Does information of predators influence general wariness?

Antipredator behavior includes several qualitatively distinct activities, but few studies have determined the degree to which these activities are independent. If behaviors are not independent, then the nature of the relationship would illustrate potential performance constraints. We studied crimson rosellas (Platycercus elegans) and first focused on acoustic predator discrimination. We measured time allocation before and after playback of one of three experimental treatments (peregrine falcons—Falco peregrinus, wedge-tailed eagles—Aquila audax, and crimson rosellas) to determine whether or not rosellas discriminated predators from non-predators, and specifically whether or not they discriminated large from small predators. We then focused on the decision to flee. We experimentally approached subjects and measured the distance at which they oriented to us (alert distance) and the distance at which they fled (flight initiation distance; FID). We found that rosellas could distinguish among predators; however, there was no effect on general wariness as measured by FID. These two processes of antipredator behavior may, thus, be independent.     

基于放射源理论的区域生态系统评价方法

研究区域生态系统定量评价方法对区域生态系统的建设与保护具有十分重要的意义。从放射源理论出发,首次将生态影响距离、生态源及生态影响效应的概念引入分析评价中,提出了区域生态系统的定量评价方法,并建立了基于景观空间格局的区域生态系统生态影响的定量计算公式。甘垛镇新庄片和横泾镇沿荡片的应用实例表明,该方法原理简明、结果直观,为区域生态系统的科学评价提供了定量评价方法。     

Time course of pyrrolizidine alkaloid sequestration in <Emphasis Type="Italic">Longitarsus</Emphasis> flea beetles (Coleoptera,Chrysomelidae)

Summary. Several species of Longitarsus take up, metabolize and store pyrrolizidine alkaloids (PAs) from their host plants. In feeding experiments using radioactively labeled PAs of different types we examined the time course of the sequestration process in L. jacobaeae and L. aeruginosus. We found that adapted species efficiently store PAs for at least two weeks without major losses. During that time, there is virtually no change in the ratio of tertiary alkaloids to stored non-toxic N-oxides, regardless of chemical form fed to the beetles. This implies a transient N-oxidation process where the alkaloids are only temporarily accessible to the enzyme. A dissection experiment with L. aeruginosus six days after uptake of labeled PAs showed that the tertiary alkaloids are not found in the hemolymph but are stored in the elytra and other body compartments. This conforms with earlier experiments that localized the enzymes site of action in the hemolymph. Furthermore we show that different total alkaloid doses in the diet of L. jacobaeae and the potentially less adapted L. succineus do not affect the ratio of recovered N-oxides to tertiary molecules. Thus, the efficiency of the N-oxidizing enzyme is not dependent on the concentration of alkaloids offered.     

湿式煤气柜施工安全措施的制订

针对正在运行的湿式煤气柜防火间距不够的位置动火建造大10倍的湿式煤气柜的实际情况,采取现场调查、安全系统分析,制订切实可行的措施,顺利完成施工任务。     

One-step estimation method and nomogram to predict safety distances of pressurized gas pipelines from blast sources

Pressurized gas pipelines may be endangered by accidental or intentional activities causing excess ground vibrations leading to failure. Thus, many papers have been published on this issue, yet most of these efforts suffer from complexity and inability to ascertain that all engaged factors are taken into account. These factors are attributed, namely, to explosion source, explosion-ground interaction, energy transfer through the ground, ground-pipeline interaction, and response of the pipeline. The deterministic method developed previously by the author has derived useful prediction mathematical formulas that can be used to calculate, either the stand-off distance of purposefully used explosives, or the maximum quantity of explosives to be used at a given distance, or the equivalent stress of a pipeline induced by an explosive charge at a given standoff distance. The method can also be applied to accidental blast events in factories or other activities. Yet, the complex formulas developed are hard to be used in the field and a simpler approach is needed to facilitate and accelerate in-field estimations. Thus, a nomogram was prepared to make the safety estimations easy and fast and taking into account all engaged critical factors starting from the explosion source through the integrity of the structure.     

Insight into the safety distance of ground and underground installations in typical petrochemical plants

Petrochemical plants are continuously turning into large-size corporations, the installations of facilities show a developing trend from ground to underground because of the difference in land using rate. In this regard, the safety distance of petrochemical equipment buried in both ground and underground cases were investigated based on risk assessment. As a case study, gasoline tank and LPG tank set on the ground and underground are singled out to compare the risks involved. The research showed that the setting case of installation had a great influence on safety distance. Two cases have 80% reduction of equivalent safety distance compared with the rest of the cases. It was found that when the gasoline storage tank was placed underground alone, the PLL value decreased by 36.7%. Only LPG tank was placed underground, and the PLL decreased by 6.33%, and the gasoline and LPG storage tanks were placed underground simultaneously, the PLL value declined by 42.3%. Thus, the layout of plants could be further optimized, which can greatly improve the performances of land use efficiency and safety. In addition, this paper, the selection of embedding methods and the sensitivity of underground case to overpressure was resumed from two aspects: soil properties and burial depth. For the soil properties, it was found that the water saturated sandy soil with high air content and the low density unsaturated sandy soil had better effects on weakening overpressure. Such properties are particularly beneficial to reducing the occurrence rate of accidents. In terms of burial depth, it can be observed that as the burial depth was changed from 0.5m to 1.1m, the value of overpressure has dropped dramatically. When the burial depth was 2m, the damage to personnel and buildings has been greatly reduced beyond 2m from the explosion center.     

基于随机森林的飞机长着陆预警方法

为降低飞机冲出跑道事故造成的人员伤亡和财产损失,以长着陆事件为研究对象,探讨1种有效的长着陆事件预警方法。提出应用随机森林模型对长着陆事件进行预警,给出模型的特征筛选、构建及评价方法,并使用实际飞行数据验证模型有效性。结果表明:基于随机森林的飞机长着陆预警模型精确率为88.41%,召回率为87.14%,模型可以有效对长着陆事件进行预警。     

考虑驾驶员反应时间的车辆碰撞预警模型

为了保证车辆在行驶过程中的安全性,提出了一种考虑驾驶员反应时间的车辆碰撞预警模型,改进了传统模型中驾驶员反应时间定值化的缺点。首先,依据车辆的制动过程分析了驾驶员反应时间对制动距离的影响。其次,设计驾驶员反应时间的模糊推理算法,选取驾龄、疲劳强度和应变能力3个主要因素作为评价指标来计算反应时间。最后,采用分等级的预警策略建立考虑驾驶员反应时间的碰撞预警模型,并通过Carsim-Matlab/Simulink联合仿真与传统模型进行对比分析。结果表明,设计的预警模型可以对不同类型的驾驶员进行差异化碰撞预警,在30 km/h和80 km/h两种车速下实际停车距离与理论值的最大误差为8%。