上海市城区典型道路行驶特征研究

对上海市城区快速干道、主干道和次于道等3种典型道路上的机动车行驶特征和交通状况进行试验和调查，得出了上海市城区各类道路上机动车行驶特征参数和交通密度。结果显示，上海市城区各类道路综合行驶特征为平均速度低，加减速频繁。其中又以主干道交通状况最差。文中的数据和结论不仅可以用于上海城市交通规划，而且对控制道路两旁机动车污染具有重要意义。     

Single umbilical artery: Prenatal findings

In 450 patients with pregnancy at high risk for fetal malformation and/or intrauterine growth retardation, the umbilical cord was investigated sonographically for the presence of a single umbilical artery. A single umbilical artery was diagnosed in four fetuses between 23 and 33 weeks of gestation and suspected in two. Three cases were overlooked at sonography. All seven surviving fetuses had growth retardation at delivery and four also showed severe malformations. Whenever a single umbilical artery is found at sonography, further work-up is required to rule out associated anomalies, intrauterine growth retardation, or chromosomal abnormality.     

Numerical methods for improving sensitivity analysis and parameter estimation of virus transport simulated using sorptive-reactive processes

Using one- and two-dimensional homogeneous simulations, this paper addresses challenges associated with sensitivity analysis and parameter estimation for virus transport simulated using sorptive-reactive processes. Head, flow, and conservative- and virus-transport observations are considered. The paper examines the use of (1) observed-value weighting, (2) breakthrough-curve temporal moment observations, and (3) the significance of changes in the transport time-step size. The results suggest that (1) sensitivities using observed-value weighting are more susceptible to numerical solution variability, (2) temporal moments of the breakthrough curve are a more robust measure of sensitivity than individual conservative-transport observations, and (3) the transport-simulation time step size is more important than the inactivation rate in solution and about as important as at least two other parameters, reflecting the ease with which results can be influenced by numerical issues. The approach presented allows more accurate evaluation of the information provided by observations for estimation of parameters and generally improves the potential for reasonable parameter-estimation results.     

Idiothetic orientation of a wandering spider: Compensation of detours and estimates of goal distance

Summary The wandering spider Cupiennius salei Keys uses idiothetic orientation, i.e., memorized information about its own previous movements, to retrieve lost prey. Spiders, having been chased away from a prey fly, return to the capture site (the goal) over a distance of more than 75 cm even though all external orientation cues were precluded. This behavior and its sensory basis were examined by varying the proprioceptive and motor command inputs to the memory and by ablating particular lyriform slit sense organs on the legs of the spider.The success rate of returns to the goal after rectilinear chases over 6 discrete distances ranging from 20 cm to>41 cm declines with increasing distances. At distances>41 cm, more than 50% of the performances of intact spiders are nevertheless successful, in that the animals approach the capture site as close as 5 cm (or less).Animals that have been operated on (lyriform organs on all femora destroyed) are much less successful even at short distances. The mean starting angles of the returns by intact spiders and by those operated on do not differ signficantly. Walking error e _n for each segment of the entire return path shows that intact animals deviate little from the ideal return route and correctly estimate the distance to the goal. The operated spiders tend to drift off the ideal return route, while their distance estimates remain largely accurate.Returns after curvilinear chases through a semicircular corridor do not retrace the curved path; instead the spiders take a shortcut. Of all performances by intact and by control spiders (with sham operations) 85% are successful. By contrast, most of the 8 groups with sensory ablations have a success rate of less than 50%.Compensation for the semicircular detours is not quite complete: the mean starting directions of returns are biased, pointing to the corridor, and the shape of many return paths reflects the curved corridor shape. Spiders with unilateral ablations of their femoral lyriform organs show low success rates only if the operated legs are on the inner curve perimeter during the chase, while their return parameters resemble those of the intact group in the reverse situation (operated legs on outer perimeter). These side-specific ablation effects, which are correlated with the geometrical situation existing while idiothetic information is gathered and memorized, suggest that the idiothetic memory depends at least partly on input from proprioceptors.     

