91 results match your criteria: "University of Leuven K.U.Leuven[Affiliation]"

The current study aims to fill the existing research gaps by investigating the role of teacher care in protecting African American adolescents in under-resourced neighborhoods from negative outcomes of adverse life events. The study included 638 adolescents from four under-resourced neighborhoods in Chicago's Southside who were assessed to determine the moderating role of caring teachers on the relationship between adverse adolescent experiences and risky sexual behaviors, substance use, bullying perpetration, and violent behaviors. Caring teachers had a significant moderating effect on the association between adverse experiences and both bullying perpetration and violent behaviors.

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Dubious Claims about Simplicity and Likelihood: Comment on Pinna and Conti (2019).

Brain Sci

January 2020

Department of Brain & Cognition, University of Leuven (K.U. Leuven), Tiensestraat 102-box 3711, B-3000 Leuven, Belgium.

Pinna and Conti (, 2019, , 149, doi:10.3390/brainsci9060149) presented phenomena concerning the salience and role of contrast polarity in human visual perception, particularly in amodal completion. These phenomena are indeed illustrative thereof, but here, the focus is on their claims (1) that neither simplicity nor likelihood approaches can account for these phenomena; and (2) that simplicity and likelihood are equivalent.

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The challenges raised in this article are not with information theory per se, but the assumptions surrounding it. Neuroscience isn't sufficiently critical about the appropriate 'receiver' or 'channel', focuses on decoding 'parts', and often relies on a flawed 'veridicality' assumption. If these problematic assumptions were questioned, information theory could be better directed to help us understand how the brain works.

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Q-Switch Nd:YAG Laser-Assisted Decontamination of Implant Surface.

Dent J (Basel)

October 2019

Department of Dental Science, Faculty of Medicine, University of Liege, 4000 Liege, Belgium.

Peri-implantitis (PI) is an inflammatory disease of peri-implant tissues, it represents the most frequent complication of dental implants. Evidence revealed that microorganisms play the chief role in causing PI. The purpose of our study is to evaluate the cleaning of contaminated dental implant surfaces by means of the Q-switch Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser and an increase in temperature at lased implant surfaces during the cleaning process.

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The problem of perceptual organization was studied by Gestalt psychologists in terms of figure-ground segregation. In this paper we explore a new principle of figure-ground segregation: accentuation. We demonstrate the effectiveness of accentuation relative to other Gestalt principles, and also consider it autonomous as it can agree with or oppose them.

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A returning idea among some Bayesians in research on human visual perceptual organization is that the surprisal of something (i.e., the negative logarithm of its probability) expresses its complexity (i.

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Human visual perceptual organization beats thinking on speed.

Atten Percept Psychophys

May 2017

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102 - Box 3711, Leuven, 3000, Belgium.

What is the degree to which knowledge influences visual perceptual processes? This question, which is central to the seeing-versus-thinking debate in cognitive science, is often discussed using examples claimed to be proof of one stance or another. It has, however, also been muddled by the usage of different and unclear definitions of perception. Here, for the well-defined process of perceptual organization, I argue that including speed (or efficiency) into the equation opens a new perspective on the limits of top-down influences of thinking on seeing.

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A group theoretical model of symmetry cognition.

Acta Psychol (Amst)

November 2016

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102, Box 3711, B-3000 Leuven, Belgium.

We report on two experiments, published originally in Japanese, on judged goodness and simplicity of dot patterns with reflectional and rotational symmetries (with 1-4 reflection axes and repeats, respectively) under free-viewing tasks. We found that (a) both goodness and simplicity increase monotonously with the number of transformations under which a pattern is invariant; (b) stimulus outlines, such as squares and hexagons, affect both goodness and simplicity; and (c) factors such as contrast polarity and collinearity affect simplicity rather than goodness. The employed free-viewing tasks contrast with detection tasks involving short presentation times, and based on behavioural and neurophysiological evidence, we conclude that this transformational approach captures late rather than early aspects of visio-cognitive processing of visual regularities.

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The performance of implant placement technologies are often evaluated based on their achieved post-operative implant alignment. Therefore accurate assessment techniques are necessary to compare pre-operatively planned implant positions with the corresponding post-operatively placed implant positions in total knee arthroplasty. This paper describes a CT based 3D measurement method for evaluation of implant positioning accuracy comparing post-operative implant position to the corresponding pre-operative planned implant position using 3D virtual models.

