Significant Increase In Response Time Research Articles

Response Time of III-V Multistage Detectors Based on the “Ga-Free” InAs/InAsSb Type-II Superlattice

This paper presents a response time/time constant of III-V material-based interband long wavelength multistage infrared detector optimized for a wavelength of 10.6 µm at 200 K. The device is based on the InAs/InAsSb type-II superlattice with highly doped p+/n+ tunneling junctions among the stages. The detector exhibits a response time of 9.87 ns under zero voltage condition, while for 0.15 V reverse bias, that time decreases to approximately 350 ps. The presented device shows a significant increase in response time, especially for low bias, and for a voltage of −0.2 V, the decrease in the detector’s response time by an order of magnitude was estimated. Higher voltage slightly affects the time constant, and between −0.3 V and −1 V, it varies between 300 and 400 ps. The significant change in the detector’s response time between −0.1 V and −0.2 V probably results from electric field drop over entire absorber region. The optimal operating condition can be reached for −0.15 V, where the time constant reaches approximately 350 ns with peak detectivity at a level of ~3 × 109 Jones.

The functional relevance of right DLPFC and VMPFC in risk-taking behavior.

The prefrontal cortex can be partialized in various anatomical and functional sub regions. Among those regions, both right dorsolateral prefrontal cortex (rDLPFC) and ventromedial prefrontal cortex (VMPFC) have been associated with risk-taking behavior based on neuroimaging studies. Noninvasive brain stimulation (NIBS) studies aiming at demonstrating the functional relevance of neural activity in these areas almost exclusively focused on the rDLPFC, where its experimental stimulation with a (generally) inhibitory protocol lead to a measurable increase in risk-taking behavior due to reduced cognitive control. The functional relevance of VMPFC in risk-taking behavior has not yet been addressed using NIBS, although multiple neuroimaging studies correlate this area's activity with valuation. Here, we used NIBS to investigate the functional relevance of both, the rDLPFC and VMPFC in risk-taking behavior. We hypothesized that, compared to sham stimulation, VMPFC suppression leads to a reduction in risk-taking behavior by reducing the appeal to higher value options and consequently the attractiveness of riskier options, whereas rDLPFC suppression leads to an increase in risk taking, replicating previous findings. We applied continuous theta burst stimulation (cTBS), a generally inhibitory protocol, to stimulate either VMPFC or DLPFC before the execution of the computerized Maastricht Gambling Task (MGT) in a within-subject design with 30 participants. The MGT allowed the analysis of potential brain region-specific effects of cTBS on risk-taking behavior such as participants' choices of average values, probabilities, and response time. cTBS applied to either rDLPFC or VMPFC both led to an increase in risk-taking behavior and in the average value chosen as compared to sham transcranial magnetic stimulation. No effect on the choice of probabilities was found. A significant increase in response time was observed exclusively after suppressing rDLPFC. We speculate that these similar behavioral consequences following cTBS over DLPFC and VMPFC are likely due to the strong anatomical and functional interconnection between both brain regions.

Assessment of hypoxia tolerance to high-altitude exposure following sleep deprivation

Objectives: The adverse effects of hypoxia and sleep deprivation (SD) have been studied separately but there is little literature on their effects when acting in conjunction. Hence, the effects of SD on hypoxia tolerance and cognitive performance when exposed to altitude were investigated. Material and Methods: In a cross-sectional repetitive measure design, 15 healthy volunteers assessed on cognitive performance were made to perform cognitive tests (Dual Task Test, Stroop Test [ST], and Digit Symbol Substitution Test [DSST] of Psychometric Evaluation Designed for Aviators test battery) on the ground and at a simulated altitude of 17,000 ft in a hypobaric chamber on 4 days. On the 2nd and 3rd day, the tests were done following 2 h of SD the previous night, and on the 4th day, the same was repeated following normal recovery sleep. Heart rate (HR) and respiratory rate (RR) were measured on the ground and 17,000 ft. The Lake Louise Acute Mountain Sickness (LLAMS) scores were used to assess the severity of symptoms of hypoxia and time to arterial oxygen desaturation of 75% was used to measure hypoxia tolerance. Results: Although not statistically significant, the LLAMS scores showed an increasing trend on SD days with an improvement in recovery of sleep. No statistically significant differences in the HR (F = 0.569, P = 0.637) and RR (F = 0.569, P = 0.637) were observed across the days of SD or recovery. The time to oxygen desaturation to 75% also showed no significant effect (F = 0.587, P = 0.625). A statistically significant increase in response times of two cognitive tests (ST and DSST) was observed on exposure to altitude on all 4 days. The three cognitive tests did not show any statistically significant effect following 2 h of SD or recovery. Conclusion: The study could not elicit a statistically significant effect of 2 h of SD across 2 consecutive nights on the cognitive performance measures on exposure to hypoxia.

