Comparing the cooling effectiveness of operationalisable urban surface combination scenarios for summer heat mitigation

Extreme summer heat in cities exacerbates the vulnerability of urban communities to heatwaves. Vegetative and reflective urban surfaces can help reduce urban heat. This study investigated the impacts of urban trees, green roofs and cool roofs on heat mitigation during average and extreme summer conditions in temperate oceanic Melbourne, Australia. We simulated the city climate using 'The Air Pollution Model' (TAPM) at a 1 km spatial resolution over 10 years, which according to our review of the literature, was the most prolonged period for simulation in Melbourne. During a widespread heatwave event, some of the tested scenarios with combined surface parameters could reduce the extreme values of the energy budget components- sensible heat, latent heat, and storage heat fluxes up to seasonal averages compared to the existing situation for Melbourne (control). The scenario with the highest (reasonable maximum) ground-level vegetation, green roofs, and cool roofs could reduce air temperatures up to 2.4 °C. The simulations suggest that a combined strategy with vegetative and high-albedo surfaces will deliver higher effectiveness with maximum cooling benefits and cost-effectiveness than individual strategies in cities. These results suggest the importance of collaborative strategic planning of urban surfaces to make cities healthier, sustainable, and liveable.

Neural correlates of dual task interference can be dissociated from those of divided attention: an fMRI study

When people perform two tasks simultaneously, the tasks are often executed slower and with more errors than when they are carried out as single tasks. This is called dual task interference. With functional magnetic resonance imaging (fMRI), we show that concurrently performed visual and somatosensory reaction time (RT) tasks engage almost identical volumes of cortical and subcortical motor structures. Moreover, dual RT tasks engaged additional cortical regions that are not activated by the component RT tasks had they been performed as single tasks. When the inter-stimulus interval was <300 ms, the first task interfered with the second, and a field in the right inferior frontal gyrus (RIFG) appeared with activity correlated with the increased RT to the second stimulus. This activation was spatially distinct from the cortical activity of the main effect of dual task performance. Thus, the performance of single RT tasks, dual RT tasks and dual RT tasks that interfere differ psychophysically and in the brain structures subserving these tasks. A short occupancy of the common motor structures can explain the interference effect. The increased activity of the RIFG correlated with the interference effect is very likely to be a specific outcome of situations where two concurrent tasks interfere with each other. The brain appears to recruit the RIFG for a subsequent (delayed) response when there is interference between dual tasks.

Visual recognition: evidence for two distinctive mechanisms from a PET study

In this study, we examined the hypothesis that two distinct sets of cortical areas subserve two dissociable neurophysiological mechanisms of visual recognition. We posited that one such mechanism uses category specific cues extractable from the viewed pattern for the purpose of recognition. The other mechanism matches the pattern to be recognized with a pre-encoded memory representation of the pattern. In order to distinguish the cortical areas active in these two strategies, we measured changes in regional cerebral blood flow (rCBF) with positron emission tomography (PET) and (15)O Butanol as the radiotracer. Ten subjects performed pattern recognition tasks based on three different short-term memory conditions and a condition based on visual categories of the patterns. When subjects used representations of the patterns held in short-term memory for the purpose of recognition, the precunei were bilaterally activated. Recognition based on visual categories of the patterns activated the right (R) angular gyrus, left (L) inferior temporal gyrus, and L superior parieto-occipital cortex. These findings demonstrate that the R angular gyrus, the L inferior temporal gyrus, and the L superior parieto-occipital cortex are associated with recognition of patterns based on visual categories, whereas recognition of patterns using memory representations is associated with the activity of the precunei. This study is the first to show functional dual dissociation of active cortical fields for different mechanisms of visual pattern recognition.

Visual recognition: evidence for two distinctive mechanisms from a PET study

In this study, we examined the hypothesis that two distinct sets of cortical areas subserve two dissociable neurophysiological mechanisms of visual recognition. We posited that one such mechanism uses category specific cues extractable from the viewed pattern for the purpose of recognition. The other mechanism matches the pattern to be recognized with a pre-encoded memory representation of the pattern. In order to distinguish the cortical areas active in these two strategies, we measured changes in regional cerebral blood flow (rCBF) with positron emission tomography (PET) and (15)O Butanol as the radiotracer. Ten subjects performed pattern recognition tasks based on three different short-term memory conditions and a condition based on visual categories of the patterns. When subjects used representations of the patterns held in short-term memory for the purpose of recognition, the precunei were bilaterally activated. Recognition based on visual categories of the patterns activated the right (R) angular gyrus, left (L) inferior temporal gyrus, and L superior parieto-occipital cortex. These findings demonstrate that the R angular gyrus, the L inferior temporal gyrus, and the L superior parieto-occipital cortex are associated with recognition of patterns based on visual categories, whereas recognition of patterns using memory representations is associated with the activity of the precunei. This study is the first to show functional dual dissociation of active cortical fields for different mechanisms of visual pattern recognition.