Momentary Changes Research Articles

Time and causality: editorial

Time and causality: editorial

Task Relevance Induces Momentary Changes in the Functional Visual Field During Reading

In the research reported here, we examined whether task demands can induce momentary tunnel vision during reading. More specifically, we examined whether the size of the functional visual field depends on task relevance. Forty participants read an expository text with a specific task in mind while their eye movements were recorded. A display-change paradigm with random-letter strings as preview masks was used to study the size of the functional visual field within sentences that contained task-relevant and task-irrelevant information. The results showed that orthographic parafoveal-on-foveal effects and preview benefits were observed for words within task-irrelevant but not task-relevant sentences. The results indicate that the size of the functional visual field is flexible and depends on the momentary processing demands of a reading task. The higher cognitive processing requirements experienced when reading task-relevant text rather than task-irrelevant text induce momentary tunnel vision, which narrows the functional visual field.

Interaction rules underlying group decisions in homing pigeons.

Travelling in groups gives animals opportunities to share route information by following cues from each other's movement. The outcome of group navigation will depend on how individuals respond to each other within a flock, school, swarm or herd. Despite the abundance of modelling studies, only recently have researchers developed techniques to determine the interaction rules among real animals. Here, we use high-resolution GPS (global positioning system) tracking to study these interactions in pairs of pigeons flying home from a familiar site. Momentary changes in velocity indicate alignment with the neighbour's direction, as well as attraction or avoidance depending on distance. Responses were stronger when the neighbour was in front. From the flocking behaviour, we develop a model to predict features of group navigation. Specifically, we show that the interactions between pigeons stabilize a side-by-side configuration, promoting bidirectional information transfer and reducing the risk of separation. However, if one bird gets in front it will lead directional choices. Our model further predicts, and observations confirm, that a faster bird (as measured from solo flights) will fly slightly in front and thus dominate the choice of homing route. Our results explain how group decisions emerge from individual differences in homing flight behaviour.

Power gets the job: Priming power improves interview outcomes

The current research explores whether momentary changes in power can shift professional interview outcomes. Two experiments manipulated power by asking applicants to recall a time they had or lacked power prior to writing a job application letter (Experiment 1) or being interviewed for admission to business schools (Experiment 2). Independent judges, who were unaware of the applicants' experimental condition or even the existence of the power manipulation, significantly preferred the written and face-to-face interview performance of powerful applicants to that of powerless (Experiments 1 and 2) or power-neutral applicants (Experiment 2). In addition, the judges' preference for power-primed applicants was mediated by perceptions of the applicant's persuasiveness. Overall, merely asking participants to remember a personal experience with power dramatically affected the impressions that interviewers had of them. Our findings illustrate power's far-reaching effects and have potentially important implications for understanding the psychology of job interviews.

Situational Differences in Working Together: Examples From Veterinary Anatomy, Physiology And Radiographic Interpretation Sessions

In the framework of quality of learning the social interactions between veterinary students were investigated. Observational data were collected during anatomy, physiology and radiology face-to-face small group sessions using Bales’ interaction process analysis framework, and in a radiology context the students’ observations were compared with the results of a checklist (yes or no) completed by the teacher of these students. During radiology group sessions solidarity, tension release and agreement with constructive disagreement element were showed. Observations also revealed variable level of task-oriented (asking and providing information) action depending on day and task under consideration. The students were interested in each other, even though this was not supported by teacher’s checklist perhaps due to the teacher’s role as a learning resource. In contrast, during anatomy and physiology group sessions variable level of emotion-oriented (positive or negative) action was found. Students were task-oriented with variable interest in each other. The quality of group work in all cases may be dependent on the number of students and their fragmentation into sub-groups, or momentary changes in group dynamics, which might influence the teacher’s role as an active tutor during entire learning session.

