1925 research outputs found
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Harnessing spontaneous Brillouin scattering for nonequilibrium phonon spectroscopy
No full textPhonon spectroscopy allows access to phonon populations of individual acoustic modes within a material, thereby offering information about the material’s optical and mechanical properties. Selectivemanipulation of phonon populations has been demonstrated using spontaneous backward Brillouin
scattering in photonic systems [29, 43, 20]. In this work we demonstrate phonon spectroscopy in liquid core optical fibers using spontaneous backward Brillouin scattering and introduce a novel method
for isolating and measuring thermal phonon populations. This inelastic scattering process paired
with heterodyne spectroscopy offers an elegant solution for measuring Stokes and anti-Stokes phonon
mode populations where one backscattered photon corresponds to one phase-matched phonon. An
optical field is injected into a liquid core optical fiber and interacts with the material’s spontaneously
generated vibrational modes. In the case of optical scattering from a forward propagating wave, the
backscattered Stokes light is red-shifted in frequency where energy is deposited from the optical field
into the phase-matched acoustic mode [32, 34, 2]. Similarly, backscattered anti-Stokes light is blue-shifted when the optical field interacts with a counter-propagating traveling acoustic wave. Through
heterodyne detection, the backscattered signal combined with a known local oscillator produces a
beatnote frequency directly corresponding to the phase-matched phonon population distribution.
Additional damping of the anti-Stokes acoustic mode scales with optical power allowing for a form
of laser modal cooling for the backward traveling acoustic phonons [29]. We introduce a method
including two orthogonally polarized optical fields to isolate thermal phonon contributions intrinsic
to the material from those driven by the optical field for the first time. In this way, we determine the
thermal phonon occupation for the Stokes and anti-Stokes sidebands and demonstrate attenuation
of the anti-Stokes phonon population
Finding the Point: A Personal, Extrospective Analysis of Life as Art through Pointillism
Get PDFWhat if our lives are like art pieces? If so, then there must be an artist, the art piece itself, and an audience. In this compilation of creative nonfiction essays, I speculate what it would look like to view our lives as pointillist paintings. Instead of individually painted dots covering a canvas, I view individual moments, glances, thoughts, and the like to be composing my life. The entirety of my life can’t be boiled down to one single moment, but rather a compilation of instances. In order to view my life this way, I have paired my essays with my own pointillist drawings to illustrate how each dot on the page is a significant piece of the whole. These ruminations are to help myself consider what makes each detail in my life important, how I might better appreciate those points, and where to go after understanding my life as composed like a stippled art piece. Such distinctions have also provoked me to consider further who the artist of my life’s painting might be: is it me? Is it my community? Or is it a higher power? My essays, accompanied by my original artwork, have led me to decide upon the final option, which helps me find the “point” of my life, as I point back to the One who I argue painted it all in the first place
Evaluating student achievement within alternative education schools: a comparison of district schools and charter schools in Arizona
No full textThe purpose of this study was to determine whether students enrolled in Secondary (9-12) alternative educational schools, i.e.- district schools vs. charter schools, demonstrate significant differences in achievement as measured by the 2019 A-F Letter Grade Accountability System, as well as to determine whether district and charter schools differ in enrollment characteristics of their student bodies. This quantitative study took place in Arizona using data provided to the Arizona Department of Education. Data collected were from publicly accessible records representing most of the alternative education school from 13 of Arizona’s 15 counties. Survey data were collected from only 128 out of the 164 alternative schools due to lack of data reporting from educational agencies.
Research question one (is there a statistically significant difference in student proficiency scores in secondary alternative public schools and secondary alternative charter schools using the revised 2019 A-F School Letter Grade Business Rules?) consisted of evaluating alternative school A-F rating scores based upon 5 weighted categorical indicators: 1) Academic proficiency at 15%, 2) Growth toward graduation at 30%, 3) English learners (EL) proficiency at 10%, 4) Graduation rates at 10%, and finally 5) College and career readiness for enrollees at 35% as well as available bonus points and assessed if a statistical difference existed between alternative charter and alternative district schools in overall achievement scores and letter grade rankings.
Research question two (what, if any, are the differences in enrollment characteristics, i.e. - demographics including SPED, between alternative district schools and. alternative charter schools?) was developed to address the potential of enrollment selection bias. Data collected were disaggregated by student subgroups, i.e. - ethnicity, income eligibility, EL proficiency, and by students with disabilities and reported using descriptive statistics. This study did not use summations to conclude significance levels of any of the subgroups comparisons. Student body enrollments characteristics were adjusted on a per capita basis as well as a reported with the proportional range of overall student bodies based upon the standard deviations calculated.
