BACKGROUND Immune checkpoint inhibitor-associated interstitial lung disease(ICI-ILD)and opportunistic pneumonias are the main pulmonary complications during immunotherapy for malignancies.The organizing pneumonia(OP)p...BACKGROUND Immune checkpoint inhibitor-associated interstitial lung disease(ICI-ILD)and opportunistic pneumonias are the main pulmonary complications during immunotherapy for malignancies.The organizing pneumonia(OP)pattern is one of the common radiological manifestations of ICI-ILD,and OP is the most common cause of reversed halo cycles and consolidations.However,opportunistic pneumonias should be excluded.CASE SUMMARY In this report,we described a case of a 44-year-old man with esophageal cancer who showed multiple reversed-halo cycles and consolidations on chest computed tomography(CT)after he had a cold during immunotherapy.He was diagnosed with esophageal squamous-cell cancer(T2NIM0)after surgery.Then,he was successfully treated with 6 cycles of chemotherapy plus tislelizumab,one cycle of radiotherapy and 9 cycles of tislelizumab.Two months later,he complained of low-grade fever and cough with nonpurulent sputum after he had a cold.Community-acquired pneumonia was considered,but moxifloxacin was ineffective.Chest CT showed multiple reversed-halo cycles and consolidations.Mycobacterium tuberculosis was identified with next-generation sequence analysis of bronchoalveolar lavage fluid(BALF).Two months later,he improved with standard anti-tuberculosis medications.Both the cycles and consolidations disappeared in the repeat CT after 6 mo of medications.CONCLUSION When chest CT shows reversed-halo cycles and consolidations in patients during anticancer immunotherapy,both ICI-ILD and infectious pneumonia should be considered.BALF microbiological analysis was helpful to differentiate them.展开更多
From 2001 to 2012,many local governments in China closed down village teaching sites for primary school students in the first and second grades,consolidating them into larger township schools more distant from village...From 2001 to 2012,many local governments in China closed down village teaching sites for primary school students in the first and second grades,consolidating them into larger township schools more distant from village students’homes.School closure and consolidation are particularly striking in China’s central and western regions,where swathes of rural labor migrated to cities for jobs.As a result,numerous primary school pupils are forced to study at boarding schools in the first and second grades,which is considered as too early for pupils to live without parental care.This paper employs survey data from 137 township schools with boarding qualifications collected by a project team consisting of researchers from the China Institute for Educational Finance Research(CIEFR)of Peking University,the Institute of Population and Labor Economics of the Chinese Academy of Social Sciences(IPLE-CASS)and the Capital University of Economics and Business(CUEB).By matching the home-school distance with village teaching site information as the proxy variable for the school consolidation policy,this paper evaluates the policy's impact on the likelyhood of premature boarding for primary school pupils,as well as the impact on their human capital accumulation.Our study finds that the creation of teaching sites makes it less likely for primary school pupils to board at school.Premature boarding impedes children’s human capital accumulation,and the harmful effect is particularly striking for children lacking pastoral teachers,raised by grandparents and from families above average income levels,as well as girls.展开更多
Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional...Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.展开更多
The production of vanadium-titanium magnetite(VTM)pellets has the problems of low consolidation strength and high energy consumption in the preheating and roasting process.High-pressure grinding roll(HPGR)pretreatment...The production of vanadium-titanium magnetite(VTM)pellets has the problems of low consolidation strength and high energy consumption in the preheating and roasting process.High-pressure grinding roll(HPGR)pretreatment process was used to increase the fine-grained content and specific surface area of VTM concentrates,to strengthen the oxidation consolidation process of VTM pellets,and oxidation kinetic experiments were carried out.The results showed that the specific surface area of VTM concentrates was increased from 872 to 1457 cm^(2)/g by HPGR and then pelletising and roasting.With preheating at 1000℃ for 10 min and roasting at 1260℃ for 10 min,the strengths of preheated pellets were increased from 329 to 535 N,and the strengths of roasted pellets were increased from 1010 to 2591 N.The limiting link in the early stage of VTM pellets oxidation was the control of chemical reaction,while the limiting link in the later stage of oxidation was the mixed control of chemical reaction and gas diffusion.The activation energies of VTM pellets before and after HPGR pretreatment were 53.07 and 40.03 kJ/mol in the early stage of oxidation reaction,while the activation energies in the later stage of oxidation were 29.24 and 22.75 kJ/mol,respectively.展开更多
Standards are the common language that consolidates global consensus and builds the most solid foundation for international partnerships.They are the cornerstone for global sustainable and high-quality development.You...Standards are the common language that consolidates global consensus and builds the most solid foundation for international partnerships.They are the cornerstone for global sustainable and high-quality development.Young students,with their active and vibrant minds,represent the future and hope of standardization.展开更多
Precast driven piles are extensively used for infrastructure on soft soils,but the buildup of excess pore water pressure associated with pile driving is a challenging issue.The process of soil consolidation could take...Precast driven piles are extensively used for infrastructure on soft soils,but the buildup of excess pore water pressure associated with pile driving is a challenging issue.The process of soil consolidation could take several months.Measures are sought to shorten the drainage path in the ground,and permeable pipe pile is a concept that involves drainage channels at the peak pore pressure locations around the pile circumference.Centrifuge tests were conducted to understand the responses of permeable pipe pile treated ground,experiencing the whole pile driving,soil consolidating,and axially loading process.Results show that the dissipation rate of pore pressures can be improved,especially at a greater depth or at a shorter distance from the pile,since the local hydraulic gradient was higher.Less significant buildup of pore pressures can be anticipated with the use of permeable pipe pile.For this,the bearing capacity of composite foundation with permeable pipe pile can be increased by over 36.9%,compared to the case with normal pipe pile at a specific time period.All these demonstrate the ability of permeable pipe pile in accelerating the consolidation process,mobilizing the bearing capacity of treated ground at an early stage,and minimizing the set-up effect.展开更多
