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The relationship between sex, insulin sensitivity, and blood pressure reactivity in Hispanics
No full textHyperinsulinemia is a predictor of hypertension, a condition that increases the risk for heart disease and stroke (Gans & Donker, 1991; Kannel, 2009). Hyperinsulinemia, a precursor to type II diabetes, is particularly prevalent in the Hispanic population which also carries several genetic markers associated with the dysregulation of insulin and glucose (Mercader & Florez, 2017). Studies that quantify a relationship between insulin and hypertension often fail to account for sex and ethnicity, therefore the purpose of this study was to quantify insulin status and blood pressure (BP) reactivity within the Hispanic population to provide insight into whether a relationship between sex, insulin status, and control of BP exists. Testing was completed in 11 males (M) (age: 27 ± 8 yrs) and 15 females (F) (age: 22 ± 4 yrs). Insulin sensitivity index (ISI) was measured through a modified 75-gram oral glucose tolerance test, where blood samples were drawn for measurement of glucose and insulin at baseline and minutes 30, 60, and 120. The following anthropometric measurements were obtained: waist circumference, waist to thigh ratio, and waist to hip ratio (waist circumference, M: 80.3 ± 7.7 cm, F: 74.2 ± 6.3 cm, p<0.05; waist to thigh ratio, M: 1.68 ± 0.10, F: 1.58 ± 0.13, p<0.05; waist to hip ratio, M: 0.84 ± 0.05, F: 0.76 ± 0.04, p<0.05). Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured during the cold pressor test (CPT), mental stress test (MST), and graded exercise test (GXT). CPT was a 2-min of test where the subject placed their hand in ice water. MST consisted of a 3-min test where the subject performed verbal mathematical subtraction. GXT was performed on a stationary bicycle to peak-V ̇O_2. BP reactivity was calculated as the difference between baseline and the maximum value in SBP and DBP, expressed as a delta (Δ). Data were analyzed using ANCOVA and multiple regression modeling. There were no significant differences in ISI between males and females (8.4 ± 5.1 and 6.3 ± 3.8 comp, respectively). For CPT, no sex differences were found across all variables (ΔSBP: R2= 0.04, p= 0.81; ΔDBP: R2= 0.03, p=0.90). For MST, there were no differences between males and females across all variables (ΔSBP: R2 = 0.06, p= 0.71; ΔDBP: R2= 0.08, p= 0.61). For GXT, sex differences were present in ISI and ΔSBP relationship. Males had higher values of reactivity than females. Both groups had a positive correlation between ISI and ΔSBP (R2= 0.44, p <0.01). No sex differences were present for ΔDBP. There was a trend for increasing values of ISI correlating with greater DBP reactivity (R2= 0.26, p=0.09). When waist to thigh ratio and other measures of body composition were entered as covariates, both ISI and sex terms were significant (waist to thigh ratio: R2= 0.38, p<0.01). Our data illustrate a positive association between ISI and BP reactivity during the GXT and that sex differences exist in this relationship. Once the effects of body composition parameters were removed from the model, both ISI and sex were shown to be significant predictors of diastolic BP reactivity. This suggests body composition may also be an important indicator in the overall relationship between sex, insulin status, and control of BP in the Hispanic population
An evaluation of machine learning to detect recent moisture in street level images
No full textFloods are major disasters which threaten communities across the globe, and predicting flooding is an importantpart of mitigation strategies. Flood prediction models benefit from having access to ground-level observations of
where flooding is occurring and extending the lead time on these observations as much as possible is also valuable.
This project complements the FloodAware research project, which is based on using image processing and existing
networks of static cameras common in modern urban environments to determine water levels around a city. Where
FloodAware focuses on detecting standing water, this project seeks to explore whether a machine learning model can
determine the presence of significant moisture, indicative of recent rain, in the images gathered by these cameras
to increase the lead time offered by the system. Because these cameras are static and observing a scene with a
consistent perspective, this project presents a study to analyze if training a model for a single camera site could
improve its performance, as well as address other practical questions regarding the implementation of this technique.
