Problem: The prospect that urban heat island (UHI) effects and climate change may increase urban temperatures is a problem for cities that actively promote urban redevelopment and higher densities. One possible UHI mitigation strategy is to plant more trees and other irrigated vegetation to prevent daytime heat storage and facilitate nighttime cooling, but this requires water resources that are limited in a desert city like Phoenix.
Purpose: We investigated the tradeoffs between water use and nighttime cooling inherent in urban form and land use choices.
Methods: We used a Local-Scale Urban Meteorological Parameterization Scheme (LUMPS) model to examine the variation in temperature and evaporation in 10 census tracts in Phoenix's urban core. After validating results with estimates of outdoor water use based on tract-level city water records and satellite imagery, we used the model to simulate the temperature and water use consequences of implementing three different scenarios.
Results and conclusions: We found that increasing irrigated landscaping lowers nighttime temperatures, but this relationship is not linear; the greatest reductions occur in the least vegetated neighborhoods. A ratio of the change in water use to temperature impact reached a threshold beyond which increased outdoor water use did little to ameliorate UHI effects.
Takeaway for practice: There is no one design and landscape plan capable of addressing increasing UHI and climate effects everywhere. Any one strategy will have inconsistent results if applied across all urban landscape features and may lead to an inefficient allocation of scarce water resources.
Research Support: This work was supported by the National Science Foundation (NSF) under Grant SES-0345945 (Decision Center for a Desert City) and by the City of Phoenix Water Services Department. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of NSF.
This study addresses a classic sustainability challenge—the tradeoff between water conservation and temperature amelioration in rapidly growing cities, using Phoenix, Arizona and Portland, Oregon as case studies. An urban energy balance model— LUMPS (Local-Scale Urban Meteorological Parameterization Scheme)—is used to represent the tradeoff between outdoor water use and nighttime cooling during hot, dry summer months. Tradeoffs were characterized under three scenarios of land use change and three climate-change assumptions. Decreasing vegetation density reduced outdoor water use but sacrificed nighttime cooling. Increasing vegetated surfaces accelerated nighttime cooling, but increased outdoor water use by ~20%. Replacing impervious surfaces with buildings achieved similar improvements in nighttime cooling with minimal increases in outdoor water use; it was the most water-efficient cooling strategy. The fact that nighttime cooling rates and outdoor water use were more sensitive to land use scenarios than climate-change simulations suggested that cities can adapt to a warmer climate by manipulating land use.
Critical flicker fusion thresholds (CFFTs) describe when quick amplitude modulations of a light source become undetectable as the frequency of the modulation increases and are thought to underlie a number of visual processing skills, including reading. Here, we compare the impact of two vision-training approaches, one involving contrast sensitivity training and the other directional dot-motion training, compared to an active control group trained on Sudoku. The three training paradigms were compared on their effectiveness for altering CFFT. Directional dot-motion and contrast sensitivity training resulted in significant improvement in CFFT, while the Sudoku group did not yield significant improvement. This finding indicates that dot-motion and contrast sensitivity training similarly transfer to effect changes in CFFT. The results, combined with prior research linking CFFT to high-order cognitive processes such as reading ability, and studies showing positive impact of both dot-motion and contrast sensitivity training in reading, provide a possible mechanistic link of how these different training approaches impact reading abilities.
Although autism spectrum disorder (ASD) is a serious lifelong condition, its underlying neural mechanism remains unclear. Recently, neuroimaging-based classifiers for ASD and typically developed (TD) individuals were developed to identify the abnormality of functional connections (FCs). Due to over-fitting and interferential effects of varying measurement conditions and demographic distributions, no classifiers have been strictly validated for independent cohorts. Here we overcome these difficulties by developing a novel machine-learning algorithm that identifies a small number of FCs that separates ASD versus TD. The classifier achieves high accuracy for a Japanese discovery cohort and demonstrates a remarkable degree of generalization for two independent validation cohorts in the USA and Japan. The developed ASD classifier does not distinguish individuals with major depressive disorder and attention-deficit hyperactivity disorder from their controls but moderately distinguishes patients with schizophrenia from their controls. The results leave open the viable possibility of exploring neuroimaging-based dimensions quantifying the multiple-disorder spectrum.
The SARS-CoV-2 (Covid-19) virus has had severe impacts on college students' ways of life. To examine how students were coping and perceiving the Covid-19 pandemic, a secondary analysis of an online survey across the three Arizona public universities investigated students’ knowledge about Covid-19, engagement with preventive strategies, pandemic preparedness and gauged their risk perception. Results from our analysis indicate that the students were knowledgeable about Covid-19 and were changing their habits and engaging with preventive measures. Results further suggest that students were prepared for the pandemic in terms of resources and were exhibiting high-risk perceptions. The data also revealed that students who were being cautious and engaging with preventive behaviors had a higher risk-perception than individuals who were not. As for individuals who were prepared for the pandemic in terms of supplies, their risk perception was similar to those who did not have supplies. Individuals who were prepared and capable of providing a single caretaker to tend to their sick household members and isolate them in a separate room had a higher risk perception than those who could not. These results can help describe how college students will react to a future significant event, what resources students may be in need of, and how universities can take additional steps to keep their students safe and healthy. The results from this study and recommendations will provide for a stronger and more understanding campus community during times of distress and can improve upon already established university protocols for health crises and even natural disasters.
The SARS-CoV-2 (Covid-19) virus has had severe impacts on college students' ways of life. To examine how students were coping and perceiving the Covid-19 pandemic, a secondary analysis of an online survey across the three Arizona public universities investigated students’ knowledge about Covid-19, engagement with preventive strategies, pandemic preparedness and gauged their risk-perception. Results from our analysis indicate that the students were knowledgeable about Covid-19 and were changing their habits and engaging with preventive measures. Results further suggest that students were prepared for the pandemic in terms of resources and were exhibiting high-risk perceptions. The data also revealed that students who were being cautious and engaging with preventive behaviors had a higher risk-perception than individuals who were not. As for individuals who were prepared for the pandemic in terms of supplies, their risk perception was similar to those who did not have supplies. Individuals who were prepared and capable of providing a single caretaker to tend to their sick household members and isolate them in a separate room had a higher risk perception than those who could not. These results can help describe how college students will react to a future significant event, what resources students may be in need of, and how universities can take additional steps to keep their students safe and healthy. The results from this study and recommendations will provide for a stronger and more understanding campus community during times of distress and can improve upon already established university protocols for health crises and even natural disasters.