Zhangye City Research Articles

Effect of various temperature indicators on patients' hospitalization with cardiovascular diseases in Zhangye city, China.

This study assessed the impact of various temperature indices, including mean temperature (MT), diurnal temperature range (DTR), and temperature changes between neighboring days (TCN) on hospitalization rates for cardiovascular system diseases among residents of Zhangye City, a typical western city in China. The Quasi-Poisson generalized additive regression model (GAM) in conjunction with a distributed lag nonlinear model (DLNM) was applied to estimate the association of temperature indices with CVD hospitalization rates in Zhangye City during the periods of 2015-2021. The exposure-response relationship and relative risk were discussed and stratified analyses by age and gender were conducted. We found that the hospitalization rates of cardiovascular disease (CVD) patients in Zhangye City was significantly related to different temperature indicators (MT, DTR, TCN). Both low and high MT, DTR, and TCN increased the risk of cardiovascular disease (CVD) among residents. Besides, different demographic populations exhibited distinct sensitivities to temperature conditions. Relevant authorities should devise corresponding preventive and control measures to protect vulnerable populations.

Sex differences in Helicobacter pylori infection and recurrence rate among 81,754 Chinese adults: a cross-sectional study

ObjectiveTo compare the sex differences of Helicobacter pylori (HP) infection rate and 1-year recurrence rate.MethodsA cross-sectional study was conducted on the prevalence of HP infection in 81,754 people who underwent physical examination in physical examination centers and outpatient clinics of the Affiliated Hospital of Gansu University of Traditional Chinese Medicine, the Second People’s Hospital of Zhangye City, Tianshui City Hospital of Integrated Chinese and Western Medicine, the First and Second Department of The First Hospital of Lanzhou University Physical Examination Center, from March 2010 to December 2019. Among them, 53,771 (65.77%) were males (18–91 years old) and 27,983 (34.23%) were females (18–94 years old). According to age, they were divided into young group, middle-aged group and old group. 1448 asymptomatic infected patients were selected and treated with bismuth-containing quadruple drug eradication therapy for 2 weeks. The eradication rate and recurrence rate after 1 year were compared between males and females.ResultsThe overall infection rate was 49.59%, including 49.74% in males and 49.3% in females. The risk of infection in young women was lower than that in men (OR = 0.908, 95%CI: 0.868–0.95, P < 0.01), the risk of infection in older women was higher than that in men (OR = 1.137, 95%CI: 1.041–1.243, P < 0.01). The female infection rate was positively correlated with age from 18 to 60, and Spearman’s correlation coefficient was 0.825 (P < 0.01). The overall eradication rate was 84.67% in intention-to-treat analysis (ITT) and 88.46% in protocol analysis (PP). The eradication rates of ITT and PP in the older group were 78.38% and 82.27%, respectively, which were lower than 87.25% and 89.39% in the male group (P < 0.05). The 1-year overall recurrence rate was 3.86%, including 2.82% in males and 5.44% in females (P < 0.05), female was a risk factor for recurrence after eradication after controlling for age (OR = 2.177, 95%CI 1.166–4.066, P < 0.05). There were no obvious adverse reactions during the treatment.ConclusionThere is a positive linear correlation between HP infection rate and age increase in women. Older women have the characteristics of high HP infection rate, low eradication rate and high recurrence rate.

Analysis and evaluation of development characteristics of debris flow in Longshougou

Long Shougou is located at the exit of Hei he River in Zhang ye City, which is directly facing the reservoir of Long Shougou Hydropower Station. Through site survey, UAV flight and indoor simulation calculation, the development characteristics and risk of Long Shougou debris flow were analyzed and evaluated. The results show that: Long Shougou debris flow is in the "development period", belonging to "small", "easy" and "high frequency" debris flow; The length of Long Shougou Channel is 1.70 km, the circumference is 3.76 km, the area is 0.72 km2 , the relative height difference is nearly 584 m, the longitudinal gradient is 342.27 ‰, and the overall bending coefficient is 1.14; Gully sediments are mainly gully bed deposits and slope collapse deposits, with total reserves of 20.94 ×104 m3 and dynamic reserves of 7.76 ×104 m3 ; Calculated according to the designed rainstorm frequency of 1%, the flow velocity of debris flow at the gully mouth is 2.64m /s, the total amount of primary overflow is 17,296.41m3 , the primary outflow of solid matter is 7956.35m3 , and the overall impact pressure of debris flow is 16.32kPa. The maximum impact force of a single stone is 2.56kN according to 0.5m; It is suggested to consider the impact of the annual inflow of debris flow on the water quality of the Longshou hydropower station reservoir and the impact on the power station switching station near the Gulou port, and do a good job in the relevant sediment discharge measures.