To accomplish this, this project ran experiments on three convolutional neural network models of varying depth, a
K-nearest neighbors model, and a linear classifier both across all camera sites and on a site by site basis. It found that
these models achieved better performance when trained on a site by site basis, but that there are suggestions a general
model could more easily be extended to entirely new sites
Foreign aid and Ghana’s development: United States Agency for International Development’s (usaid) contributions to Savelugu-Nanton
No full textUSAID has for decades been one of the major donors to Ghana as a country and to some communities in the country. The USAID undertakes varying aid programs and projects in different communities. How do these projects or programs affect community development in the recipient countries? This study identifies some of the key projects of USAID in providing the basic health needs of the people in the Savelugu-Nanton district, which are the health aid projects of Indoor Residual Spraying (IRS) and Resiliency In Northern Ghana (RING). The study questions the impacts of USAID’s projects in rural communities, specifically, the Savelugu/Nanton district. The analysis of the study makes use of a qualitative method, with a specific focus on a comparative case study method and a before-after analysis. Primary sources of data for this research were gathered using sources from archival work and interview questions. Purposive sampling was also used to gather respondents for the interview.The study theorizes that in countries, health aid projects should be more likely to lead to community development due to the external benefits they can yield besides the specified objectives of the projects. The study also theorizes that health aid projects in beneficiary communities should lead to the development of those beneficiaries more than the development of the non-beneficiary communities. The findings that the study gathered suggest that health aid from USAID correlated with rural development in the studied cases. The study also found that aid received in beneficiary communities contributed to those rural communities’ development whereas non-beneficiary communities continued to remain underdeveloped. The study further makes a conjecture that the broader effect of the analysis is that aid that is channeled toward rural sector development can contribute to the overall development of the country.
Keywords: USAID, Savelugu-Nanton District, Ghana, Development, International Aid Organizations rural communities, RING, and IRS
The phenology of aboveground tree growth and forest carbon cycling
No full textPhenology is the study of recurring biological events and how they are affected by interannual variations in climate. Phenology has a direct effect on the annual productivity of forest ecosystems because it determines the length of the growing season and physiological activity. Longer growing seasons tend to have positive effects on forest ecosystem productivity in areas not limited by water, in others, longer growing seasons could amplify water stress and have a net negative effect on forest productivity. This dissertation entails three studies that investigate how forest phenology responds to changing environmental conditions. Each of the projects utilizes high-frequency measurements of forest phenology across different forest types to address knowledge gaps and better understand how forests cope with a changing climate. The first chapter investigates how the phenology of aboveground tree growth varies along an elevation gradient in the semi-arid southwestern United States (US). The timing of growth in these semi-arid ecosystems showed high variability among years, particularly at low elevations, indicating growth phenology in water-limited ecosystems is more variable than temperate forest ecosystems not limited by water. The second chapter utilizes digital repeat photography to extract phenology dates and model future changes in spring and fall transition dates in temperate deciduous forests in the eastern US. The models suggested season length will be more affected in the fall in response to future climate change than spring, but spring will have a larger positive effect on the forest productivity. The third chapter investigates the link between low temporal resolution tree growth measurements (i.e., annual tree rings) and high-resolution forest carbon uptake measurements (i.e., net ecosystem productivity) to identify potential lags in allocation of carbon to structural aboveground biomass. Lags in allocation of previous year carbon uptake to structural growth were detected at half of the sites studied, suggesting trees use stored carbon from previous years, but the role of stored carbohydrates for growth may not be as important in slow growing ecosystems due to other limitations on growth. By using multiple different sites in each of the outlined chapters, forest phenology was shown to respond strongly to the seasonality of most limiting factors. Phenology of forest ecosystems in the southwestern US had stronger links to water limitation, while the phenology of northeastern US was more strongly temperature limited. The widespread linkage of phenology to temperature in the literature suggests water-limitation is an undervalued driver of phenological change across the US, and globally
Methods to secure access control and encryption based on physical unclonable function
No full textToo many cyber-attacks succeed by hacking password databases and stealing users’credentials; hacking databases means the users’ information becomes compromised.