Research question three (is there a statistically significant difference in student dropout rates between alternative district schools and alternative charter schools?) evaluated total dropout rates for all student subgroups, i.e.- ethnicity, gender, homelessness status, income eligibility, and student with disabilities. This study examined if a statistical difference existed between alternative charter and alternative district schools in student graduation rates by examining both the subgroup characteristics as well as the aggregate total student body populations. Comparison mean scores were converted to percentiles to reflect the per capita enrollment representation with higher scores indicating higher dropout rates.
Upon evaluation this study concluded that there is a statistical significant difference in the A-F letter grades between alternative district schools and alternative charter schools, with charter schools showing higher final cut scores as well as higher A-F school letter grade rankings. This study also determined that those gains were predominately due to the college and career readiness indicators, and not from increased academic performance, on-track graduation rates, credits earned, EL proficiency, or overall graduation rates. This study also concluded that alternative charter and alternative district schools showed similar student body enrollment subgroup consistencies, suggesting that there is no inherent enrollment selection bias or over represented subgroups in either institution. This study also determined that there was not a statistical difference between alternative district and alternative charter schools and their graduation rates in their overall student populations
Socioscientific perspective taking in a four quadrant-based curriculum on climate change
No full textEmpirical research within science education settings tells us that there is a need for new curricular approaches in the teaching of complex and contentious science-based issues, such as climate change. A lot of science educational research looks at a need to teach students functional scientific literacy in that we are not just learning about science, but also looking at the ways in which society uses that science through dialogue, comprehension, and action. The significance of this dissertation is that perspective taking, as an educational practice, can offer reflective and reflexive tools so that whether an individual holds a moral stance on an issue or not, at least we can begin to see how others may view the same issue through a moral lens, while thinking critically about the scientific nature of the issue. Socioscientific perspective taking is an educational framework which guided this dissertation in developing a Four Quadrant-designed curriculum capable of teaching individual and collective perspectives on climate change
The Truth of All Endings
Get PDFDark recesses pock the world, cavities of degradation, predation, and perversion both overt and obfuscated. Those places are not just inhabited by us, but are us: the unspoken or unwitnessed potential—made real or fiercely hidden—for horror and evil. One of the major drives of my writing is to contextualize and explore the capacity for the disturbing and maligned. In this collection of work, I both want to speak to this capacity and display a multifaceted approach to writing horror fiction. One of the major themes threaded throughout this collection is amorphic self-identity and its intersection with the supernatural. The unexplainable or the maligned not only challenges and changes the protagonists, but also offers a lens through which to see their make-up and interiority. In this way, my fiction and the horror genre in general reveals the best and worse we have to offer ourselves in spite of ourselves. That connection extends my characters’ identities to a vast, dangerous world beyond comprehension, emulating the tradition of cosmic horror. Cosmicism and the supernatural/paranormal are what suggests a reality beyond our scope and understanding, and I use these elements as antagonistic forces that drive the behaviors and decisions of my characters. This is most notably displayed in “Circle 6,” my cosmic horror story, and my novella, Those That Walk That Do Not Walk. Another concept explored in this collection is dark futurology, or viewing transhumanism and near-future technology through a pessimistic lens. Instead of enriching our lives, technology in this viewpoint is a peril and constraint against agency, autonomy, and the human condition. My essay, “Zersetzung de Dasein,” is a rumination on dark futurology and such complications of constraints of “post-modernity.” Agency and survival, or reductively “fighting against the evil,” is a motif I wish to expound upon as well.