Carbon balance analysis of agricultural production systems in oasis areas

China is the biggest emitter of greenhouse gases (GHGs) in the world, and agricultural GHG emission accounts for nearly a fifth of the total emission in China. To understand the carbon absorption and emission characteristics of agricultural production systems in those arid oasis areas, a typical representative city in northwestern China, Zhangye City, was selected for study.The emission factor method was used to analyze and calculate the characteristics of changing carbon emission dynamics in the whole agricultural production system in Zhangye city region (38,592 km2) from 2010 to 2021.The results revealed that carbon emissions during agricultural planting mainly come from fertilizers, which account for the highest proportion (47.9%) of total carbon emissions in agricultural planting. Animal enteric fermentation emissions from local livestock farming are the main contributor (86%) to GHG emissions. The annual average carbon absorption intensity is 4.4 t C-eq ha−1 for crop and 2.6 t C-eq ha−1 for the agricultural production system. The ratio of total carbon emissions from agricultural production to carbon sequestration of crops is 1:1.7. We find that the total carbon sequestration slightly exceeds its total carbon emissions in the study region, with an annual average of 41% for its sustainable development index. Carbon emissions of the agricultural production system in this oasis area are mainly driven by the livestock industry, mostly CH4 emissions from cattle raising.Reducing the local carbon emissions from the livestock industry, typically the cattle raising, will play a crucial role in reducing carbon emissions from this local agricultural production system and maintaining its net positive carbon balance.

Discovery and characterization of a novel pathogen Erwinia pyri sp. nov. associated with pear dieback: taxonomic insights and genomic analysis.

In 2022, a novel disease similar to pear fire blight was found in a pear orchard in Zhangye City, Gansu Province, China. The disease mainly damages the branches, leaves, and fruits of the plant. To identify the pathogen, tissue isolation and pathogenicity testing (inoculating the potential pathogen on healthy plant tissues) were conducted. Furthermore, a comprehensive analysis encompassing the pathogen's morphological, physiological, and biochemical characteristics and whole-genome sequencing was conducted. The results showed that among the eight isolates, the symptoms on the detached leaves and fruits inoculated with isolate DE2 were identical to those observed in the field. Verifying Koch's postulates confirmed that DE2 was the pathogenic bacterium that causes the disease. Based on a 16S rRNA phylogenetic tree, isolate DE2 belongs to the genus Erwinia. Biolog and API 20E results also indicated that isolate DE2 is an undescribed species of Erwinia. Isolate DE2 was negative for oxidase. Subsequently, the complete genome sequence of isolate DE2 was determined and compared to the complete genome sequences of 29 other Erwinia species based on digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses. The ANI and dDDH values between strain DE2 and Erwinia species were both below the species thresholds (ANI < 95-96%, dDDH<70%), suggesting that isolate DE2 is a new species of Erwinia. We will temporarily name strain DE2 as Erwinia pyri sp. nov. There were 548 predicted virulence factors in the genome of strain DE2, comprising 534 on the chromosome and 5 in the plasmids. The whole genome sequence of strain DE2 has been submitted to the NCBI database (ASM3075845v1) with accession number GCA_030758455.1. The strain DE2 has been preserved at the China Center for Type Culture Collection (CCTCC) under the deposit number CCTCC AB 2024080. This study represents the initial report of a potentially new bacterial species in the genus Erwinia that causes a novel pear dieback disease. The findings provide a valuable strain resource for the study of the genus Erwinia and establish a robust theoretical foundation for the prevention and control of emerging pear dieback diseases.

