With the increasing proportion of wind power integration, the volatility of wind power brings huge challenges to the safe and stable operation of the electric power system. At present, the indexes commonly used to eva...With the increasing proportion of wind power integration, the volatility of wind power brings huge challenges to the safe and stable operation of the electric power system. At present, the indexes commonly used to evaluate the volatility of wind power only consider its overall characteristics, such as the standard deviation of wind power, the average of power variables, etc., while ignoring the detailed volatility of wind power, that is, the features of the frequency distribution of power variables. However, how to accurately describe the detailed volatility of wind power is the key foundation to reduce its adverse influences. To address this, a quantitative method for evaluating the detailed volatility of wind power at multiple temporal-spatial scales is proposed. First, the volatility indexes which can evaluate the detailed fluctuation characteristics of wind power are presented, including the upper confidence limit, lower confidence limit and confidence interval of power variables under the certain confidence level. Then, the actual wind power data from a location in northern China is used to illustrate the application of the proposed indexes at multiple temporal(year–season–month–day) and spatial scales(wind turbine–wind turbines–wind farm–wind farms) using the calculation time windows of 10 min, 30 min, 1 h, and 4 h. Finally, the relationships between wind power forecasting accuracy and its corresponding detailed volatility are analyzed to further verify the effectiveness of the proposed indexes. The results show that the proposed volatility indexes can effectively characterize the detailed fluctuations of wind power at multiple temporal-spatial scales. It is anticipated that the results of this study will serve as an important reference for the reserve capacity planning and optimization dispatch in the electric power system which with a high proportion of renewable energy.展开更多
This study explores the essential issues pertaining to a landscape bridge based on a multi-scale methodology,in view of the paucity of design theories for contemporary landscape bridges.We contribute to reinterpret la...This study explores the essential issues pertaining to a landscape bridge based on a multi-scale methodology,in view of the paucity of design theories for contemporary landscape bridges.We contribute to reinterpret landscape bridges on their physical temporal-spatial scales,instead of from perspectives of individual disciplines or their mechanical cooperation.Envisaged in a new systematized framework,we elaborate the dominant and their opposite counterparts of landscape bridges from a binary deconstruction point of view,i.e.,(1)Development and retrogression on the temporal scale,(2)connection and separation on the spatial topographic scale,(3)skyphilia and topophilia on the spatial landscape scale,and(4)extroversion and introversion on the spatial architectural scale.The deconstructed multifaceted scales are instrumental in understanding landscape bridges from various perspectives,with a pyramid model proposed afterward to mediate the discovered oppositions and stimulate the cross-scale interactions.Various possible design paths could be derived from this well-organized and openminded multiple system,which is initially expected in this study to inspire bridge designers with dissimilar backgrounds and calls for a wider ramification.展开更多
Background:Excess submental fat(SMF)is a common facial aesthetic concern,and assessment scales play a crucial role in its evaluation.Existing SMF scales are based on Caucasian populations,although genetic background s...Background:Excess submental fat(SMF)is a common facial aesthetic concern,and assessment scales play a crucial role in its evaluation.Existing SMF scales are based on Caucasian populations,although genetic background significantly influences SMF distribution.Therefore,this study aimed to develop and validate a 5-point Chinese version of the Clinician-Reported Submental Fat Rating Scale(CR-SMFRS).Methods:The study included 150 volunteers,and captured photographs from the frontal,oblique,and lateral views were combined for each participant.A 5-point scale with descriptive criteria was primarily designed.Internal validation involved three experienced plastic surgeons,while external validation was conducted on 50 live volunteers by six additional raters.Intra-and inter-rater reliability were assessed.Results:A 5-point grading system with descriptive criteria was developed and validated as the Chinese CR-SMFRS.Internal validation demonstrated a good intra-and inter-rater consistency.During external validation,intraclass correlation coefficient values for each rater exceeded 0.850,indicating high intra-rater consistency.Moreover,the inter-rater reliability showed good consistency.Conclusion:The Chinese version of the SMF rating scale is a reliable tool for clinical use.展开更多
Multi-label image classification is a challenging task due to the diverse sizes and complex backgrounds of objects in images.Obtaining class-specific precise representations at different scales is a key aspect of feat...Multi-label image classification is a challenging task due to the diverse sizes and complex backgrounds of objects in images.Obtaining class-specific precise representations at different scales is a key aspect of feature representation.However,existing methods often rely on the single-scale deep feature,neglecting shallow and deeper layer features,which poses challenges when predicting objects of varying scales within the same image.Although some studies have explored multi-scale features,they rarely address the flow of information between scales or efficiently obtain class-specific precise representations for features at different scales.To address these issues,we propose a two-stage,three-branch Transformer-based framework.The first stage incorporates multi-scale image feature extraction and hierarchical scale attention.This design enables the model to consider objects at various scales while enhancing the flow of information across different feature scales,improving the model’s generalization to diverse object scales.The second stage includes a global feature enhancement module and a region selection module.The global feature enhancement module strengthens interconnections between different image regions,mitigating the issue of incomplete represen-tations,while the region selection module models the cross-modal relationships between image features and labels.Together,these components enable the efficient acquisition of class-specific precise feature representations.Extensive experiments on public datasets,including COCO2014,VOC2007,and VOC2012,demonstrate the effectiveness of our proposed method.Our approach achieves consistent performance gains of 0.3%,0.4%,and 0.2%over state-of-the-art methods on the three datasets,respectively.These results validate the reliability and superiority of our approach for multi-label image classification.展开更多
The impacts of lateral boundary conditions(LBCs)provided by numerical models and data-driven networks on convective-scale ensemble forecasts are investigated in this study.Four experiments are conducted on the Hangzho...The impacts of lateral boundary conditions(LBCs)provided by numerical models and data-driven networks on convective-scale ensemble forecasts are investigated in this study.Four experiments are conducted on the Hangzhou RDP(19th Hangzhou Asian Games Research Development Project on Convective-scale Ensemble Prediction and Application)testbed,with the LBCs respectively sourced from National Centers for Environmental Prediction(NCEP)Global Forecast System(GFS)forecasts with 33 vertical levels(Exp_GFS),Pangu forecasts with 13 vertical levels(Exp_Pangu),Fuxi forecasts with 13 vertical levels(Exp_Fuxi),and NCEP GFS forecasts with the vertical levels reduced to 13(the same as those of Exp_Pangu and Exp_Fuxi)(Exp_GFSRDV).In general,Exp_Pangu performs comparably to Exp_GFS,while Exp_Fuxi shows slightly inferior performance compared to Exp_Pangu,possibly due to its less accurate large-scale predictions.Therefore,the ability of using data-driven networks to efficiently provide LBCs for convective-scale ensemble forecasts has been demonstrated.Moreover,Exp_GFSRDV has the worst convective-scale forecasts among the four experiments,which indicates the potential improvement of using data-driven networks for LBCs by increasing the vertical levels of the networks.However,the ensemble spread of the four experiments barely increases with lead time.Thus,each experiment has insufficient ensemble spread to present realistic forecast uncertainties,which will be investigated in a future study.展开更多
