Converging evidence that common timing processes underlie temporal-order and simultaneity judgments: a model-based analysis

Perception of simultaneity and temporal order is studied with simultaneity judgment (SJ) and temporal-order judgment (TOJ) tasks. In the former, observers report whether presentation of two stimuli was subjectively simultaneous; in the latter, they report which stimulus was subjectively presented first. SJ and TOJ tasks typically give discrepant results, which has prompted the view that performance is mediated by different processes in each task. We looked at these discrepancies from a model that yields psychometric functions whose parameters characterize the timing, decisional, and response processes involved in SJ and TOJ tasks. We analyzed 12 data sets from published studies in which both tasks had been used in within-subjects designs, all of which had reported differences in performance across tasks. Fitting the model jointly to data from both tasks, we tested the hypothesis that common timing processes sustain simultaneity and temporal order judgments, with differences in performance arising from task-dependent decisional and response processes. The results supported this hypothesis, also showing that model psychometric functions account for aspects of SJ and TOJ data that classical analyses overlook. Implications for research on perception of simultaneity and temporal order are discussed.

Assessment of the cortisol awakening response: Real-time analysis and curvilinear effects of sample timing inaccuracy

The cortisol awakening response (CAR) is typically measured in the domestic setting. Moderate sample timing inaccuracy has been shown to result in erroneous CAR estimates and such inaccuracy has been shown partially to explain inconsistency in the CAR literature. The need for more reliable measurement of the CAR has recently been highlighted in expert consensus guidelines where it was pointed out that less than 6% of published studies provided electronic-monitoring of saliva sampling time in the post-awakening period. Analyses of a merged data-set of published studies from our laboratory are presented. To qualify for selection, both time of awakening and collection of the first sample must have been verified by electronic-monitoring and sampling commenced within 15 min of awakening. Participants (n = 128) were young (median age of 20 years) and healthy. Cortisol values were determined in the 45 min post-awakening period on 215 sampling days. On 127 days, delay between verified awakening and collection of the first sample was less than 3 min (‘no delay’ group); on 45 days there was a delay of 4–6 min (‘short delay’ group); on 43 days the delay was 7–15 min (‘moderate delay’ group). Cortisol values for verified sampling times accurately mapped on to the typical post-awakening cortisol growth curve, regardless of whether sampling deviated from desired protocol timings. This provides support for incorporating rather than excluding delayed data (up to 15 min) in CAR analyses. For this population the fitted cortisol growth curve equation predicted a mean cortisol awakening level of 6 nmols/l (±1 for 95% CI) and a mean CAR rise of 6 nmols/l (±2 for 95% CI). We also modelled the relationship between real delay and CAR magnitude, when the CAR is calculated erroneously by incorrectly assuming adherence to protocol time. Findings supported a curvilinear hypothesis in relation to effects of sample delay on the CAR. Short delays of 4–6 min between awakening and commencement of saliva sampling resulted an overestimated CAR. Moderate delays of 7–15 min were associated with an underestimated CAR. Findings emphasize the need to employ electronic-monitoring of sampling accuracy when measuring the CAR in the domestic setting.

Tempo de reação, tempo de movimento e aquisição de timing antecipatorio em idosos

Universidade Estadual de Campinas. Faculdade de Educação Física

Intercepting moving targets: does memory from practice in a specific condition of target displacement affect movement timing?

This investigation aimed at assessing the extent to which memory from practice in a specific condition of target displacement modulates temporal errors and movement timing of interceptive movements. We compared two groups practicing with certainty of future target velocity either in unchanged target velocity or in target velocity decrease. Following practice, both experimental groups were probed in the situations of unchanged target velocity and target velocity decrease either under the context of certainty or uncertainty about target velocity. Results from practice showed similar improvement of temporal accuracy between groups, revealing that target velocity decrease did not disturb temporal movement organization when fully predictable. Analysis of temporal errors in the probing trials indicated that both groups had higher timing accuracy in velocity decrease in comparison with unchanged velocity. Effect of practice was detected by increased temporal accuracy of the velocity decrease group in situations of decreased velocity; a trend consistent with the expected effect of practice was observed for temporal errors in the unchanged velocity group and in movement initiation at a descriptive level. An additional point of theoretical interest was the fast adaptation in both groups to a target velocity pattern different from that practiced. These points are discussed under the perspective of integration of vision and motor control by means of an internal forward model of external motion.