Study on anti-seepage mechanism of attapulgite-modified loess in Northwest China

Loess is distributed widely in the arid areas in northwest China. Lanzhou city is located on the loess plateau, covered by a large area of deep collapsible Malan loess. Collapsible loess is a soft soil in engineering. It has a specific bearing capacity under dry conditions but will collapse after being immersed in water, which is unfavorable to engineering construction. This paper used the attapulgite abundant in the Zhangye City of Gansu Province as a modifier to improve the loess. The permeability test tested the permeability coefficient of the specimens under different dosages of attapulgite. The anti-permeability principle of attapulgite-modified loess was analyzed from the microscopic perspective by electron microscopy scanning (EMS) and nuclear magnetic resonance (NMR). The test results show that the permeability coefficient of attapulgite-modified loess decreases significantly compared with pure loess, but the permeability coefficient decreases gently when the content of attapulgite exceeds 10%. It was found that the anti-permeability mechanism of the modified loess was that the cohesive attapulgite particles filled the macropores of the loess particles, and the acicular attapulgite combined the loess particles to form a sheet structure, which reduced the porosity and permeability of the modified soil.

Changes in the Range of Four Advantageous Grasshopper Habitats in the Hexi Corridor under Future Climate Conditions.

Angaracris rhodopa (Fischer et Walheim), Calliptamus abbreviatus (Ikonnikov), Myrmeleotettix palpalis (Zubowsky), and Oedaleus decorus asiaticus (Bey-Bienko) are the main grasshoppers that harm the natural grassland in the Hexi Corridor in Gansu, northwest China. In this study, the MaxEnt model was employed to identify the key environmental factors affecting the distribution of the four grasshoppers' habitats and to assess their distribution under current and future climate conditions. The aim was to provide a basis for grasshopper monitoring, prediction, and precise control. In this study, distribution of suitable habitats for A. rhodopa, C. abbreviates, M. palpalis, O. decorus asiaticus were predicted under current and future climatic scenarios using the Maxent model. The average AUC (area under the ROC curve) and TSS (true skill statistic) values of the four grasshoppers were greater than 0.9, and the simulation results were excellent and highly reliable. The mean annual precipitation was the main factor limiting the current range of suitable areas for these four species. Under the current climate, A. rhodopa, C. abbreviatus, and O. decorus asiaticus were mainly distributed in the central and eastern parts of the Hexi Corridor, and M. palpalis was distributed throughout the Hexi Corridor, with a suitable area of 1.29 × 104, 1.43 × 104, 1.44 × 104, and 2.12 × 104 km2, accounting for 13.7%, 15.2%, 15.3%, and 22.5% of the total area of the grasslands in the Hexi Corridor, respectively. The highly suitable areas of A. rhodopa, C. abbreviatus, and O. decorus asiaticus were mainly distributed in the eastern-central part of Zhangye City, the western part of Wuwei City, and the western and southern parts of Jinchang City, with areas of 0.20 × 104, 0.29 × 104, and 0.35 × 104 km2, accounting for 2.2%, 3%, and 3.7% of the grassland area, respectively. The high habitat of M. palpalis was mainly distributed in the southeast of Jiuquan City, the west, middle, and east of Zhangye City, the west of Wuwei City, and the west and south of Jinchang City, with an area of 0.32 × 104 km2, accounting for 3.4% of the grassland area. In the 2030s, the range of A. rhodopa, C. abbreviatus, and O. decorus asiaticus was predicted to increase; the range of M. palpalis will decrease. The results of this study could provide a theoretical basis for the precise monitoring and control of key areas of grasshoppers in the Hexi Corridor.

Reflections on the strategy of hospital development based on the characteristics of new hospitals.

