乌鲁木齐地区大气降水中δD和δ18O的变化特征

本文研究了乌鲁木齐地区近17年(1986—2002)大气降水的氢氧同位素组成,提出了大气降水线方程为δD=7.21δ18O+4.50,并与全国及全球降水线方程进行对比,揭示了该降水线方程的特征。研究表明,乌鲁木齐水分来源复杂,主要是西风带输送的海洋水汽和局地的蒸发,大气降水的加权平均18O与月平均气温相关关系显著,与雨量效应(降水量效应)较相关,降水中温度效应明显,且在一定时期很大程度上其影响掩盖了雨量效应。乌鲁木齐降水中δ18O的季节变化与温度的季节变化几乎一致,温度是制约降水中稳定同位素变化的主要影响因子。     

包头地区大气降水δD和δ~(18)O变化特征浅析

大气降水中氢氧稳定同位素包含着水循环演化过程中的历史信息,对揭示水资源的形成及演化机制具有重要的意义。文中根据包头站大气降水中稳定同位素和气象资料,分析了包头地区(1986-1992年)大气降水的氢氧稳定同位素的变化特征及其与气温和降水之间的关系,发现该区氘盈余值(d)具有冬季高夏季低的特点,且d值接近全球大部分地区降水的d值(10‰)。该区大气降水中δ18O值具有夏季高冬季低,δ18O的温度效应显著,而降水量效应只在夏半年(4-9月)间显著。同时提出了包头地区当地大气降水线方程为δD=6.4δ18O-4.07,与全国及全球降水线方程相比,反映出干旱的气候特征。     

苏云金杆菌δ－内毒素的定量生物测定方法

苏云金杆菌δ－内毒素的定量生物测定方法ＣｌａｙｔｏｎＣ．Ｂｅｅｇｌｅ１历史回顾美国苏云金杆菌（Ｂ．ｔ．）商品化的最初１０年一直为产品的标准化问题所困扰。１９５７年，太平洋酵母产品部（ＰａｃｉｆｉｃＹｅａｓｔＰｒｏｄｕｃｔｓ）生产的Ｔｈｕｒｉｃｉｄｃ，...     

苏云金芽孢杆菌及其δ-内毒素基因的分类与鉴定

苏云金芽孢杆菌作为重要的杀虫微生物在生物防治中发挥了巨大作用。其分类鉴定对于研究资源的多样性、快速筛选优良菌株、预测其杀虫活性、分离克隆新的Btδ-内毒素基因等方面具有重要意义。本文对Bt菌株的分类、δ-内毒素基因分类、鉴定方法进行了分析讨论。     

十二烷基硫酸钠－聚丙烯酰胺凝胶电泳定量测定苏云金杆菌δ－内毒素

十二烷基硫酸钠－聚丙烯酰胺凝胶电泳定量测定苏云金杆菌δ－内毒素１前言目前已研究出测定苏云金杆菌（Ｂ，ｔ．）δ－内毒素晶体蛋白含量的可靠方法。此方法首先用高ｐＨ溶液处理样品以抑制Ｂ．ｔ蛋白酶，再用聚丙烯酰胺凝胶电泳（ＳＤＳ－ＰＡＧＥ）法，从生长基质蛋白...     

许家沟泉域岩溶地下水δ13CDIC特征及碳汇效应

为确定许家沟泉域水岩相互作用过程中的碳汇效应,选取22个采样点分期采样进行水化学和同位素分析,利用同位素技术和水化学方法对泉域内碳同位素特征和岩溶碳汇效应进行了研究.结果表明:丰水期岩溶地下水δ13C为-12.16‰ ～-7.11‰,平均-9.93‰,岩溶作用所形成的溶解无机碳主要来源于土壤CO2,枯水期岩溶地下水δ1...     

