Assessment of vegetation cover changes and the contributing factors in the Al-Ahsa Oasis using Normalized Difference Vegetation Index(NDVI)

The abandonment of date palm grove of the former Al-Ahsa Oasis in the eastern region of Saudi Arabia has resulted in the conversion of delicate agricultural area into urban area.The current state of the oasis is influenced by both expansion and degradation factors.Therefore,it is important to study the spatiotemporal variation of vegetation cover for the sustainable management of oasis resources.This study used Landsat satellite images in 1987,2002,and 2021 to monitor the spatiotemporal variation of vegetation cover in the Al-Ahsa Oasis,applied multi-temporal Normalized Difference Vegetation Index(NDVI)data spanning from 1987 to 2021 to assess environmental and spatiotemporal variations that have occurred in the Al-Ahsa Oasis,and investigated the factors influencing these variation.This study reveals that there is a significant improvement in the ecological environment of the oasis during 1987–2021,with increase of NDVI values being higher than 0.10.In 2021,the highest NDVI value is generally above 0.70,while the lowest value remains largely unchanged.However,there is a remarkable increase in NDVI values between 0.20 and 0.30.The area of low NDVI values(0.00–0.20)has remained almost stable,but the region with high NDVI values(above 0.70)expands during 1987–2021.Furthermore,this study finds that in 1987–2002,the increase of vegetation cover is most notable in the northern region of the study area,whereas from 2002 to 2021,the increase of vegetation cover is mainly concentrated in the northern and southern regions of the study area.From 1987 to 2021,NDVI values exhibit the most pronounced variation,with a significant increase in the“green”zone(characterized by NDVI values exceeding 0.40),indicating a substantial enhancement in the ecological environment of the oasis.The NDVI classification is validated through 50 ground validation points in the study area,demonstrating a mean accuracy of 92.00%in the detection of vegetation cover.In general,both the user’s and producer’s accuracies of NDVI classification are extremely high in 1987,2002,and 2021.Finally,this study suggests that environmental authorities should strengthen their overall forestry project arrangements to combat sand encroachment and enhance the ecological environment of the Al-Ahsa Oasis.

老年及中青年ICU患者死亡率及OASIS评分的预测价值

目的探讨老年及中青年重症加强护理病房(ICU)患者死亡率及牛津急性疾病严重程度评分(OASIS)的预测价值。方法选取中国人民解放军联勤保障部队第904医院2019年1月—2020年2月收治的ICU患者100例为研究对象,回顾性分析100例患者的临床资料,根据预后情况分为好转组(71例)和死亡组(29例)。比较老年与中青年患者的死亡率,对比两组患者的性别、年龄、OASIS评分、住院时间、住ICU时间、机械通气情况、急性生理与慢性健康状况评分系统(APACHE)II评分、多器官功能障碍综合征(MODS)评分、创伤严重度评分(ISS)、糖尿病情况、心血管疾病情况。采取非条件Logistic逐步回归分析ICU患者预后的危险因素。结果老年患者死亡率明显高于中青年患者,比较差异有统计学意义(P<0.05);死亡组年龄≥65岁、OASIS评分>30分、住院时间≤7 d、住ICU时间>3 d、机械通气>3 d、APACHE II评分>25分、MODS评分>12分患者占比显著高于好转组,比较差异有统计学意义(P<0.05);Logistic回归性分析显示,年龄≥65岁、OASIS评分>30分、住院时间≤7 d、住ICU时间>3 d、机械通气>3 d、APACHE II评分>25分、MODS评分>12分是ICU患者预后的危险因素。结论老年ICU患者死亡率高于中青年,OASIS评分、住院时间、住ICU时间、机械通气、APACHE II评分、MODS评分是ICU患者预后不良的影响因素。

OASIS超声波果蔬清洁器

OASIS是一种超声波清洁器,用于清洗家庭中的水果和蔬菜。为了提高人们对用超声波清洗食品的认识,它的设计便于新手使用和管理。它提出了一个优化的容量,可以为一个4人家庭清洗3-4天的食品杂货,同时保持有效的清洁能力。上部容器可以与下部容器分离,便于填充和用水冲洗。清洗后,潮湿的食品杂货可以放在盖子上自然干燥。干燥过程中收集的水被设计成通过盖子上的两个小孔流入内部,让剩余的水流入内部。

