As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scal...As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.展开更多
Due to the presence of ice and unfrozen water in pores of frozen rock,the rock fracture behaviors are susceptible to temperature.In this study,the potential thawing-induced softening effects on the fracture behaviors ...Due to the presence of ice and unfrozen water in pores of frozen rock,the rock fracture behaviors are susceptible to temperature.In this study,the potential thawing-induced softening effects on the fracture behaviors of frozen rock is evaluated by testing the tension fracture toughness(KIC)of frozen rock at different temperatures(i.e.-20℃,-15℃,-12℃,-10℃,-8℃,-6℃,-4℃,-2℃,and 0℃).Acoustic emission(AE)and digital image correlation(DIC)methods are utilized to analyze the microcrack propagation during fracturing.The melting of pore ice is measured using nuclear magnetic resonance(NMR)method.The results indicate that:(1)The KIC of frozen rock decreases moderately between-20℃ and-4℃,and rapidly between-4℃ and 0℃.(2)At-20℃ to-4℃,the fracturing process,deduced from the DIC results at the notch tip,exhibits three stages:elastic deformation,microcrack propagation and microcrack coalescence.However,at-4℃e0℃,only the latter two stages are observed.(3)At-4℃e0℃,the AE activities during fracturing are less than that at-20℃ to-4℃,while more small events are reported.(4)The NMR results demonstrate a reverse variation trend in pore ice content with increasing temperature,that is,a moderate decrease is followed by a sharp decrease and-4℃ is exactly the critical temperature.Next,we interpret the thawing-induced softening effect by linking the evolution in microscopic structure of frozen rock with its macroscopic fracture behaviors as follow:from-20℃ to-4℃,the thickening of the unfrozen water film diminishes the cementation strength between ice and rock skeleton,leading to the decrease in fracture parameters.From-4℃ to 0℃,the cementation effect of ice almost vanishes,and the filling effect of pore ice is reduced significantly,which facilitates microcrack propagation and thus the easier fracture of frozen rocks.展开更多
Leakages from subsea oil and gas equipment cause substantial economic losses and damage to marine ecosystem,so it is essential to locate the source of the leak.However,due to the complexity and variability of the mari...Leakages from subsea oil and gas equipment cause substantial economic losses and damage to marine ecosystem,so it is essential to locate the source of the leak.However,due to the complexity and variability of the marine environment,the signals collected by hydrophone contain a variety of noises,which makes it challenging to extract useful signals for localization.To solve this problem,a hydrophone denoising algorithm is proposed based on variational modal decomposition(VMD)with grey wolf optimization.First,the average envelope entropy is used as the fitness function of the grey wolf optimizer to find the optimal solution for the parameters K andα.Afterward,the VMD algorithm decomposes the original signal parameters to obtain the intrinsic mode functions(IMFs).Subsequently,the number of interrelationships between each IMF and the original signal was calculated,the threshold value was set,and the noise signal was removed to calculate the time difference using the valid signal obtained by reconstruction.Finally,the arrival time difference is used to locate the origin of the leak.The localization accuracy of the method in finding leaks is investigated experimentally by constructing a simulated leak test rig,and the effectiveness and feasibility of the method are verified.展开更多
BACKGROUND Cardiovascular disease(CVD)is a leading cause of morbidity and mortality worldwide,the global burden of which is rising.It is still unclear the extent to which prediabetes contributes to the risk of CVD in ...BACKGROUND Cardiovascular disease(CVD)is a leading cause of morbidity and mortality worldwide,the global burden of which is rising.It is still unclear the extent to which prediabetes contributes to the risk of CVD in various age brackets among adults.To develop a focused screening plan and treatment for Chinese adults with prediabetes,it is crucial to identify variations in the connection between prediabetes and the risk of CVD based on age.AIM To examine the clinical features of prediabetes and identify risk factors for CVD in different age groups in China.METHODS The cross-sectional study involved a total of 46239 participants from June 2007 through May 2008.A thorough evaluation was conducted.Individuals with prediabetes were categorized into two groups based on age.Chinese atherosclerotic CVD risk prediction model was employed to evaluate the risk of developing CVD over 10 years.Random forest was established in both age groups.SHapley Additive exPlanation method prioritized the importance of features from the perspective of assessment contribution.RESULTS In total,6948 people were diagnosed with prediabetes in this study.In prediabetes,prevalences of CVD were 5(0.29%)in the younger group and 148(2.85%)in the older group.Overall,11.11%of the younger group and 29.59% of the older group were intermediate/high-risk of CVD for prediabetes without CVD based on the Prediction for ASCVD Risk in China equation in ten years.In the younger age group,the 10-year risk of CVD was found to be more closely linked to family history of CVD rather than lifestyle,whereas in the older age group,resident status was more closely linked.CONCLUSION The susceptibility to CVD is age-specific in newly diagnosed prediabetes.It is necessary to develop targeted approaches for the prevention and management of CVD in adults across various age brackets.展开更多
Alanine aminotransferase(ALT)serum levels increase because of hepatocellular damage.Metabolic dysfunction-associated fatty liver disease(MAFLD),which identifies steatotic liver disease(SLD)associated with≥2 metabolic...Alanine aminotransferase(ALT)serum levels increase because of hepatocellular damage.Metabolic dysfunction-associated fatty liver disease(MAFLD),which identifies steatotic liver disease(SLD)associated with≥2 metabolic abnormalities,has prominent sexual differences.The Metabolic Syndrome defines a cluster comprising abdominal obesity,altered glucose metabolism,dyslipidemia,and hypertension.Male sex,body mass index,glucose,lipids,ferritin,hypertension,and age independently predict ALT levels among blood donors.Over the last few decades,the reference range of ALT levels has been animatedly debated owing to attempts to update sex-specific reference ranges.With this backset,Chen et al have recently published a study which has two main findings.First,>80%of indi-viduals with MAFLD had normal ALT levels.Second,there was a linear increa-sing trend in the association between cumulative excess high-normal ALT levels and the rate of incident MAFLD.This study has biologically credible findings.However,it inaccurately considered sex differences in the MAFLD arena.Therefore,future studies on SLD owing to metabolic dysfunction should adopt locally determined and prospectively validated reference ranges of ALT and carefully consider sex differences in liver enzymes and MAFLD pathobiology.展开更多