准噶尔盆地东南部降水中δ18O的温度与降水量效应

地区大气降水线(LMWL)和降水中δ18O的温度和降水量级效应是应用稳定同位素技术研究地区水文学过程与问题的基础.通过跟踪2012-2013年准噶尔盆地东南部44次降水事件,测定了降水中的δ18O和δD,同时收集降水过程的气温变化和降水量数据,在降水事件尺度上研究了降水中δ18O、温度和降水量三者之间的关系.降水中的稳定同位素δ18O和δD存在时间尺度效应,在不同的时间尺度上温度、降水量级效应与LMWL可能不同.在降水事件尺度上,准噶尔盆地东南部LMWL是δD=(7.53±0.22)·δ18O+(0.25 ±3.29).一年中受到水热同期变化的影响,降水量效应被强烈的气温季节动态所掩盖,因此,表面看来,处于欧亚大陆腹地的准噶尔盆地东南部只存在显著的温度效应,而不存在降水量效应,但是扣除气温的影响后,显著的降水量级效应仍然存在,降水量效应主要与云下二次蒸发有关.二元线性模型拟合结果表明:在降水事件尺度上,温度和降水量级效应分别为(0.70 ±0.03)‰·℃-1和(-0.14±0.07)‰·mm-1.     

基于地理探测器分析青藏高原降水δ18O空间分异特征

地理探测器是研究地理现象的空间分异性,并且定量分析其驱动因子的一种统计方法。利用地理探测器方法对青藏高原24个站点的降水δ~(18)O年均值进行了分析,该方法可在一定程度上反映青藏高原降水δ~(18)O年均值的空间分异性,得出纬度、海拔、经度和降水量对青藏高原降水δ~(18)O年均值空间分异的解释力分别为0.82、0.71、0.57和0.49,温度对青藏高原降水δ~(18)O年均值空间分异的解释力不显著;因子之间的共同作用增强了降水δ~(18)O年均值在空间上的分异性。讨论了青藏高原站点降水δ~(18)O年均值与纬度、经度、海拔、年降水量和年均温之间的关系,并对降水δ~(18)O主控因子的季节变化进行分析,得出纬度对青藏高原降水δ~(18)O年均值、夏季均值和冬季均值空间分异的解释力均为最强。     

粘虫颗粒体病毒对苏云金杆菌δ-内毒素的酶解活化作用

粘虫颗粒体病毒(Psedualetia unipuncta granulovirus,PuGV-Ps)对苏云金杆菌(Bacillus thuring-iensis,Bt)具有增效作用.为明确其增效机制,采用SDS-PAGE方法研究PuGV-Ps对Bt δ-内毒素的降解活化作用.结果表明,碱性条件下晶体蛋白和PuGV-Ps共同孵育,130kD的δ-内毒素被进一步酶解为分子量为110、87、61、47 kD等多种不同的肽链,其酶解活化程度随缓冲液pH的升高不断加深,在pH值10.7的0.1 mol/L Na2CO3缓冲液中,δ-内毒素完全降解,并产生具有一定抗蛋白酶继续降解的分子量为47、60和61 kD的活性片段.用氨苯磺胺偶氮酪蛋白为底物测定PuGV-Ps中总蛋白酶活性的结果表明,PuGV-Ps在pH值为7.38～10.38时均具有蛋白酶活性,且蛋白酶活性随pH升高而显著提高.4种蛋白酶抑制剂均可抑制PuGV-Ps的蛋白酶活性,且以STI的抑制作用最强.SDS-PAGE试验同样显示了STI可以抑制PuGV-Ps对δ-内毒素的酶解活化.     

乌鲁木齐河源1号冰川雪坑δ^18O剖面特征与气候的关系

2004年10月至2005年9月,在天山乌鲁木齐河源1号冰川积累区采集了16组雪坑样品。利用雪坑中δ18O资料,分析干季和湿季冰川雪坑δ18O剖面特征与气候的关系。结果表明：δ18 O变化主要集中在雪坑上部,在距底部附加冰130 cm以下变化不大,且维持在较高值。其中,干季雪层剖面上部基本反映了积累期温度的变化,湿季不...     

