During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their el...During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening.We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse consolidation.The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this process.In particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental competition.The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific endings.We describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals.The downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary synapses.Finally,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to reduce transmitter release and promote withdrawal of the most unfavorable nerve terminals during elimination(the weakest in acetylcholine release and those that have already become silent).The main findings contribute to a better understanding of punishment-rewarding interactions between nerve endings during development.Identifying the molecular targets and signaling pathways that allow synapse consolidation or withdrawal of synapses in different situations is important for potential therapies in neurodegenerative diseases.展开更多
Brain size varies dramatically across populations and species in anuran species.The differences in structure,function,or size of brains are linked to processing specific cognitive tasks by different behaviors.In parti...Brain size varies dramatically across populations and species in anuran species.The differences in structure,function,or size of brains are linked to processing specific cognitive tasks by different behaviors.In particular,the causes of how male-male competition promotes the increased cognitive abilities to increase brains are as yet unexplored in anurans.To evaluate the effect of male-male competition on variation in brain size in B.andrewsi,we compared the differences in relative brain size between mated males and unpaired males under natural and experimental conditions.We found that mated males had relatively larger brains than unpaired males in a natural population when controlling the effect of body size.Likewise,we also found that there were larger brains in mated males than in unpaired males in both experiment 1 where two males competed for a female and experiment 2 where three males competed for a female,suggesting that males with mating success during male-male competition possess increased brain size and cognitive abilities.When we compared difference in relative brain size in mated males between experiment2 and experiment 1 we found that males experiencing more intense competition did not display larger brains than males experiencing relatively weak competition,suggesting that low intensity competition is already enough to trigger the increase in relative brain size in B.andrewsi.展开更多
Droughts have caused tree growth decline and high tree mortality across temperate forests,however,how to manage planted forests to alleviate drought stress is still challenging.We used tree-ring and forest inventory d...Droughts have caused tree growth decline and high tree mortality across temperate forests,however,how to manage planted forests to alleviate drought stress is still challenging.We used tree-ring and forest inventory data from different density stands to investigate how competition,tree diameter at breast height(DBH),tree age,and their interactions influence drought sensitivity and resistance for three widely-distributed and planted conifer species(Larix principis-rupprechtii,Picea meyeri,and Pinus sylvestris var.mongolica).Our results showed that the drought sensitivity of the three species was influenced by competition,tree size,and their interactions.Large L.principis-rupprechtii trees were particularly sensitive to drought during the growing season in medium to high-density stands,while the growth of large P.sylvestris var.mongolica was most affected by precipitation at low to medium density stands.Drought resistance of L.principis-rupprechtii trees decreased as tree size increased.Large L.principis-rupprechtii trees had lower drought resistance than small trees in all stands.Drought resistance of large P.meyeri trees exhibited high resistance to drought only in high-density stands.However,drought resistance of P.sylvestris var.mongolica trees was affected by tree size,competition,and their interactions.These results indicated that targeted silvicultural interventions,such as thinning,can be implemented to enhance drought resistance specifically for large L.principis-rupprechtii trees and small P.sylvestris var.mongolica trees in medium and high competition stands,and small P.meyeri trees in high competition stands.Our results highlight that properly conducted thinning can in some cases enhance growth resistance to droughts,depending on stand density,tree size,and tree species.展开更多
As a complicated optimization problem,parallel batch processing machines scheduling problem(PBPMSP)exists in many real-life manufacturing industries such as textiles and semiconductors.Machine eligibility means that a...As a complicated optimization problem,parallel batch processing machines scheduling problem(PBPMSP)exists in many real-life manufacturing industries such as textiles and semiconductors.Machine eligibility means that at least one machine is not eligible for at least one job.PBPMSP and scheduling problems with machine eligibility are frequently considered;however,PBPMSP with machine eligibility is seldom explored.This study investigates PBPMSP with machine eligibility in fabric dyeing and presents a novel shuffled frog-leaping algorithm with competition(CSFLA)to minimize makespan.In CSFLA,the initial population is produced in a heuristic and random way,and the competitive search of memeplexes comprises two phases.Competition between any two memeplexes is done in the first phase,then iteration times are adjusted based on competition,and search strategies are adjusted adaptively based on the evolution quality of memeplexes in the second phase.An adaptive population shuffling is given.Computational experiments are conducted on 100 instances.The computational results showed that the new strategies of CSFLA are effective and that CSFLA has promising advantages in solving the considered PBPMSP.展开更多
