Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain unc...Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain uncertain in arid mountain ecosystems,where climosequences are quite different from other ecosystems.To address this gap,this study investigated the distribution determinants of microbial communities,C cycling-related genes,and SOC fractions along an elevational gradient(1707–3548 m),with a mean annual precipitation(MAP)range of 38 to 344 mm,on the north slope of the central part of the Kunlun Mountains,China using a metagenomic approach.The results showed that elevation significantly influenced the α-diversity(Shannon index)and composition of microbial communities as well as the C cycling-related genes.The α-diversities of microbial taxa and C cycling-related genes linearly increased with the increase in MAP along the elevational gradient.The elevational patterns of the genes encoding glycoside hydrolases and glycosyl transferases(GTs)were mainly driven by soil electrical conductivity(EC),mean annual temperature(MAT),MAP,and plant diversity.Furthermore,mineral-associated organic C(MAOC),particulate organic C(POC),and their sum generally increased with elevation.However,the MAOC/POC ratio followed a unimodal pattern,suggesting greater stability of the SOC pool in the mid-elevation regions.This unimodal pattern was likely influenced by the abundances of Actinobacteria and the genes encoding GTs and carbohydrate esterases and the threshold effects of soil EC and MAT.In summary,our findings indicate that the distribution patterns of microbial communities and C cycling-related genes along the elevational gradient in an arid ecosystem are distinct from those in the regions with higher MAP,facilitating the prediction of climate change effects on SOC metabolism under more arid conditions.Soil salinity,plant diversity,precipitation,and temperature are the main regulatory factors of microbial C metabolism processes,and they potentially play a central role in mediating SOC pool stability.展开更多
The aim of the study is to simulate actual operation of an elevator. First, it designed elevator scheduling algorithm for control ing operation of the elevator;second, it simulated elevator operation by the use of obj...The aim of the study is to simulate actual operation of an elevator. First, it designed elevator scheduling algorithm for control ing operation of the elevator;second, it simulated elevator operation by the use of object-oriented programming language, in which double buffering technology was used to solve the problem of elevator pictures flicker at refreshing; final y, test correctness and rationality of the system.展开更多
Compared to other crops,maize production demands relatively high temperatures.However,temperatures exceeding 35℃lead to adverse effects on maize yield.High temperatures(≥35℃)are consistently experienced by summer m...Compared to other crops,maize production demands relatively high temperatures.However,temperatures exceeding 35℃lead to adverse effects on maize yield.High temperatures(≥35℃)are consistently experienced by summer maize during its reproductive growth stage in the North China Plain,which is likely to cause irreversible crop damage.This study investigated the effects of elevating temperature(ET)treatment on the yield component of summer maize,beginning at the 9th unfolding leaf stage and ending at the tasseling stage.Results demonstrated that continuous ET led to a decrease in the elongation rate and activity of silks and an elongated interval between anthesis and silking stages,and eventually decreased grain number at ear tip and reduced yield.Although continuous ET before tasseling damaged the anther structure,reduced pollen activity,delayed the start of the pollen shedding stage,and shortened the pollen shedding time,it was inferred,based on phenotypical and physiological traits,that continuous ET after the 9th unfolding leaf stage influenced ears and therefore may have more significant impacts.Overall,when maize plants were exposed to ET treatment in the ear reproductive development stage,the growth of ears and tassels was blocked,which increased the occurrence of barren ear tips and led to large yield losses.展开更多
Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study,...Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.展开更多
An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in Chin...An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in China as the research object,a set of field tests was performed on Rizhao-Lankao High-Speed Railway,the bridge and ground vibrations were measured as trains passed at 330−340 km/h,then the transferring law and spatial distribution under individual frequencies were investigated.The experiment results indicate that the bridge frequency spectrum exhibited relatively high-frequency vibration peaks caused by short-wavelength irregularity;ground vibration farther than 30 m away can be amplified with a higher frequency and numerous components.Furthermore,the wave propagation equation of a stratified rock strata was established based on direct-stiffness method to explore the vibration attenuation rules via frequency-domain analysis.It is found that the rock area has a weaker correlation between vibration transmissibility and frequency,thicker and harder rock strata loss their vibration attenuation capacity.It can be concluded that the high-speed railways induced vibration on rock strata shows a wide frequency band and large amplitude,the design of reducing vibration aimed at specific frequency is important according to next more detailed numerical study.展开更多
Effects of cerium （Ce^3＋ ） on membranous protective enzymes in rape seedlings exposed to two levels of enhanced uhraviolet-B radiation （UV-B, 280 - 320 nm） were studied by hydroponics in the laboratory. The resul...Effects of cerium （Ce^3＋ ） on membranous protective enzymes in rape seedlings exposed to two levels of enhanced uhraviolet-B radiation （UV-B, 280 - 320 nm） were studied by hydroponics in the laboratory. The results show that the chlorophyll content decreases and membrane permeability increases in the leaves under UV-B irradiation with an intensity of 0.15 and 0.35 W·m^-2. The activities of SOD, CAT and POD are first increased and then decreased in leaves exposed to a low level of UV-B radiation. POD activity in leaves exposed to a high level of UV-B radiation is enhanced constantly. The sensitivities of these enzymes to UV-B radiation are SOD 〉 CAT 〉 POD. The injury by UV-B radiation on the functions of protective enzymes is lightened, their ability to scavenge radicals is improved, and the membrane permeability is maintained by Ce. Furthermore, the protective effect of cerium is more obvious in plants exposed to low levels of UV-B radiation than to high levels of it. Accordingly, all results prove that the protective effect of Ce on plants under UV-B radiation is realized through the protective system of plants.展开更多
A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless s...A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.展开更多
