scholarly journals Effect of uncertainty on the time course for selection of verbal name codes

2005 ◽  
Vol 67 (8) ◽  
pp. 1437-1445 ◽  
Author(s):  
M. E. Berryhill ◽  
K. Kveraga ◽  
L. Webb ◽  
H. C. Hughes
Keyword(s):  
Time Course ◽  
Selection Of

Toward a Computational Model of Constraint-Driven Exploration and Haptic Object Identification

Perception ◽  
1993 ◽  
Vol 22 (5) ◽  
pp. 597-621 ◽  
Author(s):  
Roberta L Klatzky ◽  
Susan J Lederman
Keyword(s):  
Time Course ◽  
Incidental Learning ◽  
Object Identification ◽  
Architectural Elements ◽  
Haptic Exploration ◽  
Object Properties ◽  
Potential Applications ◽  
Haptic Object ◽  
Exploratory Procedures ◽  
Selection Of

A conceptual model of the human haptic system in relation to object identification is presented. The model encompasses major architectural elements including representations of haptically accessible object properties and exploratory procedures (EPs)—dedicated movement patterns that are specialized to extract particular properties. These architectural units are related in processing-specific ways. Properties are associated with exploratory procedures in keeping with the extent to which a given procedure delivers information about a given property. The EPs are associated with one another in keeping with their compatibility, as determined by parameters of motor execution and interactions with the object and the workspace. The resulting architecture is treated as a system of constraints which guide the exploration of an object during the course of identification. The selection of the next step in a sequence of exploration requires that constraints be optimally satisfied. A network approach to constraint satisfaction is implemented and shown to account for a number of previous empirical results concerning the time course of exploration, object classification speed, and incidental learning about object properties. This system has potential applications for robotic haptic exploration.

scholarly journals SARS-CoV-2 Worldwide Replication Drives Rapid Rise and Selection of Mutations across the Viral Genome: A Time-Course Study Potential Challenge for Vaccines and Therapies

2021 ◽  
Author(s):  
Stefanie Weber ◽  
Christina M. Ramirez ◽  
Barbara Weiser ◽  
Harold Burger ◽  
Walter Doerfler
Keyword(s):  
South Africa ◽  
United Kingdom ◽  
Viral Entry ◽  
Time Course ◽  
Easy Access ◽  
List Type ◽  
Mutant Selection ◽  
New Variant ◽  
Selection Of ◽  
New Mutations

AbstractScientists and the public were alarmed at the first large viral variant of SARS-CoV2 reported in December 2020. We have followed the time course of emerging viral mutants and variants during the SARS-CoV-2 pandemic in ten countries on four continents. We examined complete SARS-CoV-2 nucleotide sequences in GISAID, (Global Initiative of Sharing All Influenza Data) with sampling dates extending until January 20, 2021. These sequences originated from ten different countries: United Kingdom, South Africa, Brazil, USA, India, Russia, France, Spain, Germany, and China. Among the novel mutations, some previously reported mutations waned and some of them increased in prevalence over time. VUI2012/01 (B.1.1.7) and 501Y.V2 (B.1.351), the so-called UK and South Africa variants, respectively, and two variants from Brazil, 484K.V2, now called P.1 and P.2, increased in prevalence. Despite lockdowns, worldwide active replication in genetically and socio-economically diverse populations facilitated selection of new mutations. The data on mutant and variant SARS-CoV-2 strains provided here comprise a global resource for easy access to the myriad mutations and variants detected to date globally. Rapidly evolving new variant and mutant strains might give rise to escape variants, capable of limiting the efficacy of vaccines, therapies, and diagnostic tests.Significance and New Aspects of Study – SynopsisWe examine the time course of emerging mutations in the SARS-CoV-2 genome that have rapidly been selected in the world’s populations through the beginning of 2021. A study of the prevalence of viral mutations in the GISAID database in ten different countries – United Kingdom, South Africa, Brazil, US, India, Russia, France, Spain, Germany, and China - revealed widespread mutations along the genome.We previously identified about 10 hotspot mutations in the SARS-CoV-2 genome that became prevalent in many of the countries studied1. Since the beginning of February, many new mutations arose in the ten countries (and worldwide). The preponderance of variants and mutations correlated with the increased spread of Covid-19.There was a temporal progression from about 10 predominant mutants shared by several countries up to the end of May 2020, followed by a consistent and rapid increase in the number of new mutations between June and December along with the emergence of variants of concern, first reported in December 2020.We examine the relative frequencies of mutations, along with variants of interest, in 10 countries up until January 20, 2021. Investigations on the pathogenic properties of individual SARS-CoV-2 mutations will be urgently needed to understand the kaleidoscopic patterns of worldwide Covid-19 outbreaks and symptoms. Monitoring the frequency and speed of mutant selection have direct relevance to diagnostic testing, vaccines and therapeutics.As an explanation for efficient viral mutagenesis, we hypothesize that the viral spike protein – as documented – facilitates viral entry via the cell’s ACE receptor2. This in turn interacts with the APOBEC polypeptide, an m-RNA editing function. The actually observed frequent C to U (T) transitions and other base exchanges are thus effected. Hence, as one of the earliest steps upon viral entry, active mutagenesis commences, since SARS-CoV-2 exploits one of the cell’s defenses against viral infections.