Background:Mental health literacy(MHL)refers to one’s knowledge and understanding of mental health disorders and their treatments.This literacy may be influenced by cultural norms and values that shape individuals’e...Background:Mental health literacy(MHL)refers to one’s knowledge and understanding of mental health disorders and their treatments.This literacy may be influenced by cultural norms and values that shape individuals’experiences,beliefs,attitudes,and behaviors regarding mental health.This study focuses on adapting the Mental health literacy scale(MHLS)for use in the multicultural context of Israel.Objectives include validating its construct,assessing its accuracy in measuring MHL in this diverse setting and examining and comparing levels of MHL across different cultural groups.Methods:The data collection included 1057 participants,representing all the ethnic groups of the Israeli population aged 18 and over.The tools included the MHLS and a demographic questionnaire.Confirmatory factor analysis(CFA)was employed to assess the original structure of the MHLS.Results:The results revealed that after evaluating the original MHLS,five items were excluded,leading to the validation of a modified version—Israeli mental health scale(IMHLS)with four factors and 25 items.CFA and reliability analyses supported an established and robust four-factor model.Significant ethnic differences in MHLS scores were identified,with Muslim participants showing the highest familiarity with mental disorders,followed by Druze and Christian participants,while Jewish participants had the lowest familiarity.Conclusion:The study concluded that the IMHLS is a valid and reliable tool for assessing MHL in Israel’s diverse and multicultural population.The revised scale better reflects the cultural nuances of the Israeli context.The significant ethnic differences that the study revealed in IMHLS emphasize the importance of culturally sensitive mental health interventions tailored to different ethnic groups in Israel.展开更多
The spherically layered media theory has wide applications for electromagnetic wave scattering analysis.Due to the involved Bessel functions,the conventional formulations of spherically layered media theory suffer fro...The spherically layered media theory has wide applications for electromagnetic wave scattering analysis.Due to the involved Bessel functions,the conventional formulations of spherically layered media theory suffer from numerical overflow or underflow when the Bessel function’s order is large,the argument is small or the argument has a large imaginary part.The first two issues have been solved recently by employing small-argument asymptotic formulas of Bessel functions,while the third issue remains unsolved.In this paper,the Bessel functions in the conventional formulation of the theory are replaced by scaled Bessel functions which have good numerical properties for high loss media,and stable formulas are derived.Numerical tests show that this approach can work properly with very high lossy media.Also,this approach can be seamlessly combined with the stable computation method for cases of small argument and large order of Bessel functions.展开更多
Geological strength index(GSI)has been widely used as an input parameter in predicting the strength and deformation properties of rock masses.This study derived a series of equations to satisfy the original GSI lines ...Geological strength index(GSI)has been widely used as an input parameter in predicting the strength and deformation properties of rock masses.This study derived a series of equations to satisfy the original GSI lines on the basic GSI chart.Two axes ranging from 0 to 100 were employed for surface conditions of the discontinuities and the structure of rock mass,which are independent of the input parameters.The derived equations can analyze GSI values ranging from 0 to 100 within±5%error.The engineering dimensions(EDs)such as the slope height,tunnel width,and foundation width were used together with representative elementary volume(REV)in jointed rock mass to define scale factor(sf)from 0.2 to 1 in evaluating the rock mass structure including joint pattern.The transformation of GSI into a scaledependent parameter based on engineering scale addresses a crucial requirement in various engineering applications.The improvements proposed in this study were applied to a real slope which was close to the time of failure.The results of stability assessments show that the new proposals have sufficient capability to define rock mass quality considering EDs.展开更多
[Objective] This study aimed to analyze the temporal-spatial variation of Inner Mongolian grassland degradation during past three decades. [Method] The dis- tribution characteristics of grassland were described by lan...[Objective] This study aimed to analyze the temporal-spatial variation of Inner Mongolian grassland degradation during past three decades. [Method] The dis- tribution characteristics of grassland were described by land use types supervised classification with TM/ETM. Then, temporal-spatial changes of grassland coverage were quantified by the mean of maximum vegetation coverage in last 30 years. Lastly, the grassland degradation reasons were explored through statistic analysis between the grassland coverage and precipitation, temperature and grazing intensity. [Result] The grassland degradation index of Inner Mongolia was increased from 1.38 to 1.68, and the smallest was 1.28 in 2005s. Grassland degradation and improve- ment were concurrent after 1980s, but grassland degradation was the major change trend for Inner Mongolia grassland. The area of grassland degradation was enlarged from 18.08×10^4 km2 in 1980s to 22.47×10^4 km2 in 2010s on the whole and distribu- tion range was shifted from central-eastern to west in Inner Mongolia that mainly distributed on Hulun Buir and Xilin Gol grassland in 1980s and Ordos and Alax grassland in 2010s. The grassland area of degradation had a rising trend form 1980s to 1995s, then reduced to 10.8x104 km2 in 2005s, and decreased in 2010s, which mainly speared in the west of Xilin Gol grassland. [Conclusion] Inner Mongo-lian grassland degradation were become more seriously in last 30 years because that temperature, precipitation and graze intensities change, which not performance on decreasing coverage but grassland areas.展开更多
Irrigated agriculture in Cameroon is practiced on a large scale by large private firms and parastatals, and on a small scale by individual producers in different production areas of the country. Although small-scale i...Irrigated agriculture in Cameroon is practiced on a large scale by large private firms and parastatals, and on a small scale by individual producers in different production areas of the country. Although small-scale irrigation can supply local and sub-regional markets with food in the off-season, it has received little research and its challenges are therefore rarely addressed. In order to contribute to the knowledge of these small-scale irrigation systems, with a view to improving their structure and the management of irrigation water and energy, an assessment of small-scale irrigation in the southern slopes of the Bamboutos Mountains has been done. After direct observations, field measurements, surveys of 100 irrigators with questionnaires and interviews with administrative managers, analyses were carried out using Xlstat software. It was found out that about 226 small-scale irrigation systems designed and managed by producers have been installed on this slope between the end of December 2022 and mid-March 2023. Intended for market garden crops, 84.96% of these irrigation systems use sprinklers and 15.04% surface irrigation (furrow irrigation). Surface or underground water is mobilized using gravity (50%), fossil fuels (34.51%), electricity (14.6%) or solar energy (0.9%). Sprinkler irrigation is mainly carried out using locally manufactured hydraulic turnstiles. There is a lack of formal associations of irrigators in an environment marked by conflicts between water users, when there is not allocation for water withdrawal. Apart from the high cost of pumping energy ($1.32 per liter of fuel), the main constraint identified, which has become more acute over the years, is the lack of irrigation water during the water shortage period (from mid-January to mid-March). These constraints have led to a transition from surface irrigation to sprinkler irrigation, and the adoption of new energy supply and water mobilization technologies. The construction of collective surface and groundwater catchment structures with solar-powered pumping systems, the setting up of formal irrigators’ associations and an irrigation support service, could improve the availability of water throughout the irrigation season, thereby helping to improve the income generated by irrigated market-garden farming on the southern slopes of the Bamboutos Mountains.展开更多