Box Spline Wavelet Frames for Image Edge Analysis

We present a new box spline wavelet frame and apply it for image edge analysis. The wavelet frame is constructed using a box spline of eight directions. It is tight and has seldom been used for applications. Due to the eight different directions, it can find edges of various types in detail quite well. In addition to step edges (local discontinuities in intensity), it is able to locate Dirac edges (momentary changes of intensity) and hidden edges (local discontinuity in intensity derivatives). The method is simple and robust to noise. Many numerical examples are presented to demonstrate the effectiveness of this method. Quantitative and qualitative comparisons with other edge detection techniques are provided to show the advantages of this wavelet frame. Our test images include synthetic images with known ground truth and natural, medical images with rich geometric information.

On the specificity of sequential congruency effects in implicit learning of motor and perceptual sequences.

Individuals experience less interference from conflicting information following events that contain conflicting information. Recently, Jiménez, Lupiáñez, and Vaquero (2009) demonstrated that such adaptations to conflict occur even when the source of conflict arises from implicit knowledge of sequences. There is accumulating evidence that momentary changes in adaptations made in response to conflicting information are conflict-type specific (e.g., Funes, Lupiáñez, & Humphreys, 2010a), suggesting that there are multiple modes of control. The current study examined whether conflict-specific sequential congruency effects occur when the 2 sources of conflict are implicitly learned. Participants implicitly learned a motor sequence while simultaneously learning a perceptual sequence. In a first experiment, after learning the 2 orthogonal sequences, participants expressed knowledge of the 2 sequences independently of each other in a transfer phase. In Experiments 2 and 3, within each sequence, the presence of a single control trial disrupted the expression of this specific type of learning on the following trial. There was no evidence of cross-conflict modulations in the expression of sequence learning. The results suggest that the mechanisms involved in transient shifts in conflict-specific control, as reflected in sequential congruency effects, are also engaged when the source of conflict is implicit.

Daily Psychological Demands Are Associated With 6-Year Progression of Carotid Artery Atherosclerosis

We examine associations between the perception of ongoing psychological demands by ecological momentary assessment (EMA) and 6-year changes in carotid artery atherosclerosis by ultrasonography. A total of 270 initially healthy participants collected ambulatory blood pressure (ABP) and recorded their daily experiences, using electronic diaries, during two 3-day periods. Mean intima-media thickness (IMT) and plaque were assessed in the carotid arteries using B-mode ultrasound at baseline and again during a 6-year follow-up (mean follow-up duration = 73 months). Among those who had no exposure to antihypertensive medications during the course of follow-up (n = 192), daily psychological demands were associated with greater progression of IMT as well as plaque, after adjusting for demographic and risk factor covariates. Associations between demands and plaque change were partially accounted for by ABP differences among those reporting high demands. Among those who were employed at baseline (n = 117), 6-year IMT changes were more strongly associated with ratings of daily demands than with traditional measures of occupational stress. These data support the role of psychological demands as a correlate of subclinical atherosclerotic progression, they point to ABP as a potential mechanism facilitating these effects, and they highlight the utility of EMA measures for capturing daily psychological demands with potential effects on health.

Neural dynamics of object-based multifocal visual spatial attention and priming: Object cueing, useful-field-of-view, and crowding

How are spatial and object attention coordinated to achieve rapid object learning and recognition during eye movement search? How do prefrontal priming and parietal spatial mechanisms interact to determine the reaction time costs of intra-object attention shifts, inter-object attention shifts, and shifts between visible objects and covertly cued locations? What factors underlie individual differences in the timing and frequency of such attentional shifts? How do transient and sustained spatial attentional mechanisms work and interact? How can volition, mediated via the basal ganglia, influence the span of spatial attention? A neural model is developed of how spatial attention in the where cortical stream coordinates view-invariant object category learning in the what cortical stream under free viewing conditions. The model simulates psychological data about the dynamics of covert attention priming and switching requiring multifocal attention without eye movements. The model predicts how “attentional shrouds” are formed when surface representations in cortical area V4 resonate with spatial attention in posterior parietal cortex (PPC) and prefrontal cortex (PFC), while shrouds compete among themselves for dominance. Winning shrouds support invariant object category learning, and active surface-shroud resonances support conscious surface perception and recognition. Attentive competition between multiple objects and cues simulates reaction-time data from the two-object cueing paradigm. The relative strength of sustained surface-driven and fast-transient motion-driven spatial attention controls individual differences in reaction time for invalid cues. Competition between surface-driven attentional shrouds controls individual differences in detection rate of peripheral targets in useful-field-of-view tasks. The model proposes how the strength of competition can be mediated, though learning or momentary changes in volition, by the basal ganglia. A new explanation of crowding shows how the cortical magnification factor, among other variables, can cause multiple object surfaces to share a single surface-shroud resonance, thereby preventing recognition of the individual objects.