Cluster analysis of self-awareness levels in adults with traumatic brain injury and relationship to outcome

The purpose of this study was to investigate the relationship between self-awareness, emotional distress, motivation, and outcome in adults with severe traumatic brain injury. A sample of 55 patients were selected from 120 consecutive patients with severe traumatic brain injury admitted to the rehabilitation unit of a large metropolitan public hospital. Subjects received multidisciplinary inpatient rehabilitation and different types of outpatient rehabilitation and community-based services according to availability and need, Measures used in the cluster analysis were the Patient Competency Rating Scale, Self-Awareness of Deficits Interview, Head Injury Behavior Scale, Change Assessment Questionnaire, the Beck Depression Inventory, and Beck Anxiety Inventory; outcome measures were the Disability Rating Scale, Community Integration Questionnaire, and Sickness Impact Profile. A three-cluster solution was selected, with groups labeled as high self-awareness (n = 23), low self-awareness (n = 23), and good recovery (n = 8). The high self-awareness cluster had significantly higher levels of self-awareness, motivation, and emotional distress than the low self-awareness cluster but did not differ significantly in outcome. Self-awareness after brain injury is associated with greater motivation to change behavior and higher levels of depression and anxiety; however, it was not clear that this heightened motivation actually led to any improvement in outcome. Rehabilitation timing and approach may need to be tailored to match the individual's level of self-awareness, motivation, and emotional distress.

Analysis of soil wetting and solute transport in subsurface trickle irrigation

The increased use of trickle or drip irrigation is seen as one way of helping to improve the sustainability of irrigation systems around the world. However, soil water and solute transport properties and soil profile characteristics are often not adequately incorporated in the design and management of trickle systems. In this paper, we describe results of a simulation study designed to highlight the impacts of soil properties on water and solute transport from buried trickle emitters. The analysis addresses the influence of soil hydraulic properties, soil layering, trickle discharge rate, irrigation frequency, and timing of nutrient application on wetting patterns and solute distribution. We show that (1) trickle irrigation can improve plant water availability in medium and low permeability fine-textured soils, providing that design and management are adapted to account for their soil hydraulic properties, (2) in highly permeable coarse-textured soils, water and nutrients move quickly downwards from the emitter, making it difficult to wet the near surface zone if emitters are buried too deep, and (3) changing the fertigation strategy for highly permeable coarse-textured soils to apply nutrients at the beginning of an irrigation cycle can maintain larger amounts of nutrient near to and above the emitter, thereby making them less susceptible to leaching losses. The results demonstrate the need to account for differences in soil hydraulic properties and solute transport when designing irrigation and fertigation management strategies. Failure to do this will result in inefficient systems and lost opportunities for reducing the negative environmental impacts of irrigation.

Event-related FMRI analysis with maximum correlation modelling

Functional magnetic resonance imaging (FMRI) analysis methods can be quite generally divided into hypothesis-driven and data-driven approaches. The former are utilised in the majority of FMRI studies, where a specific haemodynamic response is modelled utilising knowledge of event timing during the scan, and is tested against the data using a t test or a correlation analysis. These approaches often lack the flexibility to account for variability in haemodynamic response across subjects and brain regions which is of specific interest in high-temporal resolution event-related studies. Current data-driven approaches attempt to identify components of interest in the data, but currently do not utilise any physiological information for the discrimination of these components. Here we present a hypothesis-driven approach that is an extension of Friman's maximum correlation modelling method (Neurolmage 16, 454-464, 2002) specifically focused on discriminating the temporal characteristics of event-related haemodynamic activity. Test analyses, on both simulated and real event-related FMRI data, will be presented.