Slipping on superlemmas

2007 ◽  
Vol 2 (3) ◽  
pp. 313-357 ◽  
Author(s):  
Koenraad Kuiper ◽  
Marie-Elaine van Egmond ◽  
Gerard Kempen ◽  
Simone Sprenger
Keyword(s):  
Speech Production ◽  
Time Course ◽  
Activation Patterns ◽  
Naturally Occurring ◽  
Slips Of The Tongue ◽  
Argument Proceeds ◽  
The Impact ◽  
Lexical Concepts ◽  
Selection Of ◽  
Experimentally Induced

Only relatively recently have theories of speech production concerned themselves with the part idioms and other multi-word lexical items (MLIs) play in the processes of speech production. Two theories of speech production which attempt to account for the accessing of idioms in speech production are those of Cutting and Bock (1997) and superlemma theory (Sprenger, 2003; Sprenger, Levelt, & Kempen, 2006). Much of the data supporting theories of speech production comes either from time course experiments or from slips of the tongue (Bock & Levelt, 1994). The latter are of two kinds: experimentally induced (Baars, 1992) or naturally observed (Fromkin, 1980). Cutting and Bock use experimentally induced speech errors while Sprenger et al. use time course experiments. The missing data type that has a bearing on speech production involving MLIs is that of naturally occurring slips. In this study the impact of data taken from naturally observed slips involving English and Dutch MLIs are brought to bear on these theories. The data are taken initially from a corpus of just over 1000 naturally observed English slips involving MLIs (the Tuggy corpus). Our argument proceeds as follows. First we show that slips occur independent of whether or not there are MLIs involved. In other words, speech production proceeds in certain of its aspects as though there were no MLI present. We illustrate these slips from the Tuggy data. Second we investigate the predictions of superlemma theory. Superlemma theory (Sprenger et al., 2006) accounts for the selection of MLIs and how their properties enter processes of speech production. It predicts certain activation patterns dependent on a MLI being selected. Each such pattern might give rise to slips of the tongue. This set of predictions is tested against the Tuggy data. Each of the predicted activation patterns yields a significant number of slips. These findings are therefore compatible with a view of MLIs as single units in so far as their activation by lexical concepts goes. However, the theory also predicts that some slips are likely not to occur. We confirm that such slips are not present in the data. These findings are further corroborated by reference a second smaller dataset of slips involving Dutch MLIs (the Kempen corpus). We then use slips involving irreversible binomials to distinguish between the predictions of superlemma theory which are supported by slips involving irreversible binomials and the Cutting and Bock model’s predictions for slips involving these MLIs which are not.

