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Hylocomium splendens (Hedw.) *** Pleurozium schreberi (Brid.) *** trace element bioindicators:Statistical comparison of bioaccumulative properties

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Journal of Environmental Sciences 2013年第2期25卷 340-347页

作者： Sabina Doegowska Zdzisaw M.Migaszewski Artur Michalik Geochemistry and the Environment division Institute of ChemistryJan Kochanowski University15GSwietokrzyska St25-406 KielcePoland

The principal objective of this study was to compare bioaccumulative properties of two terrestrial moss species Hylocomium splendens and Pleurozium schreberi from the Kielce area （south-central Poland）, using various statistical techniques. Forty-six moss samples from 23 sampling sites located within the city limits were analyzed for 33 trace elements. The results indicated that 17 elements （Ba, Ce, Co, Cu, Eu, Fe, Gd, Hg, La, Mo, Nd, Ni, Pb, Pr, Sm, V, Y） dominated in H. splendens, whereas only three elements （Mn, Sr, Zn） occurred in excessive amounts in P. schreberi. No differences in the distribution pattern of Dy, Er, Ho, Sn, Tb, Th and Yb were observed. The element concentration ratio （PI/Hy） varied from 0.50 to 1.19. For 14 elements （Ce, Co, Cu, Fe, Gd, Hg, La, Mo, Nd, Ni, Pb, Sm, Th, V）, PI/Hy 〈 1; for 4 elements （Cd, Mn, Sr, Zn）, PI/Hy 〉 1; for 7 elements （Ba, Dy, Er, Eu, Pr, Y, Yb）, PI/Hy = equalled 1. Czekanowski＇s method showed similarities in rare earth element concentrations for both moss species. The cluster analysis exhibited three significant clusters at D link /D max × 100 〈 50 for both moss species. Strong positive Spearman correlations between both moss species were recorded for the following pairs：Ba-Ba, Co-Co, Er-Er, Eu-Eu, Gd Gd, Mn-Mn, Ni-Ni, Pb-Pb, Pr-Pr, Sm-Sm, Th-Th, Y-Y, and Yb-Yb. Nonparametric tests （Sign test, Wilcoxon tests） showed statistically significant differences only for Cd, Ce, Co, Cu, Hg, Mo, Ni, Pb and Sr. The scanning electron microscope study of H. splendens and P. schreberi revealed a different morphology of these species with no injuries.

关键词： biomonitoring trace elements moss species accumulative properties comparison

Modelling reference evapotranspiration using gene expression programming and artificial neural network at Pantnagar,India

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Information Processing in Agriculture 2023年第4期10卷 547-563页

作者： Pangam Heramb Pramod Kumar Singh K.V.Ramana Rao A.Subeesh division of Irrigation and Drainage Engineering ICAR-Central Institute of Agricultural EngineeringBhopal 462038India Department of Irrigation and Drainage Engineering G.B.Pant University of Agriculture and TechnologyPantnagar 263145India division of Agricultural Mechanization ICAR-Central Institute of Agricultural EngineeringBhopal 462038India

Evapotranspiration is an essential component of the hydrological cycle that is of particular interest for water resource *** quantification is helpful in irrigation scheduling,water balance studies,water allocation,*** of reference evapotranspiration(ET0)using both gene expression programming(GEP)and artificial neural network(ANN)techniques was done using the daily meteorological data of the Pantnagar region,India,from 2010 to 2019.A total of 15 combinations of inputs were used in developing the ET0 *** model with the least number of inputs consisted of maximum and minimum air temperatures,whereas the model with the highest number of inputs consisted of maximum air temperature,minimum air temperature,mean relative humidity,number of sunshine hours,wind speed at 2mheight and extra-terrestrial radiation as inputs and with ET0 as the output for all the *** the GEP models were developed for a single functional set and pre-defined genetic operator values,while the best structure in each ANN model was found based on the performance during the testing *** was found that ANN models were superior to GEP models for the estimation *** was evident from the reduction in RMSE values ranging from 2%to 56%during training and testing phases in all the ANN models compared with GEP *** ANN models showed an increase of about 0.96%to 9.72%of R2 value compared to the respective GEP *** comparative study of these models with multiple linear regression(MLR)depicted that the ANN and GEP models were superior to MLR models.

关键词： Artificial Neural Networks Evolutionary algorithms Gene Expression Programming Machine Learning Regression Analysis Reference evapotranspiration models

Arsenobetaine:the ongoing mystery

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National Science Review 2016年第4期3卷 451-458页

作者： Aleksandra Popowich Qi Zhang X.Chris Le Department of Chemistry University of Alberta division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyUniversity of Alberta

Arsenobetaine(As B) is a non-toxic organoarsenical identiied as a major arsenic species in marine animals and a number of terrestrial *** its irst identiication nearly 40 years ago,numerous studies investigating the biosynthesis and function of As B have been carried out,although molecular mechanisms have not been fully *** and how is As B formed? Why do marine animals acquire high concentrations of As B? his review briely summarizes the current progress of As B research toward understanding its origin,function and the putative pathways for its *** paper also suggests potential future studies in the atempt to solve the As B mystery.