This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond...This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser.The airflow rate and pulse delay are the main experimental variables.The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing.The experimental results demonstrate that the expansion velocities of the plasma and combustion wave are influenced differently by the sideblowing airflow at different airflow rates(0.2 Ma,0.4 Ma,and 0.6 Ma).As the flow rate of the sideblow air stream increases,the initial expansion velocities of the plasma and combustion wave gradually decrease,and the side-blow air stream increasingly suppresses the plasma.It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action.Therefore,the side-blown airflow alone cannot completely clear the plasma.Depending on the delay conditions,the pressure of the side-blowing airflow,the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as the double combustion waves when using a nanosecond pulse laser.Both simulation and experimental results are consistent,indicating the potential for further exploration of fused silica targets in the laser field.展开更多
In recent years,fractional-order chaotic maps have been paid more attention in publications because of the memory effect.This paper presents a novel variable-order fractional sine map(VFSM)based on the discrete fracti...In recent years,fractional-order chaotic maps have been paid more attention in publications because of the memory effect.This paper presents a novel variable-order fractional sine map(VFSM)based on the discrete fractional calculus.Specially,the order is defined as an iterative function that incorporates the current state of the system.By analyzing phase diagrams,time sequences,bifurcations,Lyapunov exponents and fuzzy entropy complexity,the dynamics of the proposed map are investigated comparing with the constant-order fractional sine map.The results reveal that the variable order has a good effect on improving the chaotic performance,and it enlarges the range of available parameter values as well as reduces non-chaotic windows.Multiple coexisting attractors also enrich the dynamics of VFSM and prove its sensitivity to initial values.Moreover,the sequence generated by the proposed map passes the statistical test for pseudorandom number and shows strong robustness to parameter estimation,which proves the potential applications in the field of information security.展开更多
Aphis gossypii has become increasingly difficult to manage due to its strong insecticide resistance.In the laboratory,we established sulfoxaflor-resistant and acetamiprid-resistant strains in two A.gossypii population...Aphis gossypii has become increasingly difficult to manage due to its strong insecticide resistance.In the laboratory,we established sulfoxaflor-resistant and acetamiprid-resistant strains in two A.gossypii populations with different basal insecticide resistance levels,and evaluated the effects of basal insecticide resistance on the resistance development and cross-resistance,as well as differences in fitness.Under the same selection pressure,Yarkant A.gossypii(with low basal insecticide resistance)evolved resistance to sulfoxaflor and acetamiprid more quickly than Jinghe A.gossypii(with high basal insecticide resistance),and the evolution of A.gossypii resistance to sulfoxaflor developed faster than acetamiprid in both Yarkant and Jinghe,Xingjiang,China.The sulfoxaflor-resistant strains selected from Yarkant and Jinghe developed significant cross-resistance to acetamiprid,imidacloprid,thiamethoxam and pymetrozine;while the acetamiprid-resistant strains developed significant cross-resistance to sulfoxaflor,imidacloprid,thiamethoxam,pymetrozine,and chlorpyrifos.The relative fitness of A.gossypii decreased as the resistance to sulfoxaflor and acetamiprid developed.The relative fitness levels of the sulfoxaflor-resistant strains(Yarkant-SulR and Jinghe-SulR)were lower than those of the acetamipridresistant strains(Yarkant-AceR and Jinghe-AceR).In addition,the relative fitness levels of sulfoxaflor-and acetamiprid-resistant strains were lower in Jinghe than in Yarkant.In summary,basal insecticide resistance of A.gossypii and insecticide type affected the evolution of resistance to insecticides in A.gossypii,as well as cross-resistance to other insecticides.The sulfoxaflor-and acetamiprid-resistant A.gossypii strains had obvious fitness costs.The results of this work will contribute to the insecticide resistance management and integrated management of A.gossypii.展开更多
Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lyi...Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains unre-solved.In this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent droughts.The results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since 1960.How-ever,the decreasing trend of earlywood BAI_(res) was higher than that of latewood.Climate response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,respectively.BAI_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly affected.Decreasing stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing season.Our study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.展开更多
Sediment constitutes the fundamental basis for forming and evolving aeolian geomorphology.The characteristics of sediment particle size offer insights into the development and evolution of sandy terrain,making their s...Sediment constitutes the fundamental basis for forming and evolving aeolian geomorphology.The characteristics of sediment particle size offer insights into the development and evolution of sandy terrain,making their study critical to understanding aeolian geomorphology and sand control.In this study,we combined high-density collection of surface sediments in the Uzhumqin sand dunes and GIS spatial analysis to analyze the particle size parameters and changes in the spatial distribution of surface sediments in this region.In addition,we used an end-member analysis to identify the potential sources of the sediments.The results showed that surface sediments in the Uzhumqin sand dunes had distinct spatial distributions.Medium and coarse grain sands dominated the sediments in the dunes,and the mean grain size and the sorting coefficient generally increased along the prevailing wind direction,with high values in individual areas related to factors such as material sources and vegetation cover.Skewness was strongly influenced by factors such as landform change and human activity,and spatial variability became more complex.Kurtosis and the soil fractal dimension showed generally decreasing trends along the prevailing wind direction.With dune fixation,the contents of clay and powder particles in the soil increased;the mean particle size,the sorting coefficient,and the fractal dimension of the soil gradually increased,and the skewness and kurtosis gradually decreased.The end-member analysis results indicated the existence of five end-members(EM)in the dune sediments.EM 1 was a mixed component of wind-deposited fine sands and nearby fluvial sediments.EM 2 was the main component of sediments in the study area and was the result of sorting lake sediments by wind action and by the local topography.EM 3 may be a product of river flood deposition.EM 4 and EM 5 had coarser grain sizes.EM 4 was a lake-phase sediment product influenced by topographic and vegetation cover factors,and EM 5 was primarily a river and lake sediment product modified by weathering.The sediment particle size results from the study area indicate that the sediment in the sandy region is generally coarse due to multiple factors,including topography,climate,hydrology,and human activity.Sandy material in the study area originated from nearby,with very little sand being transported from long distances.展开更多
The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control p...The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.展开更多