Associations of Human Cognitive Abilities with Elevated Carbon Dioxide Concentrations in an Enclosed Chamber

Fifteen participants were exposed in an enclosed environmental chamber to investigate the effects of elevated carbon dioxide (CO2) concentration on their cognitive abilities. Three CO2 conditions (1500, 3500, and 5000 ppm) were achieved by constant air supply and additional ultrapure CO2. All participants received the same exposure under each condition, during which they performed six cognitive tests evaluating human perception, attention, short-term working memory, risky decision-making, and executive ability. Generalized additive mixed effects model (GAMM) results showed no statistically significant differences in performance on the reaction time (RT) tests, the speed perception test, and the 2-back test. This suggests that elevated CO2 concentrations below 5000 ppm did not affect participants’ perception and short-term working memory. However, a significant increase in response time was observed in the visual search (VS) test, the balloon simulation risk test (BART), and the Stroop test at 5000 ppm compared to lower exposure concentrations. The slower responses reflected the detrimental effects of elevated CO2 concentrations on visual attention, risky decision-making, and executive ability. The findings suggest that the control level of CO2 concentrations should be tighter in enclosed workplaces where rapid response and operational safety are required.

Having a phone conversation delays but does not disrupt cognitive mechanisms.

Previous research has shown that talking on a mobile phone leads to impairments in a number of cognitive tasks. However, it is not yet known whether the act of conversation disrupts the underlying cognitive mechanisms (the Cognitive Disruption hypothesis) or leads to a delay in response due to a limit on central cognitive resources (the Cognitive Delay hypothesis). We investigated this here using two cognitive search tasks that investigate spatial learning and time-based selection: Contextual Cueing and Visual Marking. In Contextual Cueing, responses to repeated displays are faster than those to novel displays. In Visual Marking, participants prioritize attention to new information and deprioritize old, unimportant information (the Preview Benefit). Experiments 1 to 3 investigated whether Contextual Cueing occurred while people were engaged in a phone conversation, whereas Experiments 4 to 6 investigated whether a Preview Benefit occurred, again while people were engaged in conversation. The results showed that having a conversation did not interfere with the mechanisms underlying spatial learning or time-based selection. However, in all experiments there was a significant increase in response times. The results are consistent with a Cognitive Delay account explaining the dual-task cost of having a phone conversation on concurrent cognitive tasks. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

EEG-Based Semantic Vigilance Level Classification Using Directed Connectivity Patterns and Graph Theory Analysis

This paper proposes two novel methods to classify semantic vigilance levels by utilizing EEG directed connectivity patterns with their corresponding graphical network measures. We estimate the directed connectivity using relative wavelet transform entropy (RWTE) and partial directed coherence (PDC) and the graphical network measures by graph theory analysis (GTA) at four frequency bands. The RWTE and PDC quantify the strength and directionality of information flow between EEG nodes. On the other hand, the GTA of the complex network measures summarizes the topological structure of the network. We then evaluate the proposed methods using machine learning classifiers. We carried out an experiment on nine subjects performing semantic vigilance task (Stroop color word test (SCWT)) for approximately 45 minutes. Behaviorally, all subjects demonstrated vigilance decrement as reflected by the significant increase in response time and reduced accuracy. The strength and directionality of information flow in the connectivity network by RWTE/PDC and the GTA measures significantly decrease with vigilance decrement, p<; 0.05. The classification results show that the proposed methods outperform other related and competitive methods available in the literature and achieve 100% accuracy in subject-dependent and above 89% in subject-independent level in each of the four frequency bands. The overall results indicate that the proposed methods of directed connectivity patterns and GTA provide a complementary aspect of functional connectivity. Our study suggests directed functional connectivity with GTA as informative features and highlight Support Vector Machine as the suitable classifier for classifying semantic vigilance levels.