关键词： arsenic arsenobetaine arsenocholine arsenosugars biosynthesis arsenic metabolism speciation

Soil CO_2 Flux in Different Types of Forests Under a Subtropical Microclimatic Environment

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Pedosphere 2014年第2期24卷 243-250页

作者： YAN Wen-De XU Wang-Ming CHEN Xiao-Yong TIAN Da-Lun PENG Yuan-Ying ZHEN Wei ZHANG Cao XU Jie Forest Ecology Program College of Life Science and TechnologyCentral South University of Forestry and Technology National Engineering Laboratory for Applied Forest Ecological Technology in Southern China State Forestry Administration of China division of Science College of Arts and SciencesGovernors State UniversityUniversity Park Natural Sciences division College of DuPage

The flux of carbon dioxide （CO2） from soil surface presents an important component of carbon （C） cycle in terrestrial ecosystems and is controlled by a number of biotic and abiotic factors. In order to better understand characteristics of soil CO2 flux （FCO2） in subtropical forests, soil FCO2 rates were quantified in five adjacent forest types （camphor tree forest, Masson pine forest, mixed camphor tree and Masson pine forest, Chinese sweet gum forest, and slash pine forest） at the Tianjiling National Park in Changsha, Hunan Province, in subtropical China, from January to December 2010. The influences of soil temperature （Tsoil）, volumetric soil water content （0soiI）, soil pH, soil organic carbon （SOC） and soil C/nitrogen （N） ratio on soil FCO2 rates were also investigated. The annual mean soil FCO2 rate varied with the forest types. The soil FCO2 rate was the highest in the camphor tree forest （3.53 ± 0.51 μmol m-2 s-I）, followed by, in order, the mixed, Masson pine, Chinese sweet gum, and slash pine forests （1.53 ± 0.25 μmol m-2 sl）. Soil FCO2 rates from the five forest types followed a similar seasonal pattern with the maximum values occurring in summer （July and August） and the minimum values during winter （December and January）. Soil FCO2 rates were correlated to Tsoil and 0soil, but the relationships were only significant for Tsoil. No correlations were found between soil FCO2 rates and other selected soil properties, such as soil pH, SOC, and C/N ratio, in the examined forest types. Our results indicated that soil FCO2 rates were much higher in the evergreen broadleaved forest than coniferous forest under the same microclimatic environment in the study region.

关键词： broadleaved forest carbon coniferous forest soil temperature soil water content

Global patterns of phosphorus transformation in relation to latitude,temperature and precipitation

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Pedosphere 2021年第1期31卷 214-220页

作者： Jia-Zhong ZHANG Ocean Chemistry and Ecosystems division Atlantic Oceanographic and Meteorological LaboratoryNational Oceanic and Atmospheric AdministrationMiami FL 33149USA

Dear Editor,Phosphorus (P) is essential and often a limiting nutrient for biological production on land and in the seas (Elser et al., 2007). The biologically available P to terrestrial and aquatic ecosystems ultimate... 详细信息

关键词： latitude phosphorus transformation

Trends in grassland science:Based on the shift analysis of research themes since the early 1900s

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Fundamental Research 2023年第2期3卷 201-208页

作者： Guiling Zhao division of Environment and Ecology Department of Life SciencesNational Natural Science Foundation of ChinaBeijing 100085China

Grasslands,one of the major terrestrial ecosystems,are essential for the maintenance of ecological and production functions;however,they are undergoing extensive *** development and cutting-edge explorations in grassland science are critical to addressing challenges such as climate change and the increasing influence of human *** identify research trends in grassland science,latent Dirichlet allocation(LDA)topic modelling was used to conduct an automated content analysis on 123,829 papers available on Web of Science Core Collection from 1900 to *** from this analysis showed that grassland research has become increasing multidisciplinary,accompanied by a pronounced reduction in the relative frequency of traditional production-oriented research and an increase in the themes focusing on ecological functions and modern *** in research activities have been uneven globally,with a significant increase in the number of publications in China and Brazil,which probably reflects an increased support from various governmental agencies in these ***,in 2019,China surpassed the United States in terms of the total number of ***,this study identified important topics and emerging challenges in grassland research,such as biodiversity conservation,climate changes,and genetic *** improvement of education,research,global cooperation,and funding strategies will be necessary to promote grassland science research on frontier themes and to effectively address the social and environmental challenges in the new era.