Oasis System and Its Reasonable Development in Sangong River Watershed in North of the Tianshan Mountains,Xinjiang,China

Under the guide of system theory, taking the oasis in the Sangong River watershed as a case study, this paper analyzes the oasis structure and function from 4 aspects including oasis spatial structure, water resources structure, vegetation structure, economic structure and their corresponding functions. The results indicate that as a typical small-scale watershed, Sangong River watershed has the relatively complete mountain-basin structure, and ecological and productive function. Because of human drastic activity the utilization rate of water resources was as high as 98.7%, and the utilization of groundwater was not reasonable, which resulted in an average annual decline of 0.353m in the water table of alluvial-diluvial-fan oasis, and an average annual increase of 0.047m in the alluvial-plain. The layout of crop and shelter forest benefits to the utilization of water and land resources. The development of oasis economy is at low level, and its eco-economic function is weak.

Oasis cold island effect and its influence on air temperature: a case study of Tarim Basin, Northwest China

Oasis effect can improve the regional climate and habitability of an arid region. In this study, we explored the cold island effects of oases distributed along the edge of Tarim Basin by analyzing the oasis cold island effect （OCIE） intensity, spatial-temporal variation of OCIE, factors influencing the OCIE and impacts of OCIE on air temperature using geographical statistics and GIS methods based on the MODIS land surface temperature, land use/cover change （LUCC） and observed air temperature data. Results showed that all the oases in the Tarim Basin exhibited cold island effects, with the OCIE intensity highest in summer （-9.08℃）, followed by autumn （-4.24℃） and spring （-3.85℃）. The total area of oasis cold island （OCI） and the comprehensive OCIE index showed the same seasonal change trend as the OCIE intensity. However, the changing trends in areas of OCI with strong, medium and weak OCIEs were inconsistent across different seasons. Farmland and water areas were found to be the key contributors that affected the OCIE, and the area and aggregation metrics of these two land use/cover types directly contributed to the OCIE. By contrast, natural vegetation, such as forest and grassland, almost had no contribution to the OCIE. Simulation of observed air temperature data showed that if farmland is replaced by forest or grassland in the oasis, the mean, maximum and minimum air temperatures will increase significantly. This heating effect will be higher in summer （reaching 1.14℃ to 2.08℃） and lower in spring and autumn. Moreover, the heating effect of farmland being replaced by forest will be higher than that of farmland being replaced by grassland. These results can provide a basis for understanding the cold island effect of oases in arid regions.

基于Oasis Montaj平台的航空物探数据处理软件系统

在深入研究Oasis Montaj平台特点的基础上,对已有的处理功能进行移植、优化,并开发了新的功能,集成为航空物探数据处理软件系统。这里就系统的整体架构、主要功能及其实现方法进行了详细介绍。通过大量的数据处理证明了该系统具有集成度高、实用性强、运行效率高、稳定性强、易操作、容错性强等诸多优势,能极大地提高数据处理的效率和质量。

Sustainable Development of Agriculture in Northwestern Ecologically Fragile Desert Oasis——A case study of Guazhou County of Gansu Province

Guazhou County of Gansu Province is a typical ecological fragile area lying in the transition area of desert and oasis.The development of its agricultural economy is highly dependent on natural resources and environment.Contradiction of resources characterized agriculture and the fragile ecological environment has become one of the main barriers to log the impact of local agriculture to achieve sustainable development.Aiming at fragile ecological environment and limiting factors of agricultural sustainable development,thoughts and countermeasures of realizing agricultural sustainable development have been proposed.

OASIS程序的开发与应用

全面描述了对来自法国原子能委员会 (简称CEA)的快堆系统安全分析程序OASIS的引进和开发工作 ,并在此基础上介绍了该程序在中国实验快堆 (ChinaExperimentalFastReactor,简称CEFR)初步安全分析报告中对主给水管道断裂事故的分析计算。

Comprehensive Evaluation of Environmental Effects from Land Change in Hotan Oasis,Xinjiang