Mental rotation of sequentially presented 3D figures: sex and sex hormones related differences in behavioural and ERP measures

Mental rotation of 3D objects demonstrates one of the largest sex differences. We investigated sex and sex hormones-related differences in behaviour and event related potentials (ERP) using a modified Shepard and Metzler task composed of sequentially presented 3D figures in 29 men and 32 women. We demonstrated a significant increase in response time and decrease in both accuracy and positivity of the parietal ERP with increasing angular disparity between the figures. Higher angular disparity evoked an increase of global field power (GFP) from 270 to 460 ms and different activation topographies from 470 to 583 ms with lower parietal, but higher left frontal positivity. Flatter slopes in higher angular disparity condition suggest distinct strategies being implemented depending on the difficulty of the rotation. Men performed the task more accurately than women. Performance accuracy in women tended to be negatively related to estradiol while the response time tended to increase with increasing progesterone. There were no associations with testosterone. Women demonstrated higher GFP and an increased positivity over the parietal scalp area, while men showed higher activation in the left frontal cortex. Together these findings indicate dynamic angular disparity- and sex-related differences in brain activity during mental rotation of 3D figures.

The effects of auditory satellite navigation instructions and visual blur on road hazard perception

The distracting effects of mobile telephone use while driving are well known, however the effects of other sources of distraction, such as auditory navigation devices, are less well understood. Whether the effects of auditory distraction might interact with other sensory impairments, such as vision impairment, is of interest given that visual impairment is relatively common within the population, particularly as a result of uncorrected refractive error. In this experiment, 20 current drivers (mean age of 29.4 ± 3.2 years), binocularly viewed video recordings of traffic scenes presented as part of the Hazard Perception Test and responded to potential hazards within the traffic scenes. Half of the presented scenes included auditory navigation instructions as an auditory distractor. Additionally, some of the scenes were viewed through optical lenses to induce different levels of refractive blur (+0.50 DS, +1.00 DS and +2.00 DS). Hazard perception response times increased significantly (p < 0.05) with increasing blur. Participants were significantly slower in reacting to hazards for the +1.00 DS and +2.00 DS blur conditions compared to the control condition (with no blur). There was also a significant increase in response times to hazards in the presence of the auditory navigation instructions. The combined effect of blur and auditory instructions was additive, with the worst performance being in the presence of both blur and auditory instructions. These results suggest that the delivery of auditory navigation guidance for those with visual impairments, such as blur, which are relatively common in the population, should be further investigated.

Validation of auditory detection response task method for assessing the attentional effects of cognitive load

ABSTRACTObjectives: There are 3 standardized versions of the Detection Response Task (DRT), 2 using visual stimuli (remote DRT and head-mounted DRT) and one using tactile stimuli. In this article, we present a study that proposes and validates a type of auditory signal to be used as DRT stimulus and evaluate the proposed auditory version of this method by comparing it with the standardized visual and tactile version.Methods: This was a within-subject design study performed in a driving simulator with 24 participants. Each participant performed 8 2-min-long driving sessions in which they had to perform 3 different tasks: driving, answering to DRT stimuli, and performing a cognitive task (n-back task). Presence of additional cognitive load and type of DRT stimuli were defined as independent variables. DRT response times and hit rates, n-back task performance, and pupil size were observed as dependent variables.Results: Significant changes in pupil size for trials with a cognitive task compared to trials without showed that cognitive load was induced properly. Each DRT version showed a significant increase in response times and a decrease in hit rates for trials with a secondary cognitive task compared to trials without. Similar and significantly better results in differences in response times and hit rates were obtained for the auditory and tactile version compared to the visual version. There were no significant differences in performance rate between the trials without DRT stimuli compared to trials with and among the trials with different DRT stimuli modalities.Conclusions: The results from this study show that the auditory DRT version, using the signal implementation suggested in this article, is sensitive to the effects of cognitive load on driver's attention and is significantly better than the remote visual and tactile version for auditory–vocal cognitive (n-back) secondary tasks.

Priority Scheduling for Heterogeneous Workloads: Tradeoff Between Evictions and Response Time

Nowadays, large computing clusters are executing highly heterogeneous bursty workloads with different priorities, resource demands, and performance objectives. As the schedulers control the class-specific performance by evictions, a noteworthy amount of the computing resources are wasted by the lost executions of the evicted tasks. This paper presents a system model with a slot-based priority scheduler that captures the execution progress, evictions, and response times when executing complex workloads on heterogeneous systems. To better understand the impact of evictions, we first analyze simple eviction policies and wasted resources associated with evictions by using trace-driven simulation of Google cluster trace. Our key finding is that evictions severely increase system load, which leads to a significant increase in response times, particularly of low-priority classes, due to repetitive evictions. Furthermore, by exploiting the heterogeneity of the workload, we propose a workload-aware slot configuration and task assignment methodology incorporated with slot-based priority scheduling to improve class-based response time and resource efficiency. Our experimental results show that we are able to achieve up to 29% improvement in response times by choosing the right eviction policy, namely, MRS (most recently started), and integrating workload awareness to the slot configuration and task assignment.