I want to push my imagination into stories that captivate my audience the way the world in all its terror captures mine. So many dark narratives hold the public’s attention, a recognition of what we are capable of and what evils are out there, and I want to enter that conversation with my fiction. This collection ranges from supernatural to cosmic horror, and threads philosophical pessimism, dark futurology, and transhumanism in fiction and non-fiction creative modes
Professional development for community college faculty in a guided pathways environment
No full textThis descriptive correlational case study sought to identify professional development recommendations for full-time community college faculty teaching within a guided pathways environment. Community college faculty across an urban, multi-college district in the southwestern United States were surveyed about their current learner-centered teaching practices, a teaching approach recommended for the guided pathways environment. While faculty indicated that they were implementing learner-centered teaching practices, they also indicated that as the learner-centered teaching practices became more difficult, faculty were less likely to implement them. An exploratory factor analysis was conducted and competency-based developmental pathways were developed in the areas of transparency and feedback with colleagues, student situational considerations, teaching improvements, collaboration with colleagues, faculty openness and empathy, course relevance and faculty-student cooperation.Relevance of each of these areas to guided pathways was identified and a recommended focus for professional development in each was suggested. This includes the assignment charrette model, in combination with transparency in learning and teaching, for the transparency and feedback with colleagues area; Fink’s Designing Significant Learning Experiences for the student situational considerations area; reflecting on the impact one’s own teaching has on students for the teaching improvements area; cross-functional professional development for the collaboration with colleagues area; applied, authentic learning experiences for the course relevance area; compassion, empathy, and service-learning for the faculty openness and empathy area; and sharing control with students for the faculty-student area
Education as a tool of liberation: nurturing the vital branch between Ethnic Studies and revolutionary community organizing
No full textThe pandemic and uprisings against police terror have heightened the devastation of white supremacy and capitalism. During this time of heightened devastation, revolutionary organizing efforts have amplified. As people are coming together to resist and create alternatives to these murderous systems, the purpose of this project is to strengthen the connection between revolutionary organizers and educators who struggle for the justice condition (i.e. racial liberation and decolonization). The fight for Ethnic Studies in 1968 marks the beginning of a field to bring this revolutionary struggle into schools. Ethnic Studies has taken a variety of shapes, but a revolutionary approach to Ethnic Studies is grounded in community struggles for racial liberation and decolonization. The three branches of decolonizing pedagogy, culturally responsive pedagogy, and community responsive pedagogy ground ethnic studies programs to the revolutionary roots of the field to resist the incessant co-optation of liberalism and repression of conservatism. Communities engaged in revolutionary struggles have tended the roots of the field, and yet, ethnic studies literature rarely centers their knowledge and experiences. Repeatedly, ethnic studies literature indicates that Ethnic Studies is a community-centered and community-directed approach to education; however, there is a sparsity of research that learns from people who have taken up the struggle for racial liberation and decolonization. To begin seeding this sparse area, this research will gather the stories of people engaged in the revolutionary struggle that ethnic studies educators work to bring into schools.
The purpose of this research is to bolster the connection between Ethnic Studies and community organizing for racial liberation and decolonization. To this end, I worked with revolutionary organizers to create a collaborative autoethnography. We wrote autoethnographies of revolutionary organizing and collectively analyzed them to address the following research questions: What can the stories of revolutionary organizers offer ethnic studies educators who are struggling to carry this work into schools? Moreover, what do their stories illuminate about resistance to co-optation and repression? This collaborative autoethnography uses the theoretical framework of critical race theory (CRT) to center race in analyses of systems of oppression and will rely on the experiences and knowledges of people from racialized communities for these analyses that inherently disrupt dominant ideologies. The collaborative autoethnography functions as a critical race counterstory by disrupting majoritarian stories that deny the importance of stories to produce knowledge. Furthermore, this theoretical lens fits the Chicana feminist epistemology, which uses decolonial approaches to position margins as sites of strength and necessary to fuel the struggle for liberation and decolonization. This collaborative autoethnography includes the stories of three revolutionary organizers using the four movements of the Nahui Ollin (a.k.a. the Aztec calendar) as a decolonial framework to shape our stories.
The themes in the data fit into the four movements of the Nahui Ollin and offer an embodied understanding of these elements: home, family, education, resistance, and organizing. Within these themes, there were also subthemes that appear. First, home and family aligned with the critical self-reflection of Tezcatlipoca. The three elements of culture, language, and land are present in data on home, and the two elements of roots and resistance appear under the theme of family. These themes illuminate the sacred nature of the work because it carries the intimacy of home, and they reveal what is at stake in the revolutionary struggle against US imperialism’s destruction of home and families. Secondly, education is distinct from schooling, and the precious and beautiful knowledge offered by, Quetzalcoatl, the feathered serpent radicalized us through study and organizing. Furthermore, the data illuminated the common cultural elements in ethnic studies classes (e.g. music, food, language, and family) are vehicles of embodied learning. Thirdly, the radicalization we experienced is sustained through the gifts of Huitzilopochtli as the hummingbird to the left, at the place of our hearts. Our willpower is sustained through the dialectical nature of individual and collective resistance fueled by a revolutionary spirit guided by love. The interdependence inherent in this resistance disrupts the destructive ideology of individualism embedded in whiteness and capitalism. Finally, revolutionary organizing offers the transformation of Xipe Totec that carries all of the movements. Furthermore, the transformation offered through revolutionary organizing relies on the foundation of revolutionary love.