Environmental DNA(eDNA)has been used as an important tool for fish diversity analysis,which can greatly solve the problems in traditional survey methodology.However,little work has been done on the actual monitoring a...Environmental DNA(eDNA)has been used as an important tool for fish diversity analysis,which can greatly solve the problems in traditional survey methodology.However,little work has been done on the actual monitoring accuracy of eDNA.In this study,we analyzed the current status of fish resources in Erhai Lake in Yunnan,SW China,by dividing the lake into three sectors according to habitat differences,and compared the results of eDNA and traditional capture methods to investigate the shortcomings of the current analysis of eDNA results.A total of 27 fish species were detected by eDNA and traditional capture methods,including 20 and 19 fish species,respectively,and additional differences in fish composition between the two methods.The alpha diversity showed higher fish abundance and lower fish diversity by eDNA method compared to the traditional capture method,demonstrating that eDNA was not superior for use in fish diversity analysis.Fish community similarity analysis showed that community differences were generally significant for eDNA(P<0.05).RDA analysis indicated that environmental factors did not significantly affect fish communities monitored by the eDNA method.However,water temperature,aquatic plants,and water depth had significant(P<0.05)effects on fish communities in the traditional capture method,suggesting that eDNA results are insensitive to the effects of environmental factors.Our results illustrate the effectiveness of eDNA in fish identification and the issues in quantification compared to traditional capture methods.Therefore,combining eDNA with traditional methods is a more effective method for analyzing eDNA metabarcoding,following which the protocols of both quantitative methods can be designed to explore the regularity of eDNA quantification.展开更多
The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed.When solving problems wit...The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed.When solving problems within a time domain framework,the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water surface.This provides conditions for adding artificial damping layers.Using the Runge−Kutta method to solve equations related to time.An upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves upstream.Through the comparison with the available experimental data and other numerical methods,the present method is proved to have good mesh convergence,and satisfactory results can be obtained.The constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head waves.Numerical simulations are conducted on the effects of forward speed,different longitudinal and lateral distances on the motion response of two modified Wigley ships in head waves.Then further investigations are conducted on the effects of different ship types on the motion response.展开更多
China has made great achievements in industrial development and is transforming into a powerful manufacturing country.Meanwhile,the industrial land scale is also expanding.However,whether industrial structure upgradin...China has made great achievements in industrial development and is transforming into a powerful manufacturing country.Meanwhile,the industrial land scale is also expanding.However,whether industrial structure upgrading achieves the purpose of restraining industrial land expansion remains unanswered.By calculating the industrial land structure index(ILSI)and industrial land expansion scale(ILES),this study analyzed their temporal and spatial distribution characteristics at both regional and city levels from 2007to 2020 in China.Results show that industrial land expansion presents a different trend in the four regions,the ILES in the eastern region is the largest,and the speed of industrial land expansion has declined since 2013,but it has gradually increased since 2016.The ILSI of the eastern and central regions is higher than that of the western and northeastern regions.Furthermore,a spatial Durbin model(SDM)has been established to estimate the spatial effect of industrial structure upgrading on industrial land expansion from 2007 to2020.Notably,industrial structure upgrading has not slowed industrial land expansion.The eastern and western regions require a greater amount of industrial land while upgrading the industrial structure.The improvement of the infrastructure level and international trade level has promoted industrial land expansion.展开更多
Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a m...Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and intensities.China's grassland ecosystem includes most grassland types and is a good choice for studying this issue.This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.展开更多
Fossil remains of snakes in Quaternary localities are most often represented by vertebrae.Therefore,it is necessary to carry out a comparative study of the vertebrae of modern species in the areas of interest to ident...Fossil remains of snakes in Quaternary localities are most often represented by vertebrae.Therefore,it is necessary to carry out a comparative study of the vertebrae of modern species in the areas of interest to identify fossil materials.In this study,we examined 52 specimens of viperids(7 specimens of Gloydius intermedius,12 specimens of Gloydius ussuriensis,6 specimens of Gloydius halys,4 specimens of Vipera sakhalinensis,16 specimens of Vipera berus,and 7 specimens of Vipera renardi).The features of the trunk,cervical,cloacal and caudal vertebrae of 6 species from 2 genera are described.The vertebrae of the Viperidae are highly similar across species,with variation along the vertebral column.Nevertheless,they can be distinguished if their exact position within the vertebral column is known.The most important diagnostic feature is the shape of the hypapophysis,especially when identifying the cervical vertebrae.Among other morphological features,it is important to consider the shape of the ventral surface of the vertebra,prezygapophyseal and parapophyseal processes,neurapophysis,and zygapophysis.For the epistropheus,the position of the anterior edge of the neurapophysis in relation to the anterior edge of the neural arch is also significant.The caudal vertebrae bear the greatest resemblance.There is a significant overlap between the ratios of different measurements(indices)in different species.However,if an index is out of the overlapping zone,it is possible to identify a vertebra more or less accurately,especially when considering it in conjunction with other indices and morphological characteristics.展开更多