In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s ...In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s surface.Enhanced UV-B radiation affects ecosystems in manyways directly and indirectly. The responses can bebiochemical, physiological, morphological oranatomical, and the direction of the response can varybetween different species, communities andecosystems. In this paper we firstly introduce generalconcepts, and methods for measuring the ecologicaleffects of UV-B radiation. Secondly, we provide anoverview interpretation of the effects of enhancedUV-B on terrestrial ecosystems from recent studies.These studies include effects of UV-B on growth andreproduction, composition of communities,competitive balance, decomposition of litter, andinteractions with other factors etc. Finally, werecommend future research directions to identify theeffects of elevated UV-B radiation on ecosystems inChina.展开更多
Understanding the energy balance on the Tibetan Plateau is important for better prediction of global climate change. To characterize the energy balance on the Plateau, we examined the radiation balance and the respons...Understanding the energy balance on the Tibetan Plateau is important for better prediction of global climate change. To characterize the energy balance on the Plateau, we examined the radiation balance and the response of albedo to environmental factors above an alpine meadow and an alpine wetland surfaces in the eastern Tibetan Plateau, using 2014 data. Although our two sites belong to the same climatic background, and are close geographically, the annual incident solar radiation at the alpine meadow site(6,447 MJ/(m2·a)) was about 1.1 times that at the alpine wetland site(6,012 MJ/(m2·a)),due to differences in the cloudiness between our two sites. The alpine meadow and the alpine wetland emitted about 38%and 42%, respectively, of annual incident solar radiation back into atmosphere in the form of net longwave radiation; and they reflected about 22% and 18%, respectively, of the annual incident solar radiation back into atmosphere in the form of shortwave radiation. The annual net radiation was 2,648 and 2,544 MJ/(m2·a) for the alpine meadow site and the alpine wetland site, respectively, accounting for only about 40% of the annual incident solar radiation, significantly lower than the global mean. At 30-min scales, surface albedo exponentially decreases with the increase of the solar elevation angle; and it linearly decreases with the increase of soil-water content for our two sites. But those relationships are significantly influenced by cloudiness and are site-specific.展开更多
This paper studies the libration and stabilization of a parallel partial space elevator system in circular orbits. The system is made up of two paralleled partial space elevators, each of which consists of one main sa...This paper studies the libration and stabilization of a parallel partial space elevator system in circular orbits. The system is made up of two paralleled partial space elevators, each of which consists of one main satellite, one end body and a climber moving along the tether between them.The libration characteristics of the elevator are studied through numerical analysis by a new dynamic model, and a novel control strategy is proposed to stabilize the swing of the end body by projecting the climber speeds only. Optimal control method is used to implement the new control strategy in the case where the climbers move in opposite direction. The simulation results validate the effectiveness of the proposed control strategy whose application will neither sacrifice the transport efficiency nor exacerbate libration significantly.展开更多
Liver test abnormalities have been described in up to 60% of patients with systemic lupus erythematodes(SLE) at some point during the course of their disease.Prior treatment with potentially hepatotoxic drugs or viral...Liver test abnormalities have been described in up to 60% of patients with systemic lupus erythematodes(SLE) at some point during the course of their disease.Prior treatment with potentially hepatotoxic drugs or viral hepatitis is commonly considered to be the main cause of liver disease in SLE patients.However,in rare cases elevated liver enzymes may be due to concurrent autoimmune hepatitis(AIH).To distinguish whether the patient has primary liver disease with associated autoimmune clinical and laboratory features resembling SLE- such as AIH- or the elevation of liver enzymes is a manifestation of SLE remains a difficult challenge for the treating physician.Here,we present six female patients with complex autoimmune disorders and hepatitis.Patient charts were reviewed in order to investigate the complex relationship between SLE and AIH.All patients had coexisting autoimmune disease in their medical history.At the time of diagnosis of AIH,patients presented with arthralgia,abdominal complaints,cutaneous involvement and fatigue as common symptoms.All patients fulfilled the current diagnostic criteria of both,AIH and SLE.Remission of acute hepatitis was achieved in all cases after the initiation of immunosuppressive therapy.In addition to this case study a literature review was conducted.展开更多
We performed a meta-analysis on over 100 studies applying remote sensing(RS)and geographic information systems(GIS)to understand treeline dynamics.A literature search was performed in multiple online databases,includi...We performed a meta-analysis on over 100 studies applying remote sensing(RS)and geographic information systems(GIS)to understand treeline dynamics.A literature search was performed in multiple online databases,including Web of Knowledge(Thomson Reuters),Scopus(Elsevier),BASE(Bielefeld Academic Search Engine),CAB Direct,and Google Scholar using treeline-related queries.We found that RS and GIS use has steadily increased in treeline studies since 2000.Spatialresolution RS and satellite imaging techniques varied from low-resolution MODIS,moderate-resolution Landsat,to high-resolution WorldView and aerial orthophotos.Most papers published in the 1990s used low to moderate resolution sensors such as Landsat Multispectral Scanner and Thematic Mapper,or SPOT PAN(Panchromatic)and MX(Multispectral)RS images.Subsequently,we observed a rise in high-resolution satellite sensors such as ALOS,GeoEye,IKONOS,and WorldView for mapping current and potential treelines.Furthermore,we noticed a shift in emphasis of treeline studies over time:earlier reports focused on mapping treeline positions,whereas RS and GIS are now used to determine the factors that control treeline variation.展开更多
In this paper, three different controllers are proposed and simulated for maglev guiding systems to have convenient and smooth elevator motion. The proposed controllers are PID, sliding mode, and PID sliding mode cont...In this paper, three different controllers are proposed and simulated for maglev guiding systems to have convenient and smooth elevator motion. The proposed controllers are PID, sliding mode, and PID sliding mode controllers. The advantages and disadvantages of the proposed controllers are discussed. Although, PID controller is fast, its response affected considerably by external disturbances. Unlike PID, the sliding mode controller is so robust, but its transient is unsuitable based on application conditions. However, an acceptable controller for ropeless elevator guiding system should guaranty the passengers safety and convenient. Consequently, the response of the system should be fast, robust, and without considerable overshoots and oscillations. These required advantages are compromised in the proposed parallel PID sliding mode controller. The affectivity of the introduced controllers for maglev guiding system is investigated through conducted simulations in MATLAB/Simulink environment. The obtained results illustrate that PID sliding mode controller is a so fast and robust controller for a ropeless elevator maglev guiding system.展开更多