[Objective] The aim was to study on temporal-spatial distribution model of cold chain logistics for vegetables. [Method] Broccoli was taken as an example. Detailedly, time-space distribution model of cold chain logist...[Objective] The aim was to study on temporal-spatial distribution model of cold chain logistics for vegetables. [Method] Broccoli was taken as an example. Detailedly, time-space distribution model of cold chain logistics for broccoli was proposed from standpoints of costs and benefits based on changes of time and space, and a comprehensive evaluation was made on timeliness, efficiency, risks, added- value of products and satisfaction of information in cold-chain logistics. [Result] The efficiency of cold chain logistics for vegetable can be greatly improved by temporal- spatial distribution model of cold chain logistics. [Conclusion] Costs and benefits of vegetables in temporal-apstial distribution could be evaluated by the model.展开更多
In global change research, changes of soil organic carbon (SOC) reservoirs intropical and subtropical regions are still unknown. The temporal-spatial variability of SOC stockswas determined in a basin of over 579 km^2...In global change research, changes of soil organic carbon (SOC) reservoirs intropical and subtropical regions are still unknown. The temporal-spatial variability of SOC stockswas determined in a basin of over 579 km^2 in subtropical China from 1981to 2002. ArcGIS8.l softwarewas utilized for spatial analysis of semivariance, ordinary kriging (OK), and probability kriging(PK). Grid and hierarchical approaches were employed for the sampling scenario in 2002 with 106Global Position System (GPS) established spots sampled. Bulk topsoil samples (0—30 cm) werecollected at three random sites on each spot. The SOC content for 1981 came from the SOC map of theSecond National Soil Survey. Geostatistical results of the nugget to sill ratio (0.215-0.640)in therehabilitating ecosystem indicated a moderate spatial dependence for SOC on this large scale. Therange of SOC changed from 2.04 km in 1981 to 7.15 km in 2002. The mean topsoil SOC increased by 4.6%from 10.63 g kg^(-1) (1981) to 11.12 g kg^(-1)(2002). However, during this 21-year period 25.2% ofthe total basin area experienced a decrease in SOC. Also, the probability kriging results showedthat the geometric mean probabilities of SOC <= 6.0 g kg^(-1), <= 11.0 g kg^(-1) and > 15.0 gkg^(-1) were 0.188, 0.534 and 0.378, respectively in 2002, comparing to 0.234, 0.416 and 0.234 inthat order in 1981, respectively. The SOC storage in the topsoil increased by 17.0% during this timewith the main increase occurring in forests and cultivated land,which amounted to 82.5% and 17.0%of the total increase, respectively.展开更多
Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the te...Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the temporal-spatial distribution and annual variation of sand-dust storms are analyzed on the basis of the case study of atmospheric processes. Furthermore, the tracks and source areas of sand-dust storms are determined with the aid of GIS. The results show that except some parts of Qinghai Province and Inner Mongolia as well as Beijing, sand-dust storms decrease apparently in time and space in recent decades in China. Sand-dust storms occur most frequently in spring, especially in April. According to their source areas, sand-dust storms are classified into two types, i.e., the inner-source and outer-source sand-dust storms. Most of the outer-source sand-dust storms move along the north and west tracks. The north-track outer-source sand-dust storms always intrude into China across the Sino-Mongolian border from Hami, a city in the eastern part ofXinjiang, to Xilin Gol, a league in Inner Mongolia, while the west-track ones intrude into China from both southern and northern Xinjiang. The source lands of inner-source sand-dust storms concentrate in the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in north of Xinjiang, the Hexi Corridor in western Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai.展开更多
Heavy metal contamination in soils has been of wide concern in China in the last several decades. The heavy metal contamination was caused by sewage irrigation, mining and inappropriate utilization of various agrochem...Heavy metal contamination in soils has been of wide concern in China in the last several decades. The heavy metal contamination was caused by sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides and so on. The Shenyang Zhangshi irrigation area （SZIA） in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years duration. This study investigated the spatial distribution and temporal variation of soil cadmium contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd of soils was analyzed and then the spatial distribution and temporal variation of Cd in soils was modelled using kriging methods. The kriging map showed that long-term sewage irrigation had caused serious Cd contamination in topsoil and subsoil. In 2004, the Cd mean concentrations were 1.698 and 0.741 mg/kg, and the maxima 10.150 and 7.567 mg/kg in topsoils （0-20 cm） and subsoils （20-40 cm） respectively. These values are markedly more than the Cd levels in the second grade soil standard in China. In 1990, the Cd means were 1.023 and 0.331 mg/kg, and the maxima 9.400 and 3.156 mg/kg, in topsoils and subsoils respectively. The soil area in 1990 with Cd more than 1.5 mg/kg was 2701 and 206.4 hnl2 in topsoils and subsoils respectively; and in 2004, it was 7592 and 1583 hm^2, respectively. Compared with that in 1990, the mean and maximum concentration of Cd, as well as the soil area with Cd more than 1.5 mg/kg had all increased in 2004, both in topsoils and subsoils.展开更多
The Huaihe River basin of Anhui is not only a transitional zone of physical geography, but also a convergent area of many cultures in China. It is one of the sensitive ecotones to global changes and the birthplace of ...The Huaihe River basin of Anhui is not only a transitional zone of physical geography, but also a convergent area of many cultures in China. It is one of the sensitive ecotones to global changes and the birthplace of Chinese civilization. Using the field archaeological data and the sporo-pollens and the age data of the drilling cores, we analysed Neolithic cultural development and environmental evolution in the Huaihe River basin of Anhui. According to the combination of some research results in archaeology with environmental evolution research, this paper discusses the relationship between culture and environment in the Huaihe River basin of Anhui. The Neolithic cultural development was strongly impacted by the environmental change. The primitive culture （Shishanzi） was developed in the beginning of the Holocene Megathermal Period with distinct regional feature of the culture. From 6.5 kaBP to 5.5 kaBP, the climate changed warmer and wetter. The frequent occurrence of flood and waterlog due to such a climate regime and high sea level caused the earth＇s surface environment deteriorated in the Huaihe River basin of Anhui and the interruption of the Neolithic cultural development, hence a lack of archaeological sites. From 5.5 kaBP to 4.0 kaBP, the climate changed from wet to dry, the natural environment was propitious to human survival. Dawenkou Culture and Longshan Culture flourished in this period. The Neolithic cultural development, the number of the sites and their distribution characteristics of the sites in the study area differed apparently from those in Central China and Shandong Province.展开更多
