72 research outputs found
Developmental Risk: Evidence from Large Nonrighthanded Samples
The aim of the present study is twofold. First, we tested the view that individuals who do not develop a typically strong behavioral
laterality are distributed differentially among the two genders across age. Second, we examined whether left handedness and mixed
handedness are associated with an elevated risk of some developmental or cognitive deficits. A special recruitment procedure
provided norms of the Rey-Osterrieth Complex Figure (ROCF) copy from large samples of left-handed ( = 420) and mixedhanded
( = 72) compared to right-handed ( = 420) schoolchildren and adults ( = 545). This graphic task was considered as
reflective of the growth of visual-spatial skills and impairment at copying as a developmental risk. Subjects' hand preference was
assessed by the Edinburgh Handedness Inventory. Data analysis indicated that (1) the trend towards consistent right handedness
is sex related. Girls are clearly ahead of boys in this lateralization process, and boys are overrepresented in mixed-handed subjects.
The greater prevalence of mixed-handed boys compared to girls decreases with age. (2) Performance on drawing the ROCF varies
according to age and handedness groups.Mixed-handed subjects scoredworse in all age groups.The results are discussed in relation
to the hormonal-developmental, neuropathological, and learning theories of lateralization
Spreading and retraction dynamics of sessile evaporating droplets comprising volatile binary mixtures
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Superspreading: Mechanisms and Molecular Design
The
intriguing ability of certain surfactant molecules to drive
the superspreading of liquids to complete wetting on hydrophobic substrates
is central to numerous applications that range from coating flow technology
to enhanced oil recovery. Despite significant experimental efforts,
the precise mechanisms underlying superspreading remain unknown to
date. Here, we isolate these mechanisms by analyzing coarse-grained
molecular dynamics simulations of surfactant molecules of varying
molecular architecture and substrate affinity. We observe that for
superspreading to occur, two key conditions must be simultaneously
satisfied: the adsorption of surfactants from the liquid–vapor
surface onto the three-phase contact line augmented by local bilayer
formation. Crucially, this must be coordinated with the rapid replenishment
of liquid–vapor and solid–liquid interfaces with surfactants
from the interior of the droplet. This article also highlights and
explores the differences between superspreading and conventional surfactants,
paving the way for the design of molecular architectures tailored
specifically for applications that rely on the control of wetting
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Executive function in Williams and Down syndromes
Williams (WS) and Down (DS) syndromes are characterised by roughly opposing ability profiles. Relative verbal strengths and visuospatial difficulties have been reported in those with WS, while expressive language difficulties have been observed in individuals with DS. Few investigations into the executive function (EF) skills of these groups have examined the effect of verbal/visuospatial task type on performance. Analogous verbal and visuospatial measures were administered to these populations within four EF domains: executive-loaded working memory (ELWM), inhibition, fluency and set-shifting. Performance in both groups was compared to that of typically developing (TD) children using regression techniques controlling for potentially influential cognitive/developmental factors. Individuals with WS showed the expected relative visuospatial difficulties, as indicated by poorer performance than TD individuals, on tests of ELWM and fluency. Individuals with DS displayed the expected relative verbal difficulty in the domain of set-shifting. In addition, each population showed pervasive deficits across modality in one domain; ELWM for individuals with DS, and inhibition for individuals with WS. Individuals with WS and DS showed EF difficulties in comparison to a TD group, but, their executive performance was affected by EF task type (verbal/visuospatial) and EF domain in different ways. While the findings indicated that EF in these populations is characterised by a range of specific strengths and weaknesses, it was also suggested that the relative verbal/visuospatial strengths associated with each population do not consistently manifest across EF domains. Lastly, syndrome specificity was indicated by the differences in groups’ performance patterns
Hemispheric asymmetries of visual ERPs in left-handed bilinguals
ERPs (NI, Pl, N2, P2) obtained from left and right occipital and temporal lobes were elicited in 30 left-handed highly proficient bilingual males in response to visually presented linguistic stimuli. The absence of statistically significant(P=less than or equal to 0.05) differences between left and right occipital and temporal lobes in all the components of the waveforms obtained, indicates a bilateral pattern of lateralization in left-handed males for both their native and foreign language. (C) 2001 Elsevier Science BY All rights reserved
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