The disease spectrum is constantly changing, meaning patients' medical characteristics are complex and varied, and hospital operations are facing great challenges. To provide a basis for formulating relevant policies, promoting the continuous improvement of medical quality, improving the efficiency of medical services and proposing corresponding countermeasures. Information on the first page of the medical cases of patients discharged from 2020-2021 in the case management system of The Second People's Hospital of Zhangye City was collected, and statistical analysis was performed in terms of the origin, age, gender, occupation and main diagnosis of the patients. The database was established using Excel software, and statistical description was performed using SPSS 23.0 software, in which the main indicators were the number of cases and relative numbers (%). The total number of inpatients in the hospital exhibited an overall upward trend, with the number in 2021 increasing by 40.53% compared with the previous year. Among them, 0.75% of the inpatients resided outside the province and 99.25% resided within the province. The proportion of inpatients within the city was 98.86%, including 85.50% in Ganzhou District and 14.5% in the five surrounding counties (districts). In 2021, the number of inpatients in the five surrounding districts increased by 60.67% compared with the previous year. The occupational structure of the inpatients was mainly farmers, accounting for 64.68%, which was higher than all other occupational groups, while public employees accounted for 17.9%. Inpatients aged 60 years and above accounted for 37.75%. In terms of disease spectrum ranking, circulatory, digestive, respiratory, injury and oncological system diseases ranked in the top five of the presented diseases, accounting for 64.47% of the total number of inpatients. The patients of the new hospital are mainly elderly patients and local farmers. The hospital development should be based on the disease characteristics of this group, improving the diagnosis and treatment capacity of the departments and strengthening the capacity building of the hospital and the level of the medical services.

Identification of priority areas for territorial space ecological restoration in arid area of Northwest China: A case study of Zhangye City in Heihe River basin.

Determining priority areas for territorial ecological restoration in the arid region of Northwest China based on the holistic protection and systematic governance is an important measure to build solid national ecological security barrier and promote the construction of territorial ecological civilization. Taking Zhangye City, a typical arid area city in Northwest China, as an example, we constructed the research framework of "ecological network-ecological sensitivities-ecological degradation" from two aspects of internal defects and external threats of ecological networks by using circuit theory and assessment methods of ecological service function importance, ecological sensitivity, and ecological degradation. We then identified the priority areas of territorial ecological restoration in northwest arid region and put forward the restoration strategies. The results showed that the priority areas of ecological restoration in Zhangye City were concentrated in the artificial shelterbelt along rivers and the plain-desert-oasis transition zone with fragile ecology and strong human interference. The ecological network of the study area included 39 ecological sources and 99 ecological corridors, and the highly sensitive and degraded areas were 1595.40 and 6.65 km2. Based on the internal defects and external threats of the ecological network, we identified 31 ecological pinch points, 7 obstacle points, and 753.56 km2 ecological source areas in the territorial spatial ecological restoration priority area. These areas were related to the connectivity of the ecological network internally and the stability maintenance of the ecosystem outwards, and were the areas to restoration in the future. Following the concept of overall protection and system restoration of territorial space, we put forward the idea of territorial space restoration by integrating internal defects and external threats of ecological network, which could provide scientific decision-making basis for comprehensive ecosystem management and territorial optimization of Zhangye City.

Research on the Current Situation of Kindergarten Labor Education from the Perspective of Home Co-education —Three Kindergartens in Zhangye City as an Example

Research on the Current Situation of Kindergarten Labor Education from the Perspective of Home Co-education —Three Kindergartens in Zhangye City as an Example

Evaluation of Water Resources Carrying Capacity of Zhangye City Based on Combined Weights and TOPSIS Modeling

According to the natural condition of water resources and the economic, social, and ecological environment status of Zhangye City, the water resources carrying capacity of Zhangye City is evaluated by using the water resources carrying capacity Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) model with combination assignment. The results show that: (1) From 2010 to 2020, the water resources carrying capacity of Zhangye City was generally stable at the macro level, ranking at grades III and IV. However, from the micro level, the water resources carrying capacity fluctuates to a certain extent and shows an increasing trend year by year. (2) The steady improvement of economic and social conditions is the main driving force for the improvement of the comprehensive water resources carrying capacity of Zhangye City, and the changes in the ecological environment are also important factors affecting the carrying capacity of water resources. The results provided a decision basis for future comprehensive development and utilization of water resources in Zhangye City and a reference for water resource carrying capacity and water resource security assessment in other arid and semi-arid areas in our country.