Spatial Scale and Saccade Programming

Perception ◽  
1997 ◽  
Vol 26 (9) ◽  
pp. 1159-1167 ◽  
Author(s):  
John M Findlay ◽  
Iain D Gilchrist
Keyword(s):  
Time Course ◽  
Spatial Integration ◽  
Global Effect ◽  
Centre Of Gravity ◽  
Visual Spatial ◽  
Fast Processing ◽  
Saccade Programming ◽  
Stimulus Features ◽  
High Level ◽  
Selection Of

The global effect in eye orienting occurs when saccades land at the ‘centre of gravity’ of a target stimulus configuration. Short-latency saccades are particularly prone to this effect whereas longer-latency saccades may show more influence of fine detail. Alternative explanations of these effects are considered and data are presented from an experiment in which the influence of different stimulus features on the global effect in a search task was examined. The effect shows a substantially different time course for target-distractor combinations differing in contrast polarity (black vs white) than for combinations differing in shape (circle vs square). It is concluded that the global effect cannot be explained either as a high-level strategic effect or as an effect of automatic fast processing of low-spatial-frequency information in early sensory channels. Instead it is suggested that the visual-spatial-integration characteristic of the global effect is an integral and unavoidable part of the process of selection of saccadic response.

Analytical Calculation of Mutual Information between Weakly Coupled Poisson-Spiking Neurons in Models of Dynamically Gated Communication

2017 ◽  
Vol 29 (1) ◽  
pp. 118-145 ◽  
Author(s):  
Jonathan Cannon
Keyword(s):  
Mutual Information ◽  
Time Course ◽  
Analytical Calculation ◽  
Activation Function ◽  
Neuronal Dynamics ◽  
Weakly Coupled ◽  
Flow Of Information ◽  
The Relationship ◽  
Background Input ◽  
Selection Of

Mutual information is a commonly used measure of communication between neurons, but little theory exists describing the relationship between mutual information and the parameters of the underlying neuronal interaction. Such a theory could help us understand how specific physiological changes affect the capacity of neurons to synaptically communicate, and, in particular, they could help us characterize the mechanisms by which neuronal dynamics gate the flow of information in the brain. Here we study a pair of linear-nonlinear-Poisson neurons coupled by a weak synapse. We derive an analytical expression describing the mutual information between their spike trains in terms of synapse strength, neuronal activation function, the time course of postsynaptic currents, and the time course of the background input received by the two neurons. This expression allows mutual information calculations that would otherwise be computationally intractable. We use this expression to analytically explore the interaction of excitation, information transmission, and the convexity of the activation function. Then, using this expression to quantify mutual information in simulations, we illustrate the information-gating effects of neural oscillations and oscillatory coherence, which may either increase or decrease the mutual information across the synapse depending on parameters. Finally, we show analytically that our results can quantitatively describe the selection of one information pathway over another when multiple sending neurons project weakly to a single receiving neuron.

Intelligibility Across a Reading Passage: The Effect of Dysarthria and Cued Speaking Styles

2022 ◽  
pp. 1-19
Author(s):  
Frits van Brenk ◽  
Kaila Stipancic ◽  
Alexander Kain ◽  
Kris Tjaden
Keyword(s):  
Multiple Sclerosis ◽  
Analogue Scale ◽  
Time Course ◽  
Read Aloud ◽  
Control Group ◽  
Careful Selection ◽  
Perceptual Assessment ◽  
Perceptual Characteristics ◽  
Speaking Style ◽  
Selection Of