The long-term temporal and spatial dynamics of marine coastal water quality in Tolo Harbor, Hong Kong were explored. The Harbor is divided into three zones represented as Harbor, Buffer, and Channel Subzones. The time...The long-term temporal and spatial dynamics of marine coastal water quality in Tolo Harbor, Hong Kong were explored. The Harbor is divided into three zones represented as Harbor, Buffer, and Channel Subzones. The time range for the study covers the period from the 1970s to the 1990s. The selected indicators for the comprehensive assessment of water quality consist of physical, chemical and biological aspects, including suspended solids(SS), Secchi disk depth(SD), 5-day biochemical oxygen demand(BOD\-5), total nitrogen(TN), total phosphorus(TP), faecal coliform, chlorophyll-a(Chl-a), and the number of red tide occurrences. The results indicated the presence of obvious temporal and spatial trends with regard to changes in water quality. Spatially, water quality in the Channel Subzone is the best, while that in the Harbor Subzone is the worst. On a temporal basis, the average trend from bad to good was 1980s>1990s>1970s as indicated by most of the selected water quality indicators. Water quality during the late 1980s reached its worst level with the lowest SD, the highest BOD\-5, TN, TP, Chl-a concentrations, and the number of red tide occurrences. These long-term temporal-spatial water quality trends were also found in other studies of the Tolo Harbor. The large quantity of pollutants produced as a result of increasing population, industrial and commercial actives, and urbanization and industrialization trends in both Shatin and Tai Po seem to be primarily responsible for the changes in marine coastal water quality.展开更多
To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signa...To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signals is proposed. The cost function is constructed using 12-norm Gaussian entropy combined with an additional constraint, 12-norm constraint or linear constraint. By minimizing the cost functions in the temporal and the spatial dimensions using corresponding iteration algorithms respectively, the sparse discrete Fourier transforms （DFTs） of temporal and spatial samples are obtained to represent the extrapolated sequences with much larger sizes than the original samples. Then frequency and angle estimates are obtained by performing the traditional simple methods on the extrapolated sequences. It is shown that the proposed algorithm offers increased resolution and significantly reduced sidelobes compared with the periodogram and beamforming based methods. And it achieves high precision compared with the high-resolution method with lower computational burden. Some numerical simulations and real data processing results are presented to verify the effectiveness of the method.展开更多
Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temp...Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temporal-spatial patterns of foraging activities.It is of considerable importance to investigate the effect of these fluctuations on food availability for wintering Hooded Cranes and their foraging response to these changes.Understanding their behavior patterns is beneficial in protecting the wintering crane population and restoring their wintering habitats.Methods:A field survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014.Habitat variables,as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during five stages of water level fluctuation were collected.Based on this data we analyzed the relationship of foraging behavior relative to water level fluctuations and habitat types.Results:The foraging habitats used by Hooded Cranes varied at the different water level stages.As the water level decreased,the use of meadows and mudflats increased.When the water dropped to its lowest level,the use by the Hooded Crane in the mudflats reached a peak.There were statistically significant differences in time budget in the three types of habitats over the five stages of the water level.In the mudflats,the foraging behavior and maintenance behavior varied significantly with the water level,while the alert behavior showed little variation.Analysis of a generalized linear model showed that the five water level stages and three habitat types had a significant effect on foraging behavior,while the combined effect of these two variables was significant on the foraging time budget and the length of foraging activity of the Hooded Crane.Conclusions:With the decrease in the water level,the use of mudflats by Hooded Cranes increased correspondingly.Food availability in different habitats was affected by changes in the water level.The Hooded Crane adjusted its foraging patterns and made full use of the three available types of habitat in order to acquire enough food in response to fluctuations in the water level.展开更多
By using the variation coefficient,Gini coefficient and Theil coefficient,this paper makes preliminary exploration of temporalspatial change features and driving mechanism for regional differences of domestic tourism ...By using the variation coefficient,Gini coefficient and Theil coefficient,this paper makes preliminary exploration of temporalspatial change features and driving mechanism for regional differences of domestic tourism in China from 1995 to 2009.According to the results,we drew the following conclusions:(1)The regional difference of domestic tourism in China tends to be narrowing generally,and is less than that of inbound tourism,playing an important role in narrowing the overall gap of regional tourism in China.(2)The regional internal difference features:inter-provincial difference in the eastern region and difference among the eastern,central and western regions are comparatively obvious and demonstrate a significantly shrinking tendency,the change tendency is consistent with the change tendency of overall difference and exercises a decisive role in overall difference,whereas the inter-provincial difference in the central and western regions is small and relatively stable,having less influence on the overall difference.(3)The temporal-spatial change in regional difference is featured by:low-level provinces occupy a majority and are concentrated in the central and western regions,showing a tendency of narrowing difference;high-level provinces are concentrated in the eastern region,showing a tendency of spreading to the central and western regions;spatial pattern of regional difference demonstrates 4 types,i.e."proliferation type","polarization type","quiescence type"and"collapse type."(4)The driving force for regional difference of domestic tourism in China comes down to 3 aspects:regional socio-economic attribute,regional transport accessibility level and regional development policy.展开更多
基金supported in part by the National Key R&D Program of China (No.2017YFE0109000)the project of China Datang Corporation Ltd
文摘With the increasing proportion of wind power integration, the volatility of wind power brings huge challenges to the safe and stable operation of the electric power system. At present, the indexes commonly used to evaluate the volatility of wind power only consider its overall characteristics, such as the standard deviation of wind power, the average of power variables, etc., while ignoring the detailed volatility of wind power, that is, the features of the frequency distribution of power variables. However, how to accurately describe the detailed volatility of wind power is the key foundation to reduce its adverse influences. To address this, a quantitative method for evaluating the detailed volatility of wind power at multiple temporal-spatial scales is proposed. First, the volatility indexes which can evaluate the detailed fluctuation characteristics of wind power are presented, including the upper confidence limit, lower confidence limit and confidence interval of power variables under the certain confidence level. Then, the actual wind power data from a location in northern China is used to illustrate the application of the proposed indexes at multiple temporal(year–season–month–day) and spatial scales(wind turbine–wind turbines–wind farm–wind farms) using the calculation time windows of 10 min, 30 min, 1 h, and 4 h. Finally, the relationships between wind power forecasting accuracy and its corresponding detailed volatility are analyzed to further verify the effectiveness of the proposed indexes. The results show that the proposed volatility indexes can effectively characterize the detailed fluctuations of wind power at multiple temporal-spatial scales. It is anticipated that the results of this study will serve as an important reference for the reserve capacity planning and optimization dispatch in the electric power system which with a high proportion of renewable energy.