Microbially induced calcium carbonate precipitation(MICP)technology can induce calcium carbonate crystals with cementation and stable performance in the process of microbial metabolism or enzymization through the regu...Microbially induced calcium carbonate precipitation(MICP)technology can induce calcium carbonate crystals with cementation and stable performance in the process of microbial metabolism or enzymization through the regulation of environmental factors MICP can be used as a cementing agent to cement cohesionless sand particles to form the materials with the characteristics of higher strength,better durability and environmental friendli-ness,as well as a good engineering application prospect.In this paper,the shear strength of sand column was tested by triaxial compression tests,and the strength index was obtained.In order to further study the micro-strength mechanism and the failure process,based on the discrete element method,a numerical model of MICP cemented sand column was established considering the factors of matrix soil particle gradation,particle mor-phology,content ratio of induced calcium carbonate,pore distribution characteristics,inter-particle cementation and so on.The failure process of MICP cemented sand column under load was analysed by numerical simulation,and the reliability of the numerical model was tested by combining with the stress intensity curve of samples under test conditions.The results indicate that compared with the actual triaxial tests of MICP cemented sand column,although there are deviations in stress and strain,cohesion and internal friction angle,the numerical simulation shows similar development law and intensity amplitude,and the same failure trend.The work in this paper verifies the reliability of the numerical model and provides a theoretical basis for the subsequent analysis of the factors influencing the geotechnical mechanical properties of biomineralized materials.展开更多
Objective:This review aimed to identify the barriers and facilitators to equitable coronavirus disease 2019(COVID-19)vaccine distribution in Nigeria using the consolidated framework for implementation research(CFIR).M...Objective:This review aimed to identify the barriers and facilitators to equitable coronavirus disease 2019(COVID-19)vaccine distribution in Nigeria using the consolidated framework for implementation research(CFIR).Methods:A comprehensive search strategy was applied across five databases—Web of Science,MEDLINE,EMBASE,CAB Direct,and CINAHL.The search,conducted as part of a scoping review,yielded 2,751 citations.Seven studies met the inclusion criteria after screening.Data were extracted and analyzed using CFIR constructs to identify key barriers and facilitators to equitable vaccine distribution.Results:Six barriers were identified:limited physical and socioeconomic access,bribery,nepotism,and insufficient availability of translated information.Facilitators included community involvement as local monitoring agents,unannounced staff inspections,healthcare worker training tailored to community needs,and localized outreach strategies such as jingles and call-in programs.CFIR constructs,including Local Conditions,Tailoring Strategies,Available Resources,and Physical Infrastructure,provided a framework for analyzing the findings.Conclusion:This review highlights significant barriers and promising facilitators to equitable vaccine distribution in Nigeria.Targeted interventions,such as community engagement,anti-corruption measures,and culturally tailored strategies,are critical to addressing these challenges and improving access.These findings underscore the need for localized,equity-focused approaches to enhance vaccine distribution systems in Nigeria and other low-resource settings.展开更多
1 Introduction In highway construction,flled embankments are trapezoidal,and the ground is always improved by sand wells or columns.During embankment construction,because the width and height of the embankment are cha...1 Introduction In highway construction,flled embankments are trapezoidal,and the ground is always improved by sand wells or columns.During embankment construction,because the width and height of the embankment are changing,a non-uniform load that varies with time and lateral location is applied to the underlying ground.The consolidation phenomenon under two-dimensional(2D)conditions will keep pace with the construction of the embankment.In addition,because of evaporation and rainfall,the soils are mostly unsaturated.Therefore,it is meaningful to research the consolidation properties of unsaturated ground under non-uniform loading.展开更多
The application of ecosystem services(ES)theories in land consolidation is a confusing issue that has long plagued scholars and government officials.As the upgraded version of traditional land consolidation,comprehens...The application of ecosystem services(ES)theories in land consolidation is a confusing issue that has long plagued scholars and government officials.As the upgraded version of traditional land consolidation,comprehensive land consolidation(CLC)emphasizes ecological benefits,but it does not achieve the expected effect during the pilot phase.This study first proposed a theoretical analysis framework based on ES knowledge to answer the three key questions of why,where,and how to implement CLC better.Taking mountainous counties as the study area,we found that ES trade-offs/synergies,bundles,and drivers were significantly affected by scale effects.ES knowledge can play a crucial role in designing multi-scale CLC strategies regarding the objective,zoning,intensity,and mode.Specifically,mitigating the significant trade-offs between recreational opportunities,food production,and other ES is the top priority of CLC.Land consolidation zoning based on the ES bundles analysis is more rational and can provide the scientific premise for designing locally adapted CLC measures.Land consolidation can be classified into high-intensity direct intervention and low-intensity indirect intervention modes,based on the major drivers of ES.These findings help narrow the gap between ES and CLC practices.展开更多