[Objective] This study aimed to evaluate the environmental effects coming from land changes in Hotan oasis during 1980-2010. [Method] Based on the Driving Force-State-Response model, expert weight method and entropy method were used to determine weight, and then the composite indexes of environmental effects （CIE for short） were calculated. [Result] During the period from 1980 to 2010, CIE had presented a rising trend whether expert weight method or entropy method in the study area, while the CIE presents downtrend basically in lower reaches. [Conclu- sion] It was the arable land expansion in middle reaches that led to serious land degradation in lower reaches, and may endanger ecosystem safety in Hotan River green corridor. Therefore, it is suggested that the agricultural land use should be restructured, such as reducing the sown areas of some crops with large amount of water consumption. Meanwhile, the effective measures should be taken to distribute water resources and utilize them reasonably. In addition, the oasis-desert ecotone, as well as the groundwater resources, should be also protected.

Assessment of Ecosystem Services Value in Hotan Oasis, Xingjiang

[Objective] The study aimed to assess the ecosystem services value in Hotan Oasis, Xingjiang. [Method] The visual interpretation method was adopted to process TM/ETM＋ images based on field investigation in Hotan Oasis. These inter- pretation data, along with two periods of land use data, were reclassified to farm- land, forest, grassland and so on. Then, the ecosystem services value was calculat- ed and analyzed. [Result] Analysis indicated that the ecosystem services value had been increased by 30.44x108 Yuan （16.51%） in the study area during 1980-2010, which can be explained by the increase of glacier and snowfield distributed in the south mountain with the increase of annual precipitation. At the same time, the con- tribution rate of grassland to ecosystem services value had been decreased as a result of degradation of grassland and occupation from farmland. For the whole basin, the increase of ecosystem services value came from the upper reaches, while the ecosystem services value had been reduced in the middle and lower reaches. In the middle reaches, the reduction came mainly from wetland （-1.83x10s Yuan）, waters （-1.68x10s Yuan）, forest （-0.86x108 Yuan） and grassland （-0.80x108 Yuan）. But in the lower reaches, the ecosystem services values of waters, grassland and forest were -0.61 x108 Yuan, -0.24x108 Yuan, and -0.07x10s Yuan, respectively. [Conclusion] If some effective policies, such as the implementation of returning farm- land to forest and ceasing from farming to grazing, would be taken, the ecosystem degradation can be constrained and reversed in the northwest arid region.

Effects of Different Irrigation Amounts on Wheat Growth in Arid Oasis Area

[Objective] The study was conducted to analyze the effects of different irrigation amount on the growth of wheat in arid oasis area and determine effective use measures and reasonable irrigation indices of water in farmland under arid oasis environment,so as to provide reference for the development and management of water-saving technology.[Method] Spring wheat in different growth periods was irrigated for four times.The leaf area index,dry matter content,1 000-grain weight of wheat in different growth peri...

Oasis HLB固相萃取-超快速液相-三重四极杆质谱法测定花生和花生油中黄曲霉毒素B1、B2、G1、G2

目的建立了Oasis HLB固相萃取-超快速液相-三重四极杆质谱法测定花生和花生油中黄曲霉毒素B1、B2、G1、G2的方法。方法样品用甲醇-水（V甲醇∶V水=20∶80）提取,离心后过Oasis HLB柱萃取净化,超快速液相进行梯度洗脱,质谱用电喷雾离子源（ESI）,经过正离子MRM模式,外标法定量。结果黄曲霉毒素（AFT）B1、B2、G1、G2的最低检出限分别为：0.05、0.05、0.10、0.20μg/kg,平均加标回收率在89.3%-98.7%之间,精密度（RSD）在2.6%-5.3%之间。结论本法利用Oasis HLB固相萃取柱良好的性能和质谱仪采用弯曲180度的碰撞池技术大大减少了样品中的杂质干扰,精密度和准确度高,方法操作简便,结果可靠。

Studies of Soil Physical Property on Different Abandoned Lands in the Minqin Oasis,Downstream of the Shiyang River

