds added. However, the pathways to how earthworms increased litter mass loss varied among the compounds added and the two forests studied. As indicated by structural equation modeling, earthworms mitigated the negative effects of deposited compounds by directly increasing litter mass loss and indirectly increasing soil pH and microbial biomass. Overall, the results indicate that the acceleration of litter mass loss by earthworms is little affected by deposited compounds, and that earthworms have the potential to mitigate negative impacts of pollutants on litter decomposition and ecosystem processes.Jiangsu Forestry Science and technology innovation and promotion projectKey specialized research and development breakthrough program in Henan provinceNational Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809Scholarship of China Scholarship CouncilStrategic Priority Research Program of the Chinese Academy of Sciences (A)The Key Program of Scientific Research projects of Hunan Provincial Education DepartmentOpen-Access-Publikationsfonds 202
Simulation method of spatial laser field for arbitrary distance optical transmission with carbon nanotube
No full textIn this paper, an arbitrary distance optical transmission simulation method for free-space optical communication system is presented. Based on this method, direct point-to-point performance tests between two optical terminals can be realized in the laboratory, and the test results are equivalent to those on-orbit. A theoretical analysis of this Method is presented in this paper. Verification experiments showed that there is a good linearity between the incoming power density and output photocurrent of the carbon nanotube (CNT); the relative power difference between the CNT and the charge-coupled device (CCD) camera is 4.75%, which can be ignored compared with the link redundancy.863 Program [2015AA7011009]; Ministry of Industry and Information Technology; National Defense Technology Basic Research Project during the 12th Five -Year Plan Period [J312012A001]SCI(E)ARTICLE258-26239
Point-Ahead Angle and Coalignment Error Measurement Method for Free-Space Optical Communication Systems
No full textMicroradian tracking and pointing errors significantly affect the link performance and the bit error probability in free-space optical communication. This paper proposes the measurement method for point-ahead angle and coalignment error, which can significantly mitigate the tracking and pointing error, thus reduces the power of the free-space optical communication system. By using technologies of corner cube reflector, off-axis reflecting telescope, vacuum long-light path and anti-interference support structure design, microangles can be measured accurately, especially the coalignment error angle which is formed by two wide, incoherent beams nearly antiparallel to each other. This paper introduces the measuring equipment's structure, together with the measurement method and theoretical measurement model. The measuring accuracy analysis indicated that the measurement uncertainty of both point-ahead angle and coalignment error was superior to 0.2 mu rad and the validation experimental results proved that measuring accuracies of point-ahead angle and coalignment error are all smaller than 1 mu rad.Ministry of Industry and Information Technology; National Defense Technology Basic Research Project [J312012A001]SCI(E)ARTICLE183886-38933
Distributed Document Representation for Document Classification
No full textThe distributed vector representations learned from the deep learning framework have shown its great power in capturing the semantic meaning of words, phrases and sentences, from which multiple NLP applications have benefited. As words combine to form the meaning of sentences, so do sentences combine to form the meaning of documents, the idea of representing each document with a dense distributed representation holds promise. In this paper, we propose a supervised framework (Compound RNN) for document classification based on document-level distributed representations learned from deep learning architecture. Our framework first obtains the distributed representation at sentence-level by operating on the parse tree structure from recursive neural network, and then obtains the document presentation-level by convoluting the sentence vectors from a recurrent neural network. Our framework (Compound RNN) outperforms existing document representations such as bag-of-words, LDA in multiple text classification/regression tasks.EICPCI-S(ISTP)[email protected]; [email protected]
Ground Simulation Method for Arbitrary Distance Optical Transmission of a Free-Space Laser Communication System Based on an Optical Fiber Nanoprobe
No full textThe Impact of Water-Soluble Inorganic Ions in Particulate Matter (PM2.5) on Litter Decomposition in Chinese Subtropical Forests
No full textAlthough numerous studies have demonstrated the toxic effects of fine particulates less than 2.5 µm (PM2.5) on the health of humans, little information is available on the ecotoxicity of PM2.5. Water-soluble inorganic ions (WSII, including Na+, NH4+, K+, Mg2+, Ca2+, Cl−, NO3−, and SO42−) can compose more than 60% of PM2.5. To better understand the possible impacts of WSII-PM2.5 on leaf litter decomposition, we conducted an experiment in which two leaf litters from oak (Quercus variabilis) and pine (Pinus massoniana) dominant forests in subtropical China were incubated in microcosms containing their respective forest soils and treated with WSII-PM2.5. Our results showed that, after six-months of decomposition, the WSII-PM2.5 treatments inhibited leaf litter decomposition rates, carbon and nitrogen loss, microbial biomass, and enzyme activities in the two forests. In addition, higher WSII-PM2.5 concentration led to stronger negative effects. Comparative analysis showed that the negative effects of WSII-PM2.5 on oak forest were greater than on pine forest, relating to the higher susceptibility to changes of soil microenvironment in oak forests. WSII-PM2.5 may influence decomposition through soil acidification and salinization, which could also cause a sub-lethal depression in soil isopod activity. However, in the first month of decomposition, mass loss of the oak and pine leaf litters under the low concentration WSII-PM2.5 were 21.63% and 35.64% higher than that under the control, respectively. This suggests that transitory low concentrations of WSII-PM2.5 have a promoting effect on decomposition. Long-term PM2.5 exposure, therefore, may have profound ecosystem consequences by altering the balance of ecosystem carbon flux, nutrient cycling, and humus formation in the future