Under the background of training practical compound talents in software engineering,this paper analyzes the problems existing in the current teaching of software engineering courses represented by software project man...Under the background of training practical compound talents in software engineering,this paper analyzes the problems existing in the current teaching of software engineering courses represented by software project management,puts forward the team task mechanism of software engineering courses with AI empowerment and cooperation and competition,develops a unified project management platform to support the implementation of team tasks,and proves the effectiveness of the scheme through the results obtained.展开更多
Autosamplers are indispensable key equipment in modern laboratories,playing a pivotal role in fields such as biomedicine,environmental monitoring,food safety,and materials science.However,domestic autosampler enterpri...Autosamplers are indispensable key equipment in modern laboratories,playing a pivotal role in fields such as biomedicine,environmental monitoring,food safety,and materials science.However,domestic autosampler enterprises are facing formidable challenges,confronted by the technological barriers and brand dominance of international giants,as well as increasingly fierce homogeneous competition in the domestic market.This article aims to thoroughly analyze the current market landscape and,based on seven key dimensions—strategic positioning,product technology,sales channels,brand building,service and support,supply chain optimization,and talent development—propose a series of effective market-winning strategies.This will provide theoretical guidance and practical reference for domestic autosampler enterprises to achieve breakthroughs and sustainable development amidst fierce market competition.展开更多
This article aims to explore the teaching mode of using MWorks simulation software to promote teaching in circuit fundamentals courses in vocational colleges through competitions.By analyzing the limitations of tradit...This article aims to explore the teaching mode of using MWorks simulation software to promote teaching in circuit fundamentals courses in vocational colleges through competitions.By analyzing the limitations of traditional teaching,this article elaborates on the functional advantages of MWorks software and its specific application methods in promoting teaching through competitions,including how to combine skill competitions for teaching design,organizing internal selection and training,and other aspects.Practice has shown that this model effectively enhances students’professional skills,innovation ability,and teamwork spirit,while also promoting the improvement of teachers’teaching level.Finally,the problems encountered during the application process were reflected upon,and improvement suggestions were proposed,providing a reference for relevant teaching reforms in vocational colleges.展开更多
Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimatio...Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimation is essential for understanding ecosystem functioning and informing forest management strategies to mitigate climate change.However,integrating neighborhood competition into biomass estimation models,particularly for young mixed forest stands,remains unexplored.In this study,we examined how incorporating neighborhood competition improves biomass prediction accuracy and how the influence of neighborhood competition differs between Scots pine(Pinus sylvestris L.)and Pyrenean oak(Quercus pyrenaica Willd.),as well as the relative contributions of intra-and interspecific competition to AGB.Our findings revealed that including neighborhood competition alongside tree size variables(DBH and total tree height)significantly improved the predictive accuracy of AGB models for Scots pine.This addition reduced the root mean square error(RMSE)by 14% and improved the model efficiency factor(MEF)by 15%.Furthermore,intraspecific competition in Scots pine slightly reduced AGB,whereas interspecific competition had a significant negative effect on AGB.In contrast,DBH alone was the best predictor of AGB for Pyrenean oak,as neighborhood competition did not improve model performance.Also,intra-and interspecific competition in Pyrenean oak had positive but nonsignificant effects on AGB.These findings highlight the important role of competition in biomass models and suggest species-specific approaches in competition dynamics to inform sustainable forest management and climate change adaptation strategies.展开更多
Droughts pose significant threats to forest ecosystems globally.Effective forest management strategies,adapted to local conditions,are needed to mitigate negative drought impacts.One proposed strategy is competition r...Droughts pose significant threats to forest ecosystems globally.Effective forest management strategies,adapted to local conditions,are needed to mitigate negative drought impacts.One proposed strategy is competition reduction to increase water availability and,as a result,alleviate drought stress.This study investigates the effect of competition intensity on drought stress and tree growth in European beech(Fagus sylvatica)and pedunculate oak(Quercus robur).We deployed 72 point dendrometers,placed along a competition intensity gradient,in National Park Brabantse Wouden(Belgium),to measure daily minimum tree water deficit(TWD_(min))as a drought stress proxy and daily radial growth at tree level.Our results revealed species-dependent effects of competition intensity(CI).For European beech,competition reductions positively influenced growth and alleviated(1<CI<2)or aggravated(CI<0.5)drought stress.For pedunculate oak,competition intensity did not affect drought stress or growth along the investigated gradient.Environmental variables consistently affected TWDmin and growth of both species.Precipitation reduced TWDmin and increased growth,while vapor pressure deficit led to opposite trends.Thus,environmental conditions and competition can play a critical role in forest dynamics,especially in light of climate change.However,reducing competition through increased management efforts does not seem to be a one-size-fits-all solution to alleviating drought stress.Additionally,there seems to be a trade-off between reducing drought stress and improving tree growth in European beech:tree growth continuously benefited from competition reductions,while under low competition(CI<0.5)drought stress increased.Revisiting or reviving long-term thinning intensity trials encompassing various regions,species,and soil types will be needed to gain comprehensive insights into mitigating drought stress through management interventions under different local stand conditions.展开更多
