The existence and impact of the Psychological Refractory Period effect in the driving environment

Driver distraction from in-vehicle tasks can have negative impacts on longitudinal and lateral vehicle control. The distraction problem is increasing due to advances in the functionality, availability, and number of in-vehicle systems. One approach to a solution is managing in-vehicle task presentation to reduce associated distraction. This paper reports three driving simulator experiments, designed to investigate the existence of the Psychological Refractory Period in the driving context and its effect on driver performance. The first two studies demonstrate that the effect is present when one or two surrogate in-vehicle tasks are presented in close temporal proximity to a lead vehicle braking event. Brake responding is subject to an increasing delay as the interval to an in-vehicle task is decreased. In-vehicle task modality and task presentation order modulate this effect. The final study will investigate whether the Psychological Refractory Period exists for a range of safety-critical driving events such as lead vehicle decelerations, swerving away from an out-of-control vehicle, and performing a lane-change manoeuvre. The advances on prior work include the use of an advanced driving simulator, and presentation of unpredictable safety-critical events and real-world in-vehicle tasks. The results have implications for the management of in-vehicle distractions – and driver safety; specifically through controlling the timing and modality of task presentation

The design of haptic gas pedal feedback to support eco-driving

Previous literature suggests that haptic gas pedals can assist the driver in search of maximum fuel economy. This study investigated three haptic pedal designs, each with high and low intensities of feedback, in a rapid prototyping, paired comparison design. Twenty drivers took part, experiencing the systems in a high-fidelity driving simulator. Results suggested that drivers were best guided towards an “idealized” (most fuel efficient) gas pedal position by force feedback (where a driver feels a step change in gas pedal force) as opposed to stiffness feedback (where a driver feels a changing gas pedal firmness). In either case, high levels of force/stiffness feedback were preferred. Objective performance measures mirrored the subjective results. Whilst the short-term nature (brief system exposure) of this study led to difficulties in drawing longer-term conclusions, it would appear that force feedback haptics are better suited than stiffness feedback to augment an effective driver interface supporting “green” driving

Designing an in-vehicle eco-driving support system to assist drivers in conserving fuel

Environmentally friendly driving – or eco-driving – refers to the driving of a vehicle in a way that conserves fuel and reduces emissions. Large fuel savings are possible by targeting the role of driver behaviour in the protection of the environment, and teaching them how to ‘eco-drive’. This study forms part of the ecoDriver project, which aims to develop an in-vehicle eco-driving support system. While many current systems offer after-trip feedback on the fuel efficiency of driving or simple in-trip recommendations (e.g. gear shift indicators), this study investigates a number of systems that provide real-time, feed-forward guidance on how to alter accelerator usage in the upcoming moments to minimise fuel consumption. A driving simulator was used to test three potential eco-driving interfaces which used a common eco-driving guidance algorithm. Two systems used a haptic accelerator pedal, while one presented multi-modal visual and auditory information. Objective eco-driving performance was measured as the error between desired accelerator position defined by the system and accelerator position selected by the driver. Subjective feedback on workload and acceptability of the system was analysed and driver visual distraction was monitored throughout. This study informs on the most effective and acceptable presentation methods for real-time in-vehicle guidance on eco-driving

Systematics and plastid genome evolution of the cryptically photosynthetic parasitic plant genus Cuscuta (Convolvulaceae)

<p>Abstract</p> <p>Background</p> <p>The genus <it>Cuscuta </it>L. (Convolvulaceae), commonly known as dodders, are epiphytic vines that invade the stems of their host with haustorial feeding structures at the points of contact. Although they lack expanded leaves, some species are noticeably chlorophyllous, especially as seedlings and in maturing fruits. Some species are reported as crop pests of worldwide distribution, whereas others are extremely rare and have local distributions and apparent niche specificity. A strong phylogenetic framework for this large genus is essential to understand the interesting ecological, morphological and molecular phenomena that occur within these parasites in an evolutionary context.</p> <p>Results</p> <p>Here we present a well-supported phylogeny of <it>Cuscuta </it>using sequences of the nuclear ribosomal internal transcribed spacer and plastid <it>rps2</it>, <it>rbcL </it>and <it>matK </it>from representatives across most of the taxonomic diversity of the genus. We use the phylogeny to interpret morphological and plastid genome evolution within the genus. At least three currently recognized taxonomic sections are not monophyletic and subgenus <it>Cuscuta </it>is unequivocally paraphyletic. Plastid genes are extremely variable with regards to evolutionary constraint, with <it>rbcL </it>exhibiting even higher levels of purifying selection in <it>Cuscuta </it>than photosynthetic relatives. Nuclear genome size is highly variable within <it>Cuscuta</it>, particularly within subgenus <it>Grammica</it>, and in some cases may indicate the existence of cryptic species in this large clade of morphologically similar species.</p> <p>Conclusion</p> <p>Some morphological characters traditionally used to define major taxonomic splits within <it>Cuscuta </it>are homoplastic and are of limited use in defining true evolutionary groups. Chloroplast genome evolution seems to have evolved in a punctuated fashion, with episodes of loss involving suites of genes or tRNAs followed by stabilization of gene content in major clades. Nearly all species of <it>Cuscuta </it>retain some photosynthetic ability, most likely for nutrient apportionment to their seeds, while complete loss of photosynthesis and possible loss of the entire chloroplast genome is limited to a single small clade of outcrossing species found primarily in western South America.</p

The activation of eco-driving mental models: can text messages prime drivers to use their existing knowledge and skills?

