Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and c...Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and channels)of the catchment is assumed.This study focused on sediment connectivity analysis in the SlavíčRiver catchment in the MoravskoslezskéBeskydy Mts in the eastern part of the Czech Republic.The connectivity index and connectivity index target modelling were combined with an analysis of anthropogenic interventions.Additionally,field mapping,grain size of bed sediments and stream power analysis were used to obtain information about connectivity in the catchment.Based on the analysis and obtained results,terrain topography is the current main driving factor affecting the connectivity of sediment movement in the SlavíčRiver catchment.However,the modelling provided valuable information about high sediment connectivity despite different recent land use conditions(highly forested area of the catchment)than those in historical times from the 16th to 19th centuries when the SlavíčRiver catchment was highly deforested and sediment connectivity was probably higher.The analysis of anthropogenic interventions,field mapping,grain size of bed sediments and stream power analysis revealed more deceleration of sediment movement through the catchment,decreased sediment connectivity with bed erosion,and gradual river channel process transformation in some reaches.Field mapping has identified various natural formations and human-induced changes impacting the longitudinal and lateral connectivity in the SlavíčRiver.For instance,embankments along 48%of the river's length,both on the right and left banks,significantly hinder lateral sediment supply to the channel.Stream power index analysis indicates increased energy levels in the flowing water in the river's upper reaches(up to 404.8 W m^(-2)).This high energy is also observed in certain downstream sections(up to 337.6 W m^(-2)),where it is influenced by human activities.These conditions lead to intensified erosion processes,playing a crucial role in sediment connectivity.Similar observations were described in recent studies that pointed out the long-term human interventions on many streams draining European mountains,where a decrease in sediment connectivity in these streams is linked with sediment deficits and the transformation of processes forming channels.展开更多
针对无人驾驶车辆路径规划问题,基于快速扩展随机树(rapidly-exploring random tree,RRT)算法,提出了1种5次多项式曲线(quintic polynomial curve)与MT-RRT(multi-targeting rapidly-exploring random tree)的融合算法,即QPC-MT-RRT算...针对无人驾驶车辆路径规划问题,基于快速扩展随机树(rapidly-exploring random tree,RRT)算法,提出了1种5次多项式曲线(quintic polynomial curve)与MT-RRT(multi-targeting rapidly-exploring random tree)的融合算法,即QPC-MT-RRT算法。该算法根据无人驾驶车辆路径规划的相关理论,建立无人驾驶车辆路径规划问题的车辆运动学模型,为规划无人驾驶车辆最优、最高效、最安全路径提供理论依据。将上述算法在MATLAB上仿真,并在平均路径长度、平均路径规划时间、平均采样节点个数及节点利用率4个方面与基本RRT算法及MT-RRT算法进行了对比。仿真结果表明:5次多项式曲线与MT-RRT算法的融合算法具有最高的性能,可以规划出最优路径。展开更多
Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountai...Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.展开更多
In shallow-water areas,the marine magnetotelluric(MT)method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves,which seriously contami...In shallow-water areas,the marine magnetotelluric(MT)method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves,which seriously contaminate MT data.Ocean waves can affect electric and magnetic fields to different extents.In general,their influence on magnetic fields is considerably greater than that on electric fields.In this paper,a complex adaptive filter is adopted to reduce wave-induced magnetic noises in the frequency domain.The processing results of synthetic and measured MT data indicate that the proposed method can effectively reduce wave-induced magnetic noises and provide reliable apparent resistivity and phase data.展开更多
The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay is used as a major method to evaluate cell viability. However, in some cases, the results may reflect mitochondr...The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay is used as a major method to evaluate cell viability. However, in some cases, the results may reflect mitochondrial status regardless of viability. Epalrestat (EPS) is currently available for the treatment of diabetic neuropathy. In this study, we report that EPS at near-plasma concentrations increases MTS reduction activity independent of cell number in bovine aortic endothelial cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that plays a pivotal role in inducing the expression of genes encoding detoxifying and defensive proteins. Sulforaphane (an Nrf2 activator) also increased MTS-reducing activity, similar to EPS. Knockdown of Nrf2 by short interfering RNA suppressed EPS-induced MTS reduction. These results suggest that EPS increases MTS reduction activity via the Nrf2 pathway. Furthermore, the results that EPS increases ATP production and that electron transfer chain inhibitors suppress EPS-induced MTS reduction activity suggest that EPS may activate mitochondrial status. Because mitochondrial disorders cause numerous diseases, we suggest that EPS has new beneficial properties that may prevent the development and progression of disorders caused by mitochondrial dysfunction.展开更多
基金supported by an internal grant of the University of Ostrava[SGS10/PřF/2021-Specificity of fluvial landscape in the context of historical and future changes].