Hydrogen evolution reaction(HER)is unavoidable in many electrochemical synthesis systems,such as CO_(2)reduction,N2reduction,and H_(2)O_(2)synthesis.It makes those electrochemical reactions with multiple electron-prot...Hydrogen evolution reaction(HER)is unavoidable in many electrochemical synthesis systems,such as CO_(2)reduction,N2reduction,and H_(2)O_(2)synthesis.It makes those electrochemical reactions with multiple electron-proton transfers more complex when determining kinetics and mass transfer information.Understanding how HER competes with other electrochemical reduction reactions is crucial for both fundamental studies and system performance improvements.In this study,we employed the oxygen reduction reaction(ORR)as a model reaction to investigate HER competition on a polycrystalline-Au surface,using a rotating ring and disk electrode.It’s proved that water molecules serve as the proton source for ORR in alkaline,neutral,and even acidic electrolytes,and a 4-electron process can be achieved when the overpotential is sufficiently high.The competition from H⁺reduction becomes noticeable at the H⁺concentration higher than 2 mmol L^(–1)and intensi-fies as the H^(+)concentration increases.Based on the electrochemical results,we obtained an equivalent circuit diagram for the ORR system with competition from the H+reduction reaction,showing that these reactions occur in parallel and compete with each other.Electrochemical impedance spectroscopy measurements further confirm this argument.Additionally,we discover that the contribution of H+mass transfer to the total H^(+)reduction current is significant and comparable to the kinetic current.We believe this work will deepen our understanding of HER and its competition in electrochemical reduction systems.展开更多
The deep sea holds vital resources and spatial potential for future human survival and development,reflecting the common interests and concerns of all mankind.Amidst unprecedented global transformations in a hundred y...The deep sea holds vital resources and spatial potential for future human survival and development,reflecting the common interests and concerns of all mankind.Amidst unprecedented global transformations in a hundred years,the deep sea has emerged as a critical area of international competition and serves as a new frontier for resource extraction,a strategic space for military competition,and a contested space for great power rivalry and rule-making.展开更多
For students in higher vocational colleges,the"Internet+"Innovation and Entrepreneurship Competition not only provides them with a rare platform for communication and learning but also significantly promotes...For students in higher vocational colleges,the"Internet+"Innovation and Entrepreneurship Competition not only provides them with a rare platform for communication and learning but also significantly promotes their comprehensive development and substantially enhances their innovative and entrepreneurial capabilities.This paper explores the collaboration models between higher vocational colleges and industries in advancing the"Internet+"Innovation and Entrepreneurship Competition,analyzes the impact of the competition on the educational systems and curriculum design of higher vocational colleges,and proposes pathways for research and practice on innovative and entrepreneurial talent cultivation models,aiming to cultivate high-quality and high-skilled talents who can adapt to industrial transformation and upgrading and achieve high-quality development.展开更多
The island rule,a general pattern of dwarfism in large species to gigantism in small species on islands relative to mainland,is typically seen as a macroevolutionary phenomenon.However,whether the ecological processes...The island rule,a general pattern of dwarfism in large species to gigantism in small species on islands relative to mainland,is typically seen as a macroevolutionary phenomenon.However,whether the ecological processes associated with abiotic and biotic factors generate a pattern of plant size variation similar to the island rule remains unknown.We measured plant height for 29,623 individuals of 50 common woody plant species across 43 islands in the Zhoushan Archipelago(8500 years old and yet to undergo major evolutionary adaptation)and the adjacent mainlands in China.We found pronounced variations in plant height,similar to those of the island rule.Interestingly,islands with low resource availability,such as low soil organic matter content and low precipitation,had a high degree of dwarfism;islands experiencing high environmental stress,such as high soil pH,had a high degree of dwarfism;and islands experiencing less planteplant competition had a high degree of gigantism.The magnitude of plant dwarfism was higher on small and remote islands than on larger and nearer islands.These results highlight the importance of ecological processes associated with abiotic and biotic conditions in shaping the island rule-like patterns of plant size variation.Since our studied archipelago is too young to undergo major evolution,ecological processes likely played a prominent role in generating the observed pattern,challenging the notion that the evolutionary process is the dominant factor underlying the island rule.Future studies on the island rule need to perform experiments to disentangle evolutionary from ecological mechanisms.展开更多
