Matching Items (70)
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Oxidative aging is an important factor in the long term performance of asphalt pavements. Oxidation and the associated stiffening can lead to cracking, which in turn can lead to the functional and structural failure of the pavement system. Therefore, a greater understanding of the nature of oxidative aging in asphalt

Oxidative aging is an important factor in the long term performance of asphalt pavements. Oxidation and the associated stiffening can lead to cracking, which in turn can lead to the functional and structural failure of the pavement system. Therefore, a greater understanding of the nature of oxidative aging in asphalt pavements can potentially be of great importance in estimating the performance of a pavement before it is constructed. Of particular interest are the effects of aging on asphalt rubber pavements, due to the fact that, as a newer technology, few asphalt rubber pavement sections have been evaluated for their full service life. This study endeavors to shed some light on this topic. This study includes three experimental programs on the aging of asphalt rubber binders and mixtures. The first phase addresses aging in asphalt rubber binders and their virgin bases. The binders were subjected to various aging conditions and then tested for viscosity. The change in viscosity was analyzed and it was found that asphalt rubber binders exhibited less long term aging. The second phase looks at aging in a laboratory environment, including both a comparison of accelerated oxidative aging techniques and aging effects that occur during long term storage. Dynamic modulus was used as a tool to assess the aging of the tested materials. It was found that aging materials in a compacted state is ideal, while aging in a loose state is unrealistic. Results not only showed a clear distinction in aged versus unaged material but also showed that the effects of aging on AR mixes is highly dependant on temperature; lower temperatures induce relatively minor stiffening while higher temperatures promote much more significant aging effects. The third experimental program is a field study that builds upon a previous study of pavement test sections. Field pavement samples were taken and tested after being in service for 7 years and tested for dynamic modulus and beam fatigue. As with the laboratory aging, the dynamic modulus samples show less stiffening at low temperatures and more at higher temperatures. Beam fatigue testing showed not only stiffening but also a brittle behavior.
ContributorsReed, Jordan (Author) / Kaloush, Kamil (Thesis advisor) / Mamlouk, Michael (Committee member) / Zapata, Claudia (Committee member) / Arizona State University (Publisher)
Created2010
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The aim of this study was to explore cross-sectional and longitudinal aging differences in immediate and delayed visual and verbal memory abilities in individuals with Autism Spectrum Disorder (ASD) compared with neurotypicals (NTs). We measured hippocampal size, fornix fractional anisotropy (FA), and hippocampal and fornix freewater to understand how aging

The aim of this study was to explore cross-sectional and longitudinal aging differences in immediate and delayed visual and verbal memory abilities in individuals with Autism Spectrum Disorder (ASD) compared with neurotypicals (NTs). We measured hippocampal size, fornix fractional anisotropy (FA), and hippocampal and fornix freewater to understand how aging impacts memory structures. Longitudinal findings highlight vulnerabilities in immediate verbal memory and hippocampal volume, while cross-sectional findings indicate fornix freewater may increase at a faster rate in adults with ASD. Future research will examine cognitive and structural sex differences and will study how cognitive measures correlate with structural measures.

ContributorsSullivan, Georgia Rose (Author) / Braden, B. Blair (Thesis director) / Ofori, Edward (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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RESEARCH QUESTION: Does Online "Working Out Work" as a Treatment and Prevention for Depression in Older Adults? An Analysis of a Prescribed and Monitored Exercise Program Administered via the Internet for Senior Adults with Depression.
OBJECTIVE: The purpose of this study is to investigate and access the effectiveness of an online