Evaluation of spatial downscaling for satellite retrieval of evapotranspiration from the nonparametric approach in an arid area

Evapotranspiration (ET) data is critical for monitoring the limited hydrological resources in arid areas. At present, the spatial resolution of ET derived by the thermal infrared images from satellite data is coarse (always more than 500 m). The low-resolution data cannot meet the needs of the high-precision mapping of ET. Therefore, it is important to undertake a downscaling procedure to improve the spatial resolution of ET. This paper selects the oasis region and surrounding deserts of Zhangye City of China as study area and compares with two downscaling procedures that include input and output downscaling procedure. The ET is estimated with the Remote Sensing-Non Parametric (RS-NP) model. The two downscaling procedures use Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model (ESTARFM) to improve the spatial resolution of ET from 1-km to 100 m. Compared with the result derived from the output downscaling procedure, the high-resolution ET derived from the input downscaling procedure has a slightly better performance with R2 of 0.92 and RMSE of 41.8 W/m2, respectively. Neglectingthe downscaling of land surface temperature and broadband reflectance (BBR) result in larger errors of ET estimation with bias values of 73.0 W/m2 and 23.7 W/m2, respectively. Those values account for almost 1/3 and 1/10 of ET values, respectively. In non-vegetated areas, those proportions increase further around 90.6 % and 21.3 %, respectively. Furthermore, the influence of the neglect of the downscaling of the near-infrared reflectance on the ET estimation dominates that of BBR with a proportion of 42 %. The input downscaling procedure is suitable for generating the high-precision map of ET, especially in vegetated areas and during northern hemisphere summer months. Our study is helpful to obtain ET maps in fine spatial resolutions and contribute to the comprehensive understanding of the importance of the downscaling of each kind of input for reliable ET estimations.

Water vapor-heat-carbon fluxes and meteorological observation matrix dataset in 2012 over Zhangye oasis-desert area

The oasis-desert ecosystem is a unique landscape in arid/semi-arid regions, and the observation and research of its water vapor, heat, and carbon fluxes are of great significance to the stability and sustainable development of oases. This study focuses on the oasis-desert area of Zhangye City, Gansu Province, in the middle reaches of the Heihe River Basin. Based on the state-of-art flux observation matrix experiment conducted in the region in 2012, we processed the water vapor-heat-carbon fluxes and meteorological data from the experiment in two nested matrices (30 km × 30 km and 5.5 km × 5.5 km). There are a total of 22 eddy covariance systems and 21 automatic weather stations within the 21 observation sites as well as 4 group large aperture scintillometer and 3 group thermal dissipation probe observations in the two nested matrices. The observation parameters encompass a wide range of elements, including ecosystem net carbon exchange, latent heat flux, sensible heat flux, air temperature, relative humidity, wind speed, wind direction, downward/upward short wave radiation, downward/upward long wave radiation, net radiation, atmospheric pressure, precipitation, infrared radiation temperature, photosynthetic effective radiation, soil temperature, soil moisture, soil heat flux and average soil temperature, tree transpiration, etc. This meticulously processed dataset can be used to study the characteristics and impact mechanisms of water vapor, heat, and carbon changes in oasis-desert areas. Moreover, it can provide a strong data foundation for model simulation or remote sensing estimation results.

A study on the spatial distribution and historical evolution of grotto heritage: a case study of Gansu Province, China

Grottoes are a comprehensive art treasure trove that integrate architecture, sculpture, and murals. They showcase the historical spiritual civilization of humanity and provide a solid foundation for studying the dissemination and development of Buddhist culture. Gansu Province is an important node on the transmission route of Buddhist culture, constituting a relatively complete and rich history of Buddhist art and cultural history. This article uses GIS technology to systematically analyse the spatial distribution characteristics and spatiotemporal evolution patterns of grottoes in Gansu Province from the Wei Jin to the Ming and Qing dynasties and explores the main factors affecting their distribution. The results indicate the following: (1) the grottoes in Gansu Province exhibit clustering and uneven distribution characteristics, which form the core aggregation area of Qingyang Tianshui City and the secondary aggregation area of Wuwei and Zhangye City. (2) Spatiotemporal characteristics show significant changes in the number and focus of excavation and repair of grottoes in Gansu Province over the years. The Northern and Southern Dynasties, Sui and Tang Dynasties, and Ming and Qing Dynasties had more grottoes than the Wei, Jin, and Yuan Dynasties. The overall centre of gravity shifted from northwest to southeast. Natural factors such as topography, stratigraphy, and hydrology and cultural factors such as politics and transportation significantly impacted the spatial pattern of grotto heritage in Gansu Province. Exploring and studying the spatial layout of grotto heritage from the perspective of historical geography is beneficial for understanding the cultural development and historical changes in Buddhism and is of great significance for the development of landscape environmental protection and utilization of grotto heritage.