基金This work was supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX18_0162).
文摘This study explores the essential issues pertaining to a landscape bridge based on a multi-scale methodology,in view of the paucity of design theories for contemporary landscape bridges.We contribute to reinterpret landscape bridges on their physical temporal-spatial scales,instead of from perspectives of individual disciplines or their mechanical cooperation.Envisaged in a new systematized framework,we elaborate the dominant and their opposite counterparts of landscape bridges from a binary deconstruction point of view,i.e.,(1)Development and retrogression on the temporal scale,(2)connection and separation on the spatial topographic scale,(3)skyphilia and topophilia on the spatial landscape scale,and(4)extroversion and introversion on the spatial architectural scale.The deconstructed multifaceted scales are instrumental in understanding landscape bridges from various perspectives,with a pyramid model proposed afterward to mediate the discovered oppositions and stimulate the cross-scale interactions.Various possible design paths could be derived from this well-organized and openminded multiple system,which is initially expected in this study to inspire bridge designers with dissimilar backgrounds and calls for a wider ramification.
基金supported by the National High Level Hospital Clinical Research Funding(grant no.2022-PUMCH-A-208).
文摘Background:Excess submental fat(SMF)is a common facial aesthetic concern,and assessment scales play a crucial role in its evaluation.Existing SMF scales are based on Caucasian populations,although genetic background significantly influences SMF distribution.Therefore,this study aimed to develop and validate a 5-point Chinese version of the Clinician-Reported Submental Fat Rating Scale(CR-SMFRS).Methods:The study included 150 volunteers,and captured photographs from the frontal,oblique,and lateral views were combined for each participant.A 5-point scale with descriptive criteria was primarily designed.Internal validation involved three experienced plastic surgeons,while external validation was conducted on 50 live volunteers by six additional raters.Intra-and inter-rater reliability were assessed.Results:A 5-point grading system with descriptive criteria was developed and validated as the Chinese CR-SMFRS.Internal validation demonstrated a good intra-and inter-rater consistency.During external validation,intraclass correlation coefficient values for each rater exceeded 0.850,indicating high intra-rater consistency.Moreover,the inter-rater reliability showed good consistency.Conclusion:The Chinese version of the SMF rating scale is a reliable tool for clinical use.
基金supported by the National Natural Science Foundation of China(62302167,62477013)Natural Science Foundation of Shanghai(No.24ZR1456100)+1 种基金Science and Technology Commission of Shanghai Municipality(No.24DZ2305900)the Shanghai Municipal Special Fund for Promoting High-Quality Development of Industries(2211106).
文摘Multi-label image classification is a challenging task due to the diverse sizes and complex backgrounds of objects in images.Obtaining class-specific precise representations at different scales is a key aspect of feature representation.However,existing methods often rely on the single-scale deep feature,neglecting shallow and deeper layer features,which poses challenges when predicting objects of varying scales within the same image.Although some studies have explored multi-scale features,they rarely address the flow of information between scales or efficiently obtain class-specific precise representations for features at different scales.To address these issues,we propose a two-stage,three-branch Transformer-based framework.The first stage incorporates multi-scale image feature extraction and hierarchical scale attention.This design enables the model to consider objects at various scales while enhancing the flow of information across different feature scales,improving the model’s generalization to diverse object scales.The second stage includes a global feature enhancement module and a region selection module.The global feature enhancement module strengthens interconnections between different image regions,mitigating the issue of incomplete represen-tations,while the region selection module models the cross-modal relationships between image features and labels.Together,these components enable the efficient acquisition of class-specific precise feature representations.Extensive experiments on public datasets,including COCO2014,VOC2007,and VOC2012,demonstrate the effectiveness of our proposed method.Our approach achieves consistent performance gains of 0.3%,0.4%,and 0.2%over state-of-the-art methods on the three datasets,respectively.These results validate the reliability and superiority of our approach for multi-label image classification.
基金supported by the Strategic Research and Consulting Project of the Chinese Academy of Engineering[grant number 2024-XBZD-14]the National Natural Science Foundation of China[grant numbers 42192553 and 41922036]the Fundamental Research Funds for the Central Universities–Cemac“GeoX”Interdisciplinary Program[grant number 020714380207]。
文摘The impacts of lateral boundary conditions(LBCs)provided by numerical models and data-driven networks on convective-scale ensemble forecasts are investigated in this study.Four experiments are conducted on the Hangzhou RDP(19th Hangzhou Asian Games Research Development Project on Convective-scale Ensemble Prediction and Application)testbed,with the LBCs respectively sourced from National Centers for Environmental Prediction(NCEP)Global Forecast System(GFS)forecasts with 33 vertical levels(Exp_GFS),Pangu forecasts with 13 vertical levels(Exp_Pangu),Fuxi forecasts with 13 vertical levels(Exp_Fuxi),and NCEP GFS forecasts with the vertical levels reduced to 13(the same as those of Exp_Pangu and Exp_Fuxi)(Exp_GFSRDV).In general,Exp_Pangu performs comparably to Exp_GFS,while Exp_Fuxi shows slightly inferior performance compared to Exp_Pangu,possibly due to its less accurate large-scale predictions.Therefore,the ability of using data-driven networks to efficiently provide LBCs for convective-scale ensemble forecasts has been demonstrated.Moreover,Exp_GFSRDV has the worst convective-scale forecasts among the four experiments,which indicates the potential improvement of using data-driven networks for LBCs by increasing the vertical levels of the networks.However,the ensemble spread of the four experiments barely increases with lead time.Thus,each experiment has insufficient ensemble spread to present realistic forecast uncertainties,which will be investigated in a future study.