末次冰期晚期黄土高原西部万象洞高分辨率石笋δ~(13)C记录时频分析

运用小波分析与传统谱分析技术相结合的手段,对典型季风系统交互作用的青藏高原与黄土高原过渡带-甘肃陇南万象洞WX40D石笋616个碳同位素时间序列进行了周期谱演化分析。结果表明:在23-28.3kaB.P期间,石笋碳同位素记录的小波变换系数波谱在频率域尺度其主要的变化周期为120年,200年,并隐约表现出300年和600年的周期;小波变换实部时频分析图显示清晰的能量集中中心有10个,分别为1(23613,197)、2(24000,220)、3(24298,300)、4(25354,222)、5(25565,95)、6(26239,606)、7(26792,115)、8(27085,116)、9(27388,136)、10(27853,177),表明石笋碳同位素记录的古植被演化在该时间段具有明显的5次转变。小波实部过程线分析表明万象洞石笋在末次冰期晚期存在多尺度的变化特征,大尺度的周期变化嵌套小尺度的周期变化。     

Molecular cloning and characterization of cDNA encoding a Translocon-Associated Protein (TRAPδ) from the root-lesion nematode Pratylenchus goodeyi

The translocon-associated protein (TRAP) complex comprises four subunits (α, β, γ, δ) and is located in the endoplasmic reticulum membrane at translocation sites. The TRAP complex is required for the efficient translocation of substrates and to correct or eliminate misfolded proteins. In this study, we described the cloning and characterization of a cDNA encoding a TRAP from the phytoparasitic nematode Pratylenchus goodeyi (Pg). The full-length cDNA had an estimated size of 690 bp and encodes a 177 amino acid peptide. The deduced protein after sequence analysis codes for TRAPδ subunit homologous to TRAPδ from other nematodes. The Pg-TRAPδ had a signal peptide indicating a possible involvement in the transport and binding of other proteins at the endoplasmic reticulum membrane. The increase in relative expression of Pg-trapδ, assessed by semi-quantitative PCR, was induced over time in nematodes exposed to a nematostatic/nematicide extract of Solanum nigrum, suggesting that this gene product might be influenced by response mechanisms to stress in P. goodeyi. This is the first report of the cloning and characterization of trap cDNA from plant endoparasitic nematodes.     

Evaporative enrichment of stable isotopes(δ~(18)O and δD) in lake water and the relation to lake-level change of Lake Qinghai,Northeast Tibetan Plateau of China

Stable isotopic compositions(δ18O and δD) have been utilized as a useful indicator for evaluating the current and historical climatic and environmental changes. Therefore, it is vital to understand the relationship between the stable isotopic contents in lake water and the variations of lake level, particularly in Lake Qinghai, China. In this study, we analyzed the variations of isotope compositions(δ18O, δD and d-excess) in lake water and precipitation by using the samples that were collected from Lake Qinghai region during the period from 2009 to 2012. The results showed that the average isotopic contents of δ18O and δD in lake water were higher than those in precipitation, which were contrary to the variations of d-excess. The linear regression correlations between δ18O and δD in lake water and precipitation showed that the local evaporative line(LEL) in lake water(δD=5.88δ18O–2.41) deviated significantly from the local meteoric water line(LMWL) in precipitation(δD=8.26δ18O+16.91), indicating that evaporative enrichment had a significant impact on isotopic contents in lake water. Moreover, we also quantified the E/I ratio(evaporation-to-input ratio) in Lake Qinghai based on the lake water isotopic enrichment model derived from the Rayleigh equation. The changes of E/I ratios(ranging from 0.29 to 0.36 between 2009 and 2012) clearly revealed the shifts of lake levels in Lake Qinghai in recent years. The average E/I ratio of 0.40 reflected that water budget in Lake Qinghai was positive, and consistent with the rising lake levels and the increasing lake areas in many lakes of the Tibetan Plateau. These findings provide some evidences for studying the hydrological balance or water budget by using δ18O values of lake sedimentary materials and contribute to the reconstruction of paleolake water level and paleoclimate from an isotopic enrichment model in Lake Qinghai.     