As a global strategic reserve resource,rare earth has been widely used in important industries,such as military equipment and biomedicine.However,existing analyses based solely on the total volume of rare earth trade ...As a global strategic reserve resource,rare earth has been widely used in important industries,such as military equipment and biomedicine.However,existing analyses based solely on the total volume of rare earth trade fail to uncover the underlying competition and dependency dynamics.To address this gap,this paper employs the principles of trade preference and import similarity to construct dependency and competition networks.Complex network analysis is then employed to study the evolution of the global rare earth trade network from 2002 to 2018.The main conclusions are as follows.The global rare earth trade follows the Pareto principle,and the trade network shows a scale-free distribution.China has emerged as the world’s largest importer and exporter of rare earth since 2017.In the dependency network,China has become the most dependent country since 2006.The result of community division shows that China has separated from the American community and formed new communities with the Association of Southeast Asian Nations(ASEAN)countries.The United States of America has formed a super-strong community with European and Asian countries.In the competition network,the distribution of competition intensity follows a scale-free distribution.Most countries face low-intensity competition,but there are numerous competing countries.The competition related to China has increased significantly.Lastly,the competition source for the United States of America has shifted from Mexico to China,resulting in China,the USA,and Japan becoming the core participants in the competition network.展开更多
Tree allometry plays a crucial role in tree survival,stability,and timber quantity and quality of mixed-species plantations.However,the responses of tree allometry to resource utilisation within the framework of inter...Tree allometry plays a crucial role in tree survival,stability,and timber quantity and quality of mixed-species plantations.However,the responses of tree allometry to resource utilisation within the framework of interspecific competition and complementarity remain poorly understood.Taking into consideration strong-and weakspace competition(SC and WC),as well as N_(2)-fixing and non-N_(2)-fixing tree species(FN and nFN),a mixedspecies planting trial was conducted for Betula alnoides,a pioneer tree species,which was separately mixed with Acacia melanoxylon(SC+FN),Erythrophleum fordii(WC+FN),Eucalyptus cloeziana(SC+nFN)and Pinus kesiya var.langbianensis(WC+nFN)in southern China.Six years after planting,tree growth,total nitrogen(N)and carbon(C)contents,and the natural abundances of^(15)N and^(13)C in the leaves were measured for each species,and the mycorrhizal colonisation rates of B.alnoides were investigated under each treatment.Allometric variations and their relationships with space competition and nutrient-related factors were analyzed.The results showed a consistent effect of space competition on the height-diameter relationship of B.alnoides in mixtures with FN or nFN.The tree height growth of B.alnoides was significantly promoted under high space competition,and growth in diameter at breast height(DBH),tree height and crown size were all expedited in mixtures with FN.The symbiotic relationship between ectomycorrhizal fungi and B.alnoides was significantly influenced by both space competition and N_(2) fixation by the accompanying tree species,whereas such significant effects were absent for arbuscular mycorrhizal fungi.Furthermore,high space competition significantly decreased the water use efficiency(WUE)of B.alnoides,and its N use efficiency(NUE)was much lower in the FN mixtures.Structural equation modeling further demonstrated that the stem allometry of B.alnoides was affected by its NUE and WUE via changes in its height growth,and crown allometry was influenced by the mycorrhizal symbiotic relationship.Our findings provide new insights into the mechanisms driving tree allometric responses to above-and belowground resource competition and complementarity in mixed-species plantations,which are instructive for the establishment of mixed-species plantations.展开更多
Conjugated polymers are mainly synthesized by cross-coupling polymerizations catalyzed with transition metal(Pd,Ni)catalysts through step-growth polymerization(SGP)mechanism.According to the classical theory of SGP,th...Conjugated polymers are mainly synthesized by cross-coupling polymerizations catalyzed with transition metal(Pd,Ni)catalysts through step-growth polymerization(SGP)mechanism.According to the classical theory of SGP,the polymer dispersion index(D)of the synthesized polymers will never be higher than 2.However,the cases where conjugated polymers synthesized with D value far exceeding 2 are very common in reality,which severely limits their processing property,performance and applications.To investigate the reason behind the D value deviation from the theoretical value of SGP,direct arylation polycondensation(DArP)of 2-bromo-3-hexylthiophene(3HT)was chosen as the model reaction,and the reaction process was tracked using gel permeation chromatography analysis.When Pd(OAc)_(2) was used as the catalyst,the D value linearly increased with the increase of the weight-average molecular weight(M_(w))of polymer(P3HT)after a short period and reached up to 7.2 at prolonged reaction time.Scanning transmission electron microscopic images of the reaction mixture showed the fibril-like aggregation of P3HT and assembling of Pd species in P3HT aggregates.A catalyst competition mechanism was thus proposed,together with numerical calculation,giving a good fitting to the experimental results,which is believed to have far-reaching significance for guiding the design,synthesis and processing of conjugated polymers.展开更多
Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affect...Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.展开更多
基金supported by Catalan Government,Nos.2014SGR344(to JT),2017SGR704(to JT),2021SGR01214(to MAL)MCIN/AEI/10.13039/501100011033/by“ERDF A way of making Europe,”Nos.SAF2015-67143(to JT),PID2019-106332GB-I00(to JT and MAL)and PID2022-141252NB-I00(to MAL).