Frequent cyberattacks happen because of a lack of password protection in databases or
by the interception of passwords over networks. A particularly significant vulnerability
to cyberattacks occurs when the same user’s credentials are exposed and sent multiple
times in the same format over networks, which helps hackers intercept and infer the
password. This dissertation presents and demonstrates tangible solutions to mitigate
risks of hackers obtaining passwords, whether stored in databases or intercepted when
sent over networks.
Protecting users’ credentials stored in databases with encryption is known to
mitigate theft, as long as the cryptographic keys are not exposed. One-way encryption
based on hash functions has been suggested as a solution to secure password manager
databases. However, when rainbow table mechanisms were launched, they made it
so that hash functions were no longer able to secure password manager databases.
Rainbow tables allow hackers to find matches between password hashes in the
password manager database and the rainbow table; consequently, the password can
be compromised. Accordingly, salting the password before feeding it to the hash
function has been recommended. However, because the salt must be unique and stored
somewhere in the system, it is also easy to obtain and use the salt with the rainbow
table’s passwords to crack the password.
On account of this, the issue of securing password manager databases still needs a
deep investigation to find a rational solution to mitigate this problem. The solutionsoffered in this dissertation are based on utilizing physically unclonable functions
(PUFs). PUF challenges replace the output of a hash function with salt in the database,
and without having the same PUF, it will be hard to understand the database’s content.
Stealing the PUF is hard because it is in the hardware. Usually, an image of a PUF’s
challenges and corresponding responses are generated at enrollment time and stored on
the server; the physical PUF will generate the same responses to each challenge every
time authentication is needed on the client side. Innovatively, this dissertation shows
that physical PUFs have also been utilized on the server-side. To obtain the message
digest (MD) from the password hash, each of the several bits in the MD points to one
address in the PUF, and the output of the PUF is stored in the database; therefore, it
will encrypt the password as one-way encryption based on the PUF output. Storing
the PUF output in the database makes the password unreadable, makes retrieval of the
password difficult, and makes the rainbow table not work.
Additionally, a homomorphic password method is proposed to mitigate the issue
of repeating the same password multiple times during the day or at a specific time for
users’ online accounts, which might make passwords vulnerable to exposure. Securing
users’ credentials while sending them via networks will decrease the ability to easily
intercept and steal them. This dissertation shows a newly invented method; the server
authenticates clients without ever knowing their passwords. During enrollment, users
subject their passwords to multiple hashing cycles, typically 1000 times, the resulting
MDs are communicated to the server. Rather than storing these MDs, the server uses
them to find addresses in the PUF, which generates data streams stored for future
authentication. The authentication cycles use the following steps: i) The users hash
their passwords multiple times, at levels lower than the one used during enrollment; ii)
The server generates data streams from the physical elements at the address extracted
from the MD and compares it to the data streams stored during enrollment, and iii)
The server reiterates the previous step by incrementally hashing the resulting MD
to find a match, or it rejects the password. During subsequent authentication cycles, the users again hash their passwords multiple times but at levels lower than the ones
used during the previous cycles. Thereby, it becomes pointless for third parties to
intercept previously hashed passwords; they are never used twice. Hacking a database
containing the data streams extracted from the PUF during enrollment is also pointless
without also having access to the devices. In this entire homomorphic protocol, the
users are the only ones who know their passwords. Therefore, this research provides
an analysis of the benefit of hash functions when used on both the client and the server
sides to generate a one-time password each time the user wants to log on to the system.
The benefit of that is to confuse the man in the middle, which means that the man in
the middle will not be able to learn from the network flow because, each authentication
time, new encryption of the hash of the password will be sent.
Moreover, this dissertation shows a simulation prototype for how the password
manager protocol can work depending on the SHA-3-512, SRAM, and ReRAM PUF.
In addition, the work shows how to encrypt the database content of the password
manager by using both ReRAM and SRAM PUF. Furthermore, this work provides a
software solution for the noise in both ReRAM and SRAM PUF to reduce the rate
of false rejections for the actual user and false acceptance for the non-existing user.
This work also provides a solution to guarantee authentication still works if the PUF
does not work or is compromised. Again, this research delivers techniques to generate
one-time passwords and to authenticate passwords without storing passwords in the
database.