The vast area of farmland was abandoned at downstream of the Shiyang River because of decreased water recourse. To ensure the ecological safety of Minqin Oasis and to provide management basis for the abandoned land, soil physical properties were observed and studied. The authors analyzed land with abandonment time of 1 year, 2 years, 3 years, 4 years, 5 years, 8 years, 15 years, 24 years and 31 years. Samples were took at the 0-40 cm layer of soil to measure the bulk density, porosity and grain composition of soil in the different abandoned lands. Results showed that the tendency of clay content was decreasing, conversely, the fine sand increased at the layer of 0-10 cm of different abandoned lands.The changes of grain content reached a peak at the fourth year after the land was abandoned, then varied slightly. The variation of grain content of abandoned land was obvious with the extension of the abandonment year. The soil bulk density decreased and porosity increased with the extension of the abandonment year. The difference of porosity and soil bulk density at the range of 0-40 cm of different abandoned land decreased after the land abandoned for 3 years. The quality of soil was decreased, while the soil permeability was improved. The soil physical properties changed obviously in 3 to 4 years after abandonment, so it is the key time for land management.

Evolution Stages of Oasis Economy and Its Dependence on Natural Resources in Tarim River Basin

This paper examines spatio-temporal characteristics of an oasis economy and its relationship with water and mineral resources in the Tarim River Basin from 1965 to 2005. A spatial autocorrelation model, the center of gravity model, and index system of the regional central city are used to probe the evolution laws of spatial structure of oasis economy. The study finds that: 1) The economic centre of gravity, whose variation track during this period follows linear rate law, was moving from headstream to middle reaches of the Tarim River. 2) Positive spatial autocorrelation which showed a waving and ascending trend of regional economy was significant and the neighbor effect of regional economic growth was strengthened continuously. 3) The regional economic centre was located in Hotan City before 1980, moved to Aksu City during the 1980s and to Korla City after 1990. We conclude that above all, during the recent four decades the evolution of the oasis economy in this region has gone through three stages: a traditional agriculture stage (before 1980), oasis agriculture and agricultural product processing stage (1980–1990) and oasis energy industry stage (after 1990). Furthermore, the dependence degree of the oasis economy on natural resources in different stages are studied by using dominance index, regression model, and grey relation method, which shows that an oasis econ- omy highly depends on water resources in the oasis agriculture and agricultural product processing stage while it de- pends more on mineral resources such as oil and natural gas during the oasis energy industry stage.

OASIS内置式虹膜扩张器在小瞳孔白内障超声乳化术中的应用

目的:观察OASIS内置式虹膜扩张器在小瞳孔白内障超声乳化术中的应用效果。方法:选择2016-01/2017-10在我院接受治疗的小瞳孔白内障患者44例,随机分为对照组(22例31眼)和观察组(22例30眼),对照组采用劈核器和晶状体调位钩手动撕开扩张瞳孔行常规白内障超声乳化手术治疗,观察组在术中植入OASIS内置式虹膜扩张器扩大瞳孔行常规白内障超声乳化手术治疗,对两组患者手术前后最佳矫正视力(BCVA)、角膜内皮细胞计数、瞳孔直径及眼压变化情况进行对比分析,评价OASIS内置式虹膜扩张器的应用效果。结果:术后1mo,两组患者BCVA较术前均显著改善,且观察组患者BCVA(0. 09±0. 04)显著优于对照组(0. 20±0. 03),差异均有统计学意义(P<0. 05)。术后1mo,两组患者角膜内皮细胞计数均较术前明显减少,但观察组患者角膜内皮细胞计数(2455. 77±52. 98个/mm^2)显著高于对照组(2298. 94±49. 12个/mm^2),差异均有统计学意义(P<0. 05)。术后1mo,两组患者瞳孔直径较术前均有所扩大(P<0. 05),且观察组患者瞳孔直径(3. 52±1. 14mm)大于对照组(3. 15±1. 02mm);术后6mo,两组患者瞳孔直径较术后1mo均显著扩大(P<0. 05),但两组间比较,差异无统计学意义(P>0. 05)。术后1mo,两组患者眼压较术前均有所降低(P<0. 05),且观察组眼压(13. 40±1. 73mmHg)低于对照组(13. 93±1. 98mmHg);术后6mo,两组患者眼压均低于术后1mo(P<0. 05),但两组间比较差异无统计学意义(P>0. 05)。结论:OASIS内置式虹膜扩张器用于小瞳孔白内障超声乳化术中可提高术后最佳矫正视力、降低眼压、扩张瞳孔直径,应用效果较好。

An oases dynamics model and its application in the Manas oasis

This study applies theories of systems and system dynamics to ecological economic systems in the oasis environment, with the intention of finding the basic characteristics of the oasis environment and its feedback structures. This study explores the inner mechanisms of economic development in the oasis environment and its relationship to policy variables. This model is applied to economic development in the Manas oasis of the Xinjiang Uygur Autonomous Region of China. System dynamics method starts from studying feedback structure within the system study and then searches for the best solution through identifying the right “policy point” and through model simulation in the computer. It embodies the cream of “systems cybernetics theory”. This study is justified because the nature of the oasis system and the simulation results are scientifically sound and practically feasible.