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Four analogs of HelaTx1, a 25-mer peptide from scorpion venom, were synthesized by deleting its C-terminal hexapeptide fragment and N-terminal Ser residue and by inserting an amino acid in the middle part of the molecule. CD spectrum of HelaTx1(1-19) was almost superimposable to that of native HelaTx1. Functional characterization showed that HelaTx1(1-19) retained its inhibitory activity on Kv1.

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Structural coding versus free-energy predictive coding.

Psychon Bull Rev

June 2016

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102, Box 3711, Leuven, 3000, Belgium.

Focusing on visual perceptual organization, this article contrasts the free-energy (FE) version of predictive coding (a recent Bayesian approach) to structural coding (a long-standing representational approach). Both use free-energy minimization as metaphor for processing in the brain, but their formal elaborations of this metaphor are fundamentally different. FE predictive coding formalizes it by minimization of prediction errors, whereas structural coding formalizes it by minimization of the descriptive complexity of predictions.

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Characterization of Kbot21 Reveals Novel Side Chain Interactions of Scorpion Toxins Inhibiting Voltage-Gated Potassium Channels.

PLoS One

June 2016

Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis,13 Place Pasteur, BP-74, 1002, Tunis, Tunisie.

Scorpion toxins are important pharmacological tools for probing the physiological roles of ion channels which are involved in many physiological processes and as such have significant therapeutic potential. The discovery of new scorpion toxins with different specificities and affinities is needed to further characterize the physiology of ion channels. In this regard, a new short polypeptide called Kbot21 has been purified to homogeneity from the venom of Buthus occitanus tunetanus scorpion.

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Kbot55, purified from Buthus occitanus tunetanus venom, represents the first member of a novel α-KTx subfamily.

Peptides

June 2016

Laboratoire des Venins et Molécules Thérapeutiques, Institut Pasteur de Tunis, 13 Place Pasteur, BP-74, 1002 Tunis, Tunisia. Electronic address:

Kbot55 is a 39 amino acid peptide isolated from the venom of the Tunisian scorpion Buthus occitanus tunetanus. This peptide is cross-linked by 3 disulfide bridges and has a molecular mass of 4128.65Da.

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A cognitive architecture account of the visual local advantage phenomenon in autism spectrum disorders.

Vision Res

September 2016

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102 - Box 3711, Leuven B-3000, Belgium. Electronic address:

Ideally, a cognitive architecture is a neurally plausible model that unifies mental representations and cognitive processes. Here, I apply such a model to re-evaluate the local advantage phenomenon in autism spectrum disorders (ASD), that is, the better than typical performance on visual tasks in which local stimulus features are to be discerned. The model takes (a) perceptual organization as a predominantly stimulus-driven process yielding hierarchical stimulus organizations, and (b) attention as predominantly scrutinizing the hierarchical structure of established percepts in a task-driven top-down fashion.

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Improvement of biochemical and behavioral defects in the Niemann-Pick type A mouse by intraventricular infusion of MARCKS.

Neurobiol Dis

January 2015

Centro Biología Molecular "Severo Ochoa" (CSIC-UAM), Campus Universidad Autónoma de Madrid, Nicolás Cabrera 1, 28049 Madrid, Spain. Electronic address:

Niemann-Pick disease type A (NPDA) is a fatal disease due to mutations in the acid sphingomyelinase (ASM) gene, which triggers the abnormal accumulation of sphingomyelin (SM) in lysosomes and the plasma membrane of mutant cells. Although the disease affects multiple organs, the impact on the brain is the most invalidating feature. The mechanisms responsible for the cognitive deficit characteristic of this condition are only partially understood.

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Zograscopic viewing.

Iperception

June 2013

Laboratory of Experimental Psychology, University of Leuven (K.U. Leuven), Tiensestraat 102, 3000 Leuven, Belgium; and Faculteit Sociale Wetenschappen, Psychologische Functieleer, Universiteit Utrecht, Heidelberglaan 2, 3584CS Utrecht, The Netherlands; e-mail:

The "zograscope" is a "visual aid" (commonly known as "optical machine" in the 18th century) invented in the mid-18th century, and in general use until the early 20th century. It was intended to view single pictures (thus not stereographic pairs) with both eyes. The optics approximately eliminates the physiological cues (binocular disparity, vergence, accommodation, movement parallax, and image blur) that might indicate the flatness of the picture surface.

