Search results for "physiologic"

Flow properties and hydrodynamic interactions of rigid spherical microswimmers.

2017

We analyze a minimal model for a rigid spherical microswimmer and explore the consequences of its extended surface on the interplay between its self-propulsion and flow properties. The model is the first order representation of microswimmers, such as bacteria and algae, with rigid bodies and flexible propelling appendages. The flow field of such a microswimmer at finite distances significantly differs from that of a point-force (Stokeslet) dipole. For a suspension of microswimmers, we derive the grand mobility matrix that connects the motion of an individual swimmer to the active and passive forces and torques acting on all the swimmers. Our investigation of the mobility tensors reveals tha…

Best not to bet on the horserace: A comment on Forrin and MacLeod (2017) and a relevant stimulus-response compatibility view of colour-word contingen…

2018

International audience; One powerfully robust method for the study of human contingency learning is the colour-word contingency learning paradigm. In this task, participants respond to the print colour of neutral words, each of which is presented most often in one colour. The contingencies between words and colours are learned, as indicated by faster and more accurate responses when words are presented in their expected colour relative to an unexpected colour. In a recent report, Forrin and MacLeod (2017b, Memory & Cognition) asked to what extent this performance (i.e., response time) measure of learning might depend on the relative speed of processing of the word and the colour. With keypr…

Using Redundant Visual Information From Different Dimensions for Attentional Selection

2012

The present study investigated the use of redundant information for attentional selection of a visual object. Each display contained two overlapping objects, and participants had to report the color of the occluding object. A baseline condition did not require object selection because the objects were identical. A single-cue condition required object selection based on spatial arrangement (i.e., occlusion) because the objects had the same shape. A double-cue condition afforded object selection by occlusion and shape because the objects consistently differed in shape. Behavioral results showed that the redundant shape cue facilitated attentional selection, although participants were never s…

Short article: Does the brain regularize digits and letters to the same extent?

2009

The cognitive system does not just act as a mirror from the sensory input; instead, it tends to normalize this information. Given that letter processing seems to be much more specialized than digit processing in the cortex, we examined whether the regularization process occurs differently from digits to letters than from letters to digits: We employed a masked priming same/different experiment (e.g., probe, VESZED; prime, V35Z3D; and target, VESZED). When embedded in letter strings, digits that resemble letters (e.g., 3 and 5 in V35Z3D-VESZED) tend to be encoded in a letter-like manner, whereas when embedded in digit strings, letters that resemble digits (e.g., E and S in 9ES7E2–935732) te…

Relational priming is to analogy-making as one-ball juggling is to seven-ball juggling

2008

Relational priming is argued to be a deeply inadequate model of analogy-making because of its intrinsic inability to do analogies where the base and target domains share no common attributes and the mapped relations are different. The authors rely on carefully handcrafted representations to allow their model to make a complex analogy, seemingly unaware of the debate on this issue 15 years ago. Finally, they incorrectly assume the existence of fixed, context-independent relations between objects. Although relational priming may indeed play some role in analogy-making, it is an enormous – and unjustified – stretch to say that it is “centrally implicated in analogical reasoning” (sect. 2, para…

Encoding numbers: behavioral evidence for processing-specific representations.

2006

The aim of this study was to test the hypothesis of a complex encoding of numbers according to which each numerical processing requires a specific representational format for input. In three experiments, adult participants were given two numbers presented successively on screen through a self-presentation procedure after being asked to add, to subtract, or to compare them. We considered the self-presentation time of the first number as reflecting the complexity of the encoding for a given planned processing. In line with Dehaene's triple-code model, self-presentation times were longer for additions and subtractions than for comparisons with two-digit numbers but longer for subtractions than…

ERP correlates of the processing of speech sound prototipicality in Hungarian dyslexic and normal readers

2010

Bacterial endosymbionts of insects: insights from comparative genomics.

2004

The development of molecular techniques for the study of uncultured bacteria allowed the extensive study of the widespread association between insects and intracellular symbiotic bacteria. Most of the bacterial endosymbionts involved in such associations are gamma-proteobacteria, closely related to Escherichia coli. In recent years, five genomes from insect endosymbionts have been sequenced, allowing the performance of extensive genome comparative analysis that, as a complement of phylogenetic studies, and analysis on individual genes, can help to understand the different traits of this particular association, including how the symbiotic process is established, the explanation of the specia…

Cooperation Between Strangers in Face-to-Face Dyads Produces More Cardiovascular Activation Than Competition or Working Alone

2019

Abstract. Individual and shared goals can be achieved through social interpersonal interaction, cooperation and competition being two different yet similar strategies to reach such aims and objectives. Nevertheless, there is a gap in the literature analyzing the effect of these types of social interactions, especially in cooperation, on autonomic nervous system responses using noninvasive measures, such as heart rate (HR). The regulation of HR and other cardiovascular variables of the central nervous system offers information about how to encourage or discourage social engagement and prosocial behaviors. In fact, a more flexible engagement with the environment and efficient emotions regula…

Dynamics of two competing species in the presence of Lévy noise sources

2010

We consider a Lotka-Volterra system of two competing species subject to multiplicative alpha-stable Lévy noise. The interaction parameter between the species is a random process which obeys a stochastic differential equation with a generalized bistable potential in the presence both of a periodic driving term and an additive alpha-stable Lévy noise. We study the species dynamics, which is characterized by two different regimes, exclusion of one species and coexistence of both. We find quasi-periodic oscillations and stochastic resonance phenomenon in the dynamics of the competing species, analysing the role of the Lévy noise sources.