scholarly journals High-capacity preconscious processing in concurrent groupings of colored dots

2018 ◽  
Vol 115 (52) ◽  
pp. E12153-E12162 ◽  
Author(s):  
Peng Sun ◽  
Charles Chubb ◽  
Charles E. Wright ◽  
George Sperling
Keyword(s):  
Quantitative Description ◽  
Relative Weight ◽  
High Capacity ◽  
Single Stimulus ◽  
Stimulus Exposure ◽  
Feature Maps ◽  
Detection Experiment ◽  
Ideal Detector ◽  
Complex Process ◽  
Different Color

Grouping is a perceptual process in which a subset of stimulus components (a group) is selected for a subsequent—typically implicit—perceptual computation. Grouping is a critical precursor to segmenting objects from the background and ultimately to object recognition. Here, we study grouping by color. We present subjects with 300-ms exposures of 12 dots colored with the same but unknown identical color interspersed among 14 dots of seven different colors. To indicate grouping, subjects point-click the remembered centroid (“center of gravity”) of the set of homogeneous dots, of heterogeneous dots, or of all dots. Subjects accurately judge all of these centroids. Furthermore, after a single stimulus exposure, subjects can judge both the heterogeneous and homogeneous centroids, that is, subjects simultaneously group by similarity and by dissimilarity. The centroid paradigm reveals the relative weight of each dot among targets and distractors to the underlying grouping process, offering a more detailed, quantitative description of grouping than was previously possible. A change detection experiment reveals that conscious memory contains less than two dots and their locations, whereas an ideal detector would have to perfectly process at least 15 of 26 dots to match the subjects’ centroid judgments—indicating an extraordinary capacity for preconscious grouping. A different color set yielded identical results. Grouping theories that rely on predefined feature maps would fail to explain these results. Rather, the results indicate that preconscious grouping is automatic, flexible, and rapid, and a far more complex process than previously believed.

A quantitative speciation model for the adsorption of organic pollutants on activated carbon

2013 ◽  
Vol 68 (6) ◽  
pp. 1370-1376 ◽  
Author(s):  
M. Grivé ◽  
D. García ◽  
C. Domènech ◽  
L. Richard ◽  
I. Rojo ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Organic Pollutants ◽  
Current Knowledge ◽  
Quantitative Description ◽  
High Capacity ◽  
Chemical Properties ◽  
Quantitative Model ◽  
Surface Groups ◽  
Potentiometric Titrations ◽  
Chemical Groups

Granular activated carbon (GAC) is commonly used as adsorbent in water treatment plants given its high capacity for retaining organic pollutants in aqueous phase. The current knowledge on GAC behaviour is essentially empirical, and no quantitative description of the chemical relationships between GAC surface groups and pollutants has been proposed. In this paper, we describe a quantitative model for the adsorption of atrazine onto GAC surface. The model is based on results of potentiometric titrations and three types of adsorption experiments which have been carried out in order to determine the nature and distribution of the functional groups on the GAC surface, and evaluate the adsorption characteristics of GAC towards atrazine. Potentiometric titrations have indicated the existence of at least two different families of chemical groups on the GAC surface, including phenolic- and benzoic-type surface groups. Adsorption experiments with atrazine have been satisfactorily modelled with the geochemical code PhreeqC, assuming that atrazine is sorbed onto the GAC surface in equilibrium (log Ks = 5.1 ± 0.5). Independent thermodynamic calculations suggest a possible adsorption of atrazine on a benzoic derivative. The present work opens a new approach for improving the adsorption capabilities of GAC towards organic pollutants by modifying its chemical properties.

scholarly journals A Systems Approach to Tissue Remodeling

2009 ◽  
Vol 131 (10) ◽  
Author(s):  
Ghassan S. Kassab
Keyword(s):  
Time Course ◽  
Systems Approach ◽  
Quantitative Description ◽  
Mathematical Expression ◽  
Step Function ◽  
Complex Process ◽  
New Findings ◽  
Flow Shear Stress ◽  
Time Courses ◽  
Mathematical Accuracy