文摘During the development of the nervous system,there is an overproduction of neurons and synapses.Hebbian competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or strengthening.We have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse consolidation.The purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this process.In particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental competition.The dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific endings.We describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon terminals.The downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary synapses.Finally,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to reduce transmitter release and promote withdrawal of the most unfavorable nerve terminals during elimination(the weakest in acetylcholine release and those that have already become silent).The main findings contribute to a better understanding of punishment-rewarding interactions between nerve endings during development.Identifying the molecular targets and signaling pathways that allow synapse consolidation or withdrawal of synapses in different situations is important for potential therapies in neurodegenerative diseases.
基金funded by the National Natural Science Foundation of China (32370456)the Key Project of Natural Sciences Foundation of Sichuan Province (22NSFSC0011)。
文摘Brain size varies dramatically across populations and species in anuran species.The differences in structure,function,or size of brains are linked to processing specific cognitive tasks by different behaviors.In particular,the causes of how male-male competition promotes the increased cognitive abilities to increase brains are as yet unexplored in anurans.To evaluate the effect of male-male competition on variation in brain size in B.andrewsi,we compared the differences in relative brain size between mated males and unpaired males under natural and experimental conditions.We found that mated males had relatively larger brains than unpaired males in a natural population when controlling the effect of body size.Likewise,we also found that there were larger brains in mated males than in unpaired males in both experiment 1 where two males competed for a female and experiment 2 where three males competed for a female,suggesting that males with mating success during male-male competition possess increased brain size and cognitive abilities.When we compared difference in relative brain size in mated males between experiment2 and experiment 1 we found that males experiencing more intense competition did not display larger brains than males experiencing relatively weak competition,suggesting that low intensity competition is already enough to trigger the increase in relative brain size in B.andrewsi.
基金funded by State Key Research and Development Program of China(No.2023YFD2200401)S&T Program of Hebei(Nos.226Z6801G,22326807D)Talent Introduction Program in Hebei Agricultural University(No.YJ201918).
文摘Droughts have caused tree growth decline and high tree mortality across temperate forests,however,how to manage planted forests to alleviate drought stress is still challenging.We used tree-ring and forest inventory data from different density stands to investigate how competition,tree diameter at breast height(DBH),tree age,and their interactions influence drought sensitivity and resistance for three widely-distributed and planted conifer species(Larix principis-rupprechtii,Picea meyeri,and Pinus sylvestris var.mongolica).Our results showed that the drought sensitivity of the three species was influenced by competition,tree size,and their interactions.Large L.principis-rupprechtii trees were particularly sensitive to drought during the growing season in medium to high-density stands,while the growth of large P.sylvestris var.mongolica was most affected by precipitation at low to medium density stands.Drought resistance of L.principis-rupprechtii trees decreased as tree size increased.Large L.principis-rupprechtii trees had lower drought resistance than small trees in all stands.Drought resistance of large P.meyeri trees exhibited high resistance to drought only in high-density stands.However,drought resistance of P.sylvestris var.mongolica trees was affected by tree size,competition,and their interactions.These results indicated that targeted silvicultural interventions,such as thinning,can be implemented to enhance drought resistance specifically for large L.principis-rupprechtii trees and small P.sylvestris var.mongolica trees in medium and high competition stands,and small P.meyeri trees in high competition stands.Our results highlight that properly conducted thinning can in some cases enhance growth resistance to droughts,depending on stand density,tree size,and tree species.
基金supported by the National Natural Science Foundation of China(Grant Number 61573264).
文摘As a complicated optimization problem,parallel batch processing machines scheduling problem(PBPMSP)exists in many real-life manufacturing industries such as textiles and semiconductors.Machine eligibility means that at least one machine is not eligible for at least one job.PBPMSP and scheduling problems with machine eligibility are frequently considered;however,PBPMSP with machine eligibility is seldom explored.This study investigates PBPMSP with machine eligibility in fabric dyeing and presents a novel shuffled frog-leaping algorithm with competition(CSFLA)to minimize makespan.In CSFLA,the initial population is produced in a heuristic and random way,and the competitive search of memeplexes comprises two phases.Competition between any two memeplexes is done in the first phase,then iteration times are adjusted based on competition,and search strategies are adjusted adaptively based on the evolution quality of memeplexes in the second phase.An adaptive population shuffling is given.Computational experiments are conducted on 100 instances.The computational results showed that the new strategies of CSFLA are effective and that CSFLA has promising advantages in solving the considered PBPMSP.
文摘Under the background of training practical compound talents in software engineering,this paper analyzes the problems existing in the current teaching of software engineering courses represented by software project management,puts forward the team task mechanism of software engineering courses with AI empowerment and cooperation and competition,develops a unified project management platform to support the implementation of team tasks,and proves the effectiveness of the scheme through the results obtained.