A fuzzy control scheme is presented according to the coal quantity in the main coal bunker, this method has a good dynamic response characteristic and is suited for complex nonlin-ear systems. The designation of self-...A fuzzy control scheme is presented according to the coal quantity in the main coal bunker, this method has a good dynamic response characteristic and is suited for complex nonlin-ear systems. The designation of self-adopting fuzzy controller, the working principle and functions of this system are also proposed, with the hardware and the main flow diagram of this system in-troduced in this paper.展开更多
Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas wit...Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas with complex topography, such as southwestern China. We investigated climatic effects on cropland water use efficiency in southwestern China at each 100-m elevation bin during 2001–2017. The maximum water use efficiency was 1.71 gC kg^(–1) H_2O for the 1900–1999 m elevation bin under the growing season temperature and precipitation of 14.58±0.32℃ and 965.40±136.45 mm, respectively. The water use efficiency slopes were dominated by the evapotranspiration slopes at elevations below 1999 m but were controlled by the gross primary productivity slopes at elevations above 2000 m. This difference was caused by the substantial responses of evaporation to climate change at lower elevations and the increased climatic sensitivity of gross primary productivity at higher elevations. In comparison to those at other elevations, croplands at lower elevations were more vulnerable to extreme drought because of the dominant role fluctuating evapotranspiration played in water use efficiency. The findings will improve cropland water management in the study area.展开更多
Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa ...Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa farms using cross-sectional data from areas ranging from 190 to 1021 m above sea level which were classified as low, medium, and high elevation in Davao City, considered as the chocolate capital of the Philippines. Using stochastic frontier analysis, the results showed that the cost of inputs per ha and the number of cocoa trees per ha significantly increase yield. Farms at high elevations were less technically efficient, as this entails lower temperatures and increased rainfall, and cocoa farming in those areas and conditions can be more challenging, especially with changes in farming practices, terrain, and distance to markets. Other significant variables were age of cocoa farms, married farmers, and age of the farmers. Older farms may be more developed, farmers who are married benefit from their spouses being able to readily contribute as farm labor, and lastly, older farmers' inefficiency may likely stem from nonadaptation of newer farming practices. With an average technical efficiency of 0.61, 0.63, and 0.26 in low, medium, and high elevation areas, respectively, farmers therefore have an incentive to improve farm practices and consider topographical variations found in high elevation areas. Recommendations for the improvement of technical efficiency of cocoa farms are better connectivity to markets, enhancing farm practices, and continuation and improvement of government programs on cocoa with an added emphasis on research. For farmers in high elevation areas, mitigating solutions such as sustainable agriculture practices and ecolabelling are key to improving efficiency and minimizing the potential negative impact on upland farming systems. Moreover, such adaptation measures may also contribute to sustainability of cocoa farming in high elevation areas.展开更多
European larch(Larix decidua) forests of the western Alps form extensivecultural landscapes whose resilience to global changes is currently unknown. Resilience describes the capacity of ecological systems to maintain ...European larch(Larix decidua) forests of the western Alps form extensivecultural landscapes whose resilience to global changes is currently unknown. Resilience describes the capacity of ecological systems to maintain the same state, i.e., the same function, processes, structure, and composition despite disturbances, environmental changes and internal fluctuations. Our aim is to explore the resilience of larch forests to changes in climate and land use in the western Italian Alps.To do so, we examined whether larch forests can be described as an alternative stable state in mountain forest ecosystems. We used tree basal area data obtained from field forest inventories in combination with topography, forest structure, land use, and climate information. We applied three different probabilistic methods: frequency distributions, logistic regressions, and potential analyses to infer the resilience of larch forests relative to that of other forest types.We found patters indicative of alternative stable states: bimodality in the frequency distribution of the percent of larch basal area, and the presence of an unstable state, i.e., mixed larch forests, in the potential analyses. We also found:(1) high frequency ofpurelarchforestsathighelevation,(2)the probability of pure larch forests increased mostly with elevation, and(3) pure larch forests were a stable state in the upper montane and subalpine belts.Our study shows that the resilience of larch forests may increase with elevation, most likely due to the altitudinal effect on climate. Under the same climate conditions, land use seems to be the main factor governing the dominance of larch forests. In fact, subalpine larch forests may be more resilient, and natural succession after land abandonment, e.g., towards Pinuscembra forests, seems slower than in montane larch forests. In contrast, in the upper montane belt only intense land use regimes characterized by open canopies and forest grazing may maintain larch forests.We conclude that similar approaches could be applied in other forest ecosystems to infer the resilience of tree species.展开更多
Elevators used in ultra-high buildings are prone to vibrating due to their ultra-long traction ropes,which significantly affects the comfort and safety of high-speed elevators.Therefore,vibration of the elevator has a...Elevators used in ultra-high buildings are prone to vibrating due to their ultra-long traction ropes,which significantly affects the comfort and safety of high-speed elevators.Therefore,vibration of the elevator has always been a topic of research interest.This paper presents a theoretical model for analyzing the tension–torsion coupling vibration of the time-varying elevator traction system.The constitutive relations with the tension–torsion coupling effect of the wire rope are reduced by analyzing the deformation mechanism of the spiral winding wire rope.Based on Hamilton’s principle,the equations of motion and corresponding boundary conditions for the tension–torsion coupling vibration of the elevator traction system are derived.The Galerkin method is employed to account for the influence of nonlinear boundary conditions and to transform the equations of motion into discrete ones with variable coefficients of time,which are solved using the Newmark-βmethod.The accuracy of the proposed model is justified by the good agreement between theoretical predictions and experimental results,following which,the influence of the operation status and structural parameters of the elevator traction system on its vibration performance is discussed in detail.展开更多
