Benefit of suites of defensive behavior induced by predator chemical cues on anuran tadpoles, Hyla japonica

When predator chemical cues are present, low activity of prey is a commonly seen defensive behavior. However, few studies have explored the functional implications of the defensive behaviors and, thus, elucidated the possible linkages between behavioral responses and its consequences. In this study, we experimentally investigated how behavioral responses of Hyla japonica tadpoles to predator chemical cues affect vulnerability to a dragonfly nymph Anax parthenope julius. The frequency of tadpoles attacked by dragonfly nymphs was lower with chemical cues of predator was present than without chemical cues, and most of attacks occurred when tadpoles were mobile. When tadpoles were exposed to chemical cues, on the other hand, their swimming speed was quicker and swimming distance was longer, respectively, and the rates of being approached of the swimming tadpoles by dragonfly nymph was lower than those not exposed to chemical cues. We found that the tadpoles are induced by predator chemical cues not only to generally lower activity but also to swim in bursts as additional behavior and that the suite of their behavioral responses reduce the vulnerability against dragonfly nymph. Tadpoles can receive information about the predation risks by chemical cues and adjust their defensive behavior accordingly.     

利用根箱法解析甜椒根际土壤中氮的行为(英文)

为研究甜椒根际土壤中氮的行为,与既报同样的方法进行研究,即,利用15NH4+,15NO3-双标记的硝胺(NH,4>15NO3,15NH4NO3),在温室里对甜椒进行6周的根箱栽培.收割后,对土壤全氮,NO3-N,水溶性NH4-N,KCl抽出NH4-N和其各自的15N atom%进行测定.结果表明,土壤全氮从非根际到根际逐渐增加,与栽培前相比,土壤全氮在非根际中减少,却在根际中增大.土壤NO3-N浓度朝根际增加到离根际2 mm处,然后激减到根际.NO3-N的来自施给NO3-N的比例靠近根际逐渐升高,在根际达到了69%,反而,来自施给NH4-N的比例靠近根际逐渐降低,在根际将至7%左右.水溶性NH4-N和KCl抽出NH4-N浓度靠近根际逐渐降低,而且,从非根际到根际,二者匀保持3∶10的比例.KCl抽出NH4-N的来自施给NO3-N的比例靠近根际逐渐升高,但在根际仍低于3%,反而,其来自施给NH4-N的比例在非根际约为47%～55%,在根际降到41%.在整个根箱里,施用NO3-N的有機率达到62%,但其值在根际比非根圈要低.相反,施用NH4-N的有機率仅11%左右,但其值在根际比非根际要高.以上结果表明,在甜椒根际土壤中氮的无机化-有机化活性与水稻相比显著低.     

考虑主动避让行为的养老场所人员疏散研究

为明确主动避让行为对养老场所人员疏散的影响,建立考虑主动避让弱势群体行为的元胞自动机模型,模型分别考虑避让弱势群体前方行走区域、斜前方行走区域、前方和斜前方行走区域对人员疏散的影响;分析不同避让方式下弱势群体比例、行人密度、弱势群体位置分布对整体疏散结果的影响.结果 表明:主动避让弱势群体行为能够降低疏散时间,增加疏散...     

Experimental investigation on explosion flame propagation of wood dust in a semi-closed tube

In order to explore flame propagation characteristics during wood dust explosions in a semi-closed tube, a high-speed camera, a thermal infrared imaging device and a pressure sensor were used in the study. Poplar dusts with different particle size distributions (0–50, 50–96 and 96–180 μm) were respectively placed in a Hartmann tube to mimic dust cloud explosions, and flame propagation behaviors such as flame propagation velocity, flame temperature and explosion pressure were detected and analyzed. According to the changes of flame shapes, flame propagations in wood dust explosions were divided into three stages including ignition, vertical propagation and free diffusion. Flame propagations for the two smaller particles were dominated by homogeneous combustion, while flame propagation for the largest particles was controlled by heterogeneous combustion, which had been confirmed by individual Damköhler number. All flame propagation velocities for different groups of wood particles in dust explosions were increased at first and then decreased with the augmentation of mass concentration. Flame temperatures and explosion pressures were almost similarly changed. Dust explosions in 50–96 μm wood particles were more intense than in the other two particles, of which the most severe explosion appeared at a mass concentration of 750 g/m³. Meanwhile, flame propagation velocity, flame propagation temperature and explosion pressure reached to the maximum values of 10.45 m/s, 1373 °C and 0.41 MPa. In addition, sensitive concentrations corresponding to the three groups of particles from small to large were 500, 750 and 1000 g/m³, separately, indicating that sensitive concentration in dust explosions of wood particles was elevated with the increase of particle size. Taken together, the finding demonstrated that particle size and mass concentration of wood dusts affected the occurrence and severity of dust explosions, which could provide guidance and reference for the identification, assessment and industrial safety management of wood dust explosions.     