文摘Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and channels)of the catchment is assumed.This study focused on sediment connectivity analysis in the SlavíčRiver catchment in the MoravskoslezskéBeskydy Mts in the eastern part of the Czech Republic.The connectivity index and connectivity index target modelling were combined with an analysis of anthropogenic interventions.Additionally,field mapping,grain size of bed sediments and stream power analysis were used to obtain information about connectivity in the catchment.Based on the analysis and obtained results,terrain topography is the current main driving factor affecting the connectivity of sediment movement in the SlavíčRiver catchment.However,the modelling provided valuable information about high sediment connectivity despite different recent land use conditions(highly forested area of the catchment)than those in historical times from the 16th to 19th centuries when the SlavíčRiver catchment was highly deforested and sediment connectivity was probably higher.The analysis of anthropogenic interventions,field mapping,grain size of bed sediments and stream power analysis revealed more deceleration of sediment movement through the catchment,decreased sediment connectivity with bed erosion,and gradual river channel process transformation in some reaches.Field mapping has identified various natural formations and human-induced changes impacting the longitudinal and lateral connectivity in the SlavíčRiver.For instance,embankments along 48%of the river's length,both on the right and left banks,significantly hinder lateral sediment supply to the channel.Stream power index analysis indicates increased energy levels in the flowing water in the river's upper reaches(up to 404.8 W m^(-2)).This high energy is also observed in certain downstream sections(up to 337.6 W m^(-2)),where it is influenced by human activities.These conditions lead to intensified erosion processes,playing a crucial role in sediment connectivity.Similar observations were described in recent studies that pointed out the long-term human interventions on many streams draining European mountains,where a decrease in sediment connectivity in these streams is linked with sediment deficits and the transformation of processes forming channels.
文摘针对无人驾驶车辆路径规划问题,基于快速扩展随机树(rapidly-exploring random tree,RRT)算法,提出了1种5次多项式曲线(quintic polynomial curve)与MT-RRT(multi-targeting rapidly-exploring random tree)的融合算法,即QPC-MT-RRT算法。该算法根据无人驾驶车辆路径规划的相关理论,建立无人驾驶车辆路径规划问题的车辆运动学模型,为规划无人驾驶车辆最优、最高效、最安全路径提供理论依据。将上述算法在MATLAB上仿真,并在平均路径长度、平均路径规划时间、平均采样节点个数及节点利用率4个方面与基本RRT算法及MT-RRT算法进行了对比。仿真结果表明:5次多项式曲线与MT-RRT算法的融合算法具有最高的性能,可以规划出最优路径。
基金the National Natural Science Foundation of China(No.32270454)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0501).
文摘Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.
基金supported by the National Natural Science Foundation of China(Nos.91958210 and 41904075)。
文摘In shallow-water areas,the marine magnetotelluric(MT)method faces a challenge in the investigation of seabed conductivity structures due to electrical and magnetic noises induced by ocean waves,which seriously contaminate MT data.Ocean waves can affect electric and magnetic fields to different extents.In general,their influence on magnetic fields is considerably greater than that on electric fields.In this paper,a complex adaptive filter is adopted to reduce wave-induced magnetic noises in the frequency domain.The processing results of synthetic and measured MT data indicate that the proposed method can effectively reduce wave-induced magnetic noises and provide reliable apparent resistivity and phase data.
文摘The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay is used as a major method to evaluate cell viability. However, in some cases, the results may reflect mitochondrial status regardless of viability. Epalrestat (EPS) is currently available for the treatment of diabetic neuropathy. In this study, we report that EPS at near-plasma concentrations increases MTS reduction activity independent of cell number in bovine aortic endothelial cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that plays a pivotal role in inducing the expression of genes encoding detoxifying and defensive proteins. Sulforaphane (an Nrf2 activator) also increased MTS-reducing activity, similar to EPS. Knockdown of Nrf2 by short interfering RNA suppressed EPS-induced MTS reduction. These results suggest that EPS increases MTS reduction activity via the Nrf2 pathway. Furthermore, the results that EPS increases ATP production and that electron transfer chain inhibitors suppress EPS-induced MTS reduction activity suggest that EPS may activate mitochondrial status. Because mitochondrial disorders cause numerous diseases, we suggest that EPS has new beneficial properties that may prevent the development and progression of disorders caused by mitochondrial dysfunction.