Remodeling of tissue in response to physical stress is a very complex process. The changes in the stimulus (cause) and response (effect) must be measured and the results must be organized into mathematical forms that are suitable for predictions and applications. An experiment where the stimulus (pressure, flow, shear stress, etc.) can be changed approximately as a step function (a step plus a perturbation) and the response (structure, material properties, function, etc.), which can be measured over time, can be simulated by indicial response functions (IRFs). The IRF is a mathematical expression of the ratio of the change in a particular feature of the system in response to a unit step change in stimulus. The IRF approach provides a quantitative description of the remodeling process, simplifies the interpretation of data, and greatly increases the potential of using the experimental data for prediction of the outcome for future experiments. The objective of this review is to provide an overview of the IRF approach including some exemplary systems. The goal is to illustrate how the indicial expressions make it possible to integrate biological complexity by convolution. The time courses of stimuli represent half of the convolution while the time course of changes in response represents the second half of the convolution. The IRF approach provides an understanding of the physiological problems with mathematical accuracy and may be conducive to new findings.

scholarly journals Understanding melanopsin using bayesian generative models − an Introduction

2016 ◽  
Author(s):  
Benedikt V Ehinger ◽  
Dennis Eickelbeck ◽  
Katharina Spoida ◽  
Stefan Herlitze ◽  
Peter König
Keyword(s):  
Hierarchical Modeling ◽  
Ganglion Cells ◽  
Rapid Development ◽  
Quantitative Description ◽  
Specific Protein ◽  
Generative Models ◽  
Bayesian Hierarchical ◽  
Basic Model ◽  
Hidden Markov Process ◽  
Different Color

Understanding biological processes implies a quantitative description. In recent years a new tool set, Bayesian hierarchical modeling, has seen rapid development. We use these methods to model kinetics of a specific protein in a neuroscience context: melanopsin. Melanopsin is a photoactive protein in retinal ganglion cells. Due to its photoactivity, melanopsin is widely used in optogenetic experiments and an important component in the elucidation of neuronal interactions. Thus it is important to understand the relevant processes and develop mechanistic models. Here, with a focus on methodological aspects, we develop, implement, fit and discuss Bayesian generative models of melanopsin dynamics. We start with a sketch of a basic model and then translate it into formal probabilistic language. As melanopsin occurs in at least two states, a resting and a firing state, a basic model is defined by a non-stationary two state hidden Markov process. Subsequently we add complexities in the form of (1) an hierarchical extension to fit multiple cells; (2) a wavelength dependency, to investigate the response at different color of light stimulation; (3) an additional third state to investigate whether melanopsin is bi- or tri-stable; (4) differences between different sub-types of melanopsin as found in different species. This application of modeling melanopsin dynamics demonstrates several benefits of Bayesian methods. They directly model uncertainty of parameters, are flexible in the distributions and relations of parameters in the modeling, and allow including prior knowledge, for example parameter values based on biochemical data.  

Short-Term Memory for Color Names Using Stroop Material

1995 ◽  
Vol 80 (3_suppl) ◽  
pp. 1355-1362
Author(s):  
Charles K. Allen
Keyword(s):  
Short Term Memory ◽  
Proactive Inhibition ◽  
Stimulus Exposure ◽  
Shift Condition ◽  
Short Term ◽  
Term Memory ◽  
Modified Stroop ◽  
Color Shift ◽  
Color Name ◽  
Different Color

A modified Stroop arrangement consisting of color names printed in ink of a different color was used in a release from the proactive inhibition (PI) paradigm. In Exp. 1, half of the subjects were informed prior to a trial whether they were to recall the colors or the color names while the remaining half were not informed in advance. After three trials, half of the subjects were shifted to recalling the other material while control subjects continued with the same recall material. Analysis indicated that (1) when subjects were informed in advance, PI release was found in a color name to color shift, but no PI release was found with a shift from color to color name, and (2) when subjects were not informed in advance, no PI release was observed in either shift condition. Exp. 2 replicated the not-informed condition and introduced a longer stimulus-exposure duration for 160 undergraduates. Except for higher recall scores, the same results were obtained. The results were interpreted in terms of differences in the kinds of encoding operations performed on colors and color names.

ultrastructural process of intestinal wound healing

1995 ◽  
Vol 53 ◽  
pp. 1024-1025
Author(s):  
Rick L. Vaughn ◽  
Shailendra K. Saxena ◽  
John G. Sharp
Keyword(s):  
Wound Healing ◽  
Epithelial Cells ◽  
Smooth Muscles ◽  
Microscopic Level ◽  
Light Microscopic Level ◽  
Ileal Mucosa ◽  
Wound Model ◽  
Serosal Surface ◽  
Complex Process ◽  
Orderly Fashion