Using European naturalistic driving data to assess secondary task engagement when stopped at a red light

Problem: Some evidence exists that drivers choose to engage in secondary tasks when the driving demand is low (e.g., when the car is stopped). While such a behavior might generally be considered as rather safe, it could be argued that the associated diversion of attention away from the road still leads to a reduction of situational awareness, which might increase collision risk once the car regains motion. This is especially relevant for texting, which is associated with considerable eyes-off-the-road-time. Nonetheless, it seems that previous research has barely addressed the actual engagement in secondary tasks while waiting at a red light (as compared to just addressing the tasks’ mere prevalence). Objective: The present study investigated secondary task engagement while stopped at a red light using European naturalistic driving data collected through the UDRIVE project. Attention was given to the whole engagement process, including simple prevalence and the tasks’ relation (in terms of start/end) to the red light period. Moreover, given that texting is one of the most problematic forms of distraction, it was characterized in more detail regarding glance behavior. Method: Videos of 804 red light episodes from 159 drivers were annotated. Glance behavior was also coded for a sub-set of 75 texting events and their matched baselines. Results, conclusions and practical applications: Drivers engaged in at least one secondary task across almost half of the annotated red light episodes. Drivers who texted while stopped spent most of the time looking at their cell phone. Consequently, drivers might not have been prepared for potentially unexpected events once the light turned green. Further, drivers concluded texting a considerable number of times well after the red light period, which has potential implications for traffic safety.     

Digital screen use for a road safety campaign message was not associated with road safety awareness of passers-by: A quasi-experimental study

Introduction: Recent evidence suggests fatality risks for cyclists may be increasing in Britain. Understanding how to increase levels of cycling while keeping risk low is paramount. Educating drivers about cyclists may help with road safety, and mass-media messaging is a possible avenue, potentially utilizing digital displays screens in public areas. However, no studies have examined the use of these screens for road safety campaigns. Methods: A quasi-experiment was conducted to examine if digital screens may be effective to raise awareness of a campaign message and encourage recall of car drivers. A digital campaign image was selected that encouraged car drivers and cyclists to ‘look out for each other,’ and stated than 80% of cyclists owned a driving license. Views and knowledge on driver priorities around cyclists were examined before (control) and after campaign exposure (intervention), and tested using regression modelling. Results: 364 people were interviewed over five days. Those interviewed on intervention days were more likely to rank ‘Look out for cyclists’ as being more important compared to those interviewed on control days (OR 1.20), but this was not statistically significant (p = 0.355). Those who said they had seen the image did not rank ‘Look out for cyclists’ higher than those who said they had not seen it (p = 0.778). The disparity between reported and displayed percentage of cyclists with a driving license did not differ between intervention and control days, but was 8% higher amongst those who claimed to have seen the image (p = 0.026). Conclusions: We did not find strong evidence that use of an image on digital screens increased public awareness or recall of a casualty reduction campaign message. Work is needed to investigate the effects of longer-term exposure to road safety images. Practical Applications: Short-term use of digital signage is not recommended for raising awareness of road safety campaigns.     

基于深度学习算法的叉车危险操作行为检测

随着物流仓储行业快速发展及叉车数量的不断增多,针对叉车作业过程中存在的人员碰撞、挤压、坠落等潜在风险,迫切需要对危险行为进行及时检测和预警。为解决人员值守易漏报误报及传统方法检测精度低的问题,建立基于图像特征识别的叉车检测深度学习模型和算法。通过采集、处理现场视频图像素材,完成模型的训练及性能评价,建立相应的报警规则和报警阈值,搭建测试环境并进行仿真测试,开发相应的软件系统。结果表明:模型检测速率为130 ms/帧,人员靠近叉车准确率为85.6%,叉车举升人员准确率为83.7%,达到良好的实践效果。     