Chronic pulmonary heart disease is a common and frequently occurring condition in the respiratory system.Professor Wei Gunzheng advocates a treatment approach that integrates disease management with syndrome different...Chronic pulmonary heart disease is a common and frequently occurring condition in the respiratory system.Professor Wei Gunzheng advocates a treatment approach that integrates disease management with syndrome differentiation,combining methods to eliminate pathogenic factors and reinforce healthy qi.During acute episodes,the focus should be on expelling pathogenic excess while simultaneously consolidating the root and supporting healthy qi.During remission,the priority shifts to reinforcing the body's vital energy.For effective treatment,it is essential to both tonify deficiency and purge excess,ensuring the elimination of pathogenic factors and the restoration of healthy qi.展开更多
Memory is a cognitive process through which past experiences are encoded,stored,and retrieved,playing a crucial role in intelligent behavior.It is well established that the hippocampus continues to reactivate memories...Memory is a cognitive process through which past experiences are encoded,stored,and retrieved,playing a crucial role in intelligent behavior.It is well established that the hippocampus continues to reactivate memories for several days after learning,and this process primarily occurs during sleep[1,2].The prevailing view suggests that sharp-wave ripples(SWRs)during non-rapid eye movement(NREM)sleep serve as key electrophysiological signatures of memory replay[3,4].However,only a small portion of SWRs contain memory replay[5].The direct relationship among SWRs,memory replay,and memory consolidation remains an open question.Another unresolved issue is how the hippocampus simultaneously reactivates both new and old memories while preventing interference.展开更多
Understanding the sedimentation and simultaneous consolidation behavior of xanthan gum(XG)-biopolymer-treated soils remains a significant research gap in developing environmentally friendly ground-improvement techniqu...Understanding the sedimentation and simultaneous consolidation behavior of xanthan gum(XG)-biopolymer-treated soils remains a significant research gap in developing environmentally friendly ground-improvement techniques for geotechnical applications.This study addresses this gap by conducting laboratory experiments on kaolinite suspensions with varying XG-to-kaolinite mass ratios(mb/ms).The results showed that the XG treatment modified the sedimentation patterns by promoting larger floc formation and accelerated settling.Additionally,the XG treatment enhanced the shear stiffness and shear strength,particularly at shallow depths.At mb/ms ratios less than 1%,the volume compression was reduced by the XG;the coefficient of compressibility decreased by 49%at 1%mb/ms,and the consolidation was accelerated,as indicated by a 387%increase in the hydraulic conductivity at 0.5%mb/ms under the vertical effective stress of 40 kPa.Contrastingly,at mb/ms ratios greater than 1%,viscous XG hydrogels clogged pores,resulting in a 45%reduction in the coefficient of consolidation at 2%mb/ms under a vertical effective stress of 15 kPa and a 35%decrease in the hydraulic conductivity at 2%mb/ms under a vertical effective stress of 40 kPa.These findings underscore the potential of XG treatment in improving the sedimentation and consolidation processes,highlighting its applicability in geotechnical projects,such as dredging,landfilling,and artificial island construction.展开更多
Memory enables organisms to encode,store,and retrieve information essential for interacting with and adapting to a dynamic environment.As an internal representation of the external world,memory serves as a crucial bri...Memory enables organisms to encode,store,and retrieve information essential for interacting with and adapting to a dynamic environment.As an internal representation of the external world,memory serves as a crucial bridge between past experiences and future behaviors.However,the brain continuously forms new memories,raising the question of how new memories are integrated without disrupting previously formed ones.展开更多
Low-intensity ultrasound was applied to the pressureless consolidation of AlSi10Mg powders in a broad temperature range from 600 to 860℃.Under static conditions,the consolidation of AlSi10Mg powders can only be achie...Low-intensity ultrasound was applied to the pressureless consolidation of AlSi10Mg powders in a broad temperature range from 600 to 860℃.Under static conditions,the consolidation of AlSi10Mg powders can only be achieved at 860℃,but still with the presence of some residual unconsolidated regions.The introduction of low-intensity ultrasound at this temperature eliminates the unconsolidated regions and transforms the columnar grains observed in original directional solidification into equiaxed or globular grains.Remarkably,the application of low-intensity ultrasound significantly reduces the consolidation temperature to 620℃,without compromising the microhardness of the resulting samples when compared to static conditions.Furthermore,by lowering the temperature to 600℃,a well-sintered porous material is obtained through the assistance of the low-intensity ultrasound.展开更多
Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was establi...Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities.展开更多
We study a novel replication mechanism to ensure service continuity against multiple simultaneous server failures.In this mechanism,each item represents a computing task and is replicated intoξ+1 servers for some int...We study a novel replication mechanism to ensure service continuity against multiple simultaneous server failures.In this mechanism,each item represents a computing task and is replicated intoξ+1 servers for some integerξ≥1,with workloads specified by the amount of required resources.If one or more servers fail,the affected workloads can be redirected to other servers that host replicas associated with the same item,such that the service is not interrupted by the failure of up toξservers.This requires that any feasible assignment algorithm must reserve some capacity in each server to accommodate the workload redirected from potential failed servers without overloading,and determining the optimal method for reserving capacity becomes a key issue.Unlike existing algorithms that assume that no two servers share replicas of more than one item,we first formulate capacity reservation for a general arbitrary scenario.Due to the combinatorial nature of this problem,finding the optimal solution is difficult.To this end,we propose a Generalized and Simple Calculating Reserved Capacity(GSCRC)algorithm,with a time complexity only related to the number of items packed in the server.In conjunction with GSCRC,we propose a robust replica packing algorithm with capacity optimization(RobustPack),which aims to minimize the number of servers hosting replicas and tolerate multiple server failures.Through theoretical analysis and experimental evaluations,we show that the RobustPack algorithm can achieve better performance.展开更多