Agricultural practices are the main stay of the people of Uttranchal. Out of the total population, more than 75% people are engaged either with the main occupation of agriculture or its allied practices, dominated by ...Agricultural practices are the main stay of the people of Uttranchal. Out of the total population, more than 75% people are engaged either with the main occupation of agriculture or its allied practices, dominated by traditional subsistence cereal farming. Among them, the main crops are rice, wheat, millet, barley, all types of pulses, all types of oilseeds and almost all types of fruits. The crops, vegetables and fruits of all varieties are grown in the different climatic zones such as tropical, temperate, and cold because, the region is characterized by the different altitudinal zones elevated from 200 m to more than 8000m. As a result, different climates are found from hot tropical to sub temperate and chilly cold. Pulses varieties are grown extensively. Among vegetables, potato, onion, carrot, all types of green leaf vegetables, brinzal, pumpkin, ladyfinger, pea, gram, radish, ginger, garlic, etc, are grown widely. All fruit varieties are grown in the different altitudinal zones. The main fruits are orange, malta (a big size of orange), elephant citrus, lemon and all other types of citrus, apple, stone fruits including peach and pears, many kinds of nuts, and the fruits which are grown in the low lying areas. In spite of feasible climatic conditions, agricultural dominant society, and availability of all types of crops, the production and productivity of these crops are very low, even they are unable to meet the grain-need of the people in Uttaranchal. Agricultural crops are grown almost in all the altitudinal zones — from the low-lying areas, which are called ‘Gangarh’, to the highly elevated region, where the legendary term is given as ‘Danda’. The growing seasons vary according to the heights. The present paper aims to discuss the agricultural practices including cropping season, cropping pattern, land use, production of crops and ecological aspect of agricultural system in this Himalayan state and suggest some measures for developing farming system, which could lead the sustainability, in terms of meeting the food grain needs of the people on the one hand and restoring the ecological balance on the other.展开更多
Helicopters are often used in mountain rescue both for rescuers moving in the area of accidents and for evacuating victims, but in steep or forested terrain finding a landing place can be problematic. The main aim of ...Helicopters are often used in mountain rescue both for rescuers moving in the area of accidents and for evacuating victims, but in steep or forested terrain finding a landing place can be problematic. The main aim of this research is to use Digital Elevation Model(DEM) and cartographic database analysis to select locations that can be used as landing site for the rescue helicopters. Methods were based on GIS analysis;both raster and vector data were used for identifying touchdown points for rescue helicopters. Based on DEM data, locations with a low slope gradient were identified;topographic vector data were used for identifying unforested sites. Then buffer zones for buildings and power lines were excluded, and it was checked whether the areas had any topographic features that prevented helicopter landings. The findings were verified on an orthophotomap. In result, GIS analyses have selected 1232 polygons that fulfilled initial criteria. Their verification on orthophotomap has shown that only 55% of them could be potentially used as landing site. Landing sites can be found mainly on side ridges of mountain ranges and in valley beds, when those on ridges are most important in this research. The greatest difficulties and methodological challenges are posed by: identification of sites having a shape which prevents landing, the obsolescence of data due to environment dynamics, the presence of features that are not shown on maps but prevent helicopter landings. A map of landing sites is a very useful tool to conduct rescue operations, but each use of a given landing site requires both in-field and numerical verification. The analysis demonstrated that GIS toolsare useful in pre-planning of rescue missions, and also showed that such data must be kept up-to-date and in-field verification is needed continuously, the more so as it plays an important role in ensuring the safety of rescuers and victims.展开更多
基金sponsored by the Natural Science Foundation of Xinjiang Uygur Autonomous Region,China(No.2022D01B213)the Key Scientific and Technological Research Projects in the Xinjiang Production and Construction Corps,China(No.2023AB017-02)+1 种基金the West Light Foundation for Young Scholar of Chinese Academy of Sciences(No.2021-XBQNXZ-018)the National Key Research and Development Program of China(No.2022YFF1302504)。
文摘Understanding the elevational patterns of soil microbial carbon(C)metabolic potentials is instrumental for predicting changes in soil organic C(SOC)stocks in the face of climate change.However,such patterns remain uncertain in arid mountain ecosystems,where climosequences are quite different from other ecosystems.To address this gap,this study investigated the distribution determinants of microbial communities,C cycling-related genes,and SOC fractions along an elevational gradient(1707–3548 m),with a mean annual precipitation(MAP)range of 38 to 344 mm,on the north slope of the central part of the Kunlun Mountains,China using a metagenomic approach.The results showed that elevation significantly influenced the α-diversity(Shannon index)and composition of microbial communities as well as the C cycling-related genes.The α-diversities of microbial taxa and C cycling-related genes linearly increased with the increase in MAP along the elevational gradient.The elevational patterns of the genes encoding glycoside hydrolases and glycosyl transferases(GTs)were mainly driven by soil electrical conductivity(EC),mean annual temperature(MAT),MAP,and plant diversity.Furthermore,mineral-associated organic C(MAOC),particulate organic C(POC),and their sum generally increased with elevation.However,the MAOC/POC ratio followed a unimodal pattern,suggesting greater stability of the SOC pool in the mid-elevation regions.This unimodal pattern was likely influenced by the abundances of Actinobacteria and the genes encoding GTs and carbohydrate esterases and the threshold effects of soil EC and MAT.In summary,our findings indicate that the distribution patterns of microbial communities and C cycling-related genes along the elevational gradient in an arid ecosystem are distinct from those in the regions with higher MAP,facilitating the prediction of climate change effects on SOC metabolism under more arid conditions.Soil salinity,plant diversity,precipitation,and temperature are the main regulatory factors of microbial C metabolism processes,and they potentially play a central role in mediating SOC pool stability.