Timing of rotator cuff activation during shoulder external rotation in throwers with and without symptoms of pain

Study Design: Fine-wire EMG rotator cuff onset time analysis in 2 matched groups of throwers with and without pain. Objective: To identify if there is a difference in the activation patterns of the rotator cuff muscles during a rapid shoulder external rotation task between throwers with and without pain. Background: The coordinated action of the rotator cuff is recognized as essential for glenohumeral joint control in the throwing athlete. Identification of abnormalities occurring in muscle activation patterns for injured athletes is relevant when prescribing rehabilitative exercises. Methods and Measures: Twelve throwers with shoulder pain were compared to a matched group of 11 asymptomatic throwers. Participants were matched for age, height, body mass, and habitual activity. Fine-wire EMG electrodes were inserted into the subscapularis, supraspinatus, and infraspinatus. EMG activity was measured during a reaction time task of rapid shoulder external rotation in a seated position. The timing of onset of EMG activity was analyzed in relation to visualization of a light (reaction time) and to the onset of infraspinatus activity (relative latency). Results: In the group with shoulder pain, the onset of subscapularis activity was found to be significantly delayed (reaction time, P = .0018; relative latency, P = .0005) from the onset of infraspinatus activity when compared to the control group. Conclusions: The presence of shoulder pain in these athletes was associated with a difference in the onset of subscapularis EMG activity during a rapid shoulder external rotation movement. This was an initial step in the understanding of the joint protection mechanisms of the glenohumeral joint and the problems that occur in throwers. This information may assist in providing future guidelines for more effective rehabilitation and prevention strategies for this condition.

Timing of Dose Relative to Sexual Intercourse Attempt in Previous Sildenafil Citrate Users Treated with Tadalafil: A Geographical Comparison from a Single Arm, Open-Label Study

Introduction. Previous research has demonstrated that sildenafil citrate users alter dosing-sexual attempt behavior when switched to tadalafil. The impact of geography and culture on sexual behavior with phosphodiesterase type 5 (PDE5) inhibitor treatment has not been fully investigated. Aim. To describe and compare the changes in dosing-sexual attempt behavior with sildenafil citrate vs. tadalafil treatment across four distinct geographies: Asia, Australia/New Zealand (ANZ), Central Eastern Europe/Middle East (CEE/ME), and Latin America (LA). Methods. Data from a single-arm, open-label clinical trial conducted in 21 countries from November 2002 to May 2004 were used in this analysis. Men with erectile dysfunction and a history of >= 6-week prior sildenafil citrate use continued sildenafil citrate treatment for 4 weeks then switched to tadalafil for 8 weeks. Dosing instructions were provided. Main Outcomes Measures. Timing of dose and sexual intercourse was assessed through patient diaries for the final 4 weeks of each treatment period. Results. A total of 2,760 men were enrolled: Asia 15.8%; ANZ 29.4%; CEE/ME 19.7%; LA 35.1%. The median time from dosing to intercourse was significantly increased during tadalafil treatment across all geographical regions; however, the magnitude of increase differed significantly by geography (P < 0.0001). The Asian cohort demonstrated the shortest duration between dosing and sexual intercourse attempts (irrespective of drug), and altered sexual behavior the least upon switching to tadalafil. The ANZ cohort demonstrated the longest duration between dosing and sexual intercourse attempts (irrespective of drug), and altered sexual behavior the most upon switching to tadalafil. Conclusion. Men with a history of established sildenafil citrate use alter their dose-attempt behavior when treated with tadalafil irrespective of geography. However, the extent to which sexual behavior alters is not uniform across geographical regions, suggesting that dosing instructions and duration of drug effectiveness, in combination with personal and cultural preferences, may determine sexual behavior with PDE5 inhibitor use. Rubio-Aurioles E, Glina S, Abdo CHN, Hernandez-Serrano R, Rampazzo C, Sotomayor M, West TM, Gallagher GL, and Lenero E. Timing of dose relative to sexual intercourse attempt in previous sildenafil citrate users treated with tadalafil: A geographical comparison from a single arm, open-label study. J Sex Med 2009;6:2836-2850.

