坎儿井衰减与地下水补排系统响应关系

为了探究坎儿井衰减与地下水补排系统响应关系,利用地下水位观测资料和坎儿井流量监测资料,结合鄯善县历次地下水资源调查评价资料和坎儿井统计数据,分析了地下水补给量、排泄量对坎儿井衰减的影响,并建立了最小二乘回归模型,在执行最严格水资源管理制度下对2020年、2030年坎儿井出水量进行了预测。结果表明,坎儿井流量动态与地下水位动态基本同步;北盆地的坎儿井出水量主要受地下水补给量的影响,南盆地主要受地下水开采量的影响。地下水开采量是影响鄯善县坎儿井衰减的关键因素,在最严格水资源管理制度下鄯善县坎儿井出水量将会在2020年恢复至0.83亿m~3,2030年恢复至0.87亿m~3。     

秸秆覆盖与镇压对小黑麦生长状况的影响

以小黑麦作为研究材料,通过设置5种不同的秸秆覆盖与镇压处理,在小黑麦的各个生长期对其进行生理指标的测定,研究秸秆覆盖与镇压对小黑麦鲜重和干物质重、株高、次生根、叶片数的影响.试验结果表明:5种处理下小黑麦的生长状况呈现出了:A4＞ A3＞ A＞ A1＞ A5.而且A4处理下小黑麦的生长状况明显大于其他各组处理下小黑麦的...     

Assessment of Uterine Vascular Perfusion During the Estrous Cycle of Mares in Connection to Circulating Leptin and Nitric Oxide Concentrations

The objective of this study was to find difference in vascular perfusion of uterine horns or uterine body throughout the estrous cycle and their relation to circulating nitric oxide and leptin concentrations. Five cyclic mares were subjected to transrectal Doppler ultrasonography and blood sampling for 18 days. Area of color and power Doppler modes was measured in pixels. Day (P = .0001) of the estrous cycle and ovulation (P = .0001) influenced uterine blood flow. Uterine body blood flow directed away from the transducer (blue, P = .0001) increased from day −5 until day 0 (day of ovulation), and its power (P = .0001) blood flow increased from day −6 until day 0; then, both decreased until days 12 and 10, respectively. Conversely to the contralateral uterine horn, ipsilateral uterine horn blood flow directed away from the transducer (blue, P = .0001) increased from day −5 until day −1, and its power (P = .0001) blood flow increased from day −6 until day 0; then, both decreased until day 10. Nitric oxide concentrations (P = .0001) attained two major peaks; the first on day −3 and the other persisted from day 2 until day 5. Leptin concentrations increased (P > .001) with a maximum value on day 0 and then decreased until a minimum value on day 9. In conclusion, during the estrous cycle, ipsilateral uterine horn and uterine body blood vessels had similar blood flow. Both leptin and nitric oxide played a role during follicle growth, ovulation, and corpus luteum development and modulated uterine blood flow before and after ovulation.     

The Standardization of an Apparatus for the Mixing of Soil Samples for Nematode Extractions

Quantitative determination of nematode populations in soils frequently necessitates the mixing of representative soil samples to form a homogeneous, compound sample from which the nematodes are extracted. A mixing apparatus was developed and standardized with the aid of a spectrophotometric technique by which the dispersion of a dye through the soil during mixing could be determined. It was found that the mixer is most suitable for use on sandy loam soils. Optimal mixing is obtained at a speed of 15 rpm for 2 minutes. Under these conditions mechanical damage to nematodes during mixing is minimal.     

干旱矿区不同干扰强度下土壤种子库特征

土壤种子库是矿区植被恢复的重要因素,其特征在一定程度上反映了区域的植被恢复潜力。本研究通过样地调查和室内萌发法对乌海新星煤矿区3种不同干扰条件下的土壤种子库及与其地表植被之间的关系进行分析。结果表明:1)新星矿区土壤种子库共有18种植物,隶属于7科16属,物种生活型以多年生草本植物为主;2)新星矿区土壤种子库平均储量较小(226.51~739.17粒·m^?2),并且随着土层深度增加而呈递减趋势,其90%以上的种子储藏在0?10 cm的表层土壤;3)研究区土壤种子库植物与地上植被的共有物种数少,土壤种子库与地上植被的植物群落相似性较低;4)随着干扰强度的增大,种子库的植被恢复潜力呈现先增大后减少的趋势:道路周边受到中度干扰的自然植被区朝着有利的方向发展,而采矿周边受重度干扰的自然植被区会受到较大负面影响,其多样性以及与其他分区植物群落的相似性较小,种子密度显著降低(P<0.05)。     