文摘Autosamplers are indispensable key equipment in modern laboratories,playing a pivotal role in fields such as biomedicine,environmental monitoring,food safety,and materials science.However,domestic autosampler enterprises are facing formidable challenges,confronted by the technological barriers and brand dominance of international giants,as well as increasingly fierce homogeneous competition in the domestic market.This article aims to thoroughly analyze the current market landscape and,based on seven key dimensions—strategic positioning,product technology,sales channels,brand building,service and support,supply chain optimization,and talent development—propose a series of effective market-winning strategies.This will provide theoretical guidance and practical reference for domestic autosampler enterprises to achieve breakthroughs and sustainable development amidst fierce market competition.
基金MWORKS University Application Verification Project(BX2024C081).
文摘This article aims to explore the teaching mode of using MWorks simulation software to promote teaching in circuit fundamentals courses in vocational colleges through competitions.By analyzing the limitations of traditional teaching,this article elaborates on the functional advantages of MWorks software and its specific application methods in promoting teaching through competitions,including how to combine skill competitions for teaching design,organizing internal selection and training,and other aspects.Practice has shown that this model effectively enhances students’professional skills,innovation ability,and teamwork spirit,while also promoting the improvement of teachers’teaching level.Finally,the problems encountered during the application process were reflected upon,and improvement suggestions were proposed,providing a reference for relevant teaching reforms in vocational colleges.
基金the 2019 call for the predoctoral contract at the University of Valladolid cofinanced by Banco de Santander and projects‘CLU-2019-01-Unidad de Excelencia Instituto iuFOR’,‘PID2021-126275OB-C21’and‘PID2021-126275OB-C22’-Integrated Forest Management along complexity gradients(IMFLEX)‘MCIN/AEI/10.13039/501100011033/FEDER,UE’,which received financial support from the Regional Government of Castilla and León,Spainthe European Regional Development Fund(ERDF).
文摘Neighborhood competition is a critical driver of individual tree growth,and aboveground biomass(AGB)accumulation,which together play key roles in forest dynamics and carbon storage.Therefore,accurate biomass estimation is essential for understanding ecosystem functioning and informing forest management strategies to mitigate climate change.However,integrating neighborhood competition into biomass estimation models,particularly for young mixed forest stands,remains unexplored.In this study,we examined how incorporating neighborhood competition improves biomass prediction accuracy and how the influence of neighborhood competition differs between Scots pine(Pinus sylvestris L.)and Pyrenean oak(Quercus pyrenaica Willd.),as well as the relative contributions of intra-and interspecific competition to AGB.Our findings revealed that including neighborhood competition alongside tree size variables(DBH and total tree height)significantly improved the predictive accuracy of AGB models for Scots pine.This addition reduced the root mean square error(RMSE)by 14% and improved the model efficiency factor(MEF)by 15%.Furthermore,intraspecific competition in Scots pine slightly reduced AGB,whereas interspecific competition had a significant negative effect on AGB.In contrast,DBH alone was the best predictor of AGB for Pyrenean oak,as neighborhood competition did not improve model performance.Also,intra-and interspecific competition in Pyrenean oak had positive but nonsignificant effects on AGB.These findings highlight the important role of competition in biomass models and suggest species-specific approaches in competition dynamics to inform sustainable forest management and climate change adaptation strategies.
基金supported by the Fonds Wetenschappelijk Onderzoek(FWO)[grant number 1S16824N]the Cost Action CLEANFOREST[E-COST-GRANT-CA21138-c4968ca1].
文摘Droughts pose significant threats to forest ecosystems globally.Effective forest management strategies,adapted to local conditions,are needed to mitigate negative drought impacts.One proposed strategy is competition reduction to increase water availability and,as a result,alleviate drought stress.This study investigates the effect of competition intensity on drought stress and tree growth in European beech(Fagus sylvatica)and pedunculate oak(Quercus robur).We deployed 72 point dendrometers,placed along a competition intensity gradient,in National Park Brabantse Wouden(Belgium),to measure daily minimum tree water deficit(TWD_(min))as a drought stress proxy and daily radial growth at tree level.Our results revealed species-dependent effects of competition intensity(CI).For European beech,competition reductions positively influenced growth and alleviated(1<CI<2)or aggravated(CI<0.5)drought stress.For pedunculate oak,competition intensity did not affect drought stress or growth along the investigated gradient.Environmental variables consistently affected TWDmin and growth of both species.Precipitation reduced TWDmin and increased growth,while vapor pressure deficit led to opposite trends.Thus,environmental conditions and competition can play a critical role in forest dynamics,especially in light of climate change.However,reducing competition through increased management efforts does not seem to be a one-size-fits-all solution to alleviating drought stress.Additionally,there seems to be a trade-off between reducing drought stress and improving tree growth in European beech:tree growth continuously benefited from competition reductions,while under low competition(CI<0.5)drought stress increased.Revisiting or reviving long-term thinning intensity trials encompassing various regions,species,and soil types will be needed to gain comprehensive insights into mitigating drought stress through management interventions under different local stand conditions.