Climate warming is constantly causing hydro-meteorological perturbations,especially in high-altitude mountainous regions,which lead to the occurrences of landslides.The impact of climatic variables(i.e.,precipitation ...Climate warming is constantly causing hydro-meteorological perturbations,especially in high-altitude mountainous regions,which lead to the occurrences of landslides.The impact of climatic variables(i.e.,precipitation and temperature)on the distribution of landslides in the eastern regions of the Himalayas is poorly understood.To address this,the current study analyzes the relationship between the spatial distribution of landslide characteristics and climatic variables from 2013 to 2021.Google Earth Engine(GEE)was employed to make landslide inventories using satellite data.The results show that 2163,6927,and 9601 landslides were heterogeneously distributed across the study area in 2013,2017,and 2021,respectively.The maximum annual temperature was positively correlated with the distribution of landslides,whereas precipitation was found to have a non-significant impact on the landslide distribution.Spatially,most of the landslides occurred in areas with maximum annual precipitation ranging from 800 to 1600 mm and maximum annual temperature above 15℃.However,in certain regions,earthquake disruptions marginally affected the occurrence of landslides.Landslides were highly distributed in areas with elevations ranging between 3000 and 5000 m above sea level,and many landslides occurred near the lower permafrost limit and close to glaciers.The latter indicates that temperature change-induced freeze-thaw action influences landslides in the region.Temperature changes have shown a positive correlation with the number of landslides within elevations,indicating that temperature affects their spatial distribution.Various climate projections suggest that the region will experience further warming,which will increase the likelihood of landslides in the future.Thus,it is crucial to enhance ground observation capabilities and climate datasets to effectively monitor and mitigate landslide risks.展开更多
The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in t...The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis.In this study,we used meteorological data during 2013–2019 from the portable meteorological stations at five sites(site A on the edge of the oasis,sites B,C,and D in the DOTZ,and site O in the desert)in Dunhuang,China to analyze the near-surface wind field characteristics and their causes,as well as to reveal the key role of the DOTZ in oasis protection.The results showed that the mean wind speed,frequency of sand-driving wind,and directional variability of wind decreased from west to east within the DOTZ,and wind speed was significantly affected by air temperature.The terrain influenced the prevailing winds in the region,mainly from northeast and southwest.Only some areas adjacent to the oasis were controlled by southeasterly wind.This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference.At site D,the annual drift potential(DP)was 24.95 vector units(VU),indicating a low wind energy environment,and the resultant drift direction(RDD)showed obvious seasonal differences.Additionally,the DOTZ played an important buffering role between the desert and oasis.Compared with the desert,the mean wind speed in the oasis decreased by 64.98%,and the prevailing wind direction was more concentrated.The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.展开更多
Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expressi...Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expression of mutations linked to sex chromosomes.The extent of sex-bias in mortality may also be related to environmental conditions that influence offspring development and survival.Urban areas often provide poorer conditions for nestling development resulting in higher offspring mortality compared to natural areas,which may accelerate sex differences in offspring mortality in cities.To test this hypothesis,we examined the sex ratio of dead offspring in Great Tits(Parus major),using 427 samples of unhatched eggs and dead nestlings collected in two urban and two forest sites between 2013 and 2019.The ratio of males in the whole sample of dead offspring(56.9%)was significantly higher than expected by an 1:1 ratio,and the strongest sex biases were detected in urban areas(57.6%males)and in young nestlings(<14 days old,59.0%males).However,the sex ratios of dead offspring did not differ significantly among study sites and between offspring developmental stages.29.3%of unhatched eggs contained a visible embryo,and the proportion of embryo-containing unhatched eggs did not differ significantly between urban and forest study sites.These results suggest male-biased offspring mortality in Great Tits,and highlight the need of large datasets to detect subtle differences between habitats and developmental stages.展开更多
InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hinder...InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hindered due to its sensitivity to interfaces.In this study,we have achieved notable enhancement in the electrical performance of InSe transistors through interface engineering.We engineered an InSe/h-BN heterostructure,effectively suppressing dielectric layer-induced scattering.Additionally,we successfully established excellent metal-semiconductor contacts using graphene ribbons as a buffer layer.Through a methodical approach to interface engineering,our graphene/InSe/h-BN transistor demonstrates impressive on-state current,field-effect mobility,and on/off ratio at room temperature,reaching values as high as 1.1 mA/μm,904 cm^(2)·V^(-1)·s^(-1),and>10~6,respectively.Theoretical computations corroborate that the graphene/InSe heterostructure shows significant interlayer charge transfer and weak interlayer interaction,contributing to the enhanced performance of InSe transistors.This research offers a comprehensive strategy to elevate the electrical performance of InSe transistors,paving the way for their utilization in future electronic applications.展开更多
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant Nos.2021EEEVL0204 and 2018A02。
文摘As an important part of nonstructural components,the seismic response of indoor water supply pipes deserves much attention.This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete(RC)frame structure.Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance.Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions.A seismic fragility study of displacement demand is conducted based on numerical simulation.The acceleration response and displacement response of different combinations are compared.The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes.
基金We acknowledge the funding support from the National Natural Science Foundation of China(Grant No.42271148).
文摘Due to the presence of ice and unfrozen water in pores of frozen rock,the rock fracture behaviors are susceptible to temperature.In this study,the potential thawing-induced softening effects on the fracture behaviors of frozen rock is evaluated by testing the tension fracture toughness(KIC)of frozen rock at different temperatures(i.e.-20℃,-15℃,-12℃,-10℃,-8℃,-6℃,-4℃,-2℃,and 0℃).Acoustic emission(AE)and digital image correlation(DIC)methods are utilized to analyze the microcrack propagation during fracturing.The melting of pore ice is measured using nuclear magnetic resonance(NMR)method.The results indicate that:(1)The KIC of frozen rock decreases moderately between-20℃ and-4℃,and rapidly between-4℃ and 0℃.(2)At-20℃ to-4℃,the fracturing process,deduced from the DIC results at the notch tip,exhibits three stages:elastic deformation,microcrack propagation and microcrack coalescence.However,at-4℃e0℃,only the latter two stages are observed.(3)At-4℃e0℃,the AE activities during fracturing are less than that at-20℃ to-4℃,while more small events are reported.(4)The NMR results demonstrate a reverse variation trend in pore ice content with increasing temperature,that is,a moderate decrease is followed by a sharp decrease and-4℃ is exactly the critical temperature.Next,we interpret the thawing-induced softening effect by linking the evolution in microscopic structure of frozen rock with its macroscopic fracture behaviors as follow:from-20℃ to-4℃,the thickening of the unfrozen water film diminishes the cementation strength between ice and rock skeleton,leading to the decrease in fracture parameters.From-4℃ to 0℃,the cementation effect of ice almost vanishes,and the filling effect of pore ice is reduced significantly,which facilitates microcrack propagation and thus the easier fracture of frozen rocks.