A gigantic project named Gully Land Consolidation(GLC)was launched in the hillgully region of the Chinese Loess Plateau in 2011 to cope with land degradation and create new farmlands for cultivation.The dynamic change...A gigantic project named Gully Land Consolidation(GLC)was launched in the hillgully region of the Chinese Loess Plateau in 2011 to cope with land degradation and create new farmlands for cultivation.The dynamic change of groundwater table and loess subsidence in the backfilled farmland are the main causes of site disasters and soil disease,but there is a lack of research on these issues.Based on this,the Shijiagou(SJG)backfilled farmland which is a typical GLC engineering site located in Ansai District,Yan'an City,Shaanxi Province was selected as the study area in this paper.Field site monitoring was carried out in this area,including four aspects of monitoring:rainfall,groundwater table,soil moisture and soil settlement displacement.The following findings were obtained from the analysis of the monitoring data in 2019-2020:(1)The backfilled farmlands have suffered a significant groundwater table rise.And the percentage increase of groundwater table increased from the upstream of F-1(such as 49.2%,46.3%,26.4%)to the downstream of F-5(90.0%,52.3%,34.2%correspondingly),which is related to the terrain of the valley channel and dam seepage.It is also revealed that rainfall characteristics are positively correlated with the depth of water infiltration and groundwater table.(2)The influence depth of rainfall infiltration on soil moisture of the backfilled loess in the GLC study area is no more than 2.5 m,and that within 1.5 m depth is significantly affected by rainfall.In addition,the dramatic rise in the groundwater table led to a steep increase in soil moisture,thus the soil underwent collapse deformation due to water immersion,and the farmland experienced large subsidence displacement.(3)The backfilled loess of the GLC farmland was in a continuous consolidation and settlement stage after the filling completion.With the passage of time,the settlement displacement and settlement rate of the backfilled loess gradually decreased,from 1.0-1.9 mm/d in 2019 to 0.4-0.8 mm/d in 2020,which indicates the GLC farmland tended to be stable.This study reveals the hydrological evolution characteristics and settlement deformation laws of the backfilled loess,which is important for the stability of the farmland and the management of the GLC project.展开更多
Urban spaces are becoming increasingly congested,and excavations are frequently performed close to existing underground structures such as tunnels.Understanding the mechanical response of proximal soil and tunnels to ...Urban spaces are becoming increasingly congested,and excavations are frequently performed close to existing underground structures such as tunnels.Understanding the mechanical response of proximal soil and tunnels to these excavations is important for efficient and safe underground construction.However,previous investigations of this issue have predominantly made assumptions of plane-strain conditions and normal gravity states,and focused on the performance of tunnels affected by excavation and unloading in sandy strata.In this study,a 3D centrifuge model test is conducted to investigate the influence of excavation on an adjacent existing tunnel in normally consolidated clay.The testing results indicate that the excavation has a significant impact on the horizontal deformation of the retaining wall and tunnel.Moreover,the settlements of the ground surface and the tunnel are mainly affected by the long-term period after excavation.The excavation is found to induce ground movement towards the pit,resulting in prolonged fluctuations in pore water pressure and lateral earth pressure.The testing results are compared with numerical simulations,achieving consistency.A numerical parametric study on the tunnel location shows that when the tunnel is closer to the retaining wall,the decreases in lateral earth pressure and pore water pressure during excavation are more pronounced.展开更多
As a by-product of the steelmaking process,steel slag has a large stock and poor stability,which has led to a gradual decline in its utilization.In order to enhance the utilization rate of steel slag,the preparation o...As a by-product of the steelmaking process,steel slag has a large stock and poor stability,which has led to a gradual decline in its utilization.In order to enhance the utilization rate of steel slag,the preparation of basic pellets by using steel slag as the flux was proposed,in consideration of the high basicity of steel slag.The incorporation of steel slag has been demonstrated to enhance the water-holding capacity and the decrepitation temperature of green pellets.The addition of steel slag increases the content of calcium oxide in the pellets,promotes the formation of a fusible phase in the pellets,and thus increases the liquid phase.With the increasing content of steel slag,the porosity of finished pellets gradually increases and the compressive strength decreases,but the compressive strength of finished pellets can all exceed 2500 N.The addition of steel slag can improve the reducibility index of pellets,with the maximum reducibility index increasing by 12.06%;the reduction swelling index is less than 10.9%,and the reduction degradation index is more than 58.4%.展开更多
基金Supported by National High Level Hospital Clinical Research Funding,No.2022-PUMCH-C-069 and No.2022-PUMCH-A-009.
文摘BACKGROUND Immune checkpoint inhibitor-associated interstitial lung disease(ICI-ILD)and opportunistic pneumonias are the main pulmonary complications during immunotherapy for malignancies.The organizing pneumonia(OP)pattern is one of the common radiological manifestations of ICI-ILD,and OP is the most common cause of reversed halo cycles and consolidations.However,opportunistic pneumonias should be excluded.CASE SUMMARY In this report,we described a case of a 44-year-old man with esophageal cancer who showed multiple reversed-halo cycles and consolidations on chest computed tomography(CT)after he had a cold during immunotherapy.He was diagnosed with esophageal squamous-cell cancer(T2NIM0)after surgery.Then,he was successfully treated with 6 cycles of chemotherapy plus tislelizumab,one cycle of radiotherapy and 9 cycles of tislelizumab.Two months later,he complained of low-grade fever and cough with nonpurulent sputum after he had a cold.Community-acquired pneumonia was considered,but moxifloxacin was ineffective.Chest CT showed multiple reversed-halo cycles and consolidations.Mycobacterium tuberculosis was identified with next-generation sequence analysis of bronchoalveolar lavage fluid(BALF).Two months later,he improved with standard anti-tuberculosis medications.Both the cycles and consolidations disappeared in the repeat CT after 6 mo of medications.CONCLUSION When chest CT shows reversed-halo cycles and consolidations in patients during anticancer immunotherapy,both ICI-ILD and infectious pneumonia should be considered.BALF microbiological analysis was helpful to differentiate them.
