97 research outputs found
Relationships among speed of processing, aptitude, and working memory in elementary students
2017 Spring.Includes bibliographical references.This research explores the relationships between speed of processing, verbal and quantitative aptitude, and working memory for elementary age students. Students with impaired processing speed often struggle in elementary school and can be incorrectly identified as lazy or unintelligent. This can have lasting consequences on their self-esteem and future academic success. The findings of this research suggest that the combination of processing speed, working memory and academic achievement in reading does not adequately predict verbal intelligence. However, the model indicates that there is a relationship between the variables of processing speed, working memory, and mathematic achievement to predict quantitative intelligence. Additionally, there was no statistically significant correlation of processing speed and verbal aptitude for this sample. Likewise, there was no statistically significant correlation of speed of processing and quantitative aptitude. The research shows a statistically significant difference between processing speed and academic achievement in reading and in mathematics; reading and speed of processing, as well as mathematics and speed of processing. Ultimately, this research suggests that students with impaired processing speed do not demonstrate impaired aptitude in reading or mathematics. However, this research also suggests they may struggle with academic achievement in both reading and mathematics. This gap between aptitude and achievement is an important characteristic to remediate so that students with lower processing speeds can be successful in school
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Life Cycle Modeling of Technologies and Strategies for a Sustainable Freight System in California
California’s freight transportation system is a vital part of the state’s economy but is a significant contributor to greenhouse gas emissions and generates an even higher portion of regional and local air pollution. The state’s primary strategy for reducing emissions from the on-road freight sector relies on deploying new vehicle and fuel technologies, such as electric medium- and heavy-duty vehicles. The market for electric truck technologies is developing rapidly.The goal of this research is to quantify the life cycle environmental impacts and life cycle costs for on-road goods movement in California to estimate the abatement potential and economic costs and benefits of electrifying California’s freight truck sector. The study compares the emissions and costs of urban conventional gasoline and diesel Class 3–8 vehicles with electric heavy-duty vehicles (i.e., electric trucks) for a range of freight and commercial vocations. A model of freight vehicle operations is developed based on representative vehicle location data, and linked with life cycle emissions inventory, technology cost, and pollution health damage cost data. The model is then used to assess energy and capacity requirements for electric trucks and battery systems and explore the impacts of a range of charging strategies and vehicle duty cycles (i.e., vocations) on energy, costs, and emissions between 2020 and 2040.Where emissions occur, and how emissions of different pollutants are affected by factors including vocation, duty cycle, powertrain configuration, and fuel pathway, will influence the effectiveness and economic costs of emissions reduction strategies. On a per mile basis, replacing a conventional gasoline or diesel truck can reduce CO2-equivalent (CO2e) emissions by 50%–75% compared to conventional gas and diesel vehicles. Statewide, 100% electrification of in-state Class 8 vehicles by 2040 could reduce annual CO2e emissions by nearly than 30% (50 million metric tonnes per year), and electrification of Class 3 trucks statewide would likely half current PM2.5 emissions from transportation. The costs of emissions abatement from truck electrification ranged from 182 per metric tonne of CO2e for trucks deployed in 2020, but these costs are likely to fall dramatically by 2040. Full electrification of the in-state registered Class 3–8 vehicle fleet by 2040 would significantly reduce criteria pollutants and aerosols emissions; this in turn could reduce pollution related damages in the state by 1.6 billion by 2040.View the NCST Project Webpag
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Life Cycle-Based Policies Are Required to Achieve Emissions Goals from Light-Duty Vehicles