Iron Based Chitin Composite Films for Efficient Solar Seawater Desalination
No full textSeawater desalination provides a convenient method for the sustainable production of fresh water. However, the preparation of low-cost, high-efficiency solar absorbers remains a huge challenge. To this end, our research group designed and produced a cheap absorber—a membrane made of natural polymer chitin with black FeS and Fe3O4, respectively. Due to the hierarchical pore structure, excellent photothermal performance and good hydrophilicity of the film, their water evaporation rates reached 1.47 kg/m2/h and 1.55 kg/m2/h under one sunlight, respectively. Under about 10 suns, the highest desalination efficiency of FeS/chitin and Fe3O4/chitin are 90% and 74%, respectively, and their salinities are also in line with the World Health Organization drinking water standards. These results indicate the potential of chitin-based nanomaterials as high-efficiency solar absorbers to produce fresh water
Initial microbiome and tree root status structured the soil microbial community discrepancy of the subtropical pine-oak forest in a large urban forest park
Get PDFPlant–microbe–soil interactions control over the forest biogeochemical cycling. Adaptive plant–soil interactions can shape specific microbial taxa in determining the ecosystem functioning. Different trees produce heterogeneous soil properties and can alter the composition of soil microbial community, which is relevant to the forest internal succession containing contrasting stand types such as the pine-oak forests. Considering representative microbial community characteristics are recorded in the original soil where they had adapted and resided, we constructed a soil transplant incubation experiment in a series of in situ root-ingrowth cores in a subtropical pine-oak forest, to simulate the vegetational pine-oak replacement under environmental succession. The responsive bacterial and fungal community discrepancies were studied to determine whether and how they would be changed. The pine and oak forest stands had greater heterogeneity in fungi composition than bacteria. Original soil and specific tree root status were the main factors that determined microbial community structure. Internal association network characters and intergroup variations of fungi among soil samples were more affected by original soil, while bacteria were more affected by receiving forest. Specifically, dominant tree roots had strong influence in accelerating the fungi community succession to adapt with the surrounding forest. We concluded that soil microbial responses to forest stand alternation differed between microbiome groups, with fungi from their original forest possessing higher resistance to encounter a new vegetation stand, while the bacteria community have faster resilience. The data would advance our insight into local soil microbial community dynamics during ecosystem succession and be helpful to enlighten forest management
Dual Effect of Microplastics and Cadmium on Stream Litter Decomposition and Invertebrate Feeding Behavior
No full textThis study investigates the combined effect of microplastics and cadmium on the decomposition of litter, the structure of fungal communities, and the feeding behavior of invertebrates in an aquatic ecosystem. Through a series of microcosm experiments, we demonstrate that exposure to MPs and Cd significantly reduced the decomposition of leaf litter. Notably, the cumulative impact of combined MP and Cd exposure was found to be greater than their individual effects. During this process, the carbon–nitrogen ratio of the litter increased, while dehydrogenase activity and fungal biomass were inhibited. Additionally, the relative abundance of Ascomycota and Basidiomycota fungi decreased, weakening their role in the decomposition of leaf litter. Conversely, MPs and Cd reduced the relative content of leaf litter lignin, improving its quality as food, thereby leading to an increase in the feeding rate of invertebrates. This dual effect indicates that micropollutants suppress the decomposition of litter by regulating microbial metabolic activity and fungal community structure but promote invertebrate feeding. Our findings provide crucial insights into the adverse effects of MPs and Cd on the structure and diversity of aquatic fungal communities, which could have long-term impacts on the food webs and nutrient cycling progress of aquatic ecosystems
Neuropeptides as regulators of bone metabolism: from molecular mechanisms to traditional Chinese medicine intervention strategies
Get PDFOsteoporosis (OP) is a complex bone metabolism disorder disease that affects the skeleton, nervous system, muscles, and multiple tissues. Neuropeptides, which are endogenous substances derived from both bone and brain, play a critical role in maintaining the balance of bone metabolism. This review summarizes research conducted from 1986 to 2024 on the pathological mechanisms of neuropeptides and their receptors in the context of OP. Specifically, the roles of Neuropeptide Y, Vasoactive Intestinal Peptide, Calcitonin Gene-Related Peptide, and Substance P and their receptors in key processes of OP were examined, including their function of bone formation and resorption, osteoblast differentiation, and osteoclast differentiation. Our study showed that these neuropeptides could promote bone formation and inhibit bone resorption, while their receptors in osteocytes exhibit distinct functions, indicating complex regulatory mechanisms that require further investigation. Additionally, we summarize the progress of Traditional Chinese Medicine (TCM) formulae, single TCM herbs, and bioactive compounds derived from TCM in exerting anti-OP effects through neuropeptide modulation. These studies highlight the multi-targeted and multi-mechanistic pharmacological actions of TCM in treating OP. By integrating these findings, we aim to enhance the understanding of neuropeptides’ roles in bone metabolism and to explore the development of neuropeptide-targeted TCM therapies for OP management. This comprehensive perspective highlights the potential of neuropeptides as therapeutic targets, paving the way for innovative approaches to treating OP
