Draining your Brain: The Effects of Four Fatiguing Task Domains on Executive Function and Prefrontal Cortex

The present study empirically examined the effects of four fatiguing task domains on executive function through participants\u27 reaction time, accuracy, and brain activity in prefrontal cortex (PFC). Forty college-age participants were collected (16 males and 24 females), of which eleven were examined using a functional near-infrared spectroscopy (fNIRS) imaging system. The present study used a 4×2 mixed factorial design consisting of fatiguing task (arm contractions task, vigilance task, distance-manipulated Fitts\u27 task, size-manipulated Fitts\u27 task) as a between-participant variable and n-back testing period (pre-test versus post-test 3-back task) as a within-participant variable. Results indicated significant increases in 3-back performance after the fatiguing tasks, and significant increases in 3-back compensatory brain activity in dorsomedial and dorsolateral prefrontal cortex (dmPFC and dlPFC) after the fatiguing tasks. Furthermore, results showed an interaction between 3-back target type and fatiguing task on standardized changes in reaction time, and an interaction between fatiguing task and testing period on brain activity in dmPFC. Theoretical and practical implications are discussed. Findings from this study may be used to help draw the boundaries on different domains of fatigue and their effects on the brain and body

Impact of Auditory Affect on Urgent Behaviors on a Car Simulator

Emotional content abounds the driver in different forms from billboard signs to in-vehicle devices to roadside situations. Such emotional scenes can result in unsafe driving behaviors and lead to collisions due to their ability to attract attentional resources and change driving goals to irrelevant ones (Megías et al. 2011b; Briggs et al, 2011). Recent studies have looked at the way auditory and visual emotional stimuli can impact individual’s decision under Evaluative and Urgent road environment behaviors. Evaluative behaviors are known as a categorization in which people judge a scene as risky or not, whereas Urgent behaviors are time sensitive, requiring a person to quickly respond to the scene in order to avoid negative consequences (Megias et al, 2011a). Previous research has examined the way visual emotional stimuli affects driving performance; however, relatively little is known about the effects of auditory emotional stimuli (Chan, & Singhal, 2014). Among studies that examined both types of behaviors while participants viewed images depicting a driving scenario, auditory emotional stimuli served to speed Evaluative judging (judge whether the scene is risky or not), but not under Urgent judging (judge whether to brake or not) (Serrano, et al, 2013). It was also found that negative sounds lead to more performance errors in driving (Chan, & Singhal, 2014). The current study is designed to further examine a number of task features using a medium fidelity (GE Patrol SIM) driving simulator. Urgent behaviors related to a risky driving scenario and auditory sounds will be used. Using the motivational model of emotion looking at evolutionary flight-and-fight mechanisms (Bradley et al., 2001; Lang et al. 2008), we would, in contrast to previous studies of urgent behaviors, expect to find a difference under emotional content when participants drive a car simulator. A car simulator is able to mimic a real driving environment than looking at a static picture done in Serrano et al (2013). This study aims to empirically examine the effects of driver urgent behavior and time pressure on driver’s hazard perception in a controlled driving simulation. In this experiment, a car following scene with sudden car decelerations will measure participant’s braking, steering, and speed behavior. Participants will drive while listening to emotionally charged auditory sounds that vary in valence and arousal. Valence is how pleasant to unpleasant a stimulus is, whereas arousal is how stimulating to unstimulating a stimulus is. Emotional sounds will be instigated before a braking event occurs and will be randomized. Based on theoretical principles of the motivation model of emotion, it is hypothesized that highly arousing unpleasant sounds would have a higher impact on driving performance than pleasant and neutral sounds. Theoretical and practical implications will also be discussed

The reality and constraints of FDI in Algeria during the period 2002-2018

من خلال هذه الورقة البحثية تناولنا موضوع الاستثمار الأجنبي المباشر بالتطرق إلى المفاهيم المتصلة به، مع دراسة تحليلية لواقع تدفق الاستثمارات الأجنبية المباشرة إلى الجزائر وتحليل توزيعها القطاعي، خلال الفترة 2002-2018؛ واستخلصت الدراسة أن جهود الجزائر في مجال جذب الاستثمار الأجنبي المباشر لم ترقى إلى مستوى تطلعاتها، وان أغلب التدفقات الواردة تركزت أساسا في قطاع الصناعات البترولية، كما شخصت الدراسة مختلف العقبات التي لا تزال تحذو مناخ الاستثمار بالجزائر، لذا أوصت الدراسة بضرورة العمل وبجدية أكبر لمعالجة هذه العقبات، لزيادة مشاريع الاستثمار الأجنبي لباقي القطاعات قصد دعم نموها، ومن ثم رفع مقدرة الاقتصاد الوطني على مواجهة الصدمات النفطية المتكررة.Through this paper, we have addressed the topic of FDI by addressing related concepts. With an analysis of the realities of the flow of foreign direct investment into Algeria and analysis of its sectoral distribution, 2002-2018 ; The study concluded that Algeria's efforts in attracting FDI fell short of its aspirations, Most of the inflows were concentrated mainly in the petroleum industries sector, The study also examined the various obstacles that continue to follow Algeria's investment climate. The study therefore recommended the need to work more seriously to address these obstacles, To increase foreign investment projects for other sectors in order to support their growth, To enhance the national economy's ability to cope with recurring oil shocks.  &nbsp