Meta-analysis of human connection to nature and proenvironmental behavior

Understanding what drives environmentally protective or destructive behavior is important to the design and implementation of effective public policies to encourage people's engagement in proenvironmental behavior (PEB). Research shows that a connection to nature is associated with greater engagement in PEB. However, the variety of instruments and methods used in these studies poses a major barrier to integrating research findings. We conducted a meta-analysis of the relationship between connection to nature and PEB. We identified studies through a systematic review of the literature and used Comprehensive Meta-Analysis software to analyze the results from 37 samples (n = 13,237) and to test for moderators. A random-effects model demonstrated a positive and significant association between connection to nature and PEB (r = 0.42, 95% CI 0.36, 0.47, p < 0.001). People who are more connected to nature reported greater engagement in PEB. Standard tests indicated little effect of publication bias in the sample. There was significant heterogeneity among the samples. Univariate categorical analyses showed that the scales used to measure connection to nature and PEB were significant moderators and explained the majority of the between-study variance. The geographic location of a study, age of participants, and the percentage of females in a study were not significant moderators. We found that a deeper connection to nature may partially explain why some people behave more proenvironmentally than others and that the relationship is ubiquitous. Facilitating a stronger connection to nature may result in greater engagement in PEB and conservation, although more longitudinal studies with randomized experiments are required to demonstrate causation.     

交通空气污染对大鼠子代发育及社交行为的影响

交通空气污染与儿童自闭症的关联时有报道,但其因果关系仍待进一步探索。为研究出生前后暴露于不同水平的交通空气污染环境对生长发育和自闭症相关社交行为的影响,将Wistar大鼠雌雄1∶1交配,受孕雌鼠根据子代接触交通污染的时间(出生后暴露或胚胎期暴露)及浓度(低、中和高3个水平)分为6组。在子代出生后21～27 d,测量子代的体重、身长及大脑脏器系数,并根据三箱实验评估社交行为,同时检测仔鼠脑组织组蛋白H3第4个赖氨酸(H3K4)的甲基化水平。结果显示,出生前后,尤其是胚胎发育阶段接触较高浓度的交通空气污染物可导致幼鼠体重及大脑湿重较低,身长较短、大脑脏器系数偏高等生长发育特征改变。同时,出生前后较高浓度的交通空气污染物暴露可导致幼鼠出现社交能力下降、社交记忆受损及社交新颖性减弱等典型自闭症样行为改变。虽然组蛋白H3K4甲基化水平与交通空气污染物浓度之间未见统计学关联,但出生后暴露组具有较高的H3K4甲基化水平,提示出生前后接触交通空气污染物可能与自闭症的发生发展有关,而不同暴露时期对脑组织H3K4甲基化水平的影响,为今后进一步探讨自闭症的表观遗传机制提供了线索。     

广花盆地地下水化学特征及其演化分析

粤港澳大湾区(简称大湾区)建设已经上升为中国国家重大发展战略,水资源保障能力提升是大湾区建设的重点内容。城市应急备用水源建设是解决区内供水风险、保障特殊时期供水安全的重要手段,查明水环境质量状况及其演化对于备用水源地的科学建设意义重大。以粤港澳大湾区应急备用水源地-广花盆地为研究对象,采集并测试了41口监测井水样的常规化学组分,利用主成分分析、元素比值和Gibbs模型等多种方法,探讨了地下水主要离子来源及控制因子,评估了水质状况。结果表明:地下水的TDS变化范围为51.42-1 293.36 mg·L-1,Cl-为1.81-858.65 mg·L-1,淡水样占比95.1%,微咸水占比4.9%,反映地下水化学具有较大的空间差异;地下水阳离子以Ca2+和Na+为主,阴离子以HCO3-和Cl-为主,为HCO3-Ca、HCO3-Na·Ca、HCO3·SO4-Na·Ca和HCO3·Cl-Na·Ca型水;地下水的ρ(Na+)/ρ(Na++Ca2+)值为0.02-0.59,ρ(Cl-)/(Cl-+HCO3-)值为0.03-0.88,Ca/Na值为0.69-52.66,HCO3/Na值为1.28-41.64,据Gibbs模型和元素化学计量分析表明,其化学组成主要受含水层碳酸盐岩和硅酸盐岩风化控制;Na/Cl系数为0.31-6.39,局部地下水盐化明显,在北部高Cl-质量浓度区,其主要受古咸水与现代淡水混合影响,并有Na+与Ca2+离子交换,在南部的高Cl-质量浓度区,可能是海水沿流溪河咸潮上溯和河流侧向补给地下水所致;氨氮为0.05-7.50mg·L-1,有75.6%的样品超过Ⅲ类水标准,其主要来源为农业施肥、人畜粪便。由此,氨氮污染威胁地下水安全,作为应急备用水源应引起高度重视。