基金Supported by the Principal Fund Project of Tarim University(TDZKSSZD201207)~~
文摘The aim of the study is to simulate actual operation of an elevator. First, it designed elevator scheduling algorithm for control ing operation of the elevator;second, it simulated elevator operation by the use of object-oriented programming language, in which double buffering technology was used to solve the problem of elevator pictures flicker at refreshing; final y, test correctness and rationality of the system.
基金fnancially supported by the National Key Research and Development Program of China(2018YFD0300704)the Special Funds for Public Welfare Industry(Agriculture)Research,China(201203029)+1 种基金the Open Foundation of State Key Laboratory of Crop Biology in China(2019KF03)the Open Foundation of Chinese Academy of Agricultural Sciences,China/Key Laboratory of Crop Water Use and Regulation,Ministry of Agriculture and Rural Affairs,China(FIRI2019-02-0103)。
文摘Compared to other crops,maize production demands relatively high temperatures.However,temperatures exceeding 35℃lead to adverse effects on maize yield.High temperatures(≥35℃)are consistently experienced by summer maize during its reproductive growth stage in the North China Plain,which is likely to cause irreversible crop damage.This study investigated the effects of elevating temperature(ET)treatment on the yield component of summer maize,beginning at the 9th unfolding leaf stage and ending at the tasseling stage.Results demonstrated that continuous ET led to a decrease in the elongation rate and activity of silks and an elongated interval between anthesis and silking stages,and eventually decreased grain number at ear tip and reduced yield.Although continuous ET before tasseling damaged the anther structure,reduced pollen activity,delayed the start of the pollen shedding stage,and shortened the pollen shedding time,it was inferred,based on phenotypical and physiological traits,that continuous ET after the 9th unfolding leaf stage influenced ears and therefore may have more significant impacts.Overall,when maize plants were exposed to ET treatment in the ear reproductive development stage,the growth of ears and tassels was blocked,which increased the occurrence of barren ear tips and led to large yield losses.
基金funded by the Korea Green Promotion Agency, Korea Forest Service
文摘Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.
基金Project(2016YFE0205200)supported by the National Key Research and Development Program of ChinaProjects(U1734207,51978585)supported by the National Natural Science Foundation of China。
文摘An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in China as the research object,a set of field tests was performed on Rizhao-Lankao High-Speed Railway,the bridge and ground vibrations were measured as trains passed at 330−340 km/h,then the transferring law and spatial distribution under individual frequencies were investigated.The experiment results indicate that the bridge frequency spectrum exhibited relatively high-frequency vibration peaks caused by short-wavelength irregularity;ground vibration farther than 30 m away can be amplified with a higher frequency and numerous components.Furthermore,the wave propagation equation of a stratified rock strata was established based on direct-stiffness method to explore the vibration attenuation rules via frequency-domain analysis.It is found that the rock area has a weaker correlation between vibration transmissibility and frequency,thicker and harder rock strata loss their vibration attenuation capacity.It can be concluded that the high-speed railways induced vibration on rock strata shows a wide frequency band and large amplitude,the design of reducing vibration aimed at specific frequency is important according to next more detailed numerical study.
文摘Effects of cerium （Ce^3＋ ） on membranous protective enzymes in rape seedlings exposed to two levels of enhanced uhraviolet-B radiation （UV-B, 280 - 320 nm） were studied by hydroponics in the laboratory. The results show that the chlorophyll content decreases and membrane permeability increases in the leaves under UV-B irradiation with an intensity of 0.15 and 0.35 W·m^-2. The activities of SOD, CAT and POD are first increased and then decreased in leaves exposed to a low level of UV-B radiation. POD activity in leaves exposed to a high level of UV-B radiation is enhanced constantly. The sensitivities of these enzymes to UV-B radiation are SOD 〉 CAT 〉 POD. The injury by UV-B radiation on the functions of protective enzymes is lightened, their ability to scavenge radicals is improved, and the membrane permeability is maintained by Ce. Furthermore, the protective effect of cerium is more obvious in plants exposed to low levels of UV-B radiation than to high levels of it. Accordingly, all results prove that the protective effect of Ce on plants under UV-B radiation is realized through the protective system of plants.