The patterns in the data illuminate the organic nature of the three branches of ethnic studies pedagogy outside of classrooms. Secondly, the data addresses the process of radicalization that we experienced through study and organizing outside of schools. Third, the reciprocity between the revolutionary struggle inside and outside of schools offers space to support both in the areas where there are pitfalls. In response to the first research question, these findings offer five areas of fertile ground for ethnic studies educators. First, our autoethnographies and collaborative data analysis reveal the importance of removing boundaries between inside and outside of the classroom for the branches grounded in the revolutionary struggle to flourish. Secondly, community responsive pedagogy can be the most difficult branch to flourish, and this research indicates that this branch also holds the most space to cultivate the reciprocity between Ethnic Studies and revolutionary organizing, which, in turn, strengthens both. Third, we have to recognize the prevalence of harm when people reproduce the destructive systems we seek to dismantle. A decolonial politics of caring offered by critical pan ethnic studies (CPES) can be used to mitigate these harms. This research speaks to why all three branches are necessary because community responsive pedagogy without the medicine of the other two branches, more often than not, cannot tend to these harms in ways that do not inhibit the work. Fourth, this research indicates that expecting the work to meet schooling’s expectations is not fruitful, and ethnic studies educator must develop assessment that can reflect embodied knowledge developed through the praxis of study and organizing. Finally, this research illuminates the sacred nature of the work, which is a key reminder that we must produce generative work to avoid the performative nature of producing isolated events.
To address the second research question, we offer seeds for tending to strengthen our resistance to co-optation and repression. Valentina emphasizes the importance of a strong and clear political line. Micaela offers the importance of claiming and being claimed. Finally, as someone with a foot in struggles inside and outside of schools, I maintain that we must dismantle the walls of schooling so that the reciprocal flow of the work feeds el camino of the revolutionary struggle and cultivates power that is not easily co-opted or repressed. Future research can gather more people who straddle these walls and use CAE to harvest their lessons in order to support collectively dismantling these walls. Additionally, we can gather more revolutionary organizers to harvest lessons that are not bound by the imposed timeline of a dissertation; this carries the potential to cultivate the reciprocity between educators and organizers separated by school’s walls. Finally, we can apply this research to creating paths for future educators to earn their degrees through doing this work
The effects of uranium exposure on human breast cancer cell lines MCF-7 and T-47D in vitro and in vivo
No full textUranium (U) is a toxic and radioactive heavy metal that has significant uses in industry, fuel production and weapon manufacturing. Chronic U exposure may occur through routes such as inhalation, ingestion of contaminated food and water, and dermal exposure via interaction with contaminated soil and water. U concentrations in water resources have been found in urban and rural areas at and above the EPA limit, which puts citizens in those areas at higher risk of certain disease due to U toxicity. Some illnesses that are caused from U toxicity are: lung inflammation, lung abscess, renal tubular necrosis, organ damage and cancer. Breast cancer is a disease that affects 1 in 8 women over a course of their lifetime and has been known to be impacted by exposure to heavy metals. However, linkages between U exposure and breast cancer are weak. Uranium exposure may lead to carcinogenic outcomes through disruption of estrogenic pathways. To test if breast cancer proliferation is affected by U, we exposed MCF-7 and T-47D breast cancer cell lines in vitro and in vivo and assessed metabolism, viable DNA content per cell, and tumor growth area. Our results demonstrated that human breast cancer cells exposed to U, below the United States Environmental Protection Agency’s Maximum Exposure limit (MCL) for drinking water, responded with shifts in both viable DNA and cell proliferation in a dose and cell line-dependent fashion. Lower exposure concentrations induced proliferation; however, higher exposure concentrations reduced cell number. In addition, a zebrafish in vivo xenograft model demonstrated that low U exposure, again below the USEPA MCL, resulted in an increase in tumor area. In contrast to low U concentrations, high U concentration exposure led to a decrease in cell metabolism, viable DNA content and cell proliferation. In vivo results of high concentration U exposure resulted in no significant difference in tumor growth area. With this, our results demonstrate that human breast cancer cells respond non-monotonically to high and low U concentrations. Overall, these results signify the importance in understanding estrogenic pathways and the disruption of these pathways when environmental elements mask, inhibit or act like estrogen
Detection and phylogenomics of the environmental opportunistic pathogen, Burkholderia pseudomallei, and its close phlyogenetic relatives in the B. pseudomallei complex
Get PDFBurkholderia pseudomallei, a Gram-negative environmental bacterium, is the causative agent of the disease melioidosis. Most melioidosis cases are reported from tropical regions in northern Australia and Southeast Asia where B. pseudomallei is endemic in the environment but the true global distribution appears to be much larger. The B. pseudomallei complex (Bpc) is a phylogenetic group of Burkholderia species that consist of B. pseudomallei and its closest phylogenetic relatives. Of the six described species in the Bpc, B. pseudomallei has adapted to opportunistic pathogenicity, B. mallei to obligate pathogenicity, and B. thailandensis, B. oklahomensis, B. humptydooensis, and B. singularis to environmental saprophytism with occasional pathogenicity (except B. humptydooensis).