Using the Time-Varying Effect Model (TVEM) to Examine Dynamic Associations between Negative Affect and Self Confidence on Smoking Urges: Differences between Successful Quitters and Relapsers

With technological advances, collection of intensive longitudinal data (ILD), such as ecological momentary assessments, becomes more widespread in prevention science. In ILD studies, researchers are often interested in the effects of time-varying covariates (TVCs) on a time-varying outcome to discover correlates and triggers of target behaviors (e.g., how momentary changes in affect relate to momentary smoking urges). Traditional analytical methods, however, impose important constraints, assuming a constant effect of the TVC on the outcome. In the current paper, we describe a time-varying effect model (TVEM) and its applications to data collected as part of a smoking-cessation study. Differentiating between groups of short-term successful quitters (N = 207) and relapsers (N = 40), we examine the effects of momentary negative affect and abstinence self-efficacy on the intensity of smoking urges in each subgroup in the 2 weeks following a quit attempt. Successful quitters demonstrated a rapid reduction in smoking urges over time, a gradual decoupling of the association between negative affect and smoking urges, and a consistently strong negative effect of self-efficacy on smoking urges. In comparison, relapsers exhibited a high level of smoking urges throughout the post-quit period, a time-varying and, generally, weak effect of self-efficacy on smoking urges, and a gradual reduction in the strength of the association between negative affect and smoking urges. Implications of these findings are discussed. The TVEM is made available to applied prevention researchers through a SAS macro.

Studies on the Index of Energy Momentary Change Rate for Sliding Base-Isolated Structures on Different Level of Friction Coefficient

Being the research object,the index of energy momentary change rate for sliding base-isolated structure is put forward and its corresponding design formulas are given，and three indexes of energy momentary change rate for sliding base-isolated structure including input energy,restorable energy of superstructure and friction energy dissipation on different level friction coefficient are analyzed numerically from the angle of energy.Research shows that energy momentary change rate is a very effective index for energy analysis of sliding base-isolated structure,and there are big relations between the index and isolation layer’s friction coefficient,and the index can reflect well momentary changes of all kinds of energy for every moment.

Studies on the Index of Energy Momentary Change Rate for Sliding Base-Isolated Structures on Different Level of Friction Coefficient

Being the research object,the index of energy momentary change rate for sliding base-isolated structure is put forward and its corresponding design formulas are given，and three indexes of energy momentary change rate for sliding base-isolated structure including input energy,restorable energy of superstructure and friction energy dissipation on different level friction coefficient are analyzed numerically from the angle of energy.Research shows that energy momentary change rate is a very effective index for energy analysis of sliding base-isolated structure,and there are big relations between the index and isolation layer’s friction coefficient,and the index can reflect well momentary changes of all kinds of energy for every moment.