文摘Background:Mental health literacy(MHL)refers to one’s knowledge and understanding of mental health disorders and their treatments.This literacy may be influenced by cultural norms and values that shape individuals’experiences,beliefs,attitudes,and behaviors regarding mental health.This study focuses on adapting the Mental health literacy scale(MHLS)for use in the multicultural context of Israel.Objectives include validating its construct,assessing its accuracy in measuring MHL in this diverse setting and examining and comparing levels of MHL across different cultural groups.Methods:The data collection included 1057 participants,representing all the ethnic groups of the Israeli population aged 18 and over.The tools included the MHLS and a demographic questionnaire.Confirmatory factor analysis(CFA)was employed to assess the original structure of the MHLS.Results:The results revealed that after evaluating the original MHLS,five items were excluded,leading to the validation of a modified version—Israeli mental health scale(IMHLS)with four factors and 25 items.CFA and reliability analyses supported an established and robust four-factor model.Significant ethnic differences in MHLS scores were identified,with Muslim participants showing the highest familiarity with mental disorders,followed by Druze and Christian participants,while Jewish participants had the lowest familiarity.Conclusion:The study concluded that the IMHLS is a valid and reliable tool for assessing MHL in Israel’s diverse and multicultural population.The revised scale better reflects the cultural nuances of the Israeli context.The significant ethnic differences that the study revealed in IMHLS emphasize the importance of culturally sensitive mental health interventions tailored to different ethnic groups in Israel.
文摘The spherically layered media theory has wide applications for electromagnetic wave scattering analysis.Due to the involved Bessel functions,the conventional formulations of spherically layered media theory suffer from numerical overflow or underflow when the Bessel function’s order is large,the argument is small or the argument has a large imaginary part.The first two issues have been solved recently by employing small-argument asymptotic formulas of Bessel functions,while the third issue remains unsolved.In this paper,the Bessel functions in the conventional formulation of the theory are replaced by scaled Bessel functions which have good numerical properties for high loss media,and stable formulas are derived.Numerical tests show that this approach can work properly with very high lossy media.Also,this approach can be seamlessly combined with the stable computation method for cases of small argument and large order of Bessel functions.
文摘Geological strength index(GSI)has been widely used as an input parameter in predicting the strength and deformation properties of rock masses.This study derived a series of equations to satisfy the original GSI lines on the basic GSI chart.Two axes ranging from 0 to 100 were employed for surface conditions of the discontinuities and the structure of rock mass,which are independent of the input parameters.The derived equations can analyze GSI values ranging from 0 to 100 within±5%error.The engineering dimensions(EDs)such as the slope height,tunnel width,and foundation width were used together with representative elementary volume(REV)in jointed rock mass to define scale factor(sf)from 0.2 to 1 in evaluating the rock mass structure including joint pattern.The transformation of GSI into a scaledependent parameter based on engineering scale addresses a crucial requirement in various engineering applications.The improvements proposed in this study were applied to a real slope which was close to the time of failure.The results of stability assessments show that the new proposals have sufficient capability to define rock mass quality considering EDs.
基金Supported by National Program on Key Basic Research Project of China (2011CB403206)National Key Technology Research and Development Program during the 12~(th) Five-year Plan Period of China(2012BAC19B04)~~
文摘[Objective] This study aimed to analyze the temporal-spatial variation of Inner Mongolian grassland degradation during past three decades. [Method] The dis- tribution characteristics of grassland were described by land use types supervised classification with TM/ETM. Then, temporal-spatial changes of grassland coverage were quantified by the mean of maximum vegetation coverage in last 30 years. Lastly, the grassland degradation reasons were explored through statistic analysis between the grassland coverage and precipitation, temperature and grazing intensity. [Result] The grassland degradation index of Inner Mongolia was increased from 1.38 to 1.68, and the smallest was 1.28 in 2005s. Grassland degradation and improve- ment were concurrent after 1980s, but grassland degradation was the major change trend for Inner Mongolia grassland. The area of grassland degradation was enlarged from 18.08×10^4 km2 in 1980s to 22.47×10^4 km2 in 2010s on the whole and distribu- tion range was shifted from central-eastern to west in Inner Mongolia that mainly distributed on Hulun Buir and Xilin Gol grassland in 1980s and Ordos and Alax grassland in 2010s. The grassland area of degradation had a rising trend form 1980s to 1995s, then reduced to 10.8x104 km2 in 2005s, and decreased in 2010s, which mainly speared in the west of Xilin Gol grassland. [Conclusion] Inner Mongo-lian grassland degradation were become more seriously in last 30 years because that temperature, precipitation and graze intensities change, which not performance on decreasing coverage but grassland areas.
文摘Irrigated agriculture in Cameroon is practiced on a large scale by large private firms and parastatals, and on a small scale by individual producers in different production areas of the country. Although small-scale irrigation can supply local and sub-regional markets with food in the off-season, it has received little research and its challenges are therefore rarely addressed. In order to contribute to the knowledge of these small-scale irrigation systems, with a view to improving their structure and the management of irrigation water and energy, an assessment of small-scale irrigation in the southern slopes of the Bamboutos Mountains has been done. After direct observations, field measurements, surveys of 100 irrigators with questionnaires and interviews with administrative managers, analyses were carried out using Xlstat software. It was found out that about 226 small-scale irrigation systems designed and managed by producers have been installed on this slope between the end of December 2022 and mid-March 2023. Intended for market garden crops, 84.96% of these irrigation systems use sprinklers and 15.04% surface irrigation (furrow irrigation). Surface or underground water is mobilized using gravity (50%), fossil fuels (34.51%), electricity (14.6%) or solar energy (0.9%). Sprinkler irrigation is mainly carried out using locally manufactured hydraulic turnstiles. There is a lack of formal associations of irrigators in an environment marked by conflicts between water users, when there is not allocation for water withdrawal. Apart from the high cost of pumping energy ($1.32 per liter of fuel), the main constraint identified, which has become more acute over the years, is the lack of irrigation water during the water shortage period (from mid-January to mid-March). These constraints have led to a transition from surface irrigation to sprinkler irrigation, and the adoption of new energy supply and water mobilization technologies. The construction of collective surface and groundwater catchment structures with solar-powered pumping systems, the setting up of formal irrigators’ associations and an irrigation support service, could improve the availability of water throughout the irrigation season, thereby helping to improve the income generated by irrigated market-garden farming on the southern slopes of the Bamboutos Mountains.