文摘From 2001 to 2012,many local governments in China closed down village teaching sites for primary school students in the first and second grades,consolidating them into larger township schools more distant from village students’homes.School closure and consolidation are particularly striking in China’s central and western regions,where swathes of rural labor migrated to cities for jobs.As a result,numerous primary school pupils are forced to study at boarding schools in the first and second grades,which is considered as too early for pupils to live without parental care.This paper employs survey data from 137 township schools with boarding qualifications collected by a project team consisting of researchers from the China Institute for Educational Finance Research(CIEFR)of Peking University,the Institute of Population and Labor Economics of the Chinese Academy of Social Sciences(IPLE-CASS)and the Capital University of Economics and Business(CUEB).By matching the home-school distance with village teaching site information as the proxy variable for the school consolidation policy,this paper evaluates the policy's impact on the likelyhood of premature boarding for primary school pupils,as well as the impact on their human capital accumulation.Our study finds that the creation of teaching sites makes it less likely for primary school pupils to board at school.Premature boarding impedes children’s human capital accumulation,and the harmful effect is particularly striking for children lacking pastoral teachers,raised by grandparents and from families above average income levels,as well as girls.
基金funding support from the National Natural Science Foundation of China(Nos.52304101 and 52204153)the China Postdoctoral Science Foundation(No.2023MD734215)+2 种基金the Youth Talent Support Program of Xi’an Association for Science and Technology(No.959202413070)the Key Research and Development Program of Shaanxi(No.2023-LL-QY-07)the Key Research and Development Program of Zhejiang(No.2023C03182).
文摘Backfill is routinely adopted as a ground support measure for underground mines.However,ground stability enhancement by backfill has received limited research attention.This is likely to be because of the conventional assumption that the fill material exhibits a significantly lower stiffness than the host rocks.Significantly,a recent pioneering work revealed the time-dependent ground stability around a backfilled stope with vertical walls through numerical modeling.In practice,underground stopes typically exhibit a higher or lower degree of inclination.This alters the stress state in peripheral rocks and may induce severe instability and dilution,particularly in stope-hanging walls.Hence,it is imperative to analyze the time-dependent ground stability of inclined backfilled stopes for backfill structure design.Therefore,comprehensive numerical simulations were performed using FLAC3D to address this knowledge deficiency by incorporating a coupled analysis of the backfill consolidation behavior and long-term creep deformation in surrounding rocks.The ground stability was evaluated based on the confinement effectiveness,strength-stress ratio,stress path relative to the yield surface,and time-dependent stress redistribution in the rocks.A parametric study revealed that the inclination angle of the backfilled stope reduced the confinement effectiveness in the host rocks when the wall creep was minor.This exacerbated the rock mass sloughing potential.However,a backfilled stope with a shallower dip angle achieved superior ground stability enhancement when the creep deformation was substantial,by applying a more significant compression on the backfill and effectively mobilizing its passive support performance during consolidation.Additional simulations were conducted to analyze the effects of stope height and width,mine depth,mechanical properties of rocks,backfill compressibility,and filling gap on the time-dependent stress redistribution and stability around the inclined backfilled stope.
基金supports provided from Guangxi Science and Technology Major Project(AA24263047).
文摘The production of vanadium-titanium magnetite(VTM)pellets has the problems of low consolidation strength and high energy consumption in the preheating and roasting process.High-pressure grinding roll(HPGR)pretreatment process was used to increase the fine-grained content and specific surface area of VTM concentrates,to strengthen the oxidation consolidation process of VTM pellets,and oxidation kinetic experiments were carried out.The results showed that the specific surface area of VTM concentrates was increased from 872 to 1457 cm^(2)/g by HPGR and then pelletising and roasting.With preheating at 1000℃ for 10 min and roasting at 1260℃ for 10 min,the strengths of preheated pellets were increased from 329 to 535 N,and the strengths of roasted pellets were increased from 1010 to 2591 N.The limiting link in the early stage of VTM pellets oxidation was the control of chemical reaction,while the limiting link in the later stage of oxidation was the mixed control of chemical reaction and gas diffusion.The activation energies of VTM pellets before and after HPGR pretreatment were 53.07 and 40.03 kJ/mol in the early stage of oxidation reaction,while the activation energies in the later stage of oxidation were 29.24 and 22.75 kJ/mol,respectively.
文摘Standards are the common language that consolidates global consensus and builds the most solid foundation for international partnerships.They are the cornerstone for global sustainable and high-quality development.Young students,with their active and vibrant minds,represent the future and hope of standardization.
基金supported by the National Natural Science Foundation of China(Grant Nos.52168046 and 52178321)the Natural Science Foundation of Guangxi Province,China(Grant No.2021AC18019).