RESEARCH QUESTION: Does Online "Working Out Work" as a Treatment and Prevention for Depression in Older Adults? An Analysis of a Prescribed and Monitored Exercise Program Administered via the Internet for Senior Adults with Depression.
OBJECTIVE: The purpose of this study is to investigate and access the effectiveness of an online prescribed and monitored exercise program for the treatment of depression in Older Adults. The Dependent Variable for the study is Depression. The Independent Variable for the study is the Effects of Exercise administered via the Internet and the population is geriatric adults defined as senior adults aged 50 and older. Depression is defined by Princeton University Scholars (Wordnet, 2006) as a mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity.
METHODS: The presence and severity of depression will be assessed by using The Merck Manual of Geriatrics (GDS-15) Geriatric Depression Scale. Assessments will be performed at baseline, before and after the treatment is concluded. The subjects will complete the Physical Activity Readiness Questionnaire (PAR-Q) prior to participating in an exercise program three times per week.
LIMITATIONS OF RESEARCH: The limitations of this study are: 1) There is a small sample size limited to Senior Adults aged 50 - 80, and 2) there is no control group with structured activity or placebo, therefore researcher is unable to evaluate if the marked improvement was due to a non-specific therapeutic effect associated with taking part in a social activity (group online exercise program). Further research could compare and analyze the positive effects of a muscular strength training exercise program verses a cardiovascular training exercise program.

ContributorsCaballero-Garcia, Robelyn (Author) / Waldron, Kathleen (Thesis advisor) / College of Liberal Arts and Sciences (Contributor)
Created2011-05-02
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This thesis aims to gain a broader understanding of the perceptions of Jewish identity amongst Jewish adults of three generations. In doing so, I aim to contribute to research and previous scholarly works that have examined how the views and perspectives of those the three different aging ‘tiers’ contribute to

This thesis aims to gain a broader understanding of the perceptions of Jewish identity amongst Jewish adults of three generations. In doing so, I aim to contribute to research and previous scholarly works that have examined how the views and perspectives of those the three different aging ‘tiers’ contribute to furthering cultural perceptions, stereotypes, theories, and ideologies of identity in Judaism. People of different ages possess varying views and understandings of aging and the aging process. Society, too, says different things about aging and how aging plays a role in relationships amongst people. People have certain and often strong views as to what is considered “old” and “aging”. There are societal benchmarks establishing that people of the age of 60, 62, or 65 are considered “seniors” and therefore put in a special box relegated to those of that age. In addition, there are many perceptions of aging and Jewish identity, varying among those with different backgrounds and cultures, experiences, familial relationships, and more. These views and understandings are not singularly applicable. Cultures may have their own unique customs and beliefs, and at the same time many cultures are also influenced by the larger American understanding - these perceptions contribute to many subgroups, including Judaism, and are evidenced in Jewish culture. In this study, I endeavored to survey members of the Jewish community to find out their experiences and perspectives relating to Jewish identity and what it means to them, both in the personal and Jewish cultural context.

ContributorsSokoler, Elianna (Author) / Guest, M. Aaron (Thesis director) / Mirvis, Stanley (Committee member) / Barrett, The Honors College (Contributor) / Hugh Downs School of Human Communication (Contributor) / School of Politics and Global Studies (Contributor)
Created2022-05
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This dissertation describes a series of four studies on cognitive aging, working memory, and cognitive flexibility in dogs (Canis lupus familiaris) and their wild relatives. In Chapters 2 and 3, I designed assessments for age-related cognitive deficits in pet dogs which can be deployed rapidly using inexpensive and accessible materials.

