Matching Items (183)
Description
Studies on urban heat island (UHI) have been more than a century after the phenomenon was first discovered in the early 1800s. UHI emerges as the source of many urban environmental problems and exacerbates the living environment in cities. Under the challenges of increasing urbanization and future climate changes, there is a pressing need for sustainable adaptation/mitigation strategies for UHI effects, one popular option being the use of reflective materials. While it is introduced as one effective method to reduce temperature and energy consumption in cities, its impacts on multi-dimensional environmental sustainability and large-scale non-local effect are inadequately explored. This paper provides a synthetic overview of potential environmental impacts of reflective materials at a variety of scales, ranging from energy load on a single building to regional hydroclimate. The review shows that mitigation potential of reflective materials depends on a portfolio of factors, including building characteristics, urban environment, meteorological and geographical conditions, to name a few. Precaution needs to be exercised by city planners and policy makers for large-scale deployment of reflective materials before their environmental impacts, especially on regional hydroclimates, are better understood. In general, it is recommended that optimal strategy for UHI needs to be determined on a city-by-city basis, rather than adopting a “one-solution-fits-all” strategy.
ContributorsYang, Jiachuan (Contributor) / Wang, Zhi-Hua (Correspondent) / Kaloush, Kamil (Contributor)
Created2015-06-11
Description
Nonlinear responses in the dynamics of climate system could be triggered by small change of forcing. Interactions between different components of Earth’s climate system are believed to cause abrupt and catastrophic transitions, of which anthropogenic forcing is a major and the most irreversible driver. Meantime, in the face of global climate change, extreme climatic events, such as extreme precipitations, heatwaves, droughts, etc., are projected to be more frequent, more intense, and longer in duration. These nonlinear responses in climate dynamics from tipping points to extreme events pose serious threats to human society on a large scale. Understanding the physical mechanisms behind them has potential to reduce related risks through different ways. The overarching objective of this dissertation is to quantify complex interactions, detect tipping points, and explore propagations of extreme events in the hydroclimate system from a new structure-based perspective, by integrating climate dynamics, causal inference, network theory, spectral analysis, and machine learning. More specifically, a network-based framework is developed to find responses of hydroclimate system to potential critical transitions in climate. Results show that system-based early warning signals towards tipping points can be located successfully, demonstrated by enhanced connections in the network topology. To further evaluate the long-term nonlinear interactions among the U.S. climate regions, causality inference is introduced and directed complex networks are constructed from climatology records over one century. Causality networks reveal that the Ohio valley region acts as a regional gateway and mediator to the moisture transport and thermal transfer in the U.S. Furthermore, it is found that cross-regional causality variability manifests intrinsic frequency ranging from interannual to interdecadal scales, and those frequencies are associated with the physics of climate oscillations. Besides the long-term climatology, this dissertation also aims to explore extreme events from the system-dynamic perspective, especially the contributions of human-induced activities to propagation of extreme heatwaves in the U.S. cities. Results suggest that there are long-range teleconnections among the U.S. cities and supernodes in heatwave spreading. Findings also confirm that anthropogenic activities contribute to extreme heatwaves by the fact that causality during heatwaves is positively associated with population in megacities.
ContributorsYang, Xueli (Author) / Yang, Zhihua (Thesis advisor) / Lai, Ying-Cheng (Committee member) / Li, Qi (Committee member) / Xu, Tianfang (Committee member) / Zeng, Ruijie (Committee member) / Arizona State University (Publisher)
Created2023
Description
Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by a wide range of symptoms and severities, affecting communication, behavior, and social interactions. With the prevalence of ASD rising to affect nearly 1 in 36 children in the United States, understanding and addressing the multifaceted needs of those with ASD is increasingly critical. This review explores the interplay between genetic, environmental, and immune factors in the onset of ASD, focusing on metabolic dysfunctions and the role of the gut-brain axis. Emerging research highlights the significance of abnormal metabolites and gut microbiota imbalances in contributing to the pathophysiology of ASD, suggesting that these factors may influence neurological function and behavior through modulating immune responses.
Recent analyses have uncovered metabolic disturbances in ASD, affecting amino acid metabolism, glutathione metabolism, glycolysis and the TCA cycle, homocysteine metabolism, ketone body synthesis, and lipid metabolism. These disturbances offer insights into how metabolic dysfunctions may contribute to the neurological and behavioral features of ASD. Furthermore, the gut microbiota's role in immune responses and the controversial impact of antibiotic use on gut flora composition is important to the complexity of ASD and the need for a nuanced understanding of treatment effects.
This review delves into the current understanding of metabolic dysfunctions in children with ASD, emphasizing the critical role of gut microbiota and the impact of antibiotic use. Specifically, this review discusses SCFAs, para-cresol, amino acid metabolites, and glutathione and their respective specific treatments. It also explores the potential of vitamin/mineral supplementation as a therapeutic strategy, highlighting significant improvements in metabolic markers and behavioral symptoms associated with ASD. The findings from key studies, including those by Adams et al., suggest that targeted nutritional interventions and careful management of gut health could offer promising avenues for improving the quality of life for individuals with ASD. The review also acknowledges the need for further research to confirm the long-term effects of these interventions and to develop personalized treatment approaches that consider the unique needs in individuals with ASD.
ContributorsNandakumar, Keshav (Author) / Adams, James (Thesis director) / Flynn, Christina (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor)
Created2024-05