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31.
Graceful Restart是一种旨在使路由协议重启的影响最小化的机制,其目的是尽量减少路由器重启导致的路由抖动,减少路由计算资源和网络带宽资源的浪费。在对Graceful Restart机制作深入研究的前提下,对开放路由平台Quagga进行了OSPF Graceful Restart扩展,实现了原型系统。 相似文献
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Antonios E. Goulas 《Packaging Technology and Science》2008,21(5):247-255
Changes in biochemical indices, microbial growth, headspace and sensory quality of mussels which had been packaged in two modified atmospheres [Modified atmosphere packaging (MAP) 1: 60% CO2/20% N2/20% O2 and MAP 2: 60% CO2/40% N2] and under vacuum (VP) were studied for 14 days. The results showed better quality retention and greater shelf life of mussels packaged under MAP 1 as compared to MAP 2 and VP samples. Increase in total volatile basic nitrogen followed the order: MAP 1 < MAP 2, VP < air (control) samples while increase in trimethylamine nitrogen followed the order: MAP 1 < air < MAP 2 < VP. The 2‐thiobarbituric acid (TBA) values of MAP 1 and air samples were significantly higher (p < 0.05) than the TBA values of VP and MAP 2 samples. MAP 1 showed a greater (p < 0.05) inhibition effect on total viable count of mussel samples than all other packaging conditions. Based primarily on odour scores, the MAP 1 samples remained acceptable up to ca. 10–11 days, the MAP 2 and VP up to ca. 7–8 days while the air‐packaged samples up to ca. 5–6 days of storage. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(6):1011-1020
Lipophilic toxins associated with diarrhoeic toxins were found in Mytilus chilensis (Blue mussels) and Aulacomya ater (Ribbed mussels). These shellfish samples were collected from Chiloe Island, Southern Chile. The samples were tested by liquid chromatography–tandem mass spectrometry (LC-MS/MS). After the analysis, four toxins were found: DTX-1, DTX-3, YTX and PTX. All toxins were identified by comparing their HPLC retention times with those of analytical standards and confirmed by LC-MS/MS. Dinophysistoxin-1 (DTX-1) and dinophysistoxin-3 (DTX-3) toxins were the major components within the mussel extracts. Nevertheless, the percentages of these toxins differed depending on the area they were collected from and/or the sampling date. The levels detected in Butacheuques Island for okadaic acid (OA) was 267?±?3.5?µg OA?eq?kg?1 (p?<?0.05) and for DTX-3 was 183.4?±?7.5?µg?kg?1 in ribbed mussels. Pectenotoxin (PTX) and yessotoxin (YTX) were the toxins detected in minor proportions in the toxic profile of the bivalves. The maximum concentration of YTX detected in ribbed mussels was 85.2?±?2.8?µg?kg?1 in Mechuque Island, whereas the PTX-2 level in ribbed mussels was 82.0?±?2.4?µg?kg?1 in Cailin Island. Analogues of YTX and PTX-2 were not detected in any of the analysed mussels, which did not support the supposed presence of isomers of toxins as a result of the enzymatic metabolism of bivalves. This study found evidence proving co-occurrence of lipophilic toxins – like PTX and YTX – with diarrhoeic toxin in samples collected in Southern Chile, which is, to date, the more complex mix of lipophilic toxins ever found in mussels samples from Southern Chile. 相似文献
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软烤贻贝中蜡样芽孢杆菌生长/非生长界面模型建立与评价 总被引:1,自引:0,他引:1
建立软烤贻贝中蜡样芽孢杆菌标准菌株(ATCC49064与DSMZ 4312)在不同贮藏温度(T)、pH、水分活度(Aw)下生长/非生长界面模型,对其拟合情况和来自软烤贻贝蜡样芽孢杆菌(YB001)的验证情况进行分析和评价,并与已建立的脑心浸出液肉汤(BHI)中蜡样芽孢杆菌生长/非生长界面模型进行比较。所建模型总方程为Lopit(P)=-208.457-2.167·T+35.304·pH+705.573·Bw+1.117·T·pH-7.072·T·Bw-174.946·pH·Bw,其中R2-Nagelkerke=0.979和χ~2=0.019(df=8,P=1)显示拟合度较高,而且其预测一致率明显高于BHI培养基中建立的模型,表明该模型在预测软烤贻贝中蜡样芽孢杆菌的生长/非生长情况有很高的精确度和很好的适用性。此外,贮藏温度、水分活度、pH及其交互作用显著影响蜡样芽孢杆菌的生长/非生长(P0.05)。因此可以通过所建生长/非生长界面模型量化温度、水分活度、pH值等栅栏因子并结合其交互效应来确保软烤贻贝的高品质与安全性。 相似文献