Concentrations, distribution and influencing factors of selenium (Se) in soil of arid and semi-arid climate: A case from Zhangye-Yongchang region, north-western China

Selenium (Se) is an essential trace element for human health. It is therefore important to investigate Se geochemical characteristics in the environment. However, less attention has been paid to the supergene geochemistry of selenium in alkaline soils. Based on a recently-completed geochemical survey in the Zhangye-Yongchang region of north-western China, this paper first summarizes the concentrations and spatial distribution of Se in the topsoil therein, and then discuss the influencing factors through multivariate statistical analysis, and study the bio-availability of soil Se. Our results showed that the contents of Se in the topsoil of the Zhangye-Yongchang range from 0.07 to 0.88 mg/kg, and the average concentration was 0.255 mg/kg. The Se-rich soil samples were mainly distributed in the Zhangye city and surrounding counties and towns, mainly including Dongyuan town, Shandan County, and Huocheng town of Minle county, and the potential Se-deficiency areas contain northern Dongyuan Town where develops sandy land, and Shigangdun town that covered by Gobi Desert. Relatively high Se background in local strata points out that the soil parent material is the dominant controlling factor of the Se concentrations in the topsoil. Results from factor analysis, cluster analysis and correlation analysis suggest a positive relationship between Se and F, Mo, Sr, U, MgO, CaO, and organic matter, but negative relationship between Se and SiO2 and pH value. Organic matter and certain oxides are likely to be the adsorbent of soil Se. Moreover, a high proportion of water-soluble and ion-exchange state Se (7.66 % of the total contents) and a high Se enrichment rate of crops (>30 %) indicate high bio-availability of soil Se in the Zhangye-Yongchang region, where could probably develop a green industry of Se-rich agricultural products in the future.

Active tectonics and paleo-earthquakes in north Yumu Shan, northern Tibetan Plateau: Insights from structural analysis and radiocarbon dating

The Yumu Shan is located at the northern margin of the Tibetan Plateau in northwest China. It is characterized by the development of several northeastward-protruding arcuate geomorphic bulge belts on its north slope. These bulge belts are distributed along the Wutongquan spring, the ancient Camel City, and the Xiaogengzi area, and south to Gaotai City in the Hexi Corridor. In this study, our detailed field mapping and structural analysis reveal northeastward active anticline folding along the curved bulge belts and related lacustrine sediments in their hinterlands. Radiocarbon dating of plant charcoal samples from lacustrine sedimentary layers yields a 14C age of AD 178 ± 42. This age is close to the time of the 180AD/Ms7.5 earthquake at Biaoshi City (i.e., the ancient Zhangye City) during the Eastern Han Dynasty. The similarity between seismic events and sedimentary age leads us to infer that the charcoal in the lacustrine layer records a major flood event related to the Biaoshi earthquake. We propose a fault-related fold model for the formation of the arcuate bulge belts and related sediments. First, a series of historical earthquake activities in the Holocene, especially the 180AD/Ms7.5 Biaoshi earthquake, may have led to active blind thrust faulting in the northern margin of the plateau. Then, blind thrusting may have resulted in fault-related anticline folding, causing the formation of geomorphic bulges. The latter acts as a flood-retaining dam, resulting in hinterland deposition of lacustrine sediments. For this reason, we suggest that seismogenic blind thrust faulting is responsible for the uplift and northward growth of the Tibetan Plateau. As the northernmost blind thrust in this area, the Xiaogengzi Fault could be considered the North Boundary Thrust (NBT), which defines exactly the northern margin of the plateau.

