Peripheral Advantage in Texture Segmentation: The Role of Spatial and Temporal Factors

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 273-273
Author(s):  
K Morikawa
Keyword(s):  
Receptive Fields ◽  
Human Perception ◽  
Texture Segmentation ◽  
Neural Processing ◽  
Backward Masking ◽  
Two Factors ◽  
New Type ◽  
Target Performance ◽  
And Performance

Previous studies (eg Kehrer, 1989 Spatial Vision4 45 – 62; Gurnsey et al, 1996 Journal of Experimental Psychology: Human Perception and Performance22 738 – 757) have shown that performance peaks several degrees from fixation in texture segmentation tasks, and performance falls as the target texture moves closer to the fovea or further into the periphery. There are two theories for this phenomenon: (1) neural processing speed in the fovea is slower than in the periphery (Kehrer 1989), and (2) the spatial frequency band of the texture is too low (ie too coarse) for the foveal receptive fields (Gurnsey et al 1996). However, the use of backward masking in previous studies made it impossible to decide between the two factors. The purpose of the present study was to isolate them. In experiment 1 a new stimulus configuration with backward masking was used, and previous reports were replicated. In experiment 2, the same texture was presented for 110 ms without a mask, but with added random-dot noise. Without limitations on processing time, the mid-peripheral advantage disappeared, which indicated that the previous findings were due to slower neural processing in the fovea. In experiment 3, a new type of texture was devised consisting of pairs of vertical lines with a horizontal offset. The offset was reversed for the target. Performance for unmasked 110 ms presentation was worst near the fovea and improved monotonically up to 12 deg. This peripheral advantage was spatial, not temporal, because it arose from larger receptive field sizes in periphery. When these results are taken together, the present study demonstrates that there are two independent causes for the mid-peripheral advantage in texture segregation.

Is it really a mediating construct?

2002 ◽  
Vol 21 (3) ◽  
pp. 170-183 ◽  
Author(s):  
Abubakr M.T. Suliman
Keyword(s):  
Organizational Commitment ◽  
Controversial Issues ◽  
Continuance Commitment ◽  
Mediating Role ◽  
Industrial Companies ◽  
Two Factors ◽  
And Performance ◽  
The Relationship ◽  
Self Administered Questionnaire

This paper aims at exploring the mediating role of organizational commitment that continues to be one of the most controversial issues in HRM. Using a self‐administered questionnaire, 1,000 employees from 20 industrial companies were randomly selected and surveyed in order to examine this mediating role. The results revealed that organizational commitment and its two factors (normative and continuance commitment) play different roles in mediating the relationship between perceived work climate and performance, as rated by the employees themselves and their immediate supervisors. The implications of the results for both managers and researchers are also discussed in the paper.

scholarly journals Neural correlates of acoustic dissonance in music: The role of musicianship, schematic and veridical expectations

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260728
Author(s):  
Carlota Pagès-Portabella ◽  
Mila Bertolo ◽  
Juan M. Toro
Keyword(s):  
Musical Training ◽  
Time Windows ◽  
Early Time ◽  
Neural Correlates ◽  
Neural Processing ◽  
Neural Responses ◽  
Two Factors ◽  
Integration Mechanisms

In western music, harmonic expectations can be fulfilled or broken by unexpected chords. Musical irregularities in the absence of auditory deviance elicit well-studied neural responses (e.g. ERAN, P3, N5). These responses are sensitive to schematic expectations (induced by syntactic rules of chord succession) and veridical expectations about predictability (induced by experimental regularities). However, the cognitive and sensory contributions to these responses and their plasticity as a result of musical training remains under debate. In the present study, we explored whether the neural processing of pure acoustic violations is affected by schematic and veridical expectations. Moreover, we investigated whether these two factors interact with long-term musical training. In Experiment 1, we registered the ERPs elicited by dissonant clusters placed either at the middle or the ending position of chord cadences. In Experiment 2, we presented to the listeners with a high proportion of cadences ending in a dissonant chord. In both experiments, we compared the ERPs of musicians and non-musicians. Dissonant clusters elicited distinctive neural responses (an early negativity, the P3 and the N5). While the EN was not affected by syntactic rules, the P3a and P3b were larger for dissonant closures than for middle dissonant chords. Interestingly, these components were larger in musicians than in non-musicians, while the N5 was the opposite. Finally, the predictability of dissonant closures in our experiment did not modulate any of the ERPs. Our study suggests that, at early time windows, dissonance is processed based on acoustic deviance independently of syntactic rules. However, at longer latencies, listeners may be able to engage integration mechanisms and further processes of attentional and structural analysis dependent on musical hierarchies, which are enhanced in musicians.