文摘Precast driven piles are extensively used for infrastructure on soft soils,but the buildup of excess pore water pressure associated with pile driving is a challenging issue.The process of soil consolidation could take several months.Measures are sought to shorten the drainage path in the ground,and permeable pipe pile is a concept that involves drainage channels at the peak pore pressure locations around the pile circumference.Centrifuge tests were conducted to understand the responses of permeable pipe pile treated ground,experiencing the whole pile driving,soil consolidating,and axially loading process.Results show that the dissipation rate of pore pressures can be improved,especially at a greater depth or at a shorter distance from the pile,since the local hydraulic gradient was higher.Less significant buildup of pore pressures can be anticipated with the use of permeable pipe pile.For this,the bearing capacity of composite foundation with permeable pipe pile can be increased by over 36.9%,compared to the case with normal pipe pile at a specific time period.All these demonstrate the ability of permeable pipe pile in accelerating the consolidation process,mobilizing the bearing capacity of treated ground at an early stage,and minimizing the set-up effect.
基金sponsored by the National Natural Science Foundation of China(Grant No.12002173,12262027)Research start-up project of Inner Mongolia University of Technology(No.2200000924)key Lab.of University of Geological Hazards and Geotechnical Engineering Defense in Sandy and Drought Regions,Inner Mongolia Autonomous.
文摘Microbially induced calcium carbonate precipitation(MICP)technology can induce calcium carbonate crystals with cementation and stable performance in the process of microbial metabolism or enzymization through the regulation of environmental factors MICP can be used as a cementing agent to cement cohesionless sand particles to form the materials with the characteristics of higher strength,better durability and environmental friendli-ness,as well as a good engineering application prospect.In this paper,the shear strength of sand column was tested by triaxial compression tests,and the strength index was obtained.In order to further study the micro-strength mechanism and the failure process,based on the discrete element method,a numerical model of MICP cemented sand column was established considering the factors of matrix soil particle gradation,particle mor-phology,content ratio of induced calcium carbonate,pore distribution characteristics,inter-particle cementation and so on.The failure process of MICP cemented sand column under load was analysed by numerical simulation,and the reliability of the numerical model was tested by combining with the stress intensity curve of samples under test conditions.The results indicate that compared with the actual triaxial tests of MICP cemented sand column,although there are deviations in stress and strain,cohesion and internal friction angle,the numerical simulation shows similar development law and intensity amplitude,and the same failure trend.The work in this paper verifies the reliability of the numerical model and provides a theoretical basis for the subsequent analysis of the factors influencing the geotechnical mechanical properties of biomineralized materials.
文摘Objective:This review aimed to identify the barriers and facilitators to equitable coronavirus disease 2019(COVID-19)vaccine distribution in Nigeria using the consolidated framework for implementation research(CFIR).Methods:A comprehensive search strategy was applied across five databases—Web of Science,MEDLINE,EMBASE,CAB Direct,and CINAHL.The search,conducted as part of a scoping review,yielded 2,751 citations.Seven studies met the inclusion criteria after screening.Data were extracted and analyzed using CFIR constructs to identify key barriers and facilitators to equitable vaccine distribution.Results:Six barriers were identified:limited physical and socioeconomic access,bribery,nepotism,and insufficient availability of translated information.Facilitators included community involvement as local monitoring agents,unannounced staff inspections,healthcare worker training tailored to community needs,and localized outreach strategies such as jingles and call-in programs.CFIR constructs,including Local Conditions,Tailoring Strategies,Available Resources,and Physical Infrastructure,provided a framework for analyzing the findings.Conclusion:This review highlights significant barriers and promising facilitators to equitable vaccine distribution in Nigeria.Targeted interventions,such as community engagement,anti-corruption measures,and culturally tailored strategies,are critical to addressing these challenges and improving access.These findings underscore the need for localized,equity-focused approaches to enhance vaccine distribution systems in Nigeria and other low-resource settings.
基金supported by the National Nature Science Foundation of China(No.12172211)the National Key Research and Development Program of China(No.2019YFC1509800)。
文摘1 Introduction In highway construction,flled embankments are trapezoidal,and the ground is always improved by sand wells or columns.During embankment construction,because the width and height of the embankment are changing,a non-uniform load that varies with time and lateral location is applied to the underlying ground.The consolidation phenomenon under two-dimensional(2D)conditions will keep pace with the construction of the embankment.In addition,because of evaporation and rainfall,the soils are mostly unsaturated.Therefore,it is meaningful to research the consolidation properties of unsaturated ground under non-uniform loading.
基金National Natural Science Foundation of China,No.42171255,No.41971216。
文摘The application of ecosystem services(ES)theories in land consolidation is a confusing issue that has long plagued scholars and government officials.As the upgraded version of traditional land consolidation,comprehensive land consolidation(CLC)emphasizes ecological benefits,but it does not achieve the expected effect during the pilot phase.This study first proposed a theoretical analysis framework based on ES knowledge to answer the three key questions of why,where,and how to implement CLC better.Taking mountainous counties as the study area,we found that ES trade-offs/synergies,bundles,and drivers were significantly affected by scale effects.ES knowledge can play a crucial role in designing multi-scale CLC strategies regarding the objective,zoning,intensity,and mode.Specifically,mitigating the significant trade-offs between recreational opportunities,food production,and other ES is the top priority of CLC.Land consolidation zoning based on the ES bundles analysis is more rational and can provide the scientific premise for designing locally adapted CLC measures.Land consolidation can be classified into high-intensity direct intervention and low-intensity indirect intervention modes,based on the major drivers of ES.These findings help narrow the gap between ES and CLC practices.