文摘Hydrogen evolution reaction(HER)is unavoidable in many electrochemical synthesis systems,such as CO_(2)reduction,N2reduction,and H_(2)O_(2)synthesis.It makes those electrochemical reactions with multiple electron-proton transfers more complex when determining kinetics and mass transfer information.Understanding how HER competes with other electrochemical reduction reactions is crucial for both fundamental studies and system performance improvements.In this study,we employed the oxygen reduction reaction(ORR)as a model reaction to investigate HER competition on a polycrystalline-Au surface,using a rotating ring and disk electrode.It’s proved that water molecules serve as the proton source for ORR in alkaline,neutral,and even acidic electrolytes,and a 4-electron process can be achieved when the overpotential is sufficiently high.The competition from H⁺reduction becomes noticeable at the H⁺concentration higher than 2 mmol L^(–1)and intensi-fies as the H^(+)concentration increases.Based on the electrochemical results,we obtained an equivalent circuit diagram for the ORR system with competition from the H+reduction reaction,showing that these reactions occur in parallel and compete with each other.Electrochemical impedance spectroscopy measurements further confirm this argument.Additionally,we discover that the contribution of H+mass transfer to the total H^(+)reduction current is significant and comparable to the kinetic current.We believe this work will deepen our understanding of HER and its competition in electrochemical reduction systems.
文摘The deep sea holds vital resources and spatial potential for future human survival and development,reflecting the common interests and concerns of all mankind.Amidst unprecedented global transformations in a hundred years,the deep sea has emerged as a critical area of international competition and serves as a new frontier for resource extraction,a strategic space for military competition,and a contested space for great power rivalry and rule-making.
基金2024 Annual Planning Program of China Vocational Education Association"Research and Practice on the Pathways of Innovative and Entrepreneurial Talent Cultivation Model under the Background of Industry-Education Integration"(ZJS2024YB79).
文摘For students in higher vocational colleges,the"Internet+"Innovation and Entrepreneurship Competition not only provides them with a rare platform for communication and learning but also significantly promotes their comprehensive development and substantially enhances their innovative and entrepreneurial capabilities.This paper explores the collaboration models between higher vocational colleges and industries in advancing the"Internet+"Innovation and Entrepreneurship Competition,analyzes the impact of the competition on the educational systems and curriculum design of higher vocational colleges,and proposes pathways for research and practice on innovative and entrepreneurial talent cultivation models,aiming to cultivate high-quality and high-skilled talents who can adapt to industrial transformation and upgrading and achieve high-quality development.
基金supported by the State Key Program of National Natural Science Foundation of China(Grant No.32030068)the“Lump-sum System”Project of Chongqing Talent Plan(Grant No.cstc2022ycjh-bgzxm0204).
文摘The island rule,a general pattern of dwarfism in large species to gigantism in small species on islands relative to mainland,is typically seen as a macroevolutionary phenomenon.However,whether the ecological processes associated with abiotic and biotic factors generate a pattern of plant size variation similar to the island rule remains unknown.We measured plant height for 29,623 individuals of 50 common woody plant species across 43 islands in the Zhoushan Archipelago(8500 years old and yet to undergo major evolutionary adaptation)and the adjacent mainlands in China.We found pronounced variations in plant height,similar to those of the island rule.Interestingly,islands with low resource availability,such as low soil organic matter content and low precipitation,had a high degree of dwarfism;islands experiencing high environmental stress,such as high soil pH,had a high degree of dwarfism;and islands experiencing less planteplant competition had a high degree of gigantism.The magnitude of plant dwarfism was higher on small and remote islands than on larger and nearer islands.These results highlight the importance of ecological processes associated with abiotic and biotic conditions in shaping the island rule-like patterns of plant size variation.Since our studied archipelago is too young to undergo major evolution,ecological processes likely played a prominent role in generating the observed pattern,challenging the notion that the evolutionary process is the dominant factor underlying the island rule.Future studies on the island rule need to perform experiments to disentangle evolutionary from ecological mechanisms.
基金supported by the Ministry of Education of the People’s Republic of China Humanities and Social Sciences Youth Foundation(Grant No.22YJC910014)the Social Sciences Planning Youth Project of Anhui Province(Grant No.AHSKQ2022D138)the Innovation Development Research Project of Anhui Province(Grant No.2021CX053).
