Electrophysiological measures of low-level vision reveal spatial processing deficits and hemispheric asymmetry in autism spectrum disorder

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Methods to Reproduce In-Plane Deformability of Orthotropic Floors in the Finite Element Models of Buildings

In the modelling of reinforced concrete (RC) buildings, the rigid diaphragm hypothesis to represent the in-plane behavior of floors was and still is very commonly adopted because of its simplicity and computational cheapness. However, since excessive floor in-plane deformability can cause a very different redistribution of lateral forces on vertical resisting elements, it may be necessary to consider floor deformability. This paper investigates the classical yet intriguing question of modeling orthotropic RC floor systems endowed with lightening elements by means of a uniform orthotropic slab in order to describe accurately the building response under seismic loads. The simplified method, commonly adopted by engineers and based on the equivalence between the transverse stiffness of the RC elements of the real floor and those of the orthotropic slab, is presented. A case study in which this simplified method is used is also provided. Then, an advanced finite element (FE)-based method to determine the elastic properties of the equivalent homogenized orthotropic slab is proposed. The novel aspect of this method is that it takes into account the interaction of shell elements with frame elements in the 3D FE model of the building. Based on the results obtained from the application of this method to a case study, a discussion on the adequacy of the simplified method is also provided

Methods to Reproduce In-Plane Deformability of Orthotropic Floors in the Finite Element Models of Buildings

In the modelling of reinforced concrete (RC) buildings, the rigid diaphragm hypothesis to represent the in-plane behavior of floors was and still is very commonly adopted because of its simplicity and computational cheapness. However, since excessive floor in-plane deformability can cause a very different redistribution of lateral forces on vertical resisting elements, it may be necessary to consider floor deformability. This paper investigates the classical yet intriguing question of modeling orthotropic RC floor systems endowed with lightening elements by means of a uniform orthotropic slab in order to describe accurately the building response under seismic loads. The simplified method, commonly adopted by engineers and based on the equivalence between the transverse stiffness of the RC elements of the real floor and those of the orthotropic slab, is presented. A case study in which this simplified method is used is also provided. Then, an advanced finite element (FE)-based method to determine the elastic properties of the equivalent homogenized orthotropic slab is proposed. The novel aspect of this method is that it takes into account the interaction of shell elements with frame elements in the 3D FE model of the building. Based on the results obtained from the application of this method to a case study, a discussion on the adequacy of the simplified method is also provided

Cognitive and psychological science insights to improve climate change data visualization

Visualization of climate data plays an integral role in the communication of climate change findings to both expert and non-expert audiences. The cognitive and psychological sciences can provide valuable insights into how to improve visualization of climate data based on knowledge of how the human brain processes visual and linguistic information. We review four key research areas to demonstrate their potential to make data more accessible to diverse audiences: directing visual attention, visual complexity, making inferences from visuals, and the mapping between visuals and language. We present evidence-informed guidelines to help climate scientists increase the accessibility of graphics to non-experts, and illustrate how the guidelines can work in practice in the context of Intergovernmental Panel on Climate Change graphics

Full field electroretinogram in autism spectrum disorder

Purpose To explore early findings that individuals with autism spectrum disorder (ASD) have reduced scotopic ERG b-wave amplitudes. Methods Dark adapted (DA) ERGs were acquired to a range of flash strengths, (-4.0 to 2.3 log phot cd.s.m-2), including and extending the ISCEV standard, from two subject groups: (ASD) N=11 and (Control) N=15 for DA and N=14 for light adapted (LA) ERGs who were matched for mean age and range. Naka-Rushton curves were fitted to DA b-wave amplitude growth over the first limb (-4.0 to -1.0 log phot cd.s.m-2). The derived parameters (Vmax, Km and n) were compared between groups. Scotopic 15 Hz flicker ERGs (14.93Hz) were recorded to 10 flash strengths presented in ascending order from -3.0 to 0.5 log Td.s to assess the slow and fast rod pathways respectively. LA ERGs were acquired to a range of flash strengths, (-0.5 to 1.0 log phot cd.s.m-2). Photopic 30 Hz, flicker ERGs, oscillatory potentials (OPs) and the responses to prolonged 120 ms ON- OFF stimuli were also recorded. Results For some individuals the DA b-wave amplitudes fell below the control 5th centile of the controls with up to four ASD participants (36%) at the 1.5 log phot cd.s.m-2 flash strength and two (18%) ASD participants at the lower -2 log phot cd.s.m-2 flash strength. However, across the thirteen flash strengths there were no significant group differences for b-wave amplitude’s growth (repeated measures ANOVA p=0.83). Nor were there any significant differences between the groups for the Naka-Rushton parameters (p>0.09). No group differences were observed in the 15Hz scotopic flicker phase or amplitude (p>0.1), DA ERG a- wave amplitude or time to peak (p>26). The DA b-wave time to peak at 0.5 log phot cd.s.m-2 were longer in the ASD group (corrected p=0.04). The single ISCEV LA 0.5 log phot cd.s.m-2 (p0.08) to the single flash stimuli although there was a significant interaction between group and flash strength for the b-wave amplitude (corrected p=0.006). The prolonged 120 ms ON-responses were smaller in the ASD group (corrected p=0.003), but the OFF response amplitude (p>0.6) and ON and OFF times to peaks (p>0.4) were similar between groups. The LA OPs showed an earlier bifurcation of OP2 in the younger ASD participants, however no other differences were apparent in the OPs or 30Hz flicker waveforms. Conclusion Some ASD individuals show subnormal DA ERG b-wave amplitudes. Under LA conditions the b-wave is reduced across the ASD group along with the ON response of the ERG. These exploratory findings, suggest there is altered cone-ON bipolar signalling in ASD