基于不同样带的干旱区城市景观格局时空演变特征——以张掖市为例

PDF HTML阅读 XML下载 导出引用 引用提醒 基于不同样带的干旱区城市景观格局时空演变特征——以张掖市为例 DOI: 10.5846/stxb202202210408 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（42101276）；甘肃省科技计划项目（20JR5RA529）；国家自然科学基金项目（41661035） Spatio-temporal evolution of urban landscape pattern in arid areas based on different zones: A case study of Zhangye City Author: Affiliation: Fund Project: National Natural Science Foundation of China, No.42101276; Science and Technology Project of Gansu Province, No.20JR5RA529; National Natural Science Foundation of China, No.41661035; Regional Fund of National Natural Science Foundation of China, No.41961027 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:景观格局的变化影响着区域生态安全及可持续发展，研究干旱区城市景观格局时空变化特征，对干旱区景观格局优化具有一定的指导意义。基于1987、1995、2000、2006、2011和2016年6期土地利用数据，利用景观格局指数计算方法，研究张掖市景观格局的时空演变特征。结果表明：（1）2016年张掖市景观类型主要为未利用地，最大斑块指数和斑块聚集度最高，草地和耕地次之，草地的斑块个数和密度最大。（2）张掖市景观格局呈现明显的地域分异特征，圈层梯度带上揭示了绿洲-荒漠用地变化，研究期内第1梯度带内破碎度先上升后下降，城市在2006-2016年扩张较快，其余梯度带破碎度逐年升高；空间演变上，居住地在圈层上的变化呈"L"型，未利用地呈"N"型，张掖市从中心城区到外围区域依次为绿洲城市区、绿洲农业区和自然景观区。（3）水平样带揭示了山地-绿洲-荒漠的用地变化，将张掖市分为4类区域，分别为绿洲城市区、绿洲农业区、荒漠区、山地区；西北-东南样带上景观破碎度年变化不规律，在空间上经过居民点波动变化；东北-西南样带研究期内景观水平指数经过居民点波动变化，其余范围内年变化较稳定，中心城区景观异质性较强。（4）人类围绕河流进行各种生产生活活动，将河流样带分为上中下三段，样带上段和下段景观指数年变化基本保持稳定，以未利用地为主，上段存在部分林地、草地；中段景观指数在空间上波动变化，景观类型以未利用地和耕地为主。 Abstract:The change of landscape pattern affects the regional ecological security and sustainable development. The study on the spatio-temporal change characteristics of urban landscape pattern has a certain guiding significance to the optimization of landscape pattern in arid areas. Based on the land use data of 1987, 1995, 2000, 2006, 2011 and 2016, the temporal and spatial evolution characteristics of landscape pattern in Zhangye City were studied by using landscape pattern index calculation method. The results showed that:(1) The unused land was the main landscape type in Zhangye City in 2016, and the maximum patch index and patch aggregation degree were the highest, followed by grassland and cultivated land, and the grassland patch number and density were the largest. (2) The landscape pattern of Zhangye City showed obviously regional differentiation characteristics, and the gradient zone of circle layer revealed the change of oasis-desert land. The fragmentation degree in the first gradient zone increased firstly and then decreased during the study period, and the Zhangye City expanded rapidly from 2006 to 2016, while the fragmentation degree in the rest gradient zones increased year by year. In terms of spatial evolution, the change of residential area on the circle layer is "L" shape, and the unused land is "N" shape. From the central area to the periphery area, Zhangye City was divided into oasis urban area, oasis agricultural area and natural landscape area successively. (3) The horizontal transect revealed the land use change of mountain, oasis and desert, and Zhangye City was divided into four regions:oasis urban area, oasis agricultural area, desert area and mountain area. The annual change of landscape fragmentation degree in northwest-southeast transect is irregular, and fluctuated through residential area in space. The landscape level index from the northeast to southwest transect fluctuated through residential areas during the study period, and the annual change was relatively stable in the remaining areas. The landscape heterogeneity of the central urban area was strong. (4) The river transect was divided into upper, middle and lower sections by human activities. The landscape index of the transect and the lower section remained stable, and the unused land was the main part, while the upper section had some woodland and grassland. The landscape index in the middle section fluctuated in space, and the landscape types were mainly unused land and cultivated land. 参考文献 相似文献 引证文献