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFC2806102)the National Natural Science Foundation of China(Grant Nos.52171287,52325107)+2 种基金High Tech Ship Research Project of Ministry of Industry and Information Technology(Grant Nos.2023GXB01-05-004-03,GXBZH2022-293)the Science Foundation for Distinguished Young Scholars of Shandong Province(Grant No.ZR2022JQ25)the Taishan Scholars Project(Grant No.tsqn201909063)。
文摘Leakages from subsea oil and gas equipment cause substantial economic losses and damage to marine ecosystem,so it is essential to locate the source of the leak.However,due to the complexity and variability of the marine environment,the signals collected by hydrophone contain a variety of noises,which makes it challenging to extract useful signals for localization.To solve this problem,a hydrophone denoising algorithm is proposed based on variational modal decomposition(VMD)with grey wolf optimization.First,the average envelope entropy is used as the fitness function of the grey wolf optimizer to find the optimal solution for the parameters K andα.Afterward,the VMD algorithm decomposes the original signal parameters to obtain the intrinsic mode functions(IMFs).Subsequently,the number of interrelationships between each IMF and the original signal was calculated,the threshold value was set,and the noise signal was removed to calculate the time difference using the valid signal obtained by reconstruction.Finally,the arrival time difference is used to locate the origin of the leak.The localization accuracy of the method in finding leaks is investigated experimentally by constructing a simulated leak test rig,and the effectiveness and feasibility of the method are verified.
文摘BACKGROUND Cardiovascular disease(CVD)is a leading cause of morbidity and mortality worldwide,the global burden of which is rising.It is still unclear the extent to which prediabetes contributes to the risk of CVD in various age brackets among adults.To develop a focused screening plan and treatment for Chinese adults with prediabetes,it is crucial to identify variations in the connection between prediabetes and the risk of CVD based on age.AIM To examine the clinical features of prediabetes and identify risk factors for CVD in different age groups in China.METHODS The cross-sectional study involved a total of 46239 participants from June 2007 through May 2008.A thorough evaluation was conducted.Individuals with prediabetes were categorized into two groups based on age.Chinese atherosclerotic CVD risk prediction model was employed to evaluate the risk of developing CVD over 10 years.Random forest was established in both age groups.SHapley Additive exPlanation method prioritized the importance of features from the perspective of assessment contribution.RESULTS In total,6948 people were diagnosed with prediabetes in this study.In prediabetes,prevalences of CVD were 5(0.29%)in the younger group and 148(2.85%)in the older group.Overall,11.11%of the younger group and 29.59% of the older group were intermediate/high-risk of CVD for prediabetes without CVD based on the Prediction for ASCVD Risk in China equation in ten years.In the younger age group,the 10-year risk of CVD was found to be more closely linked to family history of CVD rather than lifestyle,whereas in the older age group,resident status was more closely linked.CONCLUSION The susceptibility to CVD is age-specific in newly diagnosed prediabetes.It is necessary to develop targeted approaches for the prevention and management of CVD in adults across various age brackets.
文摘Alanine aminotransferase(ALT)serum levels increase because of hepatocellular damage.Metabolic dysfunction-associated fatty liver disease(MAFLD),which identifies steatotic liver disease(SLD)associated with≥2 metabolic abnormalities,has prominent sexual differences.The Metabolic Syndrome defines a cluster comprising abdominal obesity,altered glucose metabolism,dyslipidemia,and hypertension.Male sex,body mass index,glucose,lipids,ferritin,hypertension,and age independently predict ALT levels among blood donors.Over the last few decades,the reference range of ALT levels has been animatedly debated owing to attempts to update sex-specific reference ranges.With this backset,Chen et al have recently published a study which has two main findings.First,>80%of indi-viduals with MAFLD had normal ALT levels.Second,there was a linear increa-sing trend in the association between cumulative excess high-normal ALT levels and the rate of incident MAFLD.This study has biologically credible findings.However,it inaccurately considered sex differences in the MAFLD arena.Therefore,future studies on SLD owing to metabolic dysfunction should adopt locally determined and prospectively validated reference ranges of ALT and carefully consider sex differences in liver enzymes and MAFLD pathobiology.
基金funded by the International Science and Technology Cooperation Project of Jilin Provincial Department of Science and Technology(No.20230402078GH)。
文摘This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser.The airflow rate and pulse delay are the main experimental variables.The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing.The experimental results demonstrate that the expansion velocities of the plasma and combustion wave are influenced differently by the sideblowing airflow at different airflow rates(0.2 Ma,0.4 Ma,and 0.6 Ma).As the flow rate of the sideblow air stream increases,the initial expansion velocities of the plasma and combustion wave gradually decrease,and the side-blow air stream increasingly suppresses the plasma.It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action.Therefore,the side-blown airflow alone cannot completely clear the plasma.Depending on the delay conditions,the pressure of the side-blowing airflow,the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as the double combustion waves when using a nanosecond pulse laser.Both simulation and experimental results are consistent,indicating the potential for further exploration of fused silica targets in the laser field.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62071496,61901530,and 62061008)the Natural Science Foundation of Hunan Province of China(Grant No.2020JJ5767).
文摘In recent years,fractional-order chaotic maps have been paid more attention in publications because of the memory effect.This paper presents a novel variable-order fractional sine map(VFSM)based on the discrete fractional calculus.Specially,the order is defined as an iterative function that incorporates the current state of the system.By analyzing phase diagrams,time sequences,bifurcations,Lyapunov exponents and fuzzy entropy complexity,the dynamics of the proposed map are investigated comparing with the constant-order fractional sine map.The results reveal that the variable order has a good effect on improving the chaotic performance,and it enlarges the range of available parameter values as well as reduces non-chaotic windows.Multiple coexisting attractors also enrich the dynamics of VFSM and prove its sensitivity to initial values.Moreover,the sequence generated by the proposed map passes the statistical test for pseudorandom number and shows strong robustness to parameter estimation,which proves the potential applications in the field of information security.