文摘Chronic pulmonary heart disease is a common and frequently occurring condition in the respiratory system.Professor Wei Gunzheng advocates a treatment approach that integrates disease management with syndrome differentiation,combining methods to eliminate pathogenic factors and reinforce healthy qi.During acute episodes,the focus should be on expelling pathogenic excess while simultaneously consolidating the root and supporting healthy qi.During remission,the priority shifts to reinforcing the body's vital energy.For effective treatment,it is essential to both tonify deficiency and purge excess,ensuring the elimination of pathogenic factors and the restoration of healthy qi.
基金supported by the National Natural Science Foundation of China(32371028,32300822,U24A20373,and 82071177)the Shanghai Rising-Star Program(24QA2704800)+2 种基金the Shanghai Jiao Tong University 2030 InitiativeShanghai Municipal Health Commission(202340046)the Fund for Excellent Young Scholars of Shanghai Ninth People's Hospital,Shanghai Jiao Tong University School of Medicine.
文摘Memory is a cognitive process through which past experiences are encoded,stored,and retrieved,playing a crucial role in intelligent behavior.It is well established that the hippocampus continues to reactivate memories for several days after learning,and this process primarily occurs during sleep[1,2].The prevailing view suggests that sharp-wave ripples(SWRs)during non-rapid eye movement(NREM)sleep serve as key electrophysiological signatures of memory replay[3,4].However,only a small portion of SWRs contain memory replay[5].The direct relationship among SWRs,memory replay,and memory consolidation remains an open question.Another unresolved issue is how the hippocampus simultaneously reactivates both new and old memories while preventing interference.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(Grant No.2022R1A2C2091517).
文摘Understanding the sedimentation and simultaneous consolidation behavior of xanthan gum(XG)-biopolymer-treated soils remains a significant research gap in developing environmentally friendly ground-improvement techniques for geotechnical applications.This study addresses this gap by conducting laboratory experiments on kaolinite suspensions with varying XG-to-kaolinite mass ratios(mb/ms).The results showed that the XG treatment modified the sedimentation patterns by promoting larger floc formation and accelerated settling.Additionally,the XG treatment enhanced the shear stiffness and shear strength,particularly at shallow depths.At mb/ms ratios less than 1%,the volume compression was reduced by the XG;the coefficient of compressibility decreased by 49%at 1%mb/ms,and the consolidation was accelerated,as indicated by a 387%increase in the hydraulic conductivity at 0.5%mb/ms under the vertical effective stress of 40 kPa.Contrastingly,at mb/ms ratios greater than 1%,viscous XG hydrogels clogged pores,resulting in a 45%reduction in the coefficient of consolidation at 2%mb/ms under a vertical effective stress of 15 kPa and a 35%decrease in the hydraulic conductivity at 2%mb/ms under a vertical effective stress of 40 kPa.These findings underscore the potential of XG treatment in improving the sedimentation and consolidation processes,highlighting its applicability in geotechnical projects,such as dredging,landfilling,and artificial island construction.
文摘Memory enables organisms to encode,store,and retrieve information essential for interacting with and adapting to a dynamic environment.As an internal representation of the external world,memory serves as a crucial bridge between past experiences and future behaviors.However,the brain continuously forms new memories,raising the question of how new memories are integrated without disrupting previously formed ones.
基金National Natural Science Foundation of China(Nos.52101051,52130405,51872241,52101142)Key Research Plan of Shaanxi Province,China(No.2020ZDLGY13-03)+1 种基金Key Research and Development Program of Shaanxi Province,China(No.2023-YBGY-439)Fundamental Research Funds for the Central Universities,China(No.5000210653)。
文摘Low-intensity ultrasound was applied to the pressureless consolidation of AlSi10Mg powders in a broad temperature range from 600 to 860℃.Under static conditions,the consolidation of AlSi10Mg powders can only be achieved at 860℃,but still with the presence of some residual unconsolidated regions.The introduction of low-intensity ultrasound at this temperature eliminates the unconsolidated regions and transforms the columnar grains observed in original directional solidification into equiaxed or globular grains.Remarkably,the application of low-intensity ultrasound significantly reduces the consolidation temperature to 620℃,without compromising the microhardness of the resulting samples when compared to static conditions.Furthermore,by lowering the temperature to 600℃,a well-sintered porous material is obtained through the assistance of the low-intensity ultrasound.
基金supported by the National Natural Science Foundation of China(Grant Nos.52378321 and 52079003).
文摘Based on the energy dissipation caused by consolidation deformation of the porous media under external force and migration of the internal suspended substances,a coupled multiphase-substance flow(CMF)model was established.This model introduced the new concepts,such as particle temperature and particle entropy,to describe energy dissipation at meso-level.This model used a potential energy density function and migration coefficients to establish the corresponding connection between the dissipative force and dissipative flow.This viewpoint unifies the deformation,seepage,and suspended substance migration of geotechnical materials under the framework of granular thermodynamics.It can reflect the evolution of effective stress in the solid matrix of multi-components in a particle-reorganized state,and considers the temperature driving effect.The proposed CMF model is validated using the experimental results under coupled migration of heavy metal ions(HMs)and suspended particles(SPs).The calculation results demonstrated that the CMF model can describe the flow process under the conditions of arbitrary changes in different suspended substance types,injection concentrations,and injection velocities.
