The role of driver sleepiness in car crashes: a systematic review of epidemiological studies

To assess the available evidence for a causal role of driver sleepiness in car crashes or car crash injury, and to quantify the effect, a systematic review of the international literature was conducted. The review included all studies with a fatigue-related exposure measure, a crash or crash injury outcome measure and a comparison group, regardless of publication status, language or date of the study. Eighteen cross-sectional studies and one case-control study fulfilled the inclusion criteria. The fatigue-related exposures investigated in these studies were sleep disorders (n = 14), shift work (n = 2), sleep deprivation/fragmentation (n = 1), and excessive daytime sleepiness (n = 2). Only one study used an injury outcome measure. Studies were limited in their ability to establish a causal relationship by their design, by biases, and in many cases, by small sample sizes. The better quality cross-sectional studies were suggestive of a positive relationship between fatigue and crash risk, but could not provide reliable estimates of the strength of the association. The case-control study provided moderately strong evidence for an association between sleep apnoea and risk of driver injury, with an adjusted odds ratio of 7.2 (95% confidence interval 2.4-21.8). We conclude that the direct epidemiological evidence for a causal role of fatigue in car crashes is weak, but suggestive of an effect. To estimate the burden of injury due to fatigue-related crashes in the population, information is required from well-designed observational epidemiological studies about the prevalence of fatigue in the car driving population and the size of the risk this confers.     

Gender differences in the inhibitory effects of a reduction in ambient temperature and a reduction in food quantity on reproduction in the Southern African rodent, Rhabdomys pumilio

The effects of a reduction in ambient temperature (from 26 degrees C to 15 degrees C) and a 10% reduction in daily food consumption on reproductively active male and female four-striped field mice ( Rhabdomys pumilio) were investigated. In male R. pumilio, both reduced ambient temperature and a reduction in food quantity had an inhibitory effect on spermatogenesis and on size of the reproductive organs, and this was greatest when the two factors were combined and the effect of fat was removed. Female R. pumilio responded differently and reproduction was inhibited by a reduction in food quantity, irrespective of ambient temperature. The masses of the ovaries and uterus, the numbers of developing follicles and corpora lutea, and the development of the uterine wall were all reduced by food deprivation at 26 degrees C to levels similar to those that resulted from a reduction in ambient temperature to 15 degrees C with a reduction in food quantity. It is concluded that reproduction in R. pumilio from the Eastern Cape Province of South Africa is opportunistic, that reproduction will be inhibited by an energetic challenge and that there is sexual dimorphism in the response to ambient temperature and food supply.     

Report of a workshop on Geographical Information Systems held in London on 13 September 1985

Abstract

A workshop on Geographical Information Systems (GISs) was held on 13 September 1985 London. The objectives of the meeting included: the most appropriate approaches to be taken for integrated GIS developments, the delineation of key research issues and the provision of information on government initiatives and organizational plans. The workshop concluded with a debate on the general aspects of GIS development especially with respect to research needs and directions, government policy, organization, interorganization co-ordination and collaboration, funding and user needs and market opportunities.     

Teaching introductory autonomous robotics with JavaScript simulations and actual robots

This paper describes a flexible method of teaching introductory robotics. Students program an autonomous mobile robot to complete a set of tasks of increasing complexity, including multirobot tracking. Two proximity detectors (1 b each) and a pair of photosensors (2 b each) provide six sensory inputs to logic circuits, which control two drive motors and two internal memory flip-flops. The robot brain is a digital logic circuit programmed by loading an AS CH code that specifies the logic circuit configuration, similar in approach to a field-programmable gate array. The logic circuit design evolves with task complexity. Two internal set/reset flip-flops can be used to design a finite-state machine to implement a memory. One novelty of the method is that students develop and test their logic circuits on a Web-based graphic simulation before downloading the code to an actual robot. The simulation is written in JavaScript to acquire sensor readings and control robot motors to interact with the environment in a flexible manner. The simulation is downloaded with the Web page and runs smoothly on the client's machine, eliminating the need for high-speed connections. The ASCII code producing successful simulation performance is downloaded to an actual robot through a printer port on a PC in the robot laboratory. A microcontroller on the actual robot interprets the ASCII code in the same manner as the simulation. Classroom experience indicates that evolving a robot brain is an effective teaching tool and students enjoy applying logic circuit design to program a robot.     

DSP for practicing engineers: a case study in Internet course delivery

With the explosion of the Internet and the desire of many institutions to disseminate courses across the world, many students look to online education with promise. However, institutions planning to provide distance learning opportunities may wish to have a model to analyze before venturing forth. There are many factors that ultimately influence the methods of delivery, content, length, and technical support for an online course. This paper presents the design, implementation, and evaluation of an online course titled DSP for Practicing Engineers at the Georgia Institute of Technology, Atlanta, and analyzes feedback from students who have taken the course and the staff who administered it. Different aspects of course development are discussed at length, including curriculum and media type.     

Characterisation of Conform? and conventionally extruded Al–4Mg–1Zr. Effect of extrusion route on superplasticity

Continuous extrusion (Conform™) is a well-established technique for the production of profiles from both solid and particulate feed stock. To the first approximation it is considered to be analogous to conventional extrusion, although there are significant differences in the metal flow during both processes. Metal flow during conventional extrusion is characterised by relatively low redundant work, whereas the Conform™ process requires significant redundant work to be successful. Most of the available scientific literature to date is concerned with the simulation of the Conform™ process and not its effect on the resultant microstructure of the product. In this paper, a detailed comparison of the microstructure, texture and superplastic properties developed during Conform™ and conventional extrusion for a particulate Al–4Mg–1Zr alloy are presented.     

Monitoring the development of hepatocellular carcinoma in woodchucks using 31P-MRS

The woodchuck is one of the only lab animal models of chronic viral hepatitis infection and the development of hepatocellular carcinoma. Using this model, changes in tissue energetics in the liver due to the development of hepatocellular carcinoma can be monitored by repeated magnetic resonance imaging and localized phosphorus spectroscopy. Age- and sex-matched control (n=5) and chronically infected (n=5) adult woodchucks were imaged four times in a six-month period in a 7-T horizontal-bore magnet. Using a custom-built doubly tunable quadrature volume coil, sagittal and axial FLASH images (128×128, slice thickness = 5 mm, TR/TE=1000/4.1, 8 averages) were acquired to locate the largest portion of the liver with the least amount of signal contamination from surrounding abdominal muscle. Two-dimensional 31P chemical-shift imaging (2D-CSI) was acquired (16×16 data matrix, 24×24×2 cm³, 1024 data points, 16 averages) for all animals. The extent of liver injury was determined using serum gamma glutamyltransferase (GGT). The livers of infected woodchucks showed a significant increase (p=0.01) in phosphomonoesters (PME):β-adenosine triphosphate (NTP). Chronically infected woodchucks had higher levels of serum GGT compared to uninfected woodchucks (p=0.002). An increase in the PME:β-NTP ratio indicates cellular proliferation within the malignant tumor.