Medical investigation after a motorcoach strikes the rear of a tractor semitrailer parked on the highway; 13 fatal

Abstract

Objective: The objective of this study was to examine the medical conditions of 2 commercial drivers and the effects of physical barriers to occupant egress in a crash involving a tractor trailer and a motorcoach in order to assess and identify the factors that caused the crash and had a significant effect on occupant extrication.

Methods: Physical evidence from the scene, video evidence, commercial driver information, phone records, toxicology findings, autopsy results, and personal medical information were reviewed.

Results: On October 23, 2016, at 5:16 a.m., a motorcoach carrying a driver and 42 passengers struck the rear of a stopped semitrailer occupied by its driver in the center-right lane of Interstate 10 at highway speed outside Palm Springs, California. The motorcoach driver and 12 passengers died; 11 passengers were seriously injured.

All traffic had been stopped on I-10 early that morning to allow electrical lines to be strung over the highway. Security camera footage showed that the truck arrived at the end of a traffic queue 2?min before traffic flow resumed. Physical evidence indicated that the truck’s parking brake was still engaged at the time of the collision about 2?min later. The truck driver had a body mass index (BMI) between 45.6 and 50?kg/m², which placed him at very high risk of moderate to severe obstructive sleep apnea; he also inaccurately recalled that he had been stopped for 20–25?min and had placed the vehicle in gear just before the collision.

The motorcoach driver was on the return leg of an overnight trip to a casino. Based on his phone records, known driving time, and security camera footage, at the time of the collision he had had 4?h of sleep opportunity in the preceding 35?h. There was no evidence that the motorcoach driver attempted any evasive action before the collision. In addition, postmortem testing revealed a hemoglobin A1C of 11.4%, indicating poorly controlled diabetes; this was apparently undiagnosed prior to the crash.

The motorcoach was equipped with a single loading door at the front of the vehicle; it was rendered inoperable by the collision. Emergency egress was initially carried out through the emergency exit windows, but they repeatedly swung shut, impeding passengers’ efforts to exit. Emergency responders eventually cut open the bus wall to create a larger means of egress. Overall, it took almost 3?h to extricate the occupants from the vehicle.

Conclusions: The National Transportation Safety Board (NTSB) determined that the probable cause of the accident was the truck driver’s falling asleep, most likely due to undiagnosed moderate-to-severe obstructive sleep apnea, and the motorcoach driver’s failure to identify the stopped truck as a hazard requiring evasive action, most likely as the result of fatigue. Additional easy-to-use emergency exits would have decreased the time to extricate the occupants.     

Evaluating Flow Diversion Impacts to Groundwater‐Dependent Riparian Vegetation with Flow Alteration and Groundwater Model Analysis

An approach for assessing the potential ecologic response of groundwater‐dependent riparian vegetation to flow alteration is developed, focusing on change to groundwater. Groundwater requirements for riparian vegetation are reviewed in conjunction with flow alteration statistics. Where flow alteration coincides with groundwater‐related vegetation sensitivities, scenarios are developed for groundwater simulation. Groundwater depths and recession rates in the riparian zone are simulated for baseline and altered stream hydrographs, with changes to river stage and width represented with a transient, flow‐dependent boundary condition. Potential flow diversion from the Upper Gila River in New Mexico is examined. Statistical flow alteration analysis, applying prospective diversions to a 76‐year record of daily flow, shows that flows in the winter‐spring months and within the high‐pulse to small flood range are subject to greatest potential change. Groundwater simulation scenarios are developed for these flow conditions in representative dry, near‐average, and wet years. Differences in groundwater elevations, generally less than 0.25 m during the flow alteration period, dissipate rapidly following cessation of diversion. Relating groundwater depth, recession rates and range of fluctuations to riparian vegetation needs, we find adverse ecological response is not expected from groundwater impacts for the flow alteration examined.