Another branch of this research is the process of using PUFs to encrypt messages
without using cryptography keys. There is significant interest in encryption without
using traditional cryptography keys because key generation, key distribution, and key
storage in key cryptography are incredibly complex. Also, many issues with keys
can help a hacker extract keys, such as attacks based on differential power analysis.
Another reason for keyless encryption is protecting internet of thing (IoTs) devices.
Because IoTs devices have limitations in power and memory, the long-secret keys and some strong cryptographic schemes are difficult to implement. However, ReRAM
PUFs can be applied to keyless encryption protocol, and the ReRAM PUFs can
replace traditional cryptography keys. This work covers keyless encryption protocol
implementation and solutions to mitigate the ReRAM PUF’s erratic nature. Finally,
this work covers the evaluation of a keyless encryption protocol against frequency
analysis attacks
A case study examining how branch campuses interpret and implement institutional identity
No full textThis work explores how mission and identity are practiced and understood in a branch campus setting of a private institution. By employing multiple organization identity, exploring branch campus management models and purposes and interviews with representatives of a branch campus, this work demonstrates how mission and identity are created in a branch campus environment and some elements that are necessary to empower understanding of mission and identity to the employees at the branch campus. This permits the author to provide observations on what the impact has been for the branch campus, and to make practical suggestions as to how the findings can apply to other branch campus experiences
The mother range: investigating the power dynamics of climate change adaptation in an Arizona fire-prone contested landscape
Get PDFInterviews with diverse actors regarding wildfire, values, and individual perspectives were conducted to add to the emergent body of literature utilizing a political ecology case study approach in the context of more developed countries. The Bighorn Fire as a case study provided several unique dynamics, such as community awareness of the fire, controlled management of the fire away from structures, ecological variability, the likelihood of near-future climate stress for the Tucson area, and history of socially prominent wildfires. Semi-structured interviews best aligned with the iterative nature of data analysis required by a political ecology approach. This methodology, combined with guidance from case study literature, informed the organization of interview data and the general structure of the research process. Analysis of interview data utilizing research questions informed by political ecology yielded rich insights into barriers to future governance efforts on and around Mt. Lemmon as well as novel findings of charismatic ‘indicators’ of climate change impacts for actors with different values and power. Future case studies examining communities, wildfire, and climate change impacts would benefit from similar critical engagements with local geography to understand how power influences both discourse and resulting action in relation to adaptive governance
Writing through a pandemic: an exploration of space and self
No full textI started this program in the “before” time, when my focus was outward and my interest would land on random shiny things that caught my interest, like a sake-maker in a desert hamlet or classified ads from old newspapers. It was a short-lived interlude, and one I value all the more because I see now that there was a sweetness and innocence there that I was unaware of until it was gone. I see the rigid delineation between “before” and “after” very clearly in my work. Like the fabric of our society, I see the cohesion in my writing break down quickly in the wake of the pandemic. (To be fair, the social breakdown for me began on November 9, 2016, but even with that, I didn’t see a dramatic before and after until March 2020.) I lost focus, didn’t know what to think, how to think, what to write, how to write. The ground I hadn’t realized I was standing on crumbled in a matter of weeks. And that crumbling wasn’t confined to me, my family, town, state, or country. Across the globe, all of humanity was plunged into this frightening space, forcing us all to feel our way through the darkness.
In considering my thesis, I had pictured a cohesive unit of work, loosely based on the oddities of Arizona and my attempt to navigate the absurdities of its culture and understand its colorful history. But as I undertook the work of building this thesis, I began to see that it has decided to follow the trajectory of collective trauma by asking questions, seeking and not finding answers.
Altogether, I have decided that I want this work to honestly reflect these past three years. In this unique time and space, I’ve decided to throw out the order that I had aspired to and present a semi-accurate timeline of my writing. Not because I think the writing holds together as a unit, but because it doesn’t. I see now that the disjunction tells its own story—a fractured timeline that reflects my disjointed journey into and through the darkness.