Is children’s listening effort in background noise influenced by the speaker’s voice quality?

The present study aims at exploring the influence of voice quality on listening effort in children performing a language comprehension test with sentences of increasing difficulty. Listening effort is explored in relation to gender ( = cisgender). The study has a between-groups design. Ninety-three mainstreamed children aged 8;2 to 9;3 with typical language development participated. The children were randomly assigned to two groups (n = 46/47) with equal allocation of boys and girls and for the analysis to four groups depending of gender and voice condition. Working memory capacity and executive functions were tested in quiet. A digital version of a language comprehension test (the TROG-2) was used to measure the effect of voice quality on listening effort, measured as response time in a forced-choice paradigm. The groups listened to sentences through recordings of the same female voice, one group with a typical voice and one with a dysphonic voice, both in competing multi-talker babble noise. Response times were logged after a time buffer between the sentence-ending and indication of response. There was a significant increase in response times with increased task difficulty and response times between the two voice conditions differed significantly. The girls in the dysphonic condition were slower with increasing task difficulty. A dysphonic voice clearly adds to the noise burden and listening effort is greater in girls than in boys when the teacher speaks with dysphonic voice in a noisy background. These findings might mirror gender differences as for coping strategies in challenging contexts and have important implications for education.

Ethnopharmacological Evaluation of Breu Essential Oils from Protium Species Administered by Inhalation.

Background Breu is an aromatic oleoresin which has been used by Amazonian traditional communities as a remedy for headaches and migraines by burning and inhaling the smoke produced during its combustion. This study evaluated the antinociceptive and sedative activities of formulations containing breu essential oils administered by inhalation. Methods Five different formulations (A–E) containing breu essential oils were evaluated for their sedative and antinociceptive activities in mice. They were delivered for 20 minutes using an inhalation chamber coupled with a nebulizer and the air inside was collected by static headspace and analyzed by GC-FID. Results All nebulized formulations had similar chemical compositions and major compounds as the original essential oils. None of them resulted in significant increase in response time during the hot plate test. In the formalin test, Formulation E showed a significant inhibition of licking responses in the early (46.8%) and late (60.2%) phases. Formulation B was effective (36.9%) in the first phase and Formulation D (37.9%) in the second. None of the formulations presented sedative effects. Conclusion Breu essential oils, when inhaled, may present antinociceptive and anti-inflammatory properties without sedation. Additionally, nebulization proved to be an efficient method for administration of formulations containing these essential oils.

Patient load effects on response time to critical arrhythmias in cardiac telemetry: a randomized trial.

Remotely monitored patients may be at risk for a delayed response to critical arrhythmias if the telemetry watchers who monitor them are subject to an excessive patient load. There are no guidelines or studies regarding the appropriate number of patients that a single watcher may safely and effectively monitor. Our objective was to determine the impact of increasing the number of patients monitored on response time to simulated cardiac arrest. Randomized trial. Laboratory-based experiment. Forty-two remote telemetry technicians and nurses from cardiac units. Number of patients monitored in a simulation of cardiac telemetry monitoring work. We carried out a study to compare response times to ventricular fibrillation across five patient loads: 16, 24, 32, 40, and 48 patients. The simulation replicated the work of telemetry watchers using a combination of real recorded patient electrocardiogram signals and a simulated patient experiencing ventricular fibrillation. Study participants were assigned to one of the five patient loads and completed a 4-hour monitoring session, during which they performed tasks-including event documentation and phone calls to report events-similar to real monitoring work. When the simulated patient sustained ventricular fibrillation, the time required to report this arrhythmia was recorded. As patient loads increased, there was a statistically significant increase in response times to the ventricular fibrillation. In addition, frequency of failure to meet a response time goal of less than 20 seconds was significantly higher in the 48-patient condition than in all other conditions. Task performance decreased as patient load increased. As participants monitored more patients in a laboratory setting, their performance with respect to recognizing critical and noncritical events declined. This study has implications for the design of remote telemetry work and other patient monitoring tasks in critical and intermediate care units.

Effects of brief time delays on matching-to-sample abilities in capuchin monkeys (Sapajus spp.)