Distraction Effects of Phone Use During a Crucial Driving Maneuver

Forty-two licensed drivers were tested in an experiment that required them to react to an invehicle phone at precisely the same time as they were faced with making a crucial driving decision. Using test track facilities, we extended a previous evaluation of this form to include examination of the influence of driver gender and driver age. Specifically, each driver was given task practice and then performed two blocks of twenty-four trials each, where one trial represented a circuit of the test track. Half of the trials were control conditions in which neither the stop-light was activated or the in-vehicle phone triggered. Four trials required only stopping and a further four only phone response. The remaining four trials required the driver to complete each task simultaneously. The order of presentation of specific trials was randomized. The invehicle phone response task also contained an embedded memory task that was evaluated at the end of each trial. Results confirmed previous observations of slower task response followed by increased braking and that these patterns varied by driver age and gender. Most importantly, we recorded a critical 15% increase in non-response to the stop-light in the presence of the phone distraction task which represents stop light violations on the open road. Further, results showed that age had a much large effect on response than gender, especially on task components that required speed of response. Since driving represents a highly complex and interactive environment, it is not possible to specify a simplistic relationship between these distraction effects and outcome accident patterns. However, we can conclude that such technologies erode performance safety margin and distract drivers from their critical primary task of vehicle control. As such there is expectedly a causal relation in accident outcome that is a crucial concern for invehicle device designers and for all others seeking to ameliorate the adverse impact of vehicle accidents

Evaluating Workload Associated with Telematic Devices via a Secondary Task Protocol

There are a variety of driver distractions that negatively affect driver workload and performance. These distractions range attempting to light a cigarette, and putting on make-up, to eating or drinking, tuning the radio, using a cellular phone, or using an in-vehicle navigation system. Of particular present interest are the distracting effects of telematic devices, which include traffic information systems, telecommunication, intelligent aid and control, and navigational systems. These devices can now be found on-board various types of U.S. and foreign automobiles. Despite having many potential benefits, there are also several behavioral problems resulting from poor use of these devices. The present research was designed to investigate the deleterious effects of telematics on driver performance. It was hypothesized that all the telematic systems used in this study would degrade driver performance and increase workload. A mixed-model factorial design (2x3) was used, with telematics being a between-subject factor and allocation phase a within-subject factor (repeated measures). All participants were required to drive three, four-minute simulated (pre, during, and post) allocation phases. In the preallocation phase, participants were required to drive while performing a secondary counting task, (counting and responding to a series of randomly presented visual signals). During the allocation phase, participants were required to drive and perform the secondary counting task while either talking on the phone or tuning a radio (distractibility task). In the post-allocation phase, participants were required to drive while performing the secondary counting task. Data from the counting task (number of correct, wrong, and misses) and driving errors (collisions, crossing the median, leaving the road, maintaining the speed limit, and lane deviations) were recorded and statistically analyzed. Thirty-four participants (nine males and 25 females) from the University of Central Florida participated in this study. A series of analyses of variance (ANOVA) were conducted to test for the effects of telematics and workload on each of the dependent measures. A significant main effect of phase on lane deviations was observed, F(2, 64) = 10.58, p < .001, indicating that more lane deviations were made during the cell phone and radio tuning use (M = 9.14) than during both of the pre-allocation (M = 4.14) and post-allocation (M = 5.88) phases. ANOVA also yielded a significant main effect of phase on crossing the median, F(3, 68) = 4.63, p < .05, indicating that more crossings were made during the allocation phase (M = 5.05) than during the pre-allocation (M = 3.05) and post-allocation (M = 4.47) phases. Similarly, the results also showed a significant effect of phase on the distraction task performance, F(2, 64) = 5.70, p < .01, indicating that more errors were made during the allocation phase (M = 6.50) than during the pre-allocation (M = 4.50) and the post-allocation (M = 3.38) phases. The present findings indicate that both cellular phone and radio systems are capacity demanding. The counting task results demonstrate the increased level of workload associated with these telematic devices. In addition, driving performance errors were also higher for both the cellular phone and the radio systems. Our findings suggest the need to regulate the use of such devices in order to avoid overloading the driver’s attentional spare capacity