基金Supported by Tianjin Science and Technology Development Project (060YFGNC1900)National Key Technology R&D Program in the 11th Five-year Plan of China(2012BAD38B01)~~
文摘[Objective] The aim was to study on temporal-spatial distribution model of cold chain logistics for vegetables. [Method] Broccoli was taken as an example. Detailedly, time-space distribution model of cold chain logistics for broccoli was proposed from standpoints of costs and benefits based on changes of time and space, and a comprehensive evaluation was made on timeliness, efficiency, risks, added- value of products and satisfaction of information in cold-chain logistics. [Result] The efficiency of cold chain logistics for vegetable can be greatly improved by temporal- spatial distribution model of cold chain logistics. [Conclusion] Costs and benefits of vegetables in temporal-apstial distribution could be evaluated by the model.
基金Project supported by the National Key Basic Research Support Foundation of China (No. G1999011801) the Knowledge Innovation Program of Chinese Acacemy of Sciences (Nos. KZCX2-413 and ISSASIP0110).
文摘In global change research, changes of soil organic carbon (SOC) reservoirs intropical and subtropical regions are still unknown. The temporal-spatial variability of SOC stockswas determined in a basin of over 579 km^2 in subtropical China from 1981to 2002. ArcGIS8.l softwarewas utilized for spatial analysis of semivariance, ordinary kriging (OK), and probability kriging(PK). Grid and hierarchical approaches were employed for the sampling scenario in 2002 with 106Global Position System (GPS) established spots sampled. Bulk topsoil samples (0—30 cm) werecollected at three random sites on each spot. The SOC content for 1981 came from the SOC map of theSecond National Soil Survey. Geostatistical results of the nugget to sill ratio (0.215-0.640)in therehabilitating ecosystem indicated a moderate spatial dependence for SOC on this large scale. Therange of SOC changed from 2.04 km in 1981 to 7.15 km in 2002. The mean topsoil SOC increased by 4.6%from 10.63 g kg^(-1) (1981) to 11.12 g kg^(-1)(2002). However, during this 21-year period 25.2% ofthe total basin area experienced a decrease in SOC. Also, the probability kriging results showedthat the geometric mean probabilities of SOC <= 6.0 g kg^(-1), <= 11.0 g kg^(-1) and > 15.0 gkg^(-1) were 0.188, 0.534 and 0.378, respectively in 2002, comparing to 0.234, 0.416 and 0.234 inthat order in 1981, respectively. The SOC storage in the topsoil increased by 17.0% during this timewith the main increase occurring in forests and cultivated land,which amounted to 82.5% and 17.0%of the total increase, respectively.
基金National Key Developing Program for Basic Sciences, No. G1999043505
文摘Sand-dust storm is a special natural disaster that frequently occurs in deserts and their surrounding areas. With the data published onSurface Meteorological Monthly Bulletin andSurface Chart during 1971–1996, the temporal-spatial distribution and annual variation of sand-dust storms are analyzed on the basis of the case study of atmospheric processes. Furthermore, the tracks and source areas of sand-dust storms are determined with the aid of GIS. The results show that except some parts of Qinghai Province and Inner Mongolia as well as Beijing, sand-dust storms decrease apparently in time and space in recent decades in China. Sand-dust storms occur most frequently in spring, especially in April. According to their source areas, sand-dust storms are classified into two types, i.e., the inner-source and outer-source sand-dust storms. Most of the outer-source sand-dust storms move along the north and west tracks. The north-track outer-source sand-dust storms always intrude into China across the Sino-Mongolian border from Hami, a city in the eastern part ofXinjiang, to Xilin Gol, a league in Inner Mongolia, while the west-track ones intrude into China from both southern and northern Xinjiang. The source lands of inner-source sand-dust storms concentrate in the Taklimakan Desert and its surrounding areas in southern Xinjiang, southern part of the Junggar Basin in north of Xinjiang, the Hexi Corridor in western Gansu Province, the dry deserts of Inner Mongolia and the Qaidam Basin in Qinghai.
基金The National Natural Science Foundation of China (No. 20477029)the National Basic Research Program (973) of China (No.2004CB418506)the Basic Research Program of Educational Department of Liaoning Government (No. 05L262)
文摘Heavy metal contamination in soils has been of wide concern in China in the last several decades. The heavy metal contamination was caused by sewage irrigation, mining and inappropriate utilization of various agrochemicals and pesticides and so on. The Shenyang Zhangshi irrigation area （SZIA） in China is a representative area of heavy metal contamination of soils resulting from sewage irrigation for about 30 years duration. This study investigated the spatial distribution and temporal variation of soil cadmium contamination in the SZIA. The soil samples were collected from the SZIA in 1990 and 2004; Cd of soils was analyzed and then the spatial distribution and temporal variation of Cd in soils was modelled using kriging methods. The kriging map showed that long-term sewage irrigation had caused serious Cd contamination in topsoil and subsoil. In 2004, the Cd mean concentrations were 1.698 and 0.741 mg/kg, and the maxima 10.150 and 7.567 mg/kg in topsoils （0-20 cm） and subsoils （20-40 cm） respectively. These values are markedly more than the Cd levels in the second grade soil standard in China. In 1990, the Cd means were 1.023 and 0.331 mg/kg, and the maxima 9.400 and 3.156 mg/kg, in topsoils and subsoils respectively. The soil area in 1990 with Cd more than 1.5 mg/kg was 2701 and 206.4 hnl2 in topsoils and subsoils respectively; and in 2004, it was 7592 and 1583 hm^2, respectively. Compared with that in 1990, the mean and maximum concentration of Cd, as well as the soil area with Cd more than 1.5 mg/kg had all increased in 2004, both in topsoils and subsoils.
