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131.
本研究将交叉引物恒温扩增技术(cross priming amplification,CPA)与核酸试纸条相结合建立一种副溶血性弧菌(Vibrio parahaemolyticus)快速可视化检测方法。针对副溶血性弧菌特有的不耐热溶血素基因tlh的六个不同区域设计两对特异性引物和一对检测探针,通过优化反应条件确定了最佳反应体系。CPA-核酸试纸条方法对副溶血性弧菌的检测具有较强的特异性,对纯培养物的检测灵敏度达到58 cfu/m L,对污染牡蛎中副溶血性弧菌的检测灵敏度为5.2 cfu/g,比传统的PCR技术灵敏度提高了10倍,且具有较高的稳定性。交叉引物恒温扩增技术与核酸试纸条相结合的方法操作简便、特异性强、灵敏度高且能有效防止污染,可用于现场及基层单位副溶血性弧菌的快速检测。  相似文献   
132.
探讨了应急地图的特点,简要分析了云南省现行的应急地图制作流程及缺点;结合云南省应急地图制作的实际情况,简要阐述了基于"图库一体化"技术的多级比例应急制图预案设计的主要思想及实施关键点;实现了应急地图凭经验设计到快速设计的转变,大大缩短了制作时间,提高了成图效率,更好地发挥了应急地图在处置突发事件中的突出作用;最后就目前存在的问题提出了下一步的研究方向。  相似文献   
133.
重庆万州长滩镇碾家梁滑坡是一个古老的缓倾角滑移—弯曲型滑坡。2015年5月,随着重庆雨季的来临以及人类的等不利因素的影响,古滑坡复活,根据监测,每天以1~2个mm级的速度下滑,形成潜在险情。本文分析了滑坡控制因子,如果下滑至磨刀石河,可能形成的次生灾害,尤其是堰塞湖的堆高、溃坝的可能性、下泄坝前流量等做出了初步估算和分析,为次生灾害的防治提供必要的依据。  相似文献   
134.
采用统计方法,分析了全球海洋表层海温和印太暖池区域海表温度的长期变化特征,探讨了热带印度洋-西太平洋(印太暖池)海表温度异常(SSTA)与北极海冰快速消融之间的可能联系。结果表明,从整体来看,百年来全球SSTA呈现缓慢升高,但期间也存在年际变化的波动,近10年来全球SSTA升高有减缓的趋势,印太暖池区域的SSTA长期变化与全球基本一致。而北极海冰覆盖率自20世纪80年代初由正距平转换为负距平,且以-1.5%/10 a的速度快速减少,每年7—10月的海冰覆盖率减少速度最快,分别为-2.6%/10 a、-2.8%/10 a、-3.0%/10 a和-2.5%/10 a。由相关分析可知,北极海冰覆盖率的快速减少与印太暖池区域SSTA变化存在密切联系,它们之间存在准两年的显著相关。这种联系的重要途径是通过北极涛动(AO)作为桥梁来完成的。采用回归分析,首次建立了夏秋季北极海冰变化与印太暖池区域SSTA之间的预报方程,并对未来两年北极海冰的变化进行了预测试验,2015年和2016年6—10月北极海冰覆盖率异常变化均为-6.16%,仍为快速减少的两年。这一工作对北极海冰变化的深入研究和预测具有一定的推动作用,对全球气候变化的评估提供了理论依据。  相似文献   
135.
Which is more important for tropical cyclone (TC) intensity and intensification, sea surface temperature (SST) or tropical cyclone heat potential (TCHP)? Investigations using best-track TC central pressures, TRMM/TMI three-day mean SST data, and an estimated TCHP based on oceanic reanalysis data from 1998 to 2004, show that the central pressure is more closely related to TCHP accumulated from TC formation to its mature stages than to the accumulated SST and its duration. From an oceanic environmental viewpoint, a rapid deepening of TC central pressure occurs when TCHP is relatively high on a basin scale, while composite distributions of TCHP, vertical wind shear, lower tropospheric relative humidity, and wind speed occurring in cases of rapid intensification are different for each TC season. In order to explore the influence of TCHP on TC intensity and intensification, analyses using both oceanic reanalysis data and the results of numerical simulations based on an ocean general circulation model are performed for the cases of Typhoons Chaba (2004) and Songda (2004), which took similar tracks. The decrease in TCHP due to the passage of Chaba led to the suppression of Songda’s intensity at the mature stage, while Songda maintained its intensity for a relatively long time because induced near-inertial currents due to the passage of Chaba reproduced anticyclonic warm eddies appearing on the leftside of Chaba’s track before Songda passed by. This type of intensity-sustenance process caused by the passage of a preceding TC is often found in El Niño years. These results suggest that TCHP, but not SST, plays an important role in TC intensity and its intensification.  相似文献   
136.
Abstract. In this work we have developed a very simple stochastic mathematical model of Ulva spp. growth to quantitatively evaluate the economic costs of algal harvesting and the related benefits in terms of avoided'economic loss'of clam production due to an effective prevention of algal blooms and the consequent anoxic crises. Algal growth was simulated by means of a discrete time difference equation of Ulva biomass where the finite growth rate depends only upon water temperature. In order to explicitly include environmental variability, a seasonal autoregressive model calibrated on available data was used to simulate water temperature. Different harvesting scenarios were analysed in terms of the number of harvesting vessels employed and the threshold biomass of Ulva at which vessels start to operate. Costs of algal harvesting and disposal, as well as monetary damages resulting from the collapse of clam production as a consequence of algal blooms, were assessed by interviewing the managers of the Clam Fishermen's Union of Goro. A Monte Carlo approach was used to estimate the mean and total statistical distribution of costs and benefits of different harvesting strategies. Our analysis shows that the most cost-effective management policy is attained with 4–6 vessels operating at low algal density able to harvest as much Ulva as possible with intensive and short interventions at the beginning of the seasonal growth.  相似文献   
137.