scholarly journals Emergence of crowding: the role of contrast and orientation salience

2021 ◽  
Author(s):  
Robert J Lee ◽  
Josephine Reuther ◽  
Ramakrishna Chakravarthi ◽  
jasna martinovic
Keyword(s):  
Discrimination Threshold ◽  
Orientation Discrimination ◽  
Neural Processing ◽  
Processing Stage ◽  
Orientation Sensitivity ◽  
Low Contrast ◽  
Orientation Information ◽  
And Performance ◽  
Flanker Interference

Crowding causes difficulties in judging attributes of an object surrounded by other objects. We investigated crowding for stimuli that isolated either S-cone or luminance mechanisms or combined them. By targeting different retinogeniculate mechanisms, we aim to determine the earliest site at which crowding emerges. Discrimination was measured in an orientation judgement task where Gabor-targets were presented parafoveally among flankers. In the first experiment, we assessed flanked and unflanked orientation discrimination thresholds for S-cone, achromatic and combined stimuli. In the second experiment, we captured individual differences by measuring unflanked detection and orientation sensitivity, and performance under flanker-interference for stimuli containing luminance only or combined with S-cone contrast. We confirmed that orientation sensitivity was lower for unflanked S-cone stimuli. When flanked, the pattern of results for S-cone stimuli was the same as for achromatic stimuli with comparable (i.e., low) contrast levels. We also found that flanker interference exhibited a genuine signature of crowding only when orientation discrimination threshold was reliably surpassed. Crowding, therefore, emerges at a stage that operates on signals representing task-relevant featural (here, orientation) information. Since luminance and S-cone mechanisms have very different spatial tuning properties, it is most parsimonious to conclude that crowding takes place at a neural processing stage after they have been combined.

“THIS IS AMERICA”: Um Videoclipe estético e ativista social

2021 ◽  
Author(s):  
Claudio Fontan ◽  
Denise Azevedo Duarte Guimarães
Keyword(s):  
The Body ◽  
Technological Evolution ◽  
Political Music ◽  
Contemporary World ◽  
Political Activist ◽  
Historical Contextualization ◽  
New Type ◽  
And Performance ◽  
The Aesthetic

In this text, we present an analysis of the videoclip “This is America” and its signage, including its artistic, aesthetic processes and its media relationship, making a brief historical contextualization of its poetics and technological evolution. We understand the body of the actor / rapper Glover as a kind of activist that develops his work as a new type of cultural agent, more aware of his role of artist and political activist, a kind of a new star system of the contemporary world within Cyberculture. We also investigate how the videoclip manages to articulate sound, imagery and performance aiming to achieve a status of leader and meaning producer. Departing from the theoretical conceptions of Jacques Rancière, Gilles Deleuze, Michel Chion, Arlindo Machado and Denise Azevedo Duarte Guimarães, among others, we focus on the aesthetic analysis of the videoclip and its relations with sociocultural contexts. “This is America” is an intelligent, social and political music video, acting against racism and media’s indifference to the topic.

Trace nanoanalysis

1994 ◽  
Vol 52 ◽  
pp. 940-941
Author(s):  
D. E. Newbury ◽  
R. D. Leapman
Keyword(s):  
High Performance ◽  
Secondary Ion Mass Spectrometry ◽  
Detection Efficiency ◽  
Volume Element ◽  
And Performance ◽  
Trace Constituents ◽  
Secondary Ion ◽  
Concentration Levels ◽  
Structure Properties

Trace constituents, which can be very loosely defined as those present at concentration levels below 1 percent, often exert influence on structure, properties, and performance far greater than what might be estimated from their proportion alone. Defining the role of trace constituents in the microstructure, or indeed even determining their location, makes great demands on the available array of microanalytical tools. These demands become increasingly more challenging as the dimensions of the volume element to be probed become smaller. For example, a cubic volume element of silicon with an edge dimension of 1 micrometer contains approximately 5×1010 atoms. High performance secondary ion mass spectrometry (SIMS) can be used to measure trace constituents to levels of hundreds of parts per billion from such a volume element (e. g., detection of at least 100 atoms to give 10% reproducibility with an overall detection efficiency of 1%, considering ionization, transmission, and counting).