Single product scheduling and transportation optimization in a supply chain

In this paper we consider a basic supply chain composed of one or several suppliers that provide components needed by a manufacturer. The manufacturer has to deliver finished products to only one customer before given delivery dates. We first verify if the associated decision problem is feasible or not with unlimited transportation capacities. At this decision level we assume that for the components, the delivery dates and the associated quantities are known. We further integrate progressively to the model more realistic transportation constraints and costs to be optimized : number of travels with unlimited number of trucks with unlimited capacity, number of travels with unlimited number of trucks with limited capacity and finally we consider limited number of physical trucks as a perspective

A window time negotiation approach at the scheduling level inside supply chains

International audienceWe consider a supply chain consisting in a network of enterprises with independent decision centers. The products of the assembly enterprise are produced using components and/or sub products supplied by other enterprises or external suppliers. We are at the scheduling level and each enterprise builds its own schedules, which are dependent. Negotiations between decision centers can be expressed in term of penalty functions associated with soft and hard release and due dates. At each negotiation point, hard release and due dates are considered as imperative constraints, while soft release and due dates define soft intervals and induce earliness and tardiness penalties. Any interval can be modified during the negotiation process. A global solution is searched by an iterative decomposition approach including alternatively bilateral negotiations of the soft and hard constraints and just in time scheduling, minimizing the local total sum of penalties, built by approximation approaches. We assume that production centers are flow shop. To solve each local just-in-time scheduling problem, we propose an approximation approach based on meta-heuristics, in which a solution is described by the job order on each machine and is evaluated using a “pert cost” algorithm. A semi-decentralized control is suggested to assume the negotiation convergence

Evaluating the Presence of In-Vehicle Devices on Driver Performance: Methodological Issues

A central concern of Intelligent Transportation Systems (ITS) is the effect of in-vehicle devices (e.g. cell phones, navigation systems, radios) on driver performance and safety. As diverse and innovative technologies are designed and implemented for in-vehicle use, questions regarding the presence and use of these devices assume progressively greater importance. Concern for the safety of advanced driver training and require us to develop and validate reliable and effective procedures for assessing such effects. This work examines a number of candidate procedures, in particular the evaluation of cognitive workload as a strategy by which such goals might be achieved

BOLD Neurovascular Coupling Does Not Change Significantly with Normal Aging

Studies of cognitive function that compare the blood oxygenation level dependent (BOLD) signal across age groups often require the assumption that neurovascular coupling does not change with age. Tests of this assumption have produced mixed results regarding the strength of the coupling and its relative time course. Using deconvolution, we found that age does not have a significant effect on the time course of the hemodynamic impulse response function or on the slope of the BOLD versus stimulus duration relationship. These results suggest that in cognitive studies of healthy aging, group differences in BOLD activation are likely due to age-related changes in cognitive-neural interactions and information processing rather than to impairments in neurovascular coupling

Age-related changes in the ability to switch between temporal and spatial attention

Background: Identifying age-related changes in cognition that contribute towards reduced driving performance is important for the development of interventions to improve older adults’ driving and prolong the time that they can continue to drive. While driving, one is often required to switch from attending to events changing in time, to distribute attention spatially. Although there is extensive research into both spatial attention and temporal attention and how these change with age, the literature on switching between these modalities of attention is limited within any age group. Methods: Age groups (21–30, 40–49, 50–59, 60–69 and 70+ years) were compared on their ability to switch between detecting a target in a rapid serial visual presentation (RSVP) stream and detecting a target in a visual search display. To manipulate the cost of switching, the target in the RSVP stream was either the first item in the stream (Target 1st), towards the end of the stream (Target Mid), or absent from the stream (Distractor Only). Visual search response times and accuracy were recorded. Target 1st trials behaved as no-switch trials, as attending to the remaining stream was not necessary. Target Mid and Distractor Only trials behaved as switch trials, as attending to the stream to the end was required. Results: Visual search response times (RTs) were longer on “Target Mid” and “Distractor Only” trials in comparison to “Target 1st” trials, reflecting switch-costs. Larger switch-costs were found in both the 40–49 and 60–69 years group in comparison to the 21–30 years group when switching from the Target Mid condition. Discussion: Findings warrant further exploration as to whether there are age-related changes in the ability to switch between these modalities of attention while driving. If older adults display poor performance when switching between temporal and spatial attention while driving, then the development of an intervention to preserve and improve this ability would be beneficial