This dissertation describes a series of four studies on cognitive aging, working memory, and cognitive flexibility in dogs (Canis lupus familiaris) and their wild relatives. In Chapters 2 and 3, I designed assessments for age-related cognitive deficits in pet dogs which can be deployed rapidly using inexpensive and accessible materials. These novel tests can be easily implemented by owners, veterinarians, and clinicians and therefore, may improve care for elderly dogs by aiding in the diagnosis of dementia. In addition, these widely deployable tests may facilitate the use of dementia in pet dogs as a naturally occurring model of Alzheimer’s Disease in humans.In Chapters 4 and 5, I modified one of these tests to demonstrate for the first time that coyotes (Canis latrans) and wolves (Canis lupus lupus) develop age-related deficits in cognitive flexibility. This was an important first step towards differentiating between the genetic and environmental components of dementia in dogs and in turn, humans. Unexpectedly, I also detected cognitive deficits in young, adult dogs and wolves but not coyotes. These finding add to a recent shift in understanding cognitive development in dogs which may improve cognitive aging tests as well as training, care, and use of working and pet dogs. These findings also suggest that the ecology of coyotes may select for flexibility earlier in development. In Chapter 5, I piloted the use of the same cognitive flexibility test for red and gray foxes so that future studies may test for lifespan changes in the cognition of small-bodied captive canids. More broadly, this paradigm may accommodate physical and behavioral differences between diverse pet and captive animals. In Chapters 4 and 5, I examined which ecological traits drive the evolution of behavioral flexibility and in turn, species resilience. I found that wolves displayed less flexibility than dogs and coyotes suggesting that species which do not rely heavily on unstable resources may be ill-equipped to cope with human habitat modification. Ultimately, this comparative work may help conservation practitioners to identify and protect species that cannot cope with rapid and unnatural environmental change.
ContributorsVan Bourg, Joshua (Author) / Wynne, Clive D (Thesis advisor) / Aktipis, C. Athena (Committee member) / Gilby, Ian C (Committee member) / Young, Julie K (Committee member) / Arizona State University (Publisher)
Created2022
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Leonard Hayflick studied the processes by which cells age during the twentieth and twenty-first centuries in the United States. In 1961 at the Wistar Institute in the US, Hayflick researched a phenomenon later called the Hayflick Limit, or the claim that normal human cells can only divide forty to sixty

Leonard Hayflick studied the processes by which cells age during the twentieth and twenty-first centuries in the United States. In 1961 at the Wistar Institute in the US, Hayflick researched a phenomenon later called the Hayflick Limit, or the claim that normal human cells can only divide forty to sixty times before they cannot divide any further. Researchers later found that the cause of the Hayflick Limit is the shortening of telomeres, or portions of DNA at the ends of chromosomes that slowly degrade as cells replicate. Hayflick used his research on normal embryonic cells to develop a vaccine for polio, and from HayflickÕs published directions, scientists developed vaccines for rubella, rabies, adenovirus, measles, chickenpox and shingles.

Created2014-07-20
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Telomeres are structures at the ends of DNA strands that get longer in the DNA of sperm cells as males age. That phenomenon is different for most other types of cells, for which telomeres get shorter as organisms age. In 1992, scientists showed that telomere length (TL) in sperm increases

Telomeres are structures at the ends of DNA strands that get longer in the DNA of sperm cells as males age. That phenomenon is different for most other types of cells, for which telomeres get shorter as organisms age. In 1992, scientists showed that telomere length (TL) in sperm increases with age in contrast to most cell of most other types. Telomeres are the protective caps at the end of DNA strands that preserve chromosomal integrity and contribute to DNA length and stability. In most cells, telomeres shorten with each cell division due to incomplete replication, though the enzyme telomerase functions in some cell lines that undergo repetitive divisions to replenish any lost length and to prevent degradation. Cells, and therefore organisms, with short telomeres are more susceptible to mutations and genetic diseases. While TL increases in a subset of sperm cells and longer telomeres may prevent early disintegration of DNA, it may also prevent natural mechanisms of apoptosis, or cell death, from occurring in abnormal sperm.

Created2017-02-07
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Description

The Hayflick Limit is a concept that helps to explain the
mechanisms behind cellular aging. The concept states that a normal human
cell can only replicate and divide forty to sixty times before it
cannot divide anymore, and will break down by programmed cell death
or

The Hayflick Limit is a concept that helps to explain the
mechanisms behind cellular aging. The concept states that a normal human
cell can only replicate and divide forty to sixty times before it
cannot divide anymore, and will break down by programmed cell death
or apoptosis. The concept of the Hayflick Limit revised Alexis
Carrel's earlier theory, which stated that cells can replicate
themselves infinitely. Leonard Hayflick developed the concept while
at the Wistar Institute in Philadelphia,
Pennsylvania, in 1965. In his 1974 book Intrinsic
Mutagenesis, Frank Macfarlane Burnet named the concept after
Hayflick. The concept of the Hayflick Limit helped scientists study
the effects of cellular aging on human populations from embryonic
development to death, including the discovery of the effects of
shortening repetitive sequences of DNA, called telomeres, on the
ends of chromosomes. Elizabeth Blackburn, Jack Szostak and Carol
Greider received the Nobel Prize in Physiology or Medicine in 2009
for their work on genetic structures related to the Hayflick
Limit.