文摘As a global strategic reserve resource,rare earth has been widely used in important industries,such as military equipment and biomedicine.However,existing analyses based solely on the total volume of rare earth trade fail to uncover the underlying competition and dependency dynamics.To address this gap,this paper employs the principles of trade preference and import similarity to construct dependency and competition networks.Complex network analysis is then employed to study the evolution of the global rare earth trade network from 2002 to 2018.The main conclusions are as follows.The global rare earth trade follows the Pareto principle,and the trade network shows a scale-free distribution.China has emerged as the world’s largest importer and exporter of rare earth since 2017.In the dependency network,China has become the most dependent country since 2006.The result of community division shows that China has separated from the American community and formed new communities with the Association of Southeast Asian Nations(ASEAN)countries.The United States of America has formed a super-strong community with European and Asian countries.In the competition network,the distribution of competition intensity follows a scale-free distribution.Most countries face low-intensity competition,but there are numerous competing countries.The competition related to China has increased significantly.Lastly,the competition source for the United States of America has shifted from Mexico to China,resulting in China,the USA,and Japan becoming the core participants in the competition network.
基金supported by National Natural Science Foundation of China (31972949)National Nonprofit Institute Research Grant of Chinese Academy of Forestry,China (CAFYBB2023MB006)。
文摘Tree allometry plays a crucial role in tree survival,stability,and timber quantity and quality of mixed-species plantations.However,the responses of tree allometry to resource utilisation within the framework of interspecific competition and complementarity remain poorly understood.Taking into consideration strong-and weakspace competition(SC and WC),as well as N_(2)-fixing and non-N_(2)-fixing tree species(FN and nFN),a mixedspecies planting trial was conducted for Betula alnoides,a pioneer tree species,which was separately mixed with Acacia melanoxylon(SC+FN),Erythrophleum fordii(WC+FN),Eucalyptus cloeziana(SC+nFN)and Pinus kesiya var.langbianensis(WC+nFN)in southern China.Six years after planting,tree growth,total nitrogen(N)and carbon(C)contents,and the natural abundances of^(15)N and^(13)C in the leaves were measured for each species,and the mycorrhizal colonisation rates of B.alnoides were investigated under each treatment.Allometric variations and their relationships with space competition and nutrient-related factors were analyzed.The results showed a consistent effect of space competition on the height-diameter relationship of B.alnoides in mixtures with FN or nFN.The tree height growth of B.alnoides was significantly promoted under high space competition,and growth in diameter at breast height(DBH),tree height and crown size were all expedited in mixtures with FN.The symbiotic relationship between ectomycorrhizal fungi and B.alnoides was significantly influenced by both space competition and N_(2) fixation by the accompanying tree species,whereas such significant effects were absent for arbuscular mycorrhizal fungi.Furthermore,high space competition significantly decreased the water use efficiency(WUE)of B.alnoides,and its N use efficiency(NUE)was much lower in the FN mixtures.Structural equation modeling further demonstrated that the stem allometry of B.alnoides was affected by its NUE and WUE via changes in its height growth,and crown allometry was influenced by the mycorrhizal symbiotic relationship.Our findings provide new insights into the mechanisms driving tree allometric responses to above-and belowground resource competition and complementarity in mixed-species plantations,which are instructive for the establishment of mixed-species plantations.
基金This work was financially supported by the National Natural Science Foundation of China(No.22171083)Shanghai Leading Academic Discipline Project(No.B502)。
文摘Conjugated polymers are mainly synthesized by cross-coupling polymerizations catalyzed with transition metal(Pd,Ni)catalysts through step-growth polymerization(SGP)mechanism.According to the classical theory of SGP,the polymer dispersion index(D)of the synthesized polymers will never be higher than 2.However,the cases where conjugated polymers synthesized with D value far exceeding 2 are very common in reality,which severely limits their processing property,performance and applications.To investigate the reason behind the D value deviation from the theoretical value of SGP,direct arylation polycondensation(DArP)of 2-bromo-3-hexylthiophene(3HT)was chosen as the model reaction,and the reaction process was tracked using gel permeation chromatography analysis.When Pd(OAc)_(2) was used as the catalyst,the D value linearly increased with the increase of the weight-average molecular weight(M_(w))of polymer(P3HT)after a short period and reached up to 7.2 at prolonged reaction time.Scanning transmission electron microscopic images of the reaction mixture showed the fibril-like aggregation of P3HT and assembling of Pd species in P3HT aggregates.A catalyst competition mechanism was thus proposed,together with numerical calculation,giving a good fitting to the experimental results,which is believed to have far-reaching significance for guiding the design,synthesis and processing of conjugated polymers.
基金supported by the National Natural Science Foundation of China(22008053,52002111)the Natural Science Foundation of Hebei Province(B2021208061,B2022208006,B2023208014)the Beijing Natural Science Foundation(Z200011).
文摘Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.