基金Project (No. 50607016) supported by the National Natural ScienceFoundation of China
文摘A novel elevator door driven by tubular permanent magnet linear synchronous motor (TPMLSM) is presented. This TPMLSM applies axial magnet array topology of the secondary rod, air-cored armature windings and slotless structure of the forcer to improve the stability of the thrust. The influence of two major dimensions, the pitch and radius of the permanent magnet (PM), on magnetic field was studied and the best values were given by the finite element analysis (FEA). The magnetic field, back EMF and thrust of the motor were analyzed and the PM size was optimized to reduce the harmonic components of the magnetic field and improve the performance of the motor. Predicted results are validated by the experiment. It is shown that the performance of the motor and the novel elevator door system is satisfying.
基金the State Key Basic Research and Development Plan(G2000046802-05)the Chinese Academy of Sciencesfor Innovation Key Project(KSCX1-07-02-02)+1 种基金National Tackle-Key-Problem Project(2001BA606A-05-01) the"Western Light”Project of Chinese Academy of Sciences for Talent Plan.
文摘In the last three decades much researchhas been carried out to investigate the biologicaleffects of a thinning stratospheric ozone layeraccompanied by an enhanced level of solarultraviolet-B radiation at the Earth’s surface.Enhanced UV-B radiation affects ecosystems in manyways directly and indirectly. The responses can bebiochemical, physiological, morphological oranatomical, and the direction of the response can varybetween different species, communities andecosystems. In this paper we firstly introduce generalconcepts, and methods for measuring the ecologicaleffects of UV-B radiation. Secondly, we provide anoverview interpretation of the effects of enhancedUV-B on terrestrial ecosystems from recent studies.These studies include effects of UV-B on growth andreproduction, composition of communities,competitive balance, decomposition of litter, andinteractions with other factors etc. Finally, werecommend future research directions to identify theeffects of elevated UV-B radiation on ecosystems inChina.
基金supported by the National Natural Science Foundation of China (Grant Nos. 91537106, 41405016, 41275016, 91537104, and 41605011)
文摘Understanding the energy balance on the Tibetan Plateau is important for better prediction of global climate change. To characterize the energy balance on the Plateau, we examined the radiation balance and the response of albedo to environmental factors above an alpine meadow and an alpine wetland surfaces in the eastern Tibetan Plateau, using 2014 data. Although our two sites belong to the same climatic background, and are close geographically, the annual incident solar radiation at the alpine meadow site(6,447 MJ/(m2·a)) was about 1.1 times that at the alpine wetland site(6,012 MJ/(m2·a)),due to differences in the cloudiness between our two sites. The alpine meadow and the alpine wetland emitted about 38%and 42%, respectively, of annual incident solar radiation back into atmosphere in the form of net longwave radiation; and they reflected about 22% and 18%, respectively, of the annual incident solar radiation back into atmosphere in the form of shortwave radiation. The annual net radiation was 2,648 and 2,544 MJ/(m2·a) for the alpine meadow site and the alpine wetland site, respectively, accounting for only about 40% of the annual incident solar radiation, significantly lower than the global mean. At 30-min scales, surface albedo exponentially decreases with the increase of the solar elevation angle; and it linearly decreases with the increase of soil-water content for our two sites. But those relationships are significantly influenced by cloudiness and are site-specific.
基金supported by the Discovery Grant (No. RGPIN2018-05991)Discovery Accelerate Supplement Grant (No. RGPAS-2018-522709) of Natural Sciences and Engineering Research Council of CanadaGuangdong Basic and Applied Basic Research Foundation (No. 2019A1515111056)。
文摘This paper studies the libration and stabilization of a parallel partial space elevator system in circular orbits. The system is made up of two paralleled partial space elevators, each of which consists of one main satellite, one end body and a climber moving along the tether between them.The libration characteristics of the elevator are studied through numerical analysis by a new dynamic model, and a novel control strategy is proposed to stabilize the swing of the end body by projecting the climber speeds only. Optimal control method is used to implement the new control strategy in the case where the climbers move in opposite direction. The simulation results validate the effectiveness of the proposed control strategy whose application will neither sacrifice the transport efficiency nor exacerbate libration significantly.
文摘Liver test abnormalities have been described in up to 60% of patients with systemic lupus erythematodes(SLE) at some point during the course of their disease.Prior treatment with potentially hepatotoxic drugs or viral hepatitis is commonly considered to be the main cause of liver disease in SLE patients.However,in rare cases elevated liver enzymes may be due to concurrent autoimmune hepatitis(AIH).To distinguish whether the patient has primary liver disease with associated autoimmune clinical and laboratory features resembling SLE- such as AIH- or the elevation of liver enzymes is a manifestation of SLE remains a difficult challenge for the treating physician.Here,we present six female patients with complex autoimmune disorders and hepatitis.Patient charts were reviewed in order to investigate the complex relationship between SLE and AIH.All patients had coexisting autoimmune disease in their medical history.At the time of diagnosis of AIH,patients presented with arthralgia,abdominal complaints,cutaneous involvement and fatigue as common symptoms.All patients fulfilled the current diagnostic criteria of both,AIH and SLE.Remission of acute hepatitis was achieved in all cases after the initiation of immunosuppressive therapy.In addition to this case study a literature review was conducted.