Objective: Reading a passage out loud is a commonly used task in the perceptual assessment of dysarthria. The extent to which perceptual characteristics remain unchanged or stable over the time course of a passage is largely unknown. This study investigated crowdsourced visual analogue scale (VAS) judgments of intelligibility across a reading passage as a function of cued speaking styles commonly used in treatment to maximize intelligibility. Patients and Method: The Hunter passage was read aloud in habitual, slow, loud, and clear speaking styles by 16 speakers with Parkinson's disease (PD), 30 speakers with multiple sclerosis (MS), and 32 control speakers. VAS judgments of intelligibility from three fragments representing the beginning, middle, and end of the reading passage were obtained from 540 crowdsourced online listeners. Results: Overall passage intelligibility was reduced for the two clinical groups relative to the control group. All speaker groups exhibited intelligibility variation across the reading passage, with trends of increased intelligibility toward the end of the reading passage. For control speakers and speakers with PD, patterns of intelligibility variation across passage reading did not differ with speaking style. For the MS group, intelligibility variation across the passage was dependent on speaking style. Conclusions: The presence of intelligibility variation within a reading passage warrants careful selection of speech materials in research and clinical practice. Results further indicate that the crowdsourced VAS rating paradigm is useful to document intelligibility in a reading passage for different cued speaking styles commonly used in treatment for dysarthria.

scholarly journals Leeches run cold, then hot

2011 ◽  
Vol 7 (6) ◽  
pp. 941-943 ◽  
Author(s):  
Ann M. Petersen ◽  
Wendy Chin ◽  
Kara L. Feilich ◽  
Grace Jung ◽  
Jessica L. Quist ◽  
...  
Keyword(s):  
Time Course ◽  
Environmental Temperature ◽  
Acclimation Temperature ◽  
Body Volume ◽  
Energy Costs ◽  
Behavioural Strategy ◽  
Preferred Temperatures ◽  
Thermoregulatory Behaviour ◽  
Blood Meals ◽  
Selection Of

Food processing is costly, potentially limiting the energy and time devoted to other essential functions such as locomotion or reproduction. In ectotherms, post-prandial thermophily, the selection of a warm environmental temperature after feeding, may be advantageous in minimizing the duration of this elevated cost. Although present in many vertebrate taxa, this behaviour had not previously been observed in invertebrates. Sanguivorous leeches ingest large blood meals that are costly to process and limit mobility until excess fluid can actively be expelled to reduce body volume. When presented with a temperature gradient from 10°C to 30°C, leeches select a temperature that is significantly warmer (24.3 ± 0.9°C, n = 6) than their acclimation temperature ( T a , 21°C). Unfed leeches preferred temperatures that were significantly cooler than ambient (12.8 ± 0.9°C, n = 6). This behavioural strategy is consistent with minimizing the time course of elevated post-feeding energy costs and reducing energy expenditure during fasting. Our observations raise the possibility that thermoregulatory behaviour of this type is an unrecognized feature of other invertebrate taxa.

scholarly journals Selection and Budding Propagation of Native Bigtooth Maple for Water-conserving Landscapes

2012 ◽  
Vol 22 (5) ◽  
pp. 669-676 ◽  
Author(s):  
Melody Reed Richards ◽  
Larry A. Rupp ◽  
Roger Kjelgren ◽  
V. Philip Rasmussen
Keyword(s):  
Time Course ◽  
Wild Plants ◽  
Small Water ◽  
Acer Grandidentatum ◽  
Global Positioning ◽  
Northern Utah ◽  
Bigtooth Maple ◽  
Plant Form ◽  
Wild Accessions ◽  
Selection Of

The potential of bigtooth maple (Acer grandidentatum) as a small, water-conserving landscape tree for the western United States is limited by the selection of superior accessions from a morphologically diverse gene pool and the ability to propagate wild plants in a nursery environment. Superior accessions were selected based primarily on red fall color. Aerial digital images taken during peak fall color in 2007 and 2008 were synchronized with flight global positioning system (GPS) track files using digital image editor software and visually compared with corresponding satellite images to determine the exact latitude and longitude of selected trees on the ground. Trees were physically located using GPS technology then visually evaluated for initial selection. Criteria included fall color, habitat, relative disease and insect resistance, bud quality, and plant form. From 56 observed trees of interest, six were selected for propagation. Through time-course experiments using multistemmed, bigtooth maple seedling rootstocks in a coppiced stoolbed, the optimum time for chip budding scions of wild accessions in northern Utah was determined to be July through mid-August. Further evaluation of accessions for use in the landscape industry is required.

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