Traditionally, studies of delayed matching-to-sample (DMTS) tasks in nonhuman species have focused on the assessment of the limits of the retrieval of information stored in short- and long-term memory systems. However, it is still unclear if visual recognition in these tasks is affected by very brief delay intervals, which are typically used to study rapidly decaying types of visual memory. This study aimed at evaluating if tufted capuchin monkeys’ ability to recognise visual stimuli in a DMTS task is affected by (i) the disappearance of the sample stimulus and (ii) the introduction of delay intervals (0.5, 1.0, 2.0 and 3.0s) between the disappearance of the sample and the presentation of the comparison stimuli. The results demonstrated that the simple disappearance of the sample and the introduction of a delay of 0.5s did not affect capuchins’ performance either in terms of accuracy or response time. A delay interval of 1.0s produced a significant increase in response time but still did not affect recognition accuracy. By contrast, delays of 2.0 and 3.0s determined a significant increase in response time and a reduction in recognition accuracy. These findings indicate the existence in capuchin monkeys of processes enabling a very accurate retention of stimulus features within time frames comparable to those reported for humans’ sensory memory (0.5–1.0s). The extent to which such processes can be considered analogous to the sensory memory processes observed in human visual cognition is discussed.

TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia

This study sought to discover if an optimum 1 cm 2 area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1 Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions.

Acute Changes in Frontoparietal Activity after Repetitive Transcranial Magnetic Stimulation over the Dorsolateral Prefrontal Cortex in a Cued Reaction Time Task

Lesion and functional imaging studies in humans have suggested that the dorsolateral prefrontal cortex (DLPFC), ventrolateral prefrontal cortex (VLPFC), and intraparietal sulcus (IPS) are involved in orienting attention. A functional magnetic resonance imaging study supplemented by a behavioral experiment examined the effects of 5 Hz repetitive transcranial magnetic stimulation (rTMS) conditioning to the right and left DLPFC on reaction times and synaptic activity as indexed by changes in the blood oxygenation level-dependent (BOLD) signal during a cued choice reaction time task. Orienting precues were either correct (valid) or incorrect (invalid) with respect to the subsequent move cue. The effects of real and sham rTMS were compared for each site of stimulation. Invalid trials showed a significant increase in response times and increases in the BOLD signal in right frontal and parietal regions when compared with valid trials. Conditioning left DLPFC with rTMS led to decreased BOLD signal during performance of this reorienting task in areas including left VLPFC and left IPS. Comparing invalid to valid trials after right DLPFC conditioning revealed decreased BOLD signal in right VLPFC. Data from the behavioral study showed that right DLPFC rTMS selectively increases response times in invalid trials. This effect was only present in the first 10 min after rTMS conditioning. No effect was found in either validly or invalidly cued trials with left DLPFC conditioning. These results suggest that 5 Hz rTMS over right DLPFC exerts remote effects on the activity of areas that functionally interact with the DLPFC during attentional processes, particularly when the reorienting of attention is more demanding as in invalid trials.

Cocaine and Inhibition of Nitric Oxide Synthesis Produce Opioid-Mediated Antinociception

Cocaine and nitric oxide are known to influence the perception of pain. The present study sought to determine if the endogenous opioid peptide system participates in cocaine-induced antinociception and antinociception produced by antagonism of nitric oxide. Pain perception was measured using the hot plate test. Administration of cocaine (25 mg/kg) to male rats resulted in a significant increase in reaction time in the hot plate test, which was reversed by treatment with 3, 10, and 30 mg/kg of the opiate antagonist, naloxone. In rats that were not treated with cocaine, doses of 30 and 60 mg/kg of naloxone significantly reduced hot plate reaction time. Treatment of animals with the nitric oxide synthase inhibitor, Nωnitro-L-arginine, produced a significant increase in response time to the hot plate, which was reversed by administration of naloxone. These data indicate that antinociception produced in the rat by cocaine appears to have a supraspinal component and to involve activation of endogenous opioid peptide activity in the brain. The results also suggest a tonic inhibition of endogenous opioid peptide activity by nitric oxide, which when antagonized, results in diminished response to pain.

Improving Construction Safety by Providing Positive Feedback on Backup Alarms

Federally mandated backup alarms and safety management have been unable to eliminate fatalities and injuries due to maneuvering trucks and mobile equipment on construction sites. Workers appear to ignore the alarms as part of the general noise level. When reversing, drivers and equipment operators tend to depend on the alarm's effectiveness to clear areas in which drivers have limited visibility. Using human factors analysis, the problem was recognized as one of decremented vigilance, a person's natural inability to sustain attention without positive feedback. This paper presents experimental data on the use of a simulated, discriminating, personal alarm activated by a short range, directional transmitter to encourage safe behavior. During the experiment there was a significant increase in response time, as expected, for the conventional backup alarm and a decrease in response time for the discriminating personal alarm. The proposed backup alarm system has the potential to eliminate on-site vehicle/equipment accidents.