基金supported by 2014-2019 Title V-PPOHA-#P031M1400412018/19 AY Faculty RSCA grant at CSU Dominguez Hills for summer funding
文摘We performed a meta-analysis on over 100 studies applying remote sensing(RS)and geographic information systems(GIS)to understand treeline dynamics.A literature search was performed in multiple online databases,including Web of Knowledge(Thomson Reuters),Scopus(Elsevier),BASE(Bielefeld Academic Search Engine),CAB Direct,and Google Scholar using treeline-related queries.We found that RS and GIS use has steadily increased in treeline studies since 2000.Spatialresolution RS and satellite imaging techniques varied from low-resolution MODIS,moderate-resolution Landsat,to high-resolution WorldView and aerial orthophotos.Most papers published in the 1990s used low to moderate resolution sensors such as Landsat Multispectral Scanner and Thematic Mapper,or SPOT PAN(Panchromatic)and MX(Multispectral)RS images.Subsequently,we observed a rise in high-resolution satellite sensors such as ALOS,GeoEye,IKONOS,and WorldView for mapping current and potential treelines.Furthermore,we noticed a shift in emphasis of treeline studies over time:earlier reports focused on mapping treeline positions,whereas RS and GIS are now used to determine the factors that control treeline variation.
文摘In this paper, three different controllers are proposed and simulated for maglev guiding systems to have convenient and smooth elevator motion. The proposed controllers are PID, sliding mode, and PID sliding mode controllers. The advantages and disadvantages of the proposed controllers are discussed. Although, PID controller is fast, its response affected considerably by external disturbances. Unlike PID, the sliding mode controller is so robust, but its transient is unsuitable based on application conditions. However, an acceptable controller for ropeless elevator guiding system should guaranty the passengers safety and convenient. Consequently, the response of the system should be fast, robust, and without considerable overshoots and oscillations. These required advantages are compromised in the proposed parallel PID sliding mode controller. The affectivity of the introduced controllers for maglev guiding system is investigated through conducted simulations in MATLAB/Simulink environment. The obtained results illustrate that PID sliding mode controller is a so fast and robust controller for a ropeless elevator maglev guiding system.
文摘A fuzzy control scheme is presented according to the coal quantity in the main coal bunker, this method has a good dynamic response characteristic and is suited for complex nonlin-ear systems. The designation of self-adopting fuzzy controller, the working principle and functions of this system are also proposed, with the hardware and the main flow diagram of this system in-troduced in this paper.
基金National Natural Science Foundation of China,No.41501054Scientific Research Foundation of Shandong Technology and Business University,No.BS201735Key Research Program of Frontier Sciences of the Chinese Academy of Sciences,No.QYZDB-SSW-DQC005。
文摘Understanding climatic effects on cropland water use efficiency at different elevations is imperative for managing agricultural water and production in response to ongoing climate change in climate-sensitive areas with complex topography, such as southwestern China. We investigated climatic effects on cropland water use efficiency in southwestern China at each 100-m elevation bin during 2001–2017. The maximum water use efficiency was 1.71 gC kg^(–1) H_2O for the 1900–1999 m elevation bin under the growing season temperature and precipitation of 14.58±0.32℃ and 965.40±136.45 mm, respectively. The water use efficiency slopes were dominated by the evapotranspiration slopes at elevations below 1999 m but were controlled by the gross primary productivity slopes at elevations above 2000 m. This difference was caused by the substantial responses of evaporation to climate change at lower elevations and the increased climatic sensitivity of gross primary productivity at higher elevations. In comparison to those at other elevations, croplands at lower elevations were more vulnerable to extreme drought because of the dominant role fluctuating evapotranspiration played in water use efficiency. The findings will improve cropland water management in the study area.
文摘Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa farms using cross-sectional data from areas ranging from 190 to 1021 m above sea level which were classified as low, medium, and high elevation in Davao City, considered as the chocolate capital of the Philippines. Using stochastic frontier analysis, the results showed that the cost of inputs per ha and the number of cocoa trees per ha significantly increase yield. Farms at high elevations were less technically efficient, as this entails lower temperatures and increased rainfall, and cocoa farming in those areas and conditions can be more challenging, especially with changes in farming practices, terrain, and distance to markets. Other significant variables were age of cocoa farms, married farmers, and age of the farmers. Older farms may be more developed, farmers who are married benefit from their spouses being able to readily contribute as farm labor, and lastly, older farmers' inefficiency may likely stem from nonadaptation of newer farming practices. With an average technical efficiency of 0.61, 0.63, and 0.26 in low, medium, and high elevation areas, respectively, farmers therefore have an incentive to improve farm practices and consider topographical variations found in high elevation areas. Recommendations for the improvement of technical efficiency of cocoa farms are better connectivity to markets, enhancing farm practices, and continuation and improvement of government programs on cocoa with an added emphasis on research. For farmers in high elevation areas, mitigating solutions such as sustainable agriculture practices and ecolabelling are key to improving efficiency and minimizing the potential negative impact on upland farming systems. Moreover, such adaptation measures may also contribute to sustainability of cocoa farming in high elevation areas.