Land Surface Albedo Estimation and Cross Validation Based on GF-1 WFV Data

The land surface albedo (LSA) represents the ability of the land surface to reflect solar radiation. It is one of the driving factors in the energy balance of land surface radiation and in land–air interactions. In this paper, we estimated the land surface albedo based on GF-1 WFV satellite data that have a high spatial and temporal resolution and cross-validated the albedo estimation results. The albedo estimations and validations were performed in the Ganzhou District, Zhangye City, China, and the Sindh Province, Pakistan. We used the direct estimation method which used a radiative transfer simulation to establish the relationship between the narrow band top of the atmosphere bidirectional reflectance and the land broadband albedo to estimate the albedo data. The results were validated with ground data, Landsat data, MODIS products, and GLASS products. The results show that the method can produce highly accurate albedo estimation results on different land cover types (RMSE: 0.026, R2: 0.835) and has a good consistency with the existing albedo products. This study makes a significant contribution to improving the utilization of GF data and contributes to the understanding of land–air interactions.

Leucobacter chinensis sp. nov., with plant growth-promoting potential isolated from field soil after seven-years continuous maize cropping.

A novel Gram-stain-positive, aerobic, non-motile and rod-shaped bacterium, designated strain NC76-1T, was isolated from soil from a field that had undergone seven years continuous maize cropping from Liuba town located in Zhangye city, Gansu province, PR China. Colonies of strain NC76-1T were white, opaque and circular with a convex shape. The isolate was found to be able to grow at 10-40 °C (optimum 30 °C), pH 6.0 to 12.0 (optimum 7.0-8.0) and with 0-5.0 % (w/v) NaCl (optimum 0%). On the basis of the results of 16S rRNA gene sequence analysis, the strain fell within the clade of the genus Leucobacter, showing the highest sequence similarities with Leucobacter iarius 40T (97.4%), Leucobacter aridicollis CIP 108388T (97.0%), Leucobacter chromiireducens subsp. solipictus TAN 31504T (96.7%) and Leucobacter denitrificans M1T8B10T (96.7%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between NC76-1T and its closest relatives, L. iarius 40T, L. aridicollis CIP 108388T, L. chromiireducens subsp. solipictus TAN 31504T and L. denitrificans M1T8B10T were ≤73.5 % and 20.3%, respectively. The genomic DNA G+C content of NC76-1T was 61.5 mol%. It presented MK-11 as the predominant menaquinone. The major cellular fatty acids were anteiso-C15 : 0 (49.2 %) and iso-C16 : 0 (35.7%). The major polar lipids were found to be diphosphatidyglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminoglycolipid, five glycolipid and one unidentified lipids. The cell wall amino acids were 2,4-diaminobutyric acid, alanine, glutamic acid, glycine and threonine. On the basis of the phylogenetic, phenotypic and chemotaxonomic characteristics, strain NC76-1T is concluded to represent a novel species within the genus Leucobacter, for which the name Leucobacter chinensis sp. nov. is proposed. The type strain is NC76-1T (GDMCC 1.2286T= JCM 34651T).

Modelling and Evaluation of Potato Water Production Functions in a Cold and Arid Environment

This study was conducted at the Yimin Irrigation Experiment Station, Minle County, Zhangye City, Gansu Province, from April to October in 2019 and 2020. The relationship between water consumption and yield of potato at different stages of fertility under deficit-regulated irrigation was analyzed in a field trial study over two growing seasons. The results showed that the average annual water consumption in the tuber bulking stage was the largest, reaching 185.35~239.52 mm, followed by the average annual water consumption in the tuber initiation stage and starch accumulation stage, which were 100.02~132.30 mm and 82.48~112.36 mm, respectively, and the average annual water consumption in the seedling stage was the least, at 49.32~69.81 mm. Simultaneously, the average annual yield of potatoes in the treatment of WD1 was the highest, reaching 47,766.96 kg·hm−2, followed by CK, which was 43,707.6 kg·hm−2, and the yield of WD6 was the smallest in the treatment of moderate water deficit during tuber initiation, which was only 35,721.25 kg·hm−2. Combining the four moisture production function models of Jensen, Minhas, Blank and Stewart, the Jensen and Stewart models were identified as suitable for the potato moisture production function in a cold and arid environment. The water production function model was used to investigate the relationship between water consumption and yield in each growth period of potato, and to provide a theoretical basis for the optimization of the irrigation system under deficit-regulating irrigation conditions for potato in this irrigation area.