Characterization of visual object representations in rat primary visual cortex

For most animal species, quick and reliable identification of visual objects is critical for survival. This applies also to rodents, which, in recent years, have become increasingly popular models of visual functions. For this reason in this work we analyzed how various properties of visual objects are represented in rat primary visual cortex (V1). The analysis has been carried out through supervised (classification) and unsupervised (clustering) learning methods. We assessed quantitatively the discrimination capabilities of V1 neurons by demonstrating how photometric properties (luminosity and object position in the scene) can be derived directly from the neuronal responses

Learning with a network of competing synapses

Competition between synapses arises in some forms of correlation-based plasticity. Here we propose a game theory-inspired model of synaptic interactions whose dynamics is driven by competition between synapses in their weak and strong states, which are characterized by different timescales. The learning of inputs and memory are meaningfully definable in an effective description of networked synaptic populations. We study, numerically and analytically, the dynamic responses of the effective system to various signal types, particularly with reference to an existing empirical motor adaptation model. The dependence of the system-level behavior on the synaptic parameters, and the signal strength, is brought out in a clear manner, thus illuminating issues such as those of optimal performance, and the functional role of multiple timescales.Comment: 16 pages, 9 figures; published in PLoS ON

DNA testing for family reunification in Canada:Points to consider

Countries have adopted different laws, policies, and practices that allow immigration officers to request in certain cases DNA tests to confirm biological relationships in the context of family reunification. In Canada, Citizenship and Immigration Canada has adopted a policy of suggesting DNA testing only as a last resort in cases where no documentary evidence has been submitted or where the evidence provided is deemed unsatisfactory. However, in practice, there have been concerns on the increasing use of DNA tests in family reunification processes of nationals from certain regions including Africa, Asia, and Latin America. Moreover, the Immigration and Refugee Protection Regulations (IRPR) presents a biological definition of family as a determinant of parenthood in the context of family reunification that is inconsistent with the psychosocial definition used in provincial family laws. Although there are cases that can justify the request for DNA tests, there are also significant social, legal, and ethical issues, including discrimination and unfair practices, raised by this increasing use of genetic information in immigration. This policy brief identifies points to consider for policymakers regarding the use of DNA testing in Canadian family reunification procedures. These include (1) the need to refine the policy of “using DNA testing as a last resort” and its implementation, (2) the need to modify the definition of “dependent child” under the IRPR to reflect the intrinsic reality of psychosocial family ties, and (3) the importance of conducting more research on the use of DNA testing in other immigration contexts

The Spatial and Temporal Construction of Confidence in the Visual Scene

Human subjects can report many items of a cluttered field a few hundred milliseconds after stimulus presentation. This memory decays rapidly and after a second only 3 or 4 items can be stored in working memory. Here we compared the dynamics of objective performance with a measure of subjective report and we observed that 1) Objective performance beyond explicit subjective reports (blindsight) was significantly more pronounced within a short temporal interval and within specific locations of the visual field which were robust across sessions 2) High confidence errors (false beliefs) were largely confined to a small spatial window neighboring the cue. The size of this window did not change in time 3) Subjective confidence showed a moderate but consistent decrease with time, independent of all other experimental factors. Our study allowed us to asses quantitatively the temporal and spatial access to an objective response and to subjective reports