Water,land, and energy use efficiencies and financial evaluation of air conditioner cooled greenhouses based on field experiments

High temperature and humidity can be controlled in greenhouses by using mechanical refrigeration cooling system such as air conditioner(AC)in warm and humid regions.This study aims to evaluate the techno-financial aspects of the AC-cooled greenhouse as compared to the evaporative cooled(EV-cooled)greenhouse in winter and summer seasons.Two quonset single-span prototype greenhouses were built in the Agriculture Experiment Station of Sultan Qaboos University,Oman,with dimensions of 6.0 m long and 3.0 m wide.The AC-cooled greenhouse was covered by a rockwool insulated polyethylene plastic sheet and light emitting diodes(LED)lights were used as a source of light,while the EV-cooled greenhouse was covered by a transparent polyethylene sheet and sunlight was used as light source.Three cultivars of high-value lettuce were grown for experimentation.To evaluate the technical efficiency of greenhouse performance,we conducted measures on land use efficiency(LUE),water use efficiency(WUE),gross water use efficiency(GWUE)and energy use efficiency(EUE).Financial analysis was conducted to compare the profitability of both greenhouses.The results showed that the LUE in winter were 10.10 and 14.50 kg/m² for the AC-and EV-cooled greenhouses,respectively.However,the values reduced near to 6.80 kg/m² in both greenhouses in summer.The WUE of the AC-cooled greenhouse was higher than that of the EV-cooled greenhouse by 3.8%in winter and 26.8%in summer.The GWUE was used to measure the total yield to the total greenhouse water consumption including irrigation and cooling water;it was higher in the AC-cooled greenhouse than in the EV-cooled greenhouse in both summer and winter seasons by almost 98.0%–99.4%.The EUE in the EV-cooled greenhouse was higher in both seasons.Financial analysis showed that in winter,gross return,net return and benefit-to-cost ratio were better in the EVcooled greenhouse,while in summer,those were higher in the AC-cooled greenhouse.The values of internal rate of return in the AC-and EV-cooled greenhouses were 63.4%and 129.3%,respectively.In both greenhouses,lettuce investment was highly sensitive to changes in price,yield and energy cost.The financial performance of the AC-cooled greenhouse in summer was better than that of the EV-cooled greenhouse and the pattern was opposite in winter.Finally,more studies on the optimum LED light intensity for any particular crop have to be conducted over different growing seasons in order to enhance the yield quantity and quality of crop.     

Identifying water vapor sources of precipitation in forest and grassland in the north slope of the Tianshan Mountains,Central Asia

Identifying water vapor sources in the natural vegetation of the Tianshan Mountains is of significant importance for obtaining greater knowledge about the water cycle,forecasting water resource changes,and dealing with the adverse effects of climate change.In this study,we identified water vapor sources of precipitation and evaluated their effects on precipitation stable isotopes in the north slope of the Tianshan Mountains,China.By utilizing the temporal and spatial distributions of precipitation stable isotopes in the forest and grassland regions,Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,and isotope mass balance model,we obtained the following results.(1)The Eurasia,Black Sea,and Caspian Sea are the major sources of water vapor.(2)The contribution of surface evaporation to precipitation in forests is lower than that in the grasslands(except in spring),while the contribution of plant transpiration to precipitation in forests(5.35%)is higher than that in grasslands(3.79%)in summer.(3)The underlying surface and temperature are the main factors that affect the contribution of recycled water vapor to precipitation;meanwhile,the effects of water vapor sources of precipitation on precipitation stable isotopes are counteracted by other environmental factors.Overall,this work will prove beneficial in quantifying the effect of climate change on local water cycles.     