Oasis Functional Stability Evaluation Based on Multiple Indicators, Northwest China

We produced and analyzed oasis structure information, and evaluated oasis functional stability using the multiple indicators based on Remote Sensing(RS) and Geographical Information System(GIS) in the arid region of China in 2015. The results showed that the oases area was 193,734 km^2, accounting for 8.17% of the arid region of China. The spatial difference in the functional stability of oases was obvious. The Beijiang zone had the highest functional stability and was relatively stable state, and the Hexi Corridor-Alashan Plateau zone had the lowest functional stability and was relatively unstable. The functional stability is dominated by production and ecological functions, which have regional differences. Increasing oasis agricultural output, strengthening highway infrastructure construction and paying attention to education will become important ways to improve oasis functional stability. Water resources determine the ecological function, thus affecting the oasis functional stability. The results provide references for the formulation of related policies according to local conditions.

RECENT PROGRESS OF RESEARCH ON OASIS IN CHINA

Oasis is a kind of special ecological landscape of arid land. In the past two decades, certain progress has been made in research on Chinese oases and a series of achievements have been attained on system of oasis, evolution of oasis, maintenance and construction of oasis, regulation and control of oasis, sustainable development of oasis. To establish the science of Chinese Oasis is pressingly necessary for the development of arid land on a large scale and the opportunity is coming. We should specify the object of study and the nature of this science, and push forward it to more advanced level so that we could occupy the international leading position in this field.

Who is in the Lower Reaches,Who Suffers Disasters?——Take Minqin County,a Disappearing Oasis as a Case

Minqin Oasis is located in the lower reaches of the Shiyanghe River Basin, northeast of the Heixi Corridor, at the middle of the Silk Road. Because of the its existence, Badain Jaran Desert and Tengger Desert cannot converge and develop in the south. It has always been an important green barrier to guarantee the eco-security of Hexi Corridor and the Silk Road for thousands of years. But in recent decades, Minqin Oasis is becoming smaller and the desert is becoming larger. Many people, especially the governmental officials in the lower reaches think that the upper and middle reaches have robbed the lower reaches of water resources, and caused insufficient water usage and the deteriorated eco-environment, in the lower reaches, However, the governmental officials in the upper and middle reaches claim that the whole river basin should take the upper and middle reaches as the key regions to develop economy. To address the above argument, we analyze the reasons why Minqin Oasis is disappearing, and find that there are two main factors. One is the quick development of population and economy in the upper and middle reaches; the other is the rapid development of population and economy in the lower reaches. The two factors both have great effect on the water utilization for eco-environment in the lower reaches. So Minqin Oasis is disappearing not only because of the upper and middle reaches but also because of the growth of population and economy itself. The lower reaches should not completely blame the upper and middle reaches. The upper and middle reaches should also pay more attention to the eco-environment in the lower reaches. The whole river basin should develop a harmonious and sustainable relationship among the upper, middle and lower reaches.

Quantitative Analysis of Natural and Human Factors of Oasis Change in the Tail of Shiyang River over the Past 60 Years

The human and natural factors complicit in the driving forces of oasis change have always received considerable interest from the international research community. In this study, we used principal component analysis of natural and socio-economic statistical factors to quantitatively analyze the causal relationships and their contributions to the observed periodic expansion or shrinkage of the Minqin Oasis over almost 60 years. Our results show that human factors were the dominant factors governing expansion or shrinkage, with average contributions of 69.38% and 76.16%, respectively. Moreover, policy decisions have been the pivotal human factors. Under the influence of various policies, we have found that water resource utilization, land reclamation, population explosion, ecological protection and economic development have each played leading roles in different periods. This study provides a scientific basis for modelling the dynamics of an oasis for sustainable management.