基金supported by the National Key R&D Program of China(2022YFD1400300)the Open Fund of Key Laboratory of Integrated Pest Management on Crops in Northwestern Oasis,Ministry of Agriculture and Rural Affairs of China(KFJJ202204)the China Agriculture Research System(CARS-15-20)。
文摘Aphis gossypii has become increasingly difficult to manage due to its strong insecticide resistance.In the laboratory,we established sulfoxaflor-resistant and acetamiprid-resistant strains in two A.gossypii populations with different basal insecticide resistance levels,and evaluated the effects of basal insecticide resistance on the resistance development and cross-resistance,as well as differences in fitness.Under the same selection pressure,Yarkant A.gossypii(with low basal insecticide resistance)evolved resistance to sulfoxaflor and acetamiprid more quickly than Jinghe A.gossypii(with high basal insecticide resistance),and the evolution of A.gossypii resistance to sulfoxaflor developed faster than acetamiprid in both Yarkant and Jinghe,Xingjiang,China.The sulfoxaflor-resistant strains selected from Yarkant and Jinghe developed significant cross-resistance to acetamiprid,imidacloprid,thiamethoxam and pymetrozine;while the acetamiprid-resistant strains developed significant cross-resistance to sulfoxaflor,imidacloprid,thiamethoxam,pymetrozine,and chlorpyrifos.The relative fitness of A.gossypii decreased as the resistance to sulfoxaflor and acetamiprid developed.The relative fitness levels of the sulfoxaflor-resistant strains(Yarkant-SulR and Jinghe-SulR)were lower than those of the acetamipridresistant strains(Yarkant-AceR and Jinghe-AceR).In addition,the relative fitness levels of sulfoxaflor-and acetamiprid-resistant strains were lower in Jinghe than in Yarkant.In summary,basal insecticide resistance of A.gossypii and insecticide type affected the evolution of resistance to insecticides in A.gossypii,as well as cross-resistance to other insecticides.The sulfoxaflor-and acetamiprid-resistant A.gossypii strains had obvious fitness costs.The results of this work will contribute to the insecticide resistance management and integrated management of A.gossypii.
基金This study was supported by the National Natural Science Foundation of China(42277448,41971104 and 41807431)the National Science Foundation of Shaanxi Province(2019JQ-325)the Fundamental Research Funds for the Central Universities(GK201903068 and GK202206032).
文摘Episodes of drought-induced decline in tree growth and mortality are becoming more frequent as a result of climate warming and enhanced water stress in semi-arid areas.However,the ecophysiological mechanisms under-lying the impact of drought on tree growth remains unre-solved.In this study,earlywood and latewood tree-ring growth,δ^(13)C,andδ^(18)O chronologies of Picea mongolica from 1900 to 2013 were developed to clarify the intra-and inter-annual tree-ring growth responses to increasingly fre-quent droughts.The results indicate that annual basal area increment residuals(BAI_(res)),which removed tree age and size effects,have significantly decreased since 1960.How-ever,the decreasing trend of earlywood BAI_(res) was higher than that of latewood.Climate response analysis suggests that the dominant parameters for earlywood and latewood proxies(BAI_(res),δ^(13)C andδ^(18)O)were drought-related climate variables(Palmer drought severity index,temperature,rela-tive humidity,and vapor pressure deficit).The most signifi-cant period of earlywood and latewood proxies’responses to climate variables were focused on June-July and July-August,respectively.BAI_(res),andδ^(13)C were significantly affected by temperature and moisture conditions,whereasδ^(18)O was slightly affected.Decreasing stomatal conduct-ance due to drought outweighed the influence of increasing CO_(2) on intrinsic water use efficiency(iWUE),and ultimately led to a decline in BAI_(res).Compared to latewood,the faster decreasing BAI_(res) and smaller increasing iWUE of early-wood suggested trees were more vulnerable to water stress in the early growing season.Our study provides insights into the inter-and intra-annual mechanisms of tree-ring growth in semi-arid regions under rising CO_(2) and climate change.
基金This research was supported by the project"Research on Vegetation Restoration and Reconstruction Technology in the Ecologically Fragile Areas of Uzhumqin Sand Dunes"of the Science and Technology Program of Inner Mongolia Autonomous Region(2020GG0077).We are grateful to the Key Laboratory of Wind and Sand Physics and Sand Control Engineering of Inner Mongolia Autonomous Region for providing us with experimental equipment and space.We thank LetPub(www.letpub.com)for its linguistic assistance during the preparation of this manuscript.
文摘Sediment constitutes the fundamental basis for forming and evolving aeolian geomorphology.The characteristics of sediment particle size offer insights into the development and evolution of sandy terrain,making their study critical to understanding aeolian geomorphology and sand control.In this study,we combined high-density collection of surface sediments in the Uzhumqin sand dunes and GIS spatial analysis to analyze the particle size parameters and changes in the spatial distribution of surface sediments in this region.In addition,we used an end-member analysis to identify the potential sources of the sediments.The results showed that surface sediments in the Uzhumqin sand dunes had distinct spatial distributions.Medium and coarse grain sands dominated the sediments in the dunes,and the mean grain size and the sorting coefficient generally increased along the prevailing wind direction,with high values in individual areas related to factors such as material sources and vegetation cover.Skewness was strongly influenced by factors such as landform change and human activity,and spatial variability became more complex.Kurtosis and the soil fractal dimension showed generally decreasing trends along the prevailing wind direction.With dune fixation,the contents of clay and powder particles in the soil increased;the mean particle size,the sorting coefficient,and the fractal dimension of the soil gradually increased,and the skewness and kurtosis gradually decreased.The end-member analysis results indicated the existence of five end-members(EM)in the dune sediments.EM 1 was a mixed component of wind-deposited fine sands and nearby fluvial sediments.EM 2 was the main component of sediments in the study area and was the result of sorting lake sediments by wind action and by the local topography.EM 3 may be a product of river flood deposition.EM 4 and EM 5 had coarser grain sizes.EM 4 was a lake-phase sediment product influenced by topographic and vegetation cover factors,and EM 5 was primarily a river and lake sediment product modified by weathering.The sediment particle size results from the study area indicate that the sediment in the sandy region is generally coarse due to multiple factors,including topography,climate,hydrology,and human activity.Sandy material in the study area originated from nearby,with very little sand being transported from long distances.