实验室用超声地形测量仪   总被引:7,自引:0,他引:7  
滩海工程模拟对地形测量的速度和精度要求很高。目前国内测量地形的仪器速度太慢 ,不能满足要求。实验室用超声地形测量仪 (以下简称地形仪 )可以在实验室大水池内快速、精确测量冲刷地形 ,测量精度达到± 2 mm,能在 1.2 m/ s的运动速度下以每厘米一个测点的密度进行测量。能绘出水下地形的三维立体图和二维等高线图 ,是目前国内水工实验室内独有的测量仪器。  相似文献   
138.
This paper presents a detailed palaeoglaciological reconstruction of ice sheet dynamics in the Seno Skyring, Seno Otway and Strait of Magellan region of the former Patagonian Ice Sheet, with a particular focus on previously hypothesised zones of rapid ice flow and the evolution of proglacial lakes. Geomorphological mapping from a combination of satellite imagery and oblique and vertical aerial photographs reveals a variety of glacial landforms that are grouped into several discrete flow‐sets and associated ice margin positions. The most distinct features are represented by flow‐sets of highly elongate streamlined glacial lineations on both sides of the Strait of Magellan. Based on the shape and dimensions of the flow‐sets and their abrupt lateral margins, a transverse and longitudinal variation in glacial lineation length and elongation ratio, and the reported presence of a potentially deformable bed and thrust moraines, the flow‐sets are interpreted as zones of rapid ice flow within the Otway and Magellan lobes. We hypothesise that this provides evidence for contemporaneous surge‐like advances within the lobes, which may explain the asymmetry in the lobate margin positions on either side of the strait. The mechanisms that initiated rapid flow are unclear, but are likely to have been influenced by internal factors such as a change in thermal/hydrological conditions at the bed. The topography of the region suggests ice‐dammed lakes would have formed as the ice lobes retreated. The westernmost of the former lakes, Lake Skyring, is delimited by a series of palaeo‐shorelines surrounding the present‐day lake Laguna Blanca and we reconstruct lake evolution based on manipulation of a digital elevation model. The size and orientation of meltwater channels and a large outwash plain indicate that Lake Skyring drained eastwards towards the Strait of Magellan, probably quite rapidly. We conclude that the potential for quasi‐independent surge‐like behaviour within adjacent lobes raises the possibility that, during climate‐driven ice expansion, some advances in this region may have been partly controlled by secondary internal feedback mechanisms. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
139.
The lack of analytical techniques for halogens in geological materials is mainly due to the loss of analytes during sample preparation. This study describes a rapid bulk rock digestion method (NH4F digestion) for determination of the abundances of Cl, Br and I in geological materials by SF-ICP-MS. During high temperature (200–240 °C) digestion, NH3 released from the decomposition of molten NH4F can effectively prevent the loss of halogens released from geological samples. Chlorine, Br and I were not lost during NH4F digestion at 220 °C for 0.25–6 h. The limits of quantitation for NH4F digestion were 2.8, 0.018 and 0.003 μg g-1 Cl, Br and I, respectively. Most results for halogens in geological reference materials by NH4F digestion were in agreement with their certified values, confirming that the high-performance rapid bulk rock NH4F digestion has sufficient digestion capability to extract Cl, Br and I from rocks, sediments and soils. In comparison, results obtained following acid digestion showed that HNO3 + HF digestion could effectively extract Br and I from soil and sediment samples, and that HNO3 acid digestion is only suitable to use for the determination of Br and I in soil samples.  相似文献   
140.
In this study, we employed National Centers for Environmental Prediction(NCEP)/National Center for Atmospheric Research(NCAR) reanalysis data and records from the China Meteorological Administration(CMA)Yearbook of Tropical Cyclones to investigate three factors: sea-surface temperature(SST), vertical wind shear(VWS),and the density of the core convection(DCC), which are responsible for the rapid intensification(RI) of 1949-2013 offshore typhoons. Our analysis results of these composite factors show that in the environmental wind field the typhoons are far away from the outer strong VWS; in the SST field they are in the high SST area; and the core convective activity is robust and takes a bimodal pattern. The difference in RI between typhoons over the East China Sea(ECS) and the South China Sea(SCS) is a smaller VWS for the ECS typhoons, which may be one of the reasons why typhoons in the ECS are more intense than those in the SCS. Our study results indicate that SST, VWS, and DCC can result in an RI after a certain time interval of 36 h, 24 h to 30 h, and 24 h, respectively. The RI indicates a lag in the atmospheric response to oceanic conditions. This lag characteristic makes it possible to predict RI events. In summary, where the SST is high(≥28 ℃), the VWS is small, and the DCC is high, an RI will occur. Where mid-range SSTs occur(26 ℃≤SST≤28 ℃), with small VWS, and high DCC, the RI of typhoons is also likely to occur.  相似文献   
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