The Relation Between Financial Incentives, Motivation, and Performance

2017 ◽  
Vol 16 (2) ◽  
pp. 61-76 ◽  
Author(s):  
Anaïs Thibault Landry ◽  
Marylène Gagné ◽  
Jacques Forest ◽  
Sylvie Guerrero ◽  
Michel Séguin ◽  
...  
Keyword(s):  
Financial Incentives ◽  
Work Performance ◽  
Autonomous Motivation ◽  
Compensation Plans ◽  
Work Settings ◽  
Path Analyses ◽  
Three Samples ◽  
And Performance ◽  
Performance Results

Abstract. To this day, researchers are debating the adequacy of using financial incentives to bolster performance in work settings. Our goal was to contribute to current understanding by considering the moderating role of distributive justice in the relation between financial incentives, motivation, and performance. Based on self-determination theory, we hypothesized that when bonuses are fairly distributed, using financial incentives makes employees feel more competent and autonomous, which in turn fosters greater autonomous motivation and lower controlled motivation, and better work performance. Results from path analyses in three samples supported our hypotheses, suggesting that the effect of financial incentives is contextual, and that compensation plans using financial incentives and bonuses can be effective when properly managed.

Augmented Reality--Implications toward Virtual Reality, Human Perception and Performance

2012 ◽  
Author(s):  
R. A. Grier ◽  
H. Thiruvengada ◽  
S. R. Ellis ◽  
P. Havig ◽  
K. S. Hale ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
Human Perception ◽  
And Performance

ROLE OF ADDED PHOSPHOGYPSUM AND HUMIC ACIDS IN THE KINETIC RELEASE OF SALT FROM SALT AFFECTED SOIL (SALINE – SODIC)

2020 ◽  
pp. 15-27
Keyword(s):  
Electrical Conductivity ◽  
Humic Acids ◽  
Release Rate ◽  
Release Kinetics ◽  
Sodium Adsorption Ratio ◽  
Salt Affected Soil ◽  
Two Factors ◽  
Dissolved Ions ◽  
Kinetic Release

In order to study the effect of phosphogypsum and humic acids in the kinetic release of salt from salt-affected soil, a laboratory experiment was conducted in which columns made from solid polyethylene were 60.0 cm high and 7.1 cm in diameter. The columns were filled with soil so that the depth of the soil was 30 cm inside the column, the experiment included two factors, the first factor was phosphogypsum and was added at levels 0, 5, 10 and 15 tons ha-1 and the second-factor humic acids were added at levels 0, 50, 100 and 150 kg ha-1 by mixing them with the first 5 cm of column soil and one repeater per treatment. The continuous leaching method was used by using an electrolytic well water 2.72 dS m-1. Collect the leachate daily and continue the leaching process until the arrival of the electrical conductivity of the filtration of leaching up to 3-5 dS m-1. The electrical conductivity and the concentration of positive dissolved ions (Ca, Mg, Na) were estimated in leachate and the sodium adsorption ratio (SAR) was calculated. The results showed that the best equation for describing release kinetics of the salts and sodium adsorption ratio in soil over time is the diffusion equation. Increasing the level of addition of phosphogypsum and humic acids increased the constant release velocity (K) of salts and the sodium adsorption ratio. The interaction between phosphogypsum and humic acids was also affected by the constant release velocity of salts and the sodium adsorption ratio. The constant release velocity (K) of the salts and the sodium adsorption ratio at any level of addition of phosphogypsum increased with the addition of humic acids. The highest salts release rate was 216.57 in PG3HA3, while the lowest rate was 149.48 in PG0HA0. The highest release rate of sodium adsorption ratio was 206.09 in PG3HA3, while the lowest rate was 117.23 in PG0HA0.

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