基金supported by the National Natural Science Foundation of China(62273213,62073199,62103241)Natural Science Foundation of Shandong Province for Innovation and Development Joint Funds(ZR2022LZH001)+4 种基金Natural Science Foundation of Shandong Province(ZR2020MF095,ZR2021QF107)Taishan Scholarship Construction Engineeringthe Original Exploratory Program Project of National Natural Science Foundation of China(62250056)Major Basic Research of Natural Science Foundation of Shandong Province(ZR2021ZD14)High-level Talent Team Project of Qingdao West Coast New Area(RCTD-JC-2019-05)。
文摘The paper addresses the decentralized optimal control and stabilization problems for interconnected systems subject to asymmetric information.Compared with previous work,a closed-loop optimal solution to the control problem and sufficient and necessary conditions for the stabilization problem of the interconnected systems are given for the first time.The main challenge lies in three aspects:Firstly,the asymmetric information results in coupling between control and estimation and failure of the separation principle.Secondly,two extra unknown variables are generated by asymmetric information(different information filtration)when solving forward-backward stochastic difference equations.Thirdly,the existence of additive noise makes the study of mean-square boundedness an obstacle.The adopted technique is proving and assuming the linear form of controllers and establishing the equivalence between the two systems with and without additive noise.A dual-motor parallel drive system is presented to demonstrate the validity of the proposed algorithm.
基金Supported by the Project of Basic Investigation on Ecological Environment Quality of Erhai Lake(No.TPDL-2021-C 265)the Ecological Effects,Population Regulation and Management Strategies of Invasion of Japanese Smelt(Hypomesus nipponensis)in Erhai Lake funded by the government of Dali City,Yunnan Province,China(No.[2018]447)。
文摘Environmental DNA(eDNA)has been used as an important tool for fish diversity analysis,which can greatly solve the problems in traditional survey methodology.However,little work has been done on the actual monitoring accuracy of eDNA.In this study,we analyzed the current status of fish resources in Erhai Lake in Yunnan,SW China,by dividing the lake into three sectors according to habitat differences,and compared the results of eDNA and traditional capture methods to investigate the shortcomings of the current analysis of eDNA results.A total of 27 fish species were detected by eDNA and traditional capture methods,including 20 and 19 fish species,respectively,and additional differences in fish composition between the two methods.The alpha diversity showed higher fish abundance and lower fish diversity by eDNA method compared to the traditional capture method,demonstrating that eDNA was not superior for use in fish diversity analysis.Fish community similarity analysis showed that community differences were generally significant for eDNA(P<0.05).RDA analysis indicated that environmental factors did not significantly affect fish communities monitored by the eDNA method.However,water temperature,aquatic plants,and water depth had significant(P<0.05)effects on fish communities in the traditional capture method,suggesting that eDNA results are insensitive to the effects of environmental factors.Our results illustrate the effectiveness of eDNA in fish identification and the issues in quantification compared to traditional capture methods.Therefore,combining eDNA with traditional methods is a more effective method for analyzing eDNA metabarcoding,following which the protocols of both quantitative methods can be designed to explore the regularity of eDNA quantification.
基金supported by the National Natural Science Foundation of China(Grant Nos.52271278 and 52111530137)the Natural Science Found of Jiangsu Province(Grant No.BK20221389)the Newton Advanced Fellowships(Grant No.NAF\R1\180304)by the Royal Society.
文摘The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward speed.When solving problems within a time domain framework,the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water surface.This provides conditions for adding artificial damping layers.Using the Runge−Kutta method to solve equations related to time.An upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves upstream.Through the comparison with the available experimental data and other numerical methods,the present method is proved to have good mesh convergence,and satisfactory results can be obtained.The constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head waves.Numerical simulations are conducted on the effects of forward speed,different longitudinal and lateral distances on the motion response of two modified Wigley ships in head waves.Then further investigations are conducted on the effects of different ship types on the motion response.
基金Under the auspices of National Natural Science Foundation of China(No.72074181)National Social Science Foundation of China(No.20CJY023)Innovation Capability Support Program of Shaanxi(No.2021KJXX-12)。
文摘China has made great achievements in industrial development and is transforming into a powerful manufacturing country.Meanwhile,the industrial land scale is also expanding.However,whether industrial structure upgrading achieves the purpose of restraining industrial land expansion remains unanswered.By calculating the industrial land structure index(ILSI)and industrial land expansion scale(ILES),this study analyzed their temporal and spatial distribution characteristics at both regional and city levels from 2007to 2020 in China.Results show that industrial land expansion presents a different trend in the four regions,the ILES in the eastern region is the largest,and the speed of industrial land expansion has declined since 2013,but it has gradually increased since 2016.The ILSI of the eastern and central regions is higher than that of the western and northeastern regions.Furthermore,a spatial Durbin model(SDM)has been established to estimate the spatial effect of industrial structure upgrading on industrial land expansion from 2007 to2020.Notably,industrial structure upgrading has not slowed industrial land expansion.The eastern and western regions require a greater amount of industrial land while upgrading the industrial structure.The improvement of the infrastructure level and international trade level has promoted industrial land expansion.
基金the National Natural Science Foundation of China(42271289).
文摘Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and intensities.China's grassland ecosystem includes most grassland types and is a good choice for studying this issue.This study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.
文摘Fossil remains of snakes in Quaternary localities are most often represented by vertebrae.Therefore,it is necessary to carry out a comparative study of the vertebrae of modern species in the areas of interest to identify fossil materials.In this study,we examined 52 specimens of viperids(7 specimens of Gloydius intermedius,12 specimens of Gloydius ussuriensis,6 specimens of Gloydius halys,4 specimens of Vipera sakhalinensis,16 specimens of Vipera berus,and 7 specimens of Vipera renardi).The features of the trunk,cervical,cloacal and caudal vertebrae of 6 species from 2 genera are described.The vertebrae of the Viperidae are highly similar across species,with variation along the vertebral column.Nevertheless,they can be distinguished if their exact position within the vertebral column is known.The most important diagnostic feature is the shape of the hypapophysis,especially when identifying the cervical vertebrae.Among other morphological features,it is important to consider the shape of the ventral surface of the vertebra,prezygapophyseal and parapophyseal processes,neurapophysis,and zygapophysis.For the epistropheus,the position of the anterior edge of the neurapophysis in relation to the anterior edge of the neural arch is also significant.The caudal vertebrae bear the greatest resemblance.There is a significant overlap between the ratios of different measurements(indices)in different species.However,if an index is out of the overlapping zone,it is possible to identify a vertebra more or less accurately,especially when considering it in conjunction with other indices and morphological characteristics.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)(2019QZKK0903)the National Natural Science Foundation of China(No.42071017)the science and technology research program of the Chinese Academy of Sciences'Institute of Mountain Hazards and Environment(No.IMHE-ZDRW-03).