关键词： Grassland science Research themes Bibliometrics Temporal trends Development strategies

Artificial intelligence for satellite communication: A review

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Intelligent and Converged Networks 2021年第3期2卷 213-243页

作者： Fares Fourati Mohamed-Slim Alouini Electrical and Mathematical Sciences and Engineering division King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Kingdom of Saudi Arabia

Satellite communication offers the prospect of service continuity over uncovered and under-covered areas,service ubiquity,and service ***,several challenges must first be addressed to realize these benefits,as the resource management,network control,network security,spectrum management,and energy usage of satellite networks are more challenging than that of terrestrial ***,artificial intelligence(AI),including machine learning,deep learning,and reinforcement learning,has been steadily growing as a research field and has shown successful results in diverse applications,including wireless *** particular,the application of AI to a wide variety of satellite communication aspects has demonstrated excellent potential,including beam-hopping,anti-jamming,network traffic forecasting,channel modeling,telemetry mining,ionospheric scintillation detecting,interference managing,remote sensing,behavior modeling,space-air-ground integrating,and energy *** work thus provides a general overview of AI,its diverse sub-fields,and its state-of-the-art *** challenges facing diverse aspects of satellite communication systems are then discussed,and their proposed and potential AI-based solutions are ***,an outlook of field is drawn,and future steps are suggested.

关键词： satellite communication wireless communication artificial intelligence machine learning deep learning reinforcement learning

Response of soil respiration to nitrogen addition in two subtropical forest types

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Pedosphere 2020年第4期30卷 478-486页

作者： Wende YAN Xiaoyong CHEN Yuanying PENG Fan ZHU Wei ZHEN Xuyuan ZHANG College of Life Science and Technology Central South University of Forestry and TechnologyChangsha 410004(China) National Engineering Laboratory for Applied Forest Ecological Technology in Southern China Changsha 410004(China) division of Science College of Arts and Sciences.Governors State UniversityUniversity ParkIllinois 60484(USA) Natural Sciences division College of DuPageGlen EllynIllinois 60137(USA)

Anthropogenic activities have increased nitrogen(N)deposition in terrestrial ecosystems,which directly and indirectly affects soil biogeochemical processes,including soil ***,the effects of the increases in N availability on soil respiration are not fully *** this study,soil respiration was measured using an infrared gas analyzer system with soil chambers under four N treatments(0,5,15,and 30 g Nm^-2 year^-1 as control,low N(LN),moderate N(MN),and high N(HN),respectively)in camphor tree and slash pine forests in subtropical *** showed that soil respiration rates decreased by 37% in the camphor tree forest and 27% in the slash pine forest on average on an annual base,respectively,in the N-fertilized treatments when compared with the *** significant differences were found in the soil respiration rate among the LN,MN,and HN treatments in both forest types as these fertilized plots reached an adequate N content *** addition,soil microbial biomass carbon(C)content and fine root biomass declined in N-treated plots compared to the *** results indicated that elevated N deposition might alter the tree growth pattern,C partitioning,and microbial activity,which further affect soil C sequestration by reducing soil respiration in subtropical forests of China.

关键词： camphor tree forest fine root slash pine forest soil microbial biomass soil moisture soil temperature

Radioactive contents and background doses from northern alluvial sediment plains between rivers Ravi and Chenab,Pakistan

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Nuclear Science and Techniques 2016年第4期27卷 127-134页

作者： Abdul Jabbar Khalid Khan Tania Jabbar Muhammad Rafique S.U.Rehman Waheed Arshed Muhammad Dilband Health Physics division Pakistan Institute of Nuclear Science and Technology (PINSTECH) Department of Physics University of Azad Jammu and Kashmir Muzaffarbad Department of Medical Physics Nuclear Medicine Oncology and Radiotherapy Institute (NORI)

Radiometric analysis of soil samples, collected from northern alluvial sediment plains between rivers Ravi and Chenab, has been carried out. Activity concentrations of^(226) Ra,^(232)Th,^(40) K and the artificial radionuclide^(137) Cs were estimated by using high-purity germanium detector. Subsequent values of activity concentrations were used to find terrestrial absorbed dose rate and annual effective doses received by resident of area. The mean radioactivity levels of^(226) Ra,^(232)Th,^(40) K and^(137)Cs were found to be 45.0 ± 1.3,59.6 ± 2.8, 613.8 ± 20.0 and 4.0 ± 0.2 Bq kg^(-1), respectively. terrestrial absorbed dose rate and annual effective dose received by public were found to be 85.1 n Gy h^(-1)and0.5 m Sv, respectively. The activity concentrations of^(226) Ra,^(232)Th,^(40) K and^(137)Cs and resulting doses obtained for the current study were compared with data available in the literature and with international standards.

关键词：年有效剂量冲积平原平原河流放射性含量巴基斯坦泥沙 137Cs 226Ra