655 research outputs found
Using the shape of the basicranial portion of the temporal bone to distinguish between relatively closely-related human populations
© 2019 Elsevier Ltd Variation in cranial morphology is routinely used in archaeology to identify population affinity in human skeletal remains. The shape of the external basicranial portion of the temporal bone, in particular, has been found to have one of the strongest phylogenetic signals in the crania, and so it can be effectively used to distinguish between populations on a large, often global scale. However, its applicability to the analysis of relatively closely-related groups remains largely unexplored. The retention of population signatures in the shape of this portion of the temporal bone is particularly useful for archaeology, as the fragility of the cranium makes analysis of its shape in entirety often difficult. If the shape of the temporal bone can identify differences between relatively closely-related populations with a similar accuracy as for more distantly-related populations, this would significantly aid analyses of population history on a local scale. To test this, we initiated a study that used three-dimensional geometric morphometrics to investigate the shape variation of the temporal bone of two British archaeological populations that were separated both temporally and geographically. The results of a MANOVA found statistically significant shape differences between the two populations and a DFA found that the shape of the temporal bone can correctly classify 84.7% of individuals into their respective population. Therefore, the findings of this study suggest that the shape of the temporal bone can accurately identify differences between two relatively closely-related populations. Future research should focus on examining larger samples from a greater number of populations to determine whether this pattern is widespread
Nonlinear Dynamics of the Perceived Pitch of Complex Sounds
We apply results from nonlinear dynamics to an old problem in acoustical
physics: the mechanism of the perception of the pitch of sounds, especially the
sounds known as complex tones that are important for music and speech
intelligibility
Porosity of silica Stöber particles determined by spin-echo small angle neutron scattering.
Stöber silica particles are used in a diverse range of applications. Despite their widespread industrial and scientific uses, information on the internal structure of the particles is non-trivial to obtain and is not often reported. In this work we have used spin-echo small angle neutron scattering (SESANS) in conjunction with ultra small angle X-ray scattering (USAXS) and pycnometry to study an aqueous dispersion of Stöber particles. Our results are in agreement with models which propose that Stöber particles have a porous core, with a significant fraction of the pores inaccessible to solvent. For samples prepared from the same master sample in a range of H2O : D2O ratio solutions we were able to model the SESANS results for the solution series assuming monodisperse, smooth surfaced spheres of radius 83 nm with an internal open pore volume fraction of 32% and a closed pore fraction of 10%. Our results are consistent with USAXS measurements. The protocol developed and discussed here shows that the SESANS technique is a powerful way to investigate particles much larger than those studied using conventional small angle scattering methods
Distortions of Subjective Time Perception Within and Across Senses
Background: The ability to estimate the passage of time is of fundamental importance for perceptual and cognitive processes. One experience of time is the perception of duration, which is not isomorphic to physical duration and can be distorted by a number of factors. Yet, the critical features generating these perceptual shifts in subjective duration are not understood.
Methodology/Findings: We used prospective duration judgments within and across sensory modalities to examine the effect of stimulus predictability and feature change on the perception of duration. First, we found robust distortions of perceived duration in auditory, visual and auditory-visual presentations despite the predictability of the feature changes in the stimuli. For example, a looming disc embedded in a series of steady discs led to time dilation, whereas a steady disc embedded in a series of looming discs led to time compression. Second, we addressed whether visual (auditory) inputs could alter the perception of duration of auditory (visual) inputs. When participants were presented with incongruent audio-visual stimuli, the perceived duration of auditory events could be shortened or lengthened by the presence of conflicting visual information; however, the perceived duration of visual events was seldom distorted by the presence of auditory information and was never perceived shorter than their actual durations.
Conclusions/Significance: These results support the existence of multisensory interactions in the perception of duration and, importantly, suggest that vision can modify auditory temporal perception in a pure timing task. Insofar as distortions in subjective duration can neither be accounted for by the unpredictability of an auditory, visual or auditory-visual event, we propose that it is the intrinsic features of the stimulus that critically affect subjective time distortions
Coping with paediatric illness: Child’s play? Exploring the effectiveness of a play- and sports-based cognitive behavioural programme for children with chronic health conditions
Little is known about how play affects the development of children with a chronic condition. Studying play poses major methodological challenges in measuring differences in play behaviour, which results in a relative scarcity of research on this subject. This pilot study seeks to provide novel directions for research in this area. The effectiveness of a play- and sports-based cognitive behavioural programme for children (8–12 years) with a chronic condition was studied. The children and parents completed a battery of measurement tools before and after the programme. Moreover, the application of automated computer analyses of behaviour was piloted. Behaviour (Child Behavior Checklist) seemed to be positively affected by the programme. An increase in psychological well-being was observed (KIDSCREEN). Perceived competence (Self-Perception Profile for Children) and actual motor competence (Canadian Agility and Movement Skill Assessment) did not show any positive trends. These results of 13 participants suggest that children might learn to better cope with their illness by stimulating play behaviour. For the analysis of the effectiveness of programmes like this, we therefore propose to focus on measuring behaviour and quality of life. In addition, pilot measurements showed that automated analysis of play can provide important insights into the participation of children
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