文摘European larch(Larix decidua) forests of the western Alps form extensivecultural landscapes whose resilience to global changes is currently unknown. Resilience describes the capacity of ecological systems to maintain the same state, i.e., the same function, processes, structure, and composition despite disturbances, environmental changes and internal fluctuations. Our aim is to explore the resilience of larch forests to changes in climate and land use in the western Italian Alps.To do so, we examined whether larch forests can be described as an alternative stable state in mountain forest ecosystems. We used tree basal area data obtained from field forest inventories in combination with topography, forest structure, land use, and climate information. We applied three different probabilistic methods: frequency distributions, logistic regressions, and potential analyses to infer the resilience of larch forests relative to that of other forest types.We found patters indicative of alternative stable states: bimodality in the frequency distribution of the percent of larch basal area, and the presence of an unstable state, i.e., mixed larch forests, in the potential analyses. We also found:(1) high frequency ofpurelarchforestsathighelevation,(2)the probability of pure larch forests increased mostly with elevation, and(3) pure larch forests were a stable state in the upper montane and subalpine belts.Our study shows that the resilience of larch forests may increase with elevation, most likely due to the altitudinal effect on climate. Under the same climate conditions, land use seems to be the main factor governing the dominance of larch forests. In fact, subalpine larch forests may be more resilient, and natural succession after land abandonment, e.g., towards Pinuscembra forests, seems slower than in montane larch forests. In contrast, in the upper montane belt only intense land use regimes characterized by open canopies and forest grazing may maintain larch forests.We conclude that similar approaches could be applied in other forest ecosystems to infer the resilience of tree species.
基金supported by the Guangdong Natural Science Foundation(No.2021A1515012037).
文摘Elevators used in ultra-high buildings are prone to vibrating due to their ultra-long traction ropes,which significantly affects the comfort and safety of high-speed elevators.Therefore,vibration of the elevator has always been a topic of research interest.This paper presents a theoretical model for analyzing the tension–torsion coupling vibration of the time-varying elevator traction system.The constitutive relations with the tension–torsion coupling effect of the wire rope are reduced by analyzing the deformation mechanism of the spiral winding wire rope.Based on Hamilton’s principle,the equations of motion and corresponding boundary conditions for the tension–torsion coupling vibration of the elevator traction system are derived.The Galerkin method is employed to account for the influence of nonlinear boundary conditions and to transform the equations of motion into discrete ones with variable coefficients of time,which are solved using the Newmark-βmethod.The accuracy of the proposed model is justified by the good agreement between theoretical predictions and experimental results,following which,the influence of the operation status and structural parameters of the elevator traction system on its vibration performance is discussed in detail.
文摘Agricultural practices are the main stay of the people of Uttranchal. Out of the total population, more than 75% people are engaged either with the main occupation of agriculture or its allied practices, dominated by traditional subsistence cereal farming. Among them, the main crops are rice, wheat, millet, barley, all types of pulses, all types of oilseeds and almost all types of fruits. The crops, vegetables and fruits of all varieties are grown in the different climatic zones such as tropical, temperate, and cold because, the region is characterized by the different altitudinal zones elevated from 200 m to more than 8000m. As a result, different climates are found from hot tropical to sub temperate and chilly cold. Pulses varieties are grown extensively. Among vegetables, potato, onion, carrot, all types of green leaf vegetables, brinzal, pumpkin, ladyfinger, pea, gram, radish, ginger, garlic, etc, are grown widely. All fruit varieties are grown in the different altitudinal zones. The main fruits are orange, malta (a big size of orange), elephant citrus, lemon and all other types of citrus, apple, stone fruits including peach and pears, many kinds of nuts, and the fruits which are grown in the low lying areas. In spite of feasible climatic conditions, agricultural dominant society, and availability of all types of crops, the production and productivity of these crops are very low, even they are unable to meet the grain-need of the people in Uttaranchal. Agricultural crops are grown almost in all the altitudinal zones — from the low-lying areas, which are called ‘Gangarh’, to the highly elevated region, where the legendary term is given as ‘Danda’. The growing seasons vary according to the heights. The present paper aims to discuss the agricultural practices including cropping season, cropping pattern, land use, production of crops and ecological aspect of agricultural system in this Himalayan state and suggest some measures for developing farming system, which could lead the sustainability, in terms of meeting the food grain needs of the people on the one hand and restoring the ecological balance on the other.
文摘Helicopters are often used in mountain rescue both for rescuers moving in the area of accidents and for evacuating victims, but in steep or forested terrain finding a landing place can be problematic. The main aim of this research is to use Digital Elevation Model(DEM) and cartographic database analysis to select locations that can be used as landing site for the rescue helicopters. Methods were based on GIS analysis;both raster and vector data were used for identifying touchdown points for rescue helicopters. Based on DEM data, locations with a low slope gradient were identified;topographic vector data were used for identifying unforested sites. Then buffer zones for buildings and power lines were excluded, and it was checked whether the areas had any topographic features that prevented helicopter landings. The findings were verified on an orthophotomap. In result, GIS analyses have selected 1232 polygons that fulfilled initial criteria. Their verification on orthophotomap has shown that only 55% of them could be potentially used as landing site. Landing sites can be found mainly on side ridges of mountain ranges and in valley beds, when those on ridges are most important in this research. The greatest difficulties and methodological challenges are posed by: identification of sites having a shape which prevents landing, the obsolescence of data due to environment dynamics, the presence of features that are not shown on maps but prevent helicopter landings. A map of landing sites is a very useful tool to conduct rescue operations, but each use of a given landing site requires both in-field and numerical verification. The analysis demonstrated that GIS toolsare useful in pre-planning of rescue missions, and also showed that such data must be kept up-to-date and in-field verification is needed continuously, the more so as it plays an important role in ensuring the safety of rescuers and victims.