Effect of the W-beam central guardrails on wind-blown sand deposition on desert expressways in sandy regions

Many desert expressways are affected by the deposition of the wind-blown sand,which might block the movement of vehicles or cause accidents.W-beam central guardrails,which are used to improve the safety of desert expressways,are thought to influence the deposition of the wind-blown sand,but this has yet not to be studied adequately.To address this issue,we conducted a wind tunnel test to simulate and explore how the W-beam central guardrails affect the airflow,the wind-blown sand flux and the deposition of the wind-blown sand on desert expressways in sandy regions.The subgrade model is 3.5 cm high and 80.0 cm wide,with a bank slope ratio of 1:3.The W-beam central guardrails model is 3.7 cm high,which included a 1.4-cm-high W-beam and a 2.3-cm-high stand column.The wind velocity was measured by using pitot-static tubes placed at nine different heights(1,2,3,5,7,10,15,30 and 50 cm)above the floor of the chamber.The vertical distribution of the wind-blown sand flux in the wind tunnel was measured by using the sand sampler,which was sectioned into 20 intervals.In addition,we measured the wind-blown sand flux in the field at K50 of the Bachu-Shache desert expressway in the Taklimakan Desert on 11 May 2016,by using a customized 78-cm-high gradient sand sampler for the sand flux structure test.Obstruction by the subgrade leads to the formation of two weak wind zones located at the foot of the windward slope and at the leeward slope of the subgrade,and the wind velocity on the leeward side weakens significantly.The W-beam central guardrails decrease the leeward wind velocity,whereas the velocity increases through the bottom gaps and over the top of the W-beam central guardrails.The vertical distribution of the wind-blown sand flux measured by wind tunnel follows neither a power-law nor an exponential function when affected by either the subgrade or the W-beam central guardrails.At 0.0H and 0.5H(where H=3.5 cm,which is the height of the subgrade),the sand transport is less at the 3 cm height from the subgrade surface than at the 1 and 5 cm heights as a result of obstruction by the W-beam central guardrails,and the maximum sand transportation occurs at the 5 cm height affected by the subgrade surface.The average saltation height in the presence of the W-beam central guardrails is greater than the subgrade height.The field test shows that the sand deposits on the overtaking lane leeward of the W-beam central guardrails and that the thickness of the deposited sand is determined by the difference in the sand mass transported between the inlet and outlet points,which is consistent with the position of the minimum wind velocity in the wind tunnel test.The results of this study could help us to understand the hazards of the wind-blown sand onto subgrade with the W-beam central guardrails.     

Optimal bandwidth selection for retrieving Cu content in rock based on hyperspectral remote sensing

Hyperspectral remote sensing technology is widely used to detect element contents because of its multiple bands,high resolution,and abundant information.Although researchers have paid considerable attention to selecting the optimal bandwidth for the hyperspectral inversion of metal element contents in rocks,the influence of bandwidth on the inversion accuracy are ignored.In this study,we collected 258 rock samples in and near the Kalatage polymetallic ore concentration area in the southwestern part of Hami City,Xinjiang Uygur Autonomous Region,China and measured the ground spectra of these samples.The original spectra were resampled with different bandwidths.A Partial Least Squares Regression(PLSR)model was used to invert Cu contents of rock samples and then the influence of different bandwidths on Cu content inversion accuracy was explored.According to the results,the PLSR model obtains the highest Cu content inversion accuracy at a bandwidth of 35 nm,with the model determination coefficient(R²)of 0.5907.The PLSR inversion accuracy is relatively unaffected by the bandwidth within 5-80 nm,but the accuracy decreases significantly at 85 nm bandwidth(R²=0.5473),and the accuracy gradually decreased at bandwidths beyond 85 nm.Hence,bandwidth has a certain impact on the inversion accuracy of Cu content in rocks using the PLSR model.This study provides an indicator argument and theoretical basis for the future design of hyperspectral sensors for rock geochemistry.     