Automated Facial Action Coding System for dynamic analysis of facial expressions in neuropsychiatric disorders

Facial expression is widely used to evaluate emotional impairment in neuropsychiatric disorders. Ekman and Friesen's Facial Action Coding System (FACS) encodes movements of individual facial muscles from distinct momentary changes in facial appearance. Unlike facial expression ratings based on categorization of expressions into prototypical emotions (happiness, sadness, anger, fear, disgust, etc.), FACS can encode ambiguous and subtle expressions, and therefore is potentially more suitable for analyzing the small differences in facial affect. However, FACS rating requires extensive training, and is time consuming and subjective thus prone to bias. To overcome these limitations, we developed an automated FACS based on advanced computer science technology. The system automatically tracks faces in a video, extracts geometric and texture features, and produces temporal profiles of each facial muscle movement. These profiles are quantified to compute frequencies of single and combined Action Units (AUs) in videos, and they can facilitate a statistical study of large populations in disorders known to impact facial expression. We derived quantitative measures of flat and inappropriate facial affect automatically from temporal AU profiles. Applicability of the automated FACS was illustrated in a pilot study, by applying it to data of videos from eight schizophrenia patients and controls. We created temporal AU profiles that provided rich information on the dynamics of facial muscle movements for each subject. The quantitative measures of flatness and inappropriateness showed clear differences between patients and the controls, highlighting their potential in automatic and objective quantification of symptom severity.

Breaking Away: Effects Of Non-uniform Pacing On Power Output And Rpe Growth

RPE normally grows as a scalar function of relative competitive distance during fixed duration time trials; suggesting that it may be the 'translator' between the brain and the body relative to managing fatigue during heavy closed-loop exercise. From this, one predicts that there would be a reciprocal relationship between changes in momentary RPE and changes in muscular power output. PURPOSE: To determine whether power output would decrease when the RPE was forced above the normal growth curve during a cycle time trial. METHODS: To test this concept, well-trained, task-habituated cyclists (m=6, f=4, POmax=4.6 W·kg-1) performed two, randomly ordered, 10km cycle (Velotron) time-trial simulations. In one trial (Control), they rode at their own best pace throughout. In the other trial, the were instructed (without previous warning) to make a 1km 'burst' at the 4km mark, and then finish as rapidly as possible. RESULTS: The Control ride was significantly faster than the burst trial (16:37 vs 17:00). During the Control ride, responses between 4-5km were: PO: 240W, RPE:5-6, [HLa]:8-9 mmol·l-1. During the Burst trial, PO increased to 290W, then fell to 220W following the burst, and remained low until the beginning of the endspurt at 9km. RPE increased to 9 during the burst, but returned to the normal RPE growth pattern by 6 km; [HLa] increased to 13 mmol·l-1 following the burst, and remained elevated throughout the remainder of the trial. CONCLUSIONS: The somewhat reciprocal behavior of RPE and PO during the burst trail provides partial support for the hypothesis that RPE functions as the translator between the brain and the body during heavy exercise. However, the continuing reductions of PO following the burst, even after RPE had returned to it's normal pattern of growth during a time trial suggests that PO is regulated in a more complex manner than reflected by RPE.

Spectrophotometers

Spectrophotometers

Membrane bioreactor for pharmaceutically active compounds removal: Effects of carbamazepine on mixed microbial communities implied in the treatment

The aim of this work consists in evaluating the influence of carmabazepine (CBZ) (i) on the endogenous and exogenous respirations, in batch reactors, of bacterial populations taken from a conventional activated sludge process (CAS) and a pilot-scale membrane bioreactor (MBR) and (ii) on COD removal, sludge production and oxygen requirement of a lab-sale MBR system. In batch experiments, the increase in endogenous oxygen needs suggests an increase in maintenance requirements, essentially to manage the chemical stress induced by the CBZ presence. The decrease of exogenous oxygen needs seems to suggest a change in the metabolic pathways of the substrate or a change in the active bacterial species. However, in spite of these momentary changes, no inhibition is observed in the presence of CBZ in the test tank. This result is confirmed by the MBR experiment where no significant difference COD removal, sludge production and oxygen requirement is observed, with and without CBZ.