We have developed an intestinal wound model that includes surgical construction of an ileo-cecal patch to study the complex process of intestinal wound healing. This allows approximation of ileal mucosa to the cecal serosa and facilitates regeneration of ileal mucosa onto the serosal surface of the cecum. The regeneration of ileal mucosa can then be evaluated at different times. The wound model also allows us to determine the rate of intestinal regeneration for a known size of intestinal wound and can be compared in different situations (e.g. with and without EGF and Peyer’s patches).At the light microscopic level it appeared that epithelial cells involved in regeneration of ileal mucosa originated from the enlarged crypts adjacent to the intestinal wound and migrated in an orderly fashion onto the serosal surface of the cecum. The migrating epithelial cells later formed crypts and villi by the process of invagination and evagination respectively. There were also signs of proliferation of smooth muscles underneath the migratory epithelial cells.

High-resolution observations of metastable γ’ precipitation in Al-15at.%Ag

1996 ◽  
Vol 54 ◽  
pp. 1004-1005
Author(s):  
N. V. Larcher ◽  
I. G. Solorzano
Keyword(s):  
Discontinuous Precipitation ◽  
Equilibrium Phase ◽  
Quantitative Description ◽  
Present Contribution ◽  
Α Phase ◽  
The Matrix ◽  
Aging Sequence ◽  
Matrix Precipitation ◽  
Considerable Detail ◽  
Kinetics Of

It is currently well established that, for an Al-Ag alloy quenched from the α phase and aged within the metastable solvus, the aging sequence is: supersaturated α → GP zones → γ’ → γ (Ag2Al). While GP zones and plate-shaped γ’ are metastable phases, continuously distributed in the matrix, formation of the equilibrium phase γ takes place at grain boundaries by discontinuous precipitation (DP). The crystal structure of both γ’ and γ is hep with the following orientation relationship with respect to the fee α matrix: {0001}γ′,γ // {111}α, <1120>γ′,γ, // <110>α.The mechanisms and kinetics of continuous matrix precipitation (CMP) in dilute Al-Ag alloys have been studied in considerable detail. The quantitative description of DP kinetics, however, has received less attention. The present contribution reports the microstructural evolution resulting from aging an Al-Ag alloy with Ag content higher than those previously reported in the literature, focusing the observations of γ' plate-shaped metastable precipitates.

CuS2 sheets: a hidden anode material with a high capacity for sodium-ion batteries

2021 ◽  
Author(s):  
Shaohua Lu ◽  
Weidong Hu ◽  
Xiaojun Hu
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Material ◽  
Low Cost ◽  
High Capacity ◽  
Lithium Ion ◽  
Sodium Ion ◽  
Sodium Ion Batteries

Due to their low cost and improved safety compared to lithium-ion batteries, sodium-ion batteries have attracted worldwide attention in recent decades.

Karriere-Ressourcen messen

Diagnostica ◽  
2019 ◽  
Vol 65 (3) ◽  
pp. 133-141 ◽  
Author(s):  
Andreas Hirschi ◽  
Madeleine Hänggli ◽  
Noemi Nagy ◽  
Franziska Baumeler ◽  
Claire Johnston ◽  
...  
Keyword(s):  
Relative Weight ◽  
Wird Eine

Zusammenfassung. Die existierende Literatur schlägt eine Vielzahl von potentiellen Prädiktoren für Karriereerfolg vor, welche in ihrer Menge kaum auf eine ökonomische Art erhoben werden können. Um diesen Umstand anzugehen, haben Hirschi, Nagy, Baumeler, Johnston und Spurk (2018) den Karriere-Ressourcen Fragebogen (CRQ; Career Resources Questionnaire) entwickelt und in einer englischsprachigen Version validiert. Basierend auf einer Integration von theoretischer und metaanalytischer Forschung misst der Fragebogen 13 distinkte Faktoren, welche 4 übergeordnete Dimensionen repräsentieren: Wissen und Kompetenzen, Motivation, Umfeld und Aktivitäten bezüglich Karriere. In der vorliegenden Studie wird eine Validierung der deutschsprachigen Version mittels N = 1 666 Personen (Studierende und Berufstätige) vorgenommen. Die Ergebnisse bestätigen die Reliabilität sowie die Faktorstruktur des Fragebogens. Mittels Relative-Weight-Analysen konnte zudem die Wichtigkeit von verschiedenen Faktoren für unterschiedliche Arten von Karriereerfolg gezeigt werden. Das Messinstrument bietet Forschenden und Praktizierenden eine ökonomische, reliable und valide Möglichkeit, um Schlüsselfaktoren für Karriereerfolg zu erfassen.

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