Assessing the collapse risk of Stipa bungeana grassland in China based on its distribution changes

The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biodiversity conservation. The changed distribution area of an ecosystem is one of the key criteria in such assessments. The Stipa bungeana grassland is one of the most widely distributed grasslands in the warm-temperate semi-arid regions of China. However, the total distribution area of this grassland was noted to have shrunk and become fragmented because of its conversion to cropland and grazing-induced degradation. Following the IUCN-RLE standards, here we analyzed changes in the geographical distribution of this degraded grassland, to evaluate its degradation and risk of collapse. Past(1950-1980) distribution areas were extracted from the Vegetation Map of China(1:1,000,000). Present realizable distribution areas were equated to these past areas minus any habitat area losses. We then predicted the grassland’s present and future(under the Representative Concentration Pathway 8.5 scenario) potential distribution areas using maximum entropy algorithm(MaxEnt), based on field survey data and nine environmental layers. Our results showed that the S. bungeana grassland was mainly distributed in the Loess Plateau, Hexi Corridor, and low altitudes of the Qilian Mountains and Longshou Mountain. This ecosystem occurred mainly on loess soils, kastanozems, steppe aeolian soils and sierozems. Thermal and edaphic factors were the most important factors limiting the distribution of S. bungeana grassland across China. Since 56.1% of its past distribution area(4.9×10~4 km^2) disappeared in the last 50 a, the present realizable distribution area only amounts to 2.2×10~4 km^2. But only 15.7% of its present potential distribution area(14.0×10~4 km^2) is actually occupied by the S. bungeana grassland. The future potential distribution of S. bungeana grassland was predicted to shift towards northwest, and the total area of this ecosystem will shrink by 12.4% over the next 50 a under the most pessimistic climate change scenario. Accordingly, following the IUCN-RLE criteria, we deemed the S. bungeana grassland ecosystem in China to be endangered(EN). Revegetation projects and the establishment of protected areas are recommended as effective ways to avert this looming crisis. This empirical modeling study provides an example of how IUCN-RLE categories and criteria may be valuably used for ecosystem assessments in China and abroad.     

conomic losses from reduced freshwater under future climate scenarios: An example from the Urumqi River,Tianshan Mountains

As important freshwater resources in alpine basins,glaciers and snow cover tend to decline due to climate warming,thus affecting the amount of water available downstream and even regional economic development.However,impact assessments of the economic losses caused by reductions in freshwater supply are quite limited.This study aims to project changes in glacier meltwater and snowmelt of the Urumqi River in the Tianshan Mountains under future climate change scenarios(RCP2.6(RCP,Representative Concentration Pathway),RCP4.5,and RCP8.5)by applying a hydrological model and estimate the economic losses from future meltwater reduction for industrial,agricultural,service,and domestic water uses combined with the present value method for the 2030 s,2050 s,2070 s,and 2090 s.The results indicate that total annual glacier meltwater and snowmelt will decrease by 65.6%and 74.5%under the RCP4.5 and RCP8.5 scenarios by the 2090 s relative to the baseline period(1980-2010),respectively.Compared to the RCP2.6 scenario,the projected economic loss values of total water use from reduced glacier meltwater and snowmelt under the RCP8.5 scenario will increase by 435.10×10⁶ and 537.20×10⁶ CNY in the 2050 s and 2090 s,respectively,and the cumulative economic loss value for 2099 is approximately 2124.00×10⁶ CNY.We also find that the industrial and agricultural sectors would likely face the largest and smallest economic losses,respectively.The economic loss value of snowmelt in different sectorial sectors is greater than that of glacier meltwater.These findings highlight the need for climate mitigation actions,industrial transformation,and rational water allocation to be considered in decision-making in the Tianshan Mountains in the future.