基金National Natural Science Foundation of China, No.40271103 Natural Science Foundation of Anhui Provincial Education Department, No.2005KJ202/021
文摘The Huaihe River basin of Anhui is not only a transitional zone of physical geography, but also a convergent area of many cultures in China. It is one of the sensitive ecotones to global changes and the birthplace of Chinese civilization. Using the field archaeological data and the sporo-pollens and the age data of the drilling cores, we analysed Neolithic cultural development and environmental evolution in the Huaihe River basin of Anhui. According to the combination of some research results in archaeology with environmental evolution research, this paper discusses the relationship between culture and environment in the Huaihe River basin of Anhui. The Neolithic cultural development was strongly impacted by the environmental change. The primitive culture （Shishanzi） was developed in the beginning of the Holocene Megathermal Period with distinct regional feature of the culture. From 6.5 kaBP to 5.5 kaBP, the climate changed warmer and wetter. The frequent occurrence of flood and waterlog due to such a climate regime and high sea level caused the earth＇s surface environment deteriorated in the Huaihe River basin of Anhui and the interruption of the Neolithic cultural development, hence a lack of archaeological sites. From 5.5 kaBP to 4.0 kaBP, the climate changed from wet to dry, the natural environment was propitious to human survival. Dawenkou Culture and Longshan Culture flourished in this period. The Neolithic cultural development, the number of the sites and their distribution characteristics of the sites in the study area differed apparently from those in Central China and Shandong Province.
文摘The long-term temporal and spatial dynamics of marine coastal water quality in Tolo Harbor, Hong Kong were explored. The Harbor is divided into three zones represented as Harbor, Buffer, and Channel Subzones. The time range for the study covers the period from the 1970s to the 1990s. The selected indicators for the comprehensive assessment of water quality consist of physical, chemical and biological aspects, including suspended solids(SS), Secchi disk depth(SD), 5-day biochemical oxygen demand(BOD\-5), total nitrogen(TN), total phosphorus(TP), faecal coliform, chlorophyll-a(Chl-a), and the number of red tide occurrences. The results indicated the presence of obvious temporal and spatial trends with regard to changes in water quality. Spatially, water quality in the Channel Subzone is the best, while that in the Harbor Subzone is the worst. On a temporal basis, the average trend from bad to good was 1980s>1990s>1970s as indicated by most of the selected water quality indicators. Water quality during the late 1980s reached its worst level with the lowest SD, the highest BOD\-5, TN, TP, Chl-a concentrations, and the number of red tide occurrences. These long-term temporal-spatial water quality trends were also found in other studies of the Tolo Harbor. The large quantity of pollutants produced as a result of increasing population, industrial and commercial actives, and urbanization and industrialization trends in both Shatin and Tai Po seem to be primarily responsible for the changes in marine coastal water quality.
基金supported by the Program for New Century Excellent Talents in University (NCET-06-0856)the National Natural Science Foundation of China (60772068)
文摘To enhance the resolution of parameter estimation with limited samples received by a short passive array, an iterative nonparametric algorithm for estimating the frequencies and direction-of-arrivals （DOAs） of signals is proposed. The cost function is constructed using 12-norm Gaussian entropy combined with an additional constraint, 12-norm constraint or linear constraint. By minimizing the cost functions in the temporal and the spatial dimensions using corresponding iteration algorithms respectively, the sparse discrete Fourier transforms （DFTs） of temporal and spatial samples are obtained to represent the extrapolated sequences with much larger sizes than the original samples. Then frequency and angle estimates are obtained by performing the traditional simple methods on the extrapolated sequences. It is shown that the proposed algorithm offers increased resolution and significantly reduced sidelobes compared with the periodogram and beamforming based methods. And it achieves high precision compared with the high-resolution method with lower computational burden. Some numerical simulations and real data processing results are presented to verify the effectiveness of the method.
基金supported by the National Natural Science Foundation of China(Grant no.31172117,31472020)the Graduate Student Innovation Research Projects of Anhui University(YQH100269)
文摘Background:The Yangtze River floodplain provides important wintering habitats for Hooded Cranes(Grus monacha) in China.Fluctuations in the water level change foraging habitat and food availability,affecting their temporal-spatial patterns of foraging activities.It is of considerable importance to investigate the effect of these fluctuations on food availability for wintering Hooded Cranes and their foraging response to these changes.Understanding their behavior patterns is beneficial in protecting the wintering crane population and restoring their wintering habitats.Methods:A field survey of the winter behavior of cranes was carried out at Shengjin Lake from November in 2013 to April in 2014.Habitat variables,as well as the spatial distribution and behavior patterns of wintering cranes at their foraging sites during five stages of water level fluctuation were collected.Based on this data we analyzed the relationship of foraging behavior relative to water level fluctuations and habitat types.Results:The foraging habitats used by Hooded Cranes varied at the different water level stages.As the water level decreased,the use of meadows and mudflats increased.When the water dropped to its lowest level,the use by the Hooded Crane in the mudflats reached a peak.There were statistically significant differences in time budget in the three types of habitats over the five stages of the water level.In the mudflats,the foraging behavior and maintenance behavior varied significantly with the water level,while the alert behavior showed little variation.Analysis of a generalized linear model showed that the five water level stages and three habitat types had a significant effect on foraging behavior,while the combined effect of these two variables was significant on the foraging time budget and the length of foraging activity of the Hooded Crane.Conclusions:With the decrease in the water level,the use of mudflats by Hooded Cranes increased correspondingly.Food availability in different habitats was affected by changes in the water level.The Hooded Crane adjusted its foraging patterns and made full use of the three available types of habitat in order to acquire enough food in response to fluctuations in the water level.
基金National Natural Science Foundation of China(Grant No.41271134)the Humanities and Social Science Research Foundation of Ministry of Education(Grant No.10YJC790245)
文摘By using the variation coefficient,Gini coefficient and Theil coefficient,this paper makes preliminary exploration of temporalspatial change features and driving mechanism for regional differences of domestic tourism in China from 1995 to 2009.According to the results,we drew the following conclusions:(1)The regional difference of domestic tourism in China tends to be narrowing generally,and is less than that of inbound tourism,playing an important role in narrowing the overall gap of regional tourism in China.(2)The regional internal difference features:inter-provincial difference in the eastern region and difference among the eastern,central and western regions are comparatively obvious and demonstrate a significantly shrinking tendency,the change tendency is consistent with the change tendency of overall difference and exercises a decisive role in overall difference,whereas the inter-provincial difference in the central and western regions is small and relatively stable,having less influence on the overall difference.(3)The temporal-spatial change in regional difference is featured by:low-level provinces occupy a majority and are concentrated in the central and western regions,showing a tendency of narrowing difference;high-level provinces are concentrated in the eastern region,showing a tendency of spreading to the central and western regions;spatial pattern of regional difference demonstrates 4 types,i.e."proliferation type","polarization type","quiescence type"and"collapse type."(4)The driving force for regional difference of domestic tourism in China comes down to 3 aspects:regional socio-economic attribute,regional transport accessibility level and regional development policy.