文摘Climate warming is constantly causing hydro-meteorological perturbations,especially in high-altitude mountainous regions,which lead to the occurrences of landslides.The impact of climatic variables(i.e.,precipitation and temperature)on the distribution of landslides in the eastern regions of the Himalayas is poorly understood.To address this,the current study analyzes the relationship between the spatial distribution of landslide characteristics and climatic variables from 2013 to 2021.Google Earth Engine(GEE)was employed to make landslide inventories using satellite data.The results show that 2163,6927,and 9601 landslides were heterogeneously distributed across the study area in 2013,2017,and 2021,respectively.The maximum annual temperature was positively correlated with the distribution of landslides,whereas precipitation was found to have a non-significant impact on the landslide distribution.Spatially,most of the landslides occurred in areas with maximum annual precipitation ranging from 800 to 1600 mm and maximum annual temperature above 15℃.However,in certain regions,earthquake disruptions marginally affected the occurrence of landslides.Landslides were highly distributed in areas with elevations ranging between 3000 and 5000 m above sea level,and many landslides occurred near the lower permafrost limit and close to glaciers.The latter indicates that temperature change-induced freeze-thaw action influences landslides in the region.Temperature changes have shown a positive correlation with the number of landslides within elevations,indicating that temperature affects their spatial distribution.Various climate projections suggest that the region will experience further warming,which will increase the likelihood of landslides in the future.Thus,it is crucial to enhance ground observation capabilities and climate datasets to effectively monitor and mitigate landslide risks.
基金the National Key Research and Development Program of China(2020YFA0608403)the National Natural Science Foundation of China(42171083)the Natural Science Foundation of Gansu Province,China(23JRRA601).
文摘The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis.In this study,we used meteorological data during 2013–2019 from the portable meteorological stations at five sites(site A on the edge of the oasis,sites B,C,and D in the DOTZ,and site O in the desert)in Dunhuang,China to analyze the near-surface wind field characteristics and their causes,as well as to reveal the key role of the DOTZ in oasis protection.The results showed that the mean wind speed,frequency of sand-driving wind,and directional variability of wind decreased from west to east within the DOTZ,and wind speed was significantly affected by air temperature.The terrain influenced the prevailing winds in the region,mainly from northeast and southwest.Only some areas adjacent to the oasis were controlled by southeasterly wind.This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference.At site D,the annual drift potential(DP)was 24.95 vector units(VU),indicating a low wind energy environment,and the resultant drift direction(RDD)showed obvious seasonal differences.Additionally,the DOTZ played an important buffering role between the desert and oasis.Compared with the desert,the mean wind speed in the oasis decreased by 64.98%,and the prevailing wind direction was more concentrated.The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.
基金financially supported by the Hungarian National Research,Development and Innovation Office(NKFIH,grant K132490 to AL and grant PD142106 to IP)by the HUN-REN Hungarian Research Network(grant 16007 to AL)by the Sustainable Development and Technologies National Programme of the Hungarian Academy of Sciences(NP2022-II-6/2022)。
文摘Sex-biased mortality can occur in birds during development,for example due to sexual differences in energy requirement and/or environmental sensitivity,or the effects of sex hormones or sex differences in the expression of mutations linked to sex chromosomes.The extent of sex-bias in mortality may also be related to environmental conditions that influence offspring development and survival.Urban areas often provide poorer conditions for nestling development resulting in higher offspring mortality compared to natural areas,which may accelerate sex differences in offspring mortality in cities.To test this hypothesis,we examined the sex ratio of dead offspring in Great Tits(Parus major),using 427 samples of unhatched eggs and dead nestlings collected in two urban and two forest sites between 2013 and 2019.The ratio of males in the whole sample of dead offspring(56.9%)was significantly higher than expected by an 1:1 ratio,and the strongest sex biases were detected in urban areas(57.6%males)and in young nestlings(<14 days old,59.0%males).However,the sex ratios of dead offspring did not differ significantly among study sites and between offspring developmental stages.29.3%of unhatched eggs contained a visible embryo,and the proportion of embryo-containing unhatched eggs did not differ significantly between urban and forest study sites.These results suggest male-biased offspring mortality in Great Tits,and highlight the need of large datasets to detect subtle differences between habitats and developmental stages.
基金the support of the National Natural Science Foundation of China (Grant No.62204030)supported in part by the National Natural Science Foundation of China (Grant Nos.62122036,62034004,61921005,61974176,and 12074176)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB44000000)。
文摘InSe has emerged as a promising candidate for next-generation electronics due to its predicted ultrahigh electrical performance.However,the efficacy of the InSe transistor in meeting application requirements is hindered due to its sensitivity to interfaces.In this study,we have achieved notable enhancement in the electrical performance of InSe transistors through interface engineering.We engineered an InSe/h-BN heterostructure,effectively suppressing dielectric layer-induced scattering.Additionally,we successfully established excellent metal-semiconductor contacts using graphene ribbons as a buffer layer.Through a methodical approach to interface engineering,our graphene/InSe/h-BN transistor demonstrates impressive on-state current,field-effect mobility,and on/off ratio at room temperature,reaching values as high as 1.1 mA/μm,904 cm^(2)·V^(-1)·s^(-1),and>10~6,respectively.Theoretical computations corroborate that the graphene/InSe heterostructure shows significant interlayer charge transfer and weak interlayer interaction,contributing to the enhanced performance of InSe transistors.This research offers a comprehensive strategy to elevate the electrical performance of InSe transistors,paving the way for their utilization in future electronic applications.