In the United States, vehicle emissions are responsible for 29% of total greenhouse gas (GHG) emissions with the majority of these coming from light-duty vehicles. To reduce GHG emissions, the U.S. has adopted policies to support the development and deployment of low-carbon fuels and zero emission vehicles (ZEVs—e.g., plug-in hybrid electric vehicles [PHEVs] and battery electric vehicles [EVs]).Most current policies focus on emissions from vehicle operation only, omitting significant contributions from vehicle production and other parts of the vehicle and energy life cycle.GHG emissions from vehicle operation and even from operation plus production are almost always lower for EVs than for conventional internal combustion engine vehicles (see Figure). However, as EVs become more efficient, low-carbon electricity becomes more common, and the size of the global EV fleet increases, emissions from production and other non-operation parts of the life cycle become increasingly important.Researchers at UC Davis studied: (i) the effect of different factors on life cycle emissions; (ii) the impact of excluding life cycle emissions from policies; and (iii) potential strategies that might be used to effectively incorporate life cycle emissions in light-duty vehicle GHG policy. This policy brief summarizes the findings from that project.View the NCST Project Webpag
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Greenhouse Gas Reduction Opportunities for Local Governments: A Quantification and Prioritization Framework
Local governments have steadily increased their initiative to address global climate change, and many present their proposed strategies through climate action plans (CAPs). This study conducts a literature review on current local approaches to greenhouse gas (GHG) reduction strategies by assessing CAPs in California and presents common strategies in the transportation sector along with useful tools. One identified limitation of many CAPs is the omission of quantitative economic cost and emissions data for decision-making on the basis of cost-effectiveness. Therefore, this study proposes a framework for comparing strategies based on their life cycle emissions mitigation potential and costs. The results data can be presented in a marginal abatement cost curve (MACC) to allow for side-by-side comparison of considered strategies. Researchers partnered with Yolo and Unincorporated Los Angeles Counties to analyze 7 strategies in the transportation and energy sectors (five and two, respectively). A MACC was subsequently developed for each county. Applying the life cycle approach revealed strategies that had net cost savings over their life cycle, indicating there are opportunities for reducing emissions and costs. The MACC also revealed that some emissions reduction strategies in fact increased emissions on a life cycle basis. Applying the MACC framework to two case study jurisdictions illustrated both the feasibility and challenges of including quantitative analysis in their decision-making process. An additional barrier to using the MACC framework in the context of CAPs, is the mismatch between a life cycle and annual accounting basis for GHG emissions. Future work could explore more efficient data collection, alternative scopes of emissions for reporting, and environmental justice concerns.View the NCST Project Webpag
Dynamic Modeling of In-Use Cement Stocks in the United States
A dynamic substance-flow model is developed to characterize the stocks and flows of cement utilized during the 20th century in the United States, using the generic cement life cycle as a systems boundary. The motivation for estimating historical inventories of cement stocks and flows is to provide accurate estimates of contemporary cement in-use stocks in U.S. infrastructure and future discards to relevant stakeholders in U.S. infrastructure, such as the federal and state highway administrators, departments of transportation, public and private utilities, and the construction and cement industries. Such information will assist in planning future rehabilitation projects and better life cycle management of infrastructure systems. In the present policy environment of climate negotiations, estimates of in-use cement infrastructure can provide insights about to what extent built environment can act as a carbon sink over its lifetime. The rate of addition of new stock, its composition, and the repair of existing stock are key determinants of infrastructure sustainability. Based upon a probability of failure approach, a dynamic stock and flow model was developed utilizing three statistical lifetime distributions—Weibull, gamma, and lognormal—for each cement end-use. The model-derived estimate of the “in-use” cement stocks in the United States is in the range of 4.2 to 4.4 billion metric tons (gigatonnes, Gt). This indicates that 82% to 87% of cement utilized during the last century is still in use. On a per capita basis, this is equivalent to 14.3 to 15.0 tonnes of in-use cement stock per person. The in-use cement stock per capita has doubled over the last 50 years, although the rate of growth has slowed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72233/1/JIEC_055_sm_SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/72233/2/j.1530-9290.2008.00055.x.pd
Sustainability of bio-mediated and bio-inspired ground improvement techniques for geologic hazard mitigation: a systematic literature review