A neural network model-based observer for idle speed control of ignition in SI engine

The paper presents an algorithm of idle speed stabilization in the spark ignition automotive engine by means of spark advance control. The algorithm is based on a well-known approach of a model-based adaptive control and uses artificial neural networks. The control algorithm is based on a neural network model observer of the additional effective torque. The additional load is estimated as difference between effective torque, estimated by the neural network observer, and brake torque, estimated on the basis of a linear quadratic model. In that case the additional load is understood as the sum of the alternator brake torque (additional load form electric car equipments) and the momentary and/or permanent changes of the engine’s characteristics. On the basis of estimated values of the additional load, the required value of angular acceleration is determined to make the engine return to the specified speed. This acceleration is achieved by adjusting the spark advance. The required value of spark advance is estimated by means of a neural network model converse to that of the effective torque. The algorithm was experimentally compared with PID and adaptive algorithms in the same test bed. The tests were conducted under sudden change of external load. The proposed algorithm proved to be more effective in terms of control error.

Evaluation of real-time non-invasive diagnostic tools for the monitoring of a pilot scale atmospheric pressure plasma system

A set of real-time non-invasive multivariate analysis tools were evaluated using LabVIEW software for the process monitoring of an atmospheric pressure plasma system. During system operation, it was observed that the optical and electrical properties are subject to a deterministic jitter effect caused by momentary changes in the discharge characteristics. This temporal jitter in the voltage, current and frequency of the applied power to an atmospheric pressure plasma was monitored to assess the plasma processing conditions. Electrical diagnostic tools were used to determine the transition of the plasma from the primary glow mode to the secondary glow mode and were correlated with photo diode (PD) analysis of the plasma. Intensified charge-coupled device (ICCD) imaging of the plasma was also used to distinguish between glow and Townsend discharge properties at low applied powers (400 W). The electrical observations were recorded in real time, plotted on a principal component analysis (PCA) loading plot and analysed using non-parametric cluster analysis (NPCA). It was observed from the plotted electrical parameters that data clusters were formed which relate to both the geometry of the atmospheric plasma chambers and the mode of plasma operation. The development of these tools facilitates real-time analysis of this reel-to-reel atmospheric pressure plasma processing system.

Alcohol primes, expectancies, and the working self-concept.

Previous research has shown that alcohol consumption can lead to momentary changes in the self-concept (e.g., Steele & Josephs, 1990). In two studies (n = 150), we examined whether the implicit activation of alcohol expectancies (i.e., sociability-related expectancies) would also lead to changes in self-perception. To test this idea, participants first completed a measure of sociability-related alcohol expectancies. In a subsequent laboratory session, participants were exposed to either alcohol-related primes (i.e., pictures or words associated with alcohol) or neutral primes. After the priming task, participants completed an ostensibly unrelated self-concept survey that contained words related to sociability (e.g., "outgoing") and nonsociability related words (e.g., "clever"). For both studies, results revealed that sociability-related alcohol expectancies were positively associated with sociability-related self-concept ratings for participants exposed to alcohol primes, but not for participants exposed to the neutral primes. Implications for the role implicit self-concept activation may have on drinking behaviors are discussed.

The unique consequences of feeling lucky: Implications for consumer behavior

Cognitive priming procedures were used to identify the unique effects that luck-related concepts have on consumer behavior. The effects of these concepts could theoretically influence behavior through the elicitation of positive affect or via temporary changes in participants' self representations of how lucky they feel. An initial experiment showed that priming Asian consumers with lucky numbers independently influenced both their perceptions of personal luck and the positive affect they reported experiencing. Subsequent experiments, however, showed that the effect of these primes on consumer behavior was mediated by momentary changes in how lucky people felt (i.e. changes in the self concept) rather than by the positive affect they were experiencing at the time. Exposing consumers to lucky numbers influenced their estimates of how likely they were to win a lottery (Experiment 2), their willingness to participate in such a lottery (Experiment 4), their evaluations of different promotional strategies (Experiment 3), and also the amount of money they were willing to invest in different financial options (Experiment 4). The effect of luck on behavior was also moderated by a person's regulatory focus.