Created2014-11-14
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In 2003, molecular biology and genetics researchers Coleen T. Murphy, Steven A. McCarroll, Cornelia I. Bargmann, Andrew Fraser, Ravi S. Kamath, Julie Ahringer, Hao Li, and Cynthia Kenyon conducted an experiment that investigated the cellular aging in, Caenorhabditis elegans (C. elegans) nematodes. The researchers investigated the interactions between the transcription

In 2003, molecular biology and genetics researchers Coleen T. Murphy, Steven A. McCarroll, Cornelia I. Bargmann, Andrew Fraser, Ravi S. Kamath, Julie Ahringer, Hao Li, and Cynthia Kenyon conducted an experiment that investigated the cellular aging in, Caenorhabditis elegans (C. elegans) nematodes. The researchers investigated the interactions between the transcription factor DAF-16 and the genes that regulate the production of an insulin-like growth factor 1 (IGF-1-like) protein related to the development, reproduction, and aging in C. elegans. Transcription factors, like DAF-16, are proteins that regulate the transcription of deoxyribonucleic acid (DNA) into messenger ribonucleic acid (mRNA), which later determines which proteins the cell produces. The research team's experiment suggested that an increase in the activity of the DAF-16 protein decreases the transcription of the genes that regulate the production of IGF-1-like proteins, increasing lifespan in nematodes. The team published their results in the article 'Genes that act downstream of DAF-16 to influence the lifespan of Caenorhabditis elegans' in Nature in June 2003. By comparing the regulation of gene expression in C. elegans with similar genes and pathways in humans, Murphy's research team sought to better understand cellular function and aging in humans.

Created2017-02-16
Description

Elective cosmetic surgery has grown more popular in the last several decades, including procedures specifically targeted at older adults and anti-aging. The aim of this study is to better understand elective cosmetic surgery rationale for older adults. The first part of the study summarizes literature on elective cosmetic surgery for

Elective cosmetic surgery has grown more popular in the last several decades, including procedures specifically targeted at older adults and anti-aging. The aim of this study is to better understand elective cosmetic surgery rationale for older adults. The first part of the study summarizes literature on elective cosmetic surgery for older adults and determines what factors influence the desire for elective cosmetic procedures. From the research databases PubMed, JSTOR, and ScienceDirect, eighteen sources were referenced in the final review. The review found that there are differences in sociocultural views of men and women as they age as well as internal views of aging. The modest number of studies used in the literature review reflect a current gap in current research studying elective cosmetic surgery in older adults. For the second part of the study, data was collected from a 2018 survey designed to better understand aging, body image, and subjective age. The survey was limited to individuals living in the United States aged 40 and above and was deployed through MTurk (Mechanical Turk). A total of 1199 responses were received. Only participants 55 years and above are included for the purpose of this study. Most participants who answered the question for elective cosmetic surgery rationale answered that their primary rationale is to reduce age-related physical markers. For participants identifying as female, nine percent cited self-esteem as their rationale while no male-identifying participants responded similarly. Future research can include questions on internal and external factors older adults feel have the greatest impact on their decision to have elective cosmetic procedures.

ContributorsSirilan, Angeli (Author) / SturzSreetharan, Cindi (Thesis director) / Bernstein, Katie (Committee member) / Agostini-Walesch, Gina (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution & Social Change (Contributor) / School of Life Sciences (Contributor)
Created2022-12