Quantitative analysis of the speed and accuracy of tongue movements in dysarthria subsequent to traumatic brain injury using electromagnetic articulography

It has been recognised that in order to study the displacement, timing and co-ordination of articulatory components (i.e., tongue. lips, jaw) in speech production it is desirable to obtain high-resolution movement data on multiple structures inside and outside the vocal tract. Until recently, with the exception of X-ray techniques such as cineradiography, the study 0. speech movements has been hindered by the inaccessibility of the oral cavity during speech. X-ray techniques are generally not used because of unacceptable radiation exposure. The aim of the present study was to demonstrate the use of a new physiological device, the electromagnetic articulograph, for assessing articulatory dysfunction subsequent to traumatic brain injury. The components of the device together with the measuring principle are described and data collected from a single case presented. A 19 year-old male who exhibited dysarthria subsequent to a traumatic brain injury was fitted wit 2 the electromagnetic articulograph (Carstens AG-100) and a kinematic analysis of his tongue movements during production of the lingual consonants it, s, k/ within single syllable words was performed. Examination of kinematic parameters including movemmt trajectories, velocity, and acceleration revealed differences in the speed and accuracy of his tongue movements compared to those produced by a non-neurologically impaired adult male. It was concluded that the articulograph is a useful device for diagnosing speed and accuracy disorders in tongue movements during speech and that the device has potential for incorporation into physiologically based rehabilitation programs as a real-time biofeedback instrument.

A few what-ifs on using statistical analysis of stochastic simulation runs to extract timeliness properties

Modern real-time systems, with a more flexible and adaptive nature, demand approaches for timeliness evaluation based on probabilistic measures of meeting deadlines. In this context, simulation can emerge as an adequate solution to understand and analyze the timing behaviour of actual systems. However, care must be taken with the obtained outputs under the penalty of obtaining results with lack of credibility. Particularly important is to consider that we are more interested in values from the tail of a probability distribution (near worst-case probabilities), instead of deriving confidence on mean values. We approach this subject by considering the random nature of simulation output data. We will start by discussing well known approaches for estimating distributions out of simulation output, and the confidence which can be applied to its mean values. This is the basis for a discussion on the applicability of such approaches to derive confidence on the tail of distributions, where the worst-case is expected to be.

An analysis of the impact of bus contention on the WCET in multicores

The use of multicores is becoming widespread inthe field of embedded systems, many of which have real-time requirements. Hence, ensuring that real-time applications meet their timing constraints is a pre-requisite before deploying them on these systems. This necessitates the consideration of the impact of the contention due to shared lowlevel hardware resources like the front-side bus (FSB) on the Worst-CaseExecution Time (WCET) of the tasks. Towards this aim, this paper proposes a method to determine an upper bound on the number of bus requests that tasks executing on a core can generate in a given time interval. We show that our method yields tighter upper bounds in comparison with the state of-the-art. We then apply our method to compute the extra contention delay incurred by tasks, when they are co-scheduled on different cores and access the shared main memory, using a shared bus, access to which is granted using a round-robin arbitration (RR) protocol.

A tighter analysis of the worst-case endto- end communication delay in massive multicores

"Many-core” systems based on the Network-on- Chip (NoC) architecture have brought into the fore-front various opportunities and challenges for the deployment of real-time systems. Such real-time systems need timing guarantees to be fulfilled. Therefore, calculating upper-bounds on the end-to-end communication delay between system components is of primary interest. In this work, we identify the limitations of an existing approach proposed by [1] and propose different techniques to overcome these limitations.