Eco-driving campaigns have traditionally assumed that drivers lack the necessary knowledge and skills and that this is something that needs rectifying. Therefore, many support systems have been designed to closely guide drivers and fine-tune their proficiency. However, research suggests that drivers already possess a substantial amount of the necessary knowledge and skills regarding eco-driving. In previous studies, participants used these effectively when they were explicitly asked to drive fuel-efficiently. In contrast, they used their safe driving skills when they were instructed to drive as they would normally. Hence, it is assumed that many drivers choose not to engage purposefully in eco-driving in their everyday lives. The aim of the current study was to investigate the effect of simple, periodic text messages (nine messages in 2 weeks) on drivers’ eco- and safe driving performance. It was hypothesised that provision of eco-driving primes and advice would encourage the activation of their eco-driving mental models and that comparable safety primes increase driving safety. For this purpose, a driving simulator experiment was conducted. All participants performed a pre-test drive and were then randomly divided into four groups, which received different interventions. For a period of 2 weeks, one group received text messages with eco-driving primes and another group received safety primes. A third group received advice messages on how to eco-drive. The fourth group were instructed by the experimenter to drive fuel-efficiently, immediately before driving, with no text message intervention. A post-test drive measured behavioural changes in scenarios deemed relevant to eco- and safe driving. The results suggest that the eco-driving prime and advice text messages did not have the desired effect. In comparison, asking drivers to drive fuel-efficiently led to eco-driving behaviours. These outcomes demonstrate the difficulty in changing ingrained habits. Future research is needed to strengthen such messages or activate existing knowledge and skills in other ways, so driver behaviour can be changed in cost-efficient ways

Intestinal Microbiota Regulate Xenobiotic Metabolism in the Liver

BACKGROUND: The liver is the central organ for xenobiotic metabolism (XM) and is regulated by nuclear receptors such as CAR and PXR, which control the metabolism of drugs. Here we report that gut microbiota influences liver gene expression and alters xenobiotic metabolism in animals exposed to barbiturates. PRINCIPAL FINDINGS: By comparing hepatic gene expression on microarrays from germfree (GF) and conventionally-raised mice (SPF), we identified a cluster of 112 differentially expressed target genes predominantly connected to xenobiotic metabolism and pathways inhibiting RXR function. These findings were functionally validated by exposing GF and SPF mice to pentobarbital which confirmed that xenobiotic metabolism in GF mice is significantly more efficient (shorter time of anesthesia) when compared to the SPF group. CONCLUSION: Our data demonstrate that gut microbiota modulates hepatic gene expression and function by altering its xenobiotic response to drugs without direct contact with the liver

Phytoplankton responses to marine climate change – an introduction

Phytoplankton are one of the key players in the ocean and contribute approximately 50% to global primary production. They serve as the basis for marine food webs, drive chemical composition of the global atmosphere and thereby climate. Seasonal environmental changes and nutrient availability naturally influence phytoplankton species composition. Since the industrial era, anthropogenic climatic influences have increased noticeably – also within the ocean. Our changing climate, however, affects the composition of phytoplankton species composition on a long-term basis and requires the organisms to adapt to this changing environment, influencing micronutrient bioavailability and other biogeochemical parameters. At the same time, phytoplankton themselves can influence the climate with their responses to environmental changes. Due to its key role, phytoplankton has been of interest in marine sciences for quite some time and there are several methodical approaches implemented in oceanographic sciences. There are ongoing attempts to improve predictions and to close gaps in the understanding of this sensitive ecological system and its responses

Drivers’ ability to learn eco-driving skills; effects on fuel efficient and safe driving behaviour

Whilst driving is inherently a safety-critical task, awareness of fuel-efficient driving techniques has gained popularity in both the public and commercial domains. Green driving, whether motivated by financial or environmental savings, has the potential to reduce the production of greenhouse gases by a significant amount. This paper focusses on the interaction between the driver and their vehicle – what type of eco-driving information is easy to use and learn whilst not compromising safety. A simulator study evaluated both visual and haptic eco-driving feedback systems in the context of hill driving. The ability of drivers to accurately follow the advice, as well as their propensity to prioritise it over safe driving was investigated. We found that any type of eco-driving advice improved performance and whilst continuous real-time visual feedback proved to be the most effective, this modality obviously reduces attention to the forward view and increases subjective workload. On the other hand, the haptic force system had little effect on reported workload, but was less effective that the visual system. A compromise may be a hybrid system that adapts to drivers’ performance on an on-going basis

Managing in-vehicle distractions: evidence from the psychological refractory period paradigm

Driver distraction by in-vehicle tasks has a negative impact on driving performance and crash risk. This paper describes a study investigating the effect of interacting with a surrogate in-vehicle system task -- requiring a two-choice speeded response -- in close temporal proximity to a subsequent lead vehicle braking event. The purpose of the study was to determine the 'task-free' interval required before a braking event to ensure safe braking performance. Drivers (N = 48) were split into six groups and randomly assigned an in-vehicle task defined by stimulus (three levels) and response modality (two levels). Four blocks of intermixed single- and dual-task trials were presented. The time interval between the two tasks was varied on dual-task trials. Slower braking responses on dual-task trials relative to single-task trials indicated dual-task interference. Driver braking performance demonstrated the psychological refractory period effect -- an increase in reaction time with decreasing temporal separation of the two tasks. The impact of in-vehicle task stimulus and response modality on performance is discussed in relation to predictions based on Multiple Resource Theory. This study demonstrates a fundamental human performance limitation in the real-world driving context and has implications for driver response speeds when distracted. Specifically, the presentation of an in-vehicle task in the 350 milliseconds before a braking event could have severe safety consequences. The use of the findings to manage in-vehicle stimulus presentation is discussed. Problems with implementation of the results are reported