高效节水灌溉管道流量计算原则初探

对于管网优化及投资分析来说,最不利情况下的水力条件不是普遍条件,不能够完全代表管网应当有的优化假定条件。通过管道控制灌溉面积来确定管道的流量,按照满足在一天内,管道控制的所有灌水器都灌溉一次的原则确定,并给出公式。让管道的流量这一重要参数,在高效节水灌溉工程优化和设计计算中变得简单并容易计算。     

水头可调薄壁堰式渠道流量智能测控系统优化试验研究

采用巴赞堰流公式计算流量的水头可调薄壁堰式渠道流量智能测控系统通过渠道流量量测与控制试验,验证了其精准的测流功能和智能控制技术的可行性。为进一步提高该测控系统运行的效率和稳定性,减少运行能耗,对矩形薄壁堰堰流公式进行水力试验研究,通过分析堰上水头和流量关系,拟合出矩形薄壁堰流量计算公式。通过向该拟合公式引入修正系数λ=0.848,将测控系统测得的堰上水头数据值代入该拟合公式求得的流量值与电磁流量计测得流量值的差值的平均值为-0.004L/s,标准差为0.119,线性相关系数R2=0.989 1。该拟合公式相对于巴赞堰流公式形式简单、参数较少、运算简便,同时也满足节水灌溉对精准测流的要求,更适用于水头可调薄壁堰式渠道流量智能测控系统,对于在灌区推广和使用该测控系统具有重要的意义。     

The Fluorescent Characterization and Analysis of Two Brucella Attenuated Vaccine Infecting Mouse Macrophagocyte

The experiment was conducted to discuss the difference of binding time of green fluorescent protein B.melitensis M5 (GFP-M5) and B.abortus S19 (GFP-S19) infecting the mouse macrophagocyte (RAW264.7),lysosome,endoplasmic reticulum and golgi body in the initial stage and compare the binding rate of GFP-M5,GFP-S19 with organelle in different timeline,respectively,by confocal laser scanning microscope (CLSM) and flow cytometry.The result showed that GFP-M5 and GFP-S19 were successfully constructed.The intracellular survival ability of Brucella M5,Brucella S19,GFP-M5 and GFP-S19 were not obvisouly affected after infecting RAW264.7.GFP-M5 and GFP-S19 could enter the macrophagocyte in 30 mins,and in 2 h the Brucella could reach lysosome,endoplasmic reticulum and golgi body.In addition,the binding time for two attenuated vaccine did not show differences in 1,2,3 and 4 h.The content of GFP⁺ cell produced by RAW264.7 infected by GFP-M5 and GFP-S19 did not show significant differences (P>0.05).Therefore,the two strains did not have significant differences in the invasion ability in the initial stage of infecting host cell.     

The nearest-plant method is robust and powerful enough for different survey teams to monitor change in mesic grassland species composition

A long-term rangeland monitoring programme needs to employ a field survey technique that is practicable, precise, powerful enough to distinguish change, not prone to worker bias, and able to distinguish real change from operator error arising from staff turnover. These criteria were used to evaluate a widely used grassland sampling technique in South Africa – the nearest-plant (with 200 points) method (NP) – against common alternatives, namely NP excluding forbs (NP-nf), the plant number scale (PNS; a cover-abundance method) and quadrat frequency (QF), using multivariate ordination and permutation tests. Four trained teams surveyed four grasslands using each method. PNS took more than twice as long as the other techniques, which were similarly rapid. Estimates of composition using NP methods were the most precise and PNS was least repeatable, with QF intermediate. Compositional differences between sites were most finely distinguished using NP-nf, followed by NP and QF. PNS was able to detect only marked differences and had the greatest potential for surveyor bias. The NP method, with or without including forbs, is therefore recommended for monitoring the species composition of mesic, dense grassland. Some suggestions for monitoring agencies on how best to use multivariate methods are presented.     

Livestock grazing has minimal effect on the species richness and diversity of semi-arid shrubland in the Western Little Karoo,South Africa

The Succulent Karoo, one of two arid biodiversity hotspots in the world, is known for its high plant species richness, but little is known about the influence of topography and how it mediates the potentially deleterious effects of grazing. Changes in vegetation species composition, cover and species diversity were examined along piosphere gradients on northerly slopes, bottomlands and low-lying plains on 45 farms. Landscapes differed in the plant speciesand life-form composition, species richness and cover, with the more species-rich, heterogeneous grassy northerly slopes distinct from the plains and bottomlands, which were dominated by Pteronia pallens, Psilocaulon junceum and Drosanthenum spp. with more annual and ephemeral species. Overall, species richness declined linearly with decreasing rangeland condition. A weak grazing effect was detected only on the north-facing slopes, where shrubs and grass decreased with intense grazing. Years of overgrazing have resulted in the widespread dominance of P. pallens, especially on the plains and bottomlands, rendering them insensitive to grazing. The current condition of the northern slopes should be maintained and managed such that palatable species can spread to more degraded areas of the landscape.