This is a systematic literature review of quantitative sustainability assessments, focusing on life cycle sustainability assessment (LCSA), of bio-mediated and bio-inspired ground improvement technologies applied to geologic hazard mitigation. The aims of the systematic review are to 1) compare the sustainability of various ground improvement techniques and, 2) to evaluate the rigor and consistency of sustainability assessment methods applied to these techniques. The literature review considers studies identified through keyword searches of bibliographic databases. After selection criteria were applied to ensure identified articles were within scope, a total of 8 articles were found which assessed bio-mediated and bio-inspired ground improvement technologies. The technologies represented in the literature include enzyme induced carbonate precipitation (EICP), microbially induced carbonate precipitation (MICP), and microbially induced desaturation and carbonate precipitation (MIDP). While sustainability is typically conceived to include environmental, economic and social impacts, most studies examined only life cycle environmental impacts, three included life cycle cost accounting, and none included social impacts. Analysis of the studies’ system boundaries show inconsistencies across studies, making comparison of results inaccurate. The most common environmental impact categories included in the identified studies are global warming and eutrophication. Raw materials production and field emissions from the biogeochemical reactions that drive the technologies are the largest contributors to these impacts. Based on the review, it is clear that a set of LCSA guidelines is needed to produce high-quality LCSAs that can be used in comparative assessments and to confidently identify processes where the impacts of bio-mediated and bioinspired technologies can be reduced
Exploring associations between a biological marker of chronic stress and reported depression and anxiety in people with aphasia
PURPOSE : Living with the communication impairment of aphasia can be stressful. Chronic stress, depression, and anxiety are intimately linked, may be more pervasive in people with poststroke aphasia than the general population, and may influence cognitive function and treatment outcomes. In this project, we explored the psychological constructs of depression and anxiety and their associations with a biomarker measure of chronic stress in people with aphasia.
METHOD : Fifty-seven participants with aphasia completed measures of depression and anxiety and provided a hair sample from which to extract the stress hormone cortisol. Pearson product–moment correlational analyses were used to identify associations between depression, anxiety, and long-term level of cortisol via hair sample.
RESULTS : While cortisol level was not associated with depression and anxiety across this sample of people with aphasia, a post hoc analysis showed a significant, positive correlation between a subset of participants with moderate and higher levels of depression and elevated cortisol level.
CONCLUSIONS : Chronic stress, depression, and anxiety have been little explored in people with aphasia to date, yet they are associated with future health consequences and impaired cognitive function, motivating further research as well as consideration of these factors in aphasia rehabilitation.VA Rehabilitation Research and Developmenthttps://pubs.asha.org/journal/jslhrgl2020Speech-Language Pathology and Audiolog
The Role of Life Cycle Assessment in Reducing Greenhouse Gas Emissions from Road Construction and Maintenance
DTRT13-G-UTC29This white paper summarizes the state-of-knowledge and state-of-the-art in pavement life cycle assessment (LCA) modeling, with particular emphasis on life cycle greenhouse gas (GHG) emissions and on interpretation and analysis that lead to GHG reductions from the on-road transportation sector. The paper synthesizes research from a number of previous and current projects, highlighting both broadly agreed upon methods and findings, and those that are emerging or currently debated. It lists a number of recommendations for applying LCA to policy
Life Cycle Assessment With Primary Data on Heavy Rare Earth Oxides From Ion-Adsorption Clays
This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as: Deng, H. & Kendall, A. Int J Life Cycle Assess (2019) 24: 1643. https://doi.org/10.1007/s11367-019-01582-1Heavy and light rare earth elements (REEs) are critical to clean energy technologies, and thus the environmental impacts from their production are increasingly scrutinized. Most previous LCAs of REE production focus on sites producing light REEs. This research addresses this gap by collecting primary data from sites producing heavy rare earth oxides (HREOs) from ion-adsorption clays, conducting an LCA, and providing open-source life cycle inventory (LCI) datasets of HREO production for the LCA community
A Combined Urban Metabolism and Life Cycle Assessment Approach to Improve the Sustainability of Urban Hardscapes [Policy Brief]
Streets, sidewalks, parking areas, plazas, and other paved surfaces cover large portions of urban areas. These urban hardscapes contribute significantly to cities\u2019 resource consumption. Although urban hardscapes enable people and goods to move freely, they also have profound impacts on cities\u2019 water, air quality, energy, and material use. Reducing the environmental impacts of hardscapes will be an important component of making cities more sustainable. The necessary first step is to quantify those impacts
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