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Daryl J. McGoldrick Janice L. Metcalfe-Smith Michael T. Arts Donald W. Schloesser Teresa J. Newton Gerald L. Mackie Emy M. Monroe Johann Biberhofer Kennon Johnson 《Journal of Great Lakes research》2009
The Lake St. Clair delta (∼ 100 km2) provides an important refuge for native freshwater mussels (Unionidae) wherein 22 of the ∼ 35 historical species co-occur with invasive dreissenids. A total of 1875 live unionids representing 22 species were found during snorkeling surveys of 32 shallow (∼ 1 m) sites throughout the delta. Richness and density of unionids and zebra mussel infestation rates varied among sites from 3 to 13 unionid species, 0.02 to 0.12 unionids/m2, and < 1 to 35 zebra mussels/unionid, respectively. Zebra mussel infestation of unionids in the delta appears to be mitigated by dominant offshore currents, which limit densities of zebra mussel veligers in nearshore compared to offshore waters (13,600 vs. 28,000/m3, respectively). Glycogen concentrations in the tissues of a common and widespread species in the delta (Lampsilis siliquoidea) suggest that zebra mussels may be adversely affecting physiological condition of unionids in a portion of the Lake St. Clair delta. Physiological condition and community structure of unionids within the delta may also be influenced by differences in food quantity and quality resulting from the uneven distribution of water flowing from the St. Clair River. The delta likely supports the largest living unionid community in the lower Great Lakes and includes several species that have been listed as Endangered or Threatened in Canada and/or the state of Michigan, making it an important refuge for the conservation of native unionids. 相似文献
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A stratified random sampling design was used to examine the relations between selected hydraulic variables and the density of unionids at five sites on the Green, Licking, and Rough Rivers of Kentucky. We located the strata to ensure that samples occurred in a wide range of hydraulic conditions at each site. Eight 0.25 m2 quadrat samples were collected from each 25 m2 stratum. We measured mean water column velocity, depth, and substrate roughness before we sampled each quadrat. ‘Fliesswasserstammtisch’ (FST) hemispheres were used to estimate shear stress. In all, we collected 798 individuals of 28 species of freshwater mussels. Simple hydraulic characteristics of our study sites were not correlated consistently with mussel density. For instance, water depth and mussel density were positively correlated in the Green River, negatively correlated in the Rough River, and not significantly correlated in the Licking River. In contrast, we found consistent negative correlations in all rivers between mussel density and complex hydraulic variables, such as shear velocity and FST hemisphere number. We believe that the limited recruitment observed in these rivers may have resulted from operation of upstream flood control dams that altered flow regimes seasonally. We suspect that the increased discharge during spring and early summer resulted in shear forces sufficiently high on mussel beds to prevent settlement of newly metamorphosed juveniles. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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OpenFlow为软件定义网络提供了一种很好的实现方案,为科研人员研究下一代互联网技术提供了一种途径.OpenFlow对二层交换支持较为成熟,但缺少对三层路由的支持.提出了一种在虚拟机上运行开源路由软件Quagga进行路由计算,利用OpenFlow控制器通过获取虚拟机的路由表来控制OpenFlow交换机数据转发的OpenFlow路由实现机制. 相似文献
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