I’ll begin in the “before” time. It was fall 2019 when I officially started this program. At that time, I set myself a goal. I wanted to be published by Atlas Obscura. This website collects travel stories written with a deep respect for the people and places it highlights and feeds my thirst for travel, even if it can only be of the armchair variety. I wanted to tell a story grounded in a place. At about the same time, I heard a curious rumor about a man making sake in Holbrook. Writing about Atsuo allowed me the space to try and tell his story while weaving him into the wild tapestry of that town’s history.
Also, in the “before” time, let’s call it BC19, I decided to explore my own history by setting my stories in the context of newspaper classifieds. Using my experiences as anchor points, I spent hours in the Cline Library Special Collections room indulging my fascination with classified ads in community newspapers. These tiny ads are snippets of time dipped in amber, small afterthoughts tacked to the end of the newspaper; classifieds present a more prosaic snapshot of a time and place than the important recitations of the news that precede them. This is a project I’d love to return to, to explore classifieds from their genesis, through time until their near-disappearance as print gives way to myriad digital platforms.
These were the kinds of things I was writing and the kinds of things I was thinking about BC19. Not much changed as 2019 rolled into 2020, until everything changed. When everything changed and the world closed, my work shifted hard into a different space. At first, I could barely write at all. This was during my rosé-wine-phase of the pandemic. For about three months, everything I wrote was disjointed and harshly abbreviated. Essays turned into poems. I’m not a poet; I tried to push them back into essays, but they wouldn’t be moved.
The rosé wine phase morphed into the Ben and Jerry’s Chocolate Chip Cookie Dough phase, which carried me through the next three months (and I carry with me to this day). By this time, I could write nothing that didn’t confront the new pandemic reality straight on. My fingers weren’t strong enough to hold the braids of my essays together, and so they unfurled on the page.
Somehow, two years have passed. I’ve moved away from feeling compelled to write pandemic-specific work. But even so, the trauma remains there, between the lines. There are considerable gaps in my memory (which my doctor tells me may be attributable to long covid, stress, or menopause.) My work still feels disjointed, words flailing about at the ends of their puppet strings. By putting all the work together here, I expected to evoke even more chaos. Instead, I’ve been surprised to find not simply chaos, but a story about chaos, a diary written in smeared crayon, sharp-nibbed pen, and finger on dust
Greening spiritual disciplines: engaging in environmentally responsible behavior as a Christian spiritual practice
No full textModern Christianity has lost sight of the spiritual connection between belief in God and the need for environmentalism. In this day and age, this means action against the climate crisis. Christians who are not able to articulate relationships between their religious practice and environmental care may be unsure how their faith might compel advocacy on behalf of the climate. My project addresses this disconnect between Christianity and environmentalism. I propose that environmentally responsible behaviors like composting, gardening, and environmental advocacy could be reframed as spiritual disciplines for Christians who wish to cultivate a dialogue between their faith and environmental work. My focus is not to prove the reality of climate change or provide an ultimate solution, but rather to catalyze Christians who may harbor pro-environmental beliefs but are unsure what to do with them or Christians who love God but do not see why or how environmental care relates to their faith. I draw on the Christian tradition of spiritual disciplines to explain these ideas, suggesting that it might behoove the Christian community to embrace a set of “green” spiritual disciplines as a way to exist faithfully in this age of anthropogenic climate change. My hope is to use religion, specifically the underpinnings of Christian belief and theology that encourage environmental care, to empower Christians toward active engagement with environmental responsibility in the context of their faith
‘Being uncomfortable with the kids’: how high school history teachers talk about race in the classroom
No full textThis thesis focuses on the experiences of high school history teachers discussing race within the classroom. Race has been at the forefront of the sociopolitical context of 2020, as the Black Lives Matter movement has brought attention to the racialized history of the United States. This study brings to light the ways teachers are managing potentially sensitive discussions of race within their classrooms. This paper outlines the strategies teachers use and the challenges they face. While it is important to think and discuss about race relations, it’s also important to study how we talk about race relations with young people. High school presents a unique setting, as these are important formative years in students’ lives. Something may work in theory, but unless we speak to the folks on the ground, who are doing the actual teaching, we will come away with only a partial understanding of how race and history are taught in classrooms. Throughout this project, I interviewed 10 high school history teachers to discuss their experiences discussing race in history classrooms. This paper outlines my findings