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941.
环介导等温扩增联合横向流动试纸条快速检测扁浒苔(Ulva compressa)的研究 总被引:2,自引:1,他引:1
本研究将环介导等温扩增技术(loop-mediated isothermal amplification,LAMP)与横向流动试纸条(lateral flow dipstick,LFD)的可视化检测方法结合,建立了扁浒苔(Ulva compressa)的LAMPLFD快速检测技术。该方法以扁浒苔的内转录间隔区(ITS1-5.8S-ITS2)序列为检测靶标,设计了3对特异性引物(其中,上游内引物由生物素标记)和1条异硫氰酸荧光素标记的探针。结果表明,LAMP最适反应温度为63°C,扩增时间为60 min,从核酸扩增到LFD结果判读需70 min。利用LAMP-LFD可特异性检出扁浒苔,对浒苔、曲浒苔、缘管浒苔和孔石莼等石莼属绿藻以及塔玛亚历山大藻、无纹环沟藻、东海原甲藻、锥状斯克里普藻和赤潮异弯藻等常见微藻的检测结果为阴性。该方法最低可检测到0.1 pg的扁浒苔基因组DNA,是以Uco ITS-F3和Uco ITS-B3为特异性引物的PCR方法的100倍。对实际样品的检测结果表明,LAMP-LFD方法检测扁浒苔与传统的形态学观察的结果一致。因此,该方法可快速、特异地检测出扁浒苔,而且操作简单,仪器设备依赖性低,有潜力成为扁浒苔现场检测的常规技术手段。 相似文献
942.
The dynamic response of a towed cable system to ship maneuver is parametrically simulated. Three dimensionless parameters influence on towed cable system maneuverability is investigated. They are ratio of total length to turning radius R/L, ratio of cable mass to vehicle mass σ, and ratio of mass unit length to hydrodynamic force w/r. An oscillatory motion of towed vehicle is found in simulation of spiral towed courses. Features of this oscillation in different spiral courses are compared. The sharp turns, gradual turns and their transient states of towed cable dynamics for different course directions are discussed extensively. According to the characters of transient states and horizontal trajectories evolution of maneuvered cable system, the dynamic behaviors can be divided into three situations in Fig. 8 turning maneuvers. The behavior of towed cable system during a zigzag turning course is simulated in the end. Two ingredients of heave motion are found during small ratio of turning radii to length in this course. The primary damp to initial turning becomes weak and the response to alternative turns plays a more and more important role. The damping properties of the transient behavior in different maneuvers show a periodical invariance to σ during some turning maneuvers. 相似文献
943.
本文利用30~60天带通滤波资料, 考察了不同季节印度洋—西太平洋区域对流活动季节内尺度变率的主要模态, 发现在不同季节赤道东印度洋(5°S~10°N, 70°E~100°E)和西北太平洋(5°N~20°N, 110°E~160°E)对流活动均存在反相变化的关系, 将之称为季节内尺度的印度洋—西太平洋对流涛动(Indo-West Pacific Convection Oscillation), 简称IPCO。对IPCO两极子区域对流活动进行超前滞后相关分析, 发现IPCO事件形成—发展—消亡的生命周期是由对流活动季节内振荡及其传播造成的。对流扰动首先在赤道中西印度洋形成, 随后逐渐向东发展变强, 在其继续变强的过程中将分两支传播:一支由赤道印度洋向北传播, 至印度半岛南部后逐渐减弱消失;另一支沿赤道继续东传, 在海洋大陆受到抑制, 快速越过海洋大陆到达赤道西太平洋后又开始发展变强, 随后北传至西北太平洋区域逐渐减弱, 最终至我国长江流域中下游到日本区域消失。将这一过程划分为8个位相, 详细分析了不同位相对应的环流场和降水场特征, 最后给出了IPCO事件演化示意图。 相似文献
944.