基金supported in part by the National Key R&D Program of China under No.2023YFB2703800the National Science Foundation of China under Grants U22B2027,62172297,62102262,61902276 and 62272311+3 种基金Tianjin Intelligent Manufacturing Special Fund Project under Grants 20211097the China Guangxi Science and Technology Plan Project(Guangxi Science and Technology Base and Talent Special Project)under Grant AD23026096(Application Number 2022AC20001)Henan Provincial Natural Science Foundation of China under Grant 622RC616CCF-Nsfocus Kunpeng Fund Project under Grants CCF-NSFOCUS202207。
文摘We study a novel replication mechanism to ensure service continuity against multiple simultaneous server failures.In this mechanism,each item represents a computing task and is replicated intoξ+1 servers for some integerξ≥1,with workloads specified by the amount of required resources.If one or more servers fail,the affected workloads can be redirected to other servers that host replicas associated with the same item,such that the service is not interrupted by the failure of up toξservers.This requires that any feasible assignment algorithm must reserve some capacity in each server to accommodate the workload redirected from potential failed servers without overloading,and determining the optimal method for reserving capacity becomes a key issue.Unlike existing algorithms that assume that no two servers share replicas of more than one item,we first formulate capacity reservation for a general arbitrary scenario.Due to the combinatorial nature of this problem,finding the optimal solution is difficult.To this end,we propose a Generalized and Simple Calculating Reserved Capacity(GSCRC)algorithm,with a time complexity only related to the number of items packed in the server.In conjunction with GSCRC,we propose a robust replica packing algorithm with capacity optimization(RobustPack),which aims to minimize the number of servers hosting replicas and tolerate multiple server failures.Through theoretical analysis and experimental evaluations,we show that the RobustPack algorithm can achieve better performance.
基金funded by the National Natural Science Foundation of China for Distinguished Young People(No.41825018)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23090402)the Natural Science Foundation of China(No.41790442)。
文摘A gigantic project named Gully Land Consolidation(GLC)was launched in the hillgully region of the Chinese Loess Plateau in 2011 to cope with land degradation and create new farmlands for cultivation.The dynamic change of groundwater table and loess subsidence in the backfilled farmland are the main causes of site disasters and soil disease,but there is a lack of research on these issues.Based on this,the Shijiagou(SJG)backfilled farmland which is a typical GLC engineering site located in Ansai District,Yan'an City,Shaanxi Province was selected as the study area in this paper.Field site monitoring was carried out in this area,including four aspects of monitoring:rainfall,groundwater table,soil moisture and soil settlement displacement.The following findings were obtained from the analysis of the monitoring data in 2019-2020:(1)The backfilled farmlands have suffered a significant groundwater table rise.And the percentage increase of groundwater table increased from the upstream of F-1(such as 49.2%,46.3%,26.4%)to the downstream of F-5(90.0%,52.3%,34.2%correspondingly),which is related to the terrain of the valley channel and dam seepage.It is also revealed that rainfall characteristics are positively correlated with the depth of water infiltration and groundwater table.(2)The influence depth of rainfall infiltration on soil moisture of the backfilled loess in the GLC study area is no more than 2.5 m,and that within 1.5 m depth is significantly affected by rainfall.In addition,the dramatic rise in the groundwater table led to a steep increase in soil moisture,thus the soil underwent collapse deformation due to water immersion,and the farmland experienced large subsidence displacement.(3)The backfilled loess of the GLC farmland was in a continuous consolidation and settlement stage after the filling completion.With the passage of time,the settlement displacement and settlement rate of the backfilled loess gradually decreased,from 1.0-1.9 mm/d in 2019 to 0.4-0.8 mm/d in 2020,which indicates the GLC farmland tended to be stable.This study reveals the hydrological evolution characteristics and settlement deformation laws of the backfilled loess,which is important for the stability of the farmland and the management of the GLC project.
基金supported by the National Natural Science Foundation of China(Nos.52378341,51938005,and 52090082).
文摘Urban spaces are becoming increasingly congested,and excavations are frequently performed close to existing underground structures such as tunnels.Understanding the mechanical response of proximal soil and tunnels to these excavations is important for efficient and safe underground construction.However,previous investigations of this issue have predominantly made assumptions of plane-strain conditions and normal gravity states,and focused on the performance of tunnels affected by excavation and unloading in sandy strata.In this study,a 3D centrifuge model test is conducted to investigate the influence of excavation on an adjacent existing tunnel in normally consolidated clay.The testing results indicate that the excavation has a significant impact on the horizontal deformation of the retaining wall and tunnel.Moreover,the settlements of the ground surface and the tunnel are mainly affected by the long-term period after excavation.The excavation is found to induce ground movement towards the pit,resulting in prolonged fluctuations in pore water pressure and lateral earth pressure.The testing results are compared with numerical simulations,achieving consistency.A numerical parametric study on the tunnel location shows that when the tunnel is closer to the retaining wall,the decreases in lateral earth pressure and pore water pressure during excavation are more pronounced.
基金financially supported by Key Research Project of Hubei Province(No.2022BCA062)China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202107).
文摘As a by-product of the steelmaking process,steel slag has a large stock and poor stability,which has led to a gradual decline in its utilization.In order to enhance the utilization rate of steel slag,the preparation of basic pellets by using steel slag as the flux was proposed,in consideration of the high basicity of steel slag.The incorporation of steel slag has been demonstrated to enhance the water-holding capacity and the decrepitation temperature of green pellets.The addition of steel slag increases the content of calcium oxide in the pellets,promotes the formation of a fusible phase in the pellets,and thus increases the liquid phase.With the increasing content of steel slag,the porosity of finished pellets gradually increases and the compressive strength decreases,but the compressive strength of finished pellets can all exceed 2500 N.The addition of steel slag can improve the reducibility index of pellets,with the maximum reducibility index increasing by 12.06%;the reduction swelling index is less than 10.9%,and the reduction degradation index is more than 58.4%.