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Nine analogs of scorpion toxin peptide κ-hefutoxin 1 were synthesized by stepwise deletion of its amino acid residues. Disulfide bond pairings of the synthetic analogs were confirmed by enzymatic digestion followed by MALDI-TOF-MS measurements. Functional characterization shows that analogs in which N-terminal residues were deleted retained biological activity, whereas deletion of middle part residues resulted in loss of activity.

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The role of children's on-task behavior in the prevention of aggressive behavior was assessed among 570 Dutch speaking children followed from second- to third-grade elementary school in Flanders, Belgium. A first objective was to investigate whether individual level variation of on-task behavior moderated the impact of a universal preventive intervention, the Good Behavior Game (GBG), on aggression development, controlling for classroom levels of on-task behavior. The second goal was to study whether improved on-task behavior or reductions in peer rejection mediated intervention impact on children's aggression.

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A developmental difference in shape processing and word-shape associations between 4 and 6.5 year olds.

Iperception

November 2012

Laboratory of Experimental Psychology, University of Leuven (K U Leuven), Tiensestraat 102, box 3711, 3000 Leuven, Belgium; e-mail:

In distinguishing individual shapes (defined by their contours), older children (6.5 years of age on average) performed better than younger children (4 years of age on average), and, although the task did not involve any categorization or generalization, the error pattern was qualitatively affected by shape differences that are generally common distinctions between objects belonging to different categories. The influence of these shape differences was also observed for unfamiliar shapes, demonstrating that the influence of categorization experience was not modulated by the retrieval of shape features from known categories but rather related to a different perception of shape by age.

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Space-time disarray and visual awareness.

Iperception

November 2012

University of Leuven (K.U. Leuven), Laboratory of Experimental Psychology, Tiensestraat 102-box 3711, BE-3000 Leuven, Belgium; and Delft University of Technology, EEMCS, MMI, Mekelweg 4, NL-2628 CD Delft, The Netherlands; e-mail:

Local space-time scrambling of optical data leads to violent jerks and dislocations. On masking these, visual awareness of the scene becomes cohesive, with dislocations discounted as amodally occluding foreground. Such cohesive space-time of awareness is technically illusory because ground truth is jumbled whereas awareness is coherent.

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The present work demonstrates that bactridines (Bacts) possess different selectivities for neuronal and muscular voltage-dependent sodium (Na(V) ) channels, with subtle differences on channel isoforms. Bacts 2, 3, 4, 5 and 6 (100 nm) reduced the peak current of several skeletal and neuronal channel isoforms selectively. Bacts 2 and 3 were more potent on Na(V) 1.

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The primary structure of a new Kunitz-type protease inhibitor InhVJ from the sea anemone Heteractis crispa (Radianthus macrodactylus) was determined by protein sequencing and cDNA cloning. InhVJ amino acid sequence was shown to share high sequence identity (up to 98%) with the other known Kunitz-type sea anemones sequences. It was determined that the P1 Thr at the reactive site resulted in a decrease of the K(i) of InhVJ to trypsin and α-chymotrypsin (7.

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Crotamine, a 5-kDa peptide, possesses a unique biological versatility. Not only has its cell-penetrating activity become of clinical interest but, moreover, its potential selective antitumor activity is of great pharmacological importance. In the past, several studies have attempted to elucidate the exact molecular target responsible for the crotamine-induced skeletal muscle spasm.

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Blocking of the collection hoppers of the baghouse filters in a fluidized bed incinerator for co-incineration of high calorific industrial solid waste and sludge was observed. The composition of the flue gas cleaning residue (FGCR), both from a blocked hopper and from a normal hopper, was investigated by (differential) thermogravimetric analysis, quantitative X-ray powder diffraction and wet chemical analysis. The lower elemental carbon concentration and the higher calcium carbonate concentration of the agglomerated sample was the result of oxidation of carbon and subsequent reaction of CO2 with CaO.

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Humans can rapidly extract object and category information from an image despite surprising limitations in detecting changes to the individual parts of that image. In this article we provide evidence that the construction of a perceptual whole, or Gestalt, reduces awareness of changes to the parts of this object. This result suggests that the rapid extraction of a perceptual Gestalt, and the inaccessibility of the parts that make up that Gestalt, may in fact reflect two sides of the same coin whereby human vision provides only the most useful level of abstraction to conscious awareness.

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