Using the 1979-2009 NCEP/NACR reanalysis data and precipitation records in East China, research is performed of the climatological features of low-frequency oscillation (LFO) in OLR over the Maritime Continent (MC) as well as their associations with precipitation disturbance in the eastern part of China. Results suggest that in the MC there is significant climatological low-frequency oscillation (CLFO) in outgoing long-wave radiation (OLR), with the intraseasonal oscillation (30-60 days) being the strongest for April-September, and the MC acting as a high-value region of percentage contributions of low-frequency OLR variance. On the low-frequency time scale there occur four events of more intense active OLR during this time interval. In the January-April (May-August) phase, MC convection is relatively weak (vigorous). The CLFO makes pronounced eastward displacement at tropics, with phase propagation seen longitudinally, too. There occur low-frequency disturbance circulations similar to the EAP wavetrain or P-J teleconnection, starting from the MC via the South China Sea and the Philippines to the Yangtze valley of China. At different phases, the variation in the low-frequency circulations and heating fields shows that the rainfall disturbance in eastern China is likely to be under possible effects of the CLFO from the MC in April-September, and the low-frequency heating variation exhibits a meridional pattern as an EAP wavetrain or P-J teleconnection. As the OLR CLFO is in a peak (valley) phase the low-level divergence or convergence with the reversal at high levels over the MC is related to relatively feeble (robust) low frequency convection, thereby exciting an EAP or P-J wavetrain from the MC to the Sea of Japan. At the higher levels, the South-Asian high is eastward (westward) of normal due to effects of low-frequency cyclones (anticyclones), resulting in less (more) rainfall in the Jiangnan (areas in the middle and lower reaches of Yangtze and to the south of the river) and Hetao (the Great Bend of Yellow River) areas, and increased (decreased) rainfall in SW China, Qinghai Plateau and Gansu. At the conversion phases, low-frequency convection becomes more active in parts of the MC, consequently exciting low-frequency wavetrain of cyclones-anticyclones-cyclones at low levels, making the South-Asian high southward of the mean, so that strong convergent zones emerge in the upper and middle Yangtze basins and Jilin of NE China, responsible for plentiful precipitation there in sharp contrast to the rainfall over the band between the Yellow and Huaihe Rivers and the Yunnan-Guizhou Plateau. These results help understand in depth the climatological LFO characteristics and the phase-locked feature, thereby further improving our understanding of the causes of rainfall disturbances in different parts of the country. 相似文献
946.
947.
选用通河地震台体应变观测数据,采用功率谱密度估计方法,获得2015年5月30日日本小笠原群岛地区8.0级大地震和2017年9月8日墨西哥沿岸近海8.2级大地震激发的_0S_4—_0S_(35)基频球型自由振荡频率,并与地球初步参考模型(PREM)的理论自由振荡频率进行对比,结果发现:前者共被检测到11个基频信号,有7个信号与理论值存在偏差,1个存在频谱分裂现象;后者共被检测到17个基频信号,有9个信号与理论值存在偏差,1个存在频谱分裂现象。 相似文献
948.
Equilibrium trading of climate and weather risk and numerical simulation in a Markovian framework 总被引:3,自引:3,他引:0
Sébastien Chaumont Peter Imkeller Matthias Müller 《Stochastic Environmental Research and Risk Assessment (SERRA)》2006,20(3):184-205
We consider financial markets with agents exposed to external sources of risk caused, for example, by short-term climate events
such as the South Pacific sea surface temperature anomalies widely known by the name El Nino. Since such risks cannot be hedged
through investments on the capital market alone, we face a typical example of an incomplete financial market. In order to
make this risk tradable, we use a financial market model in which an additional insurance asset provides another possibility
of investment besides the usual capital market. Given one of the many possible market prices of risk, each agent can maximize
his individual exponential utility from his income obtained from trading in the capital market, the additional security, and
his risk-exposure function. Under the equilibrium market-clearing condition for the insurance security the market price of
risk is uniquely determined by a backward stochastic differential equation. We translate these stochastic equations via the
Feynman–Kac formalism into semi-linear parabolic partial differential equations. Numerical schemes are available by which
these semilinear pde can be simulated. We choose two simple qualitatively interesting models to describe sea surface temperature,
and with an ENSO risk exposed fisher and farmer and a climate risk neutral bank three model agents with simple risk exposure
functions. By simulating the expected appreciation price of risk trading, the optimal utility of the agents as a function
of temperature, and their optimal investment into the risk trading security we obtain first insight into the dynamics of such
a market in simple situations.
相似文献
Peter ImkellerEmail: |
949.
航道3维可视化对全面掌握运河河底地形地貌,保障运河水上交通安全具有重要意义。本文以3维可视化苏南运河镇江段航道为例,阐述如何在实现航道周边场景3维渲染的基础上,利用航道数字测深数据,创建基于格网的数字水深模型,进而生成河底数字高程模型的过程,并对航道3维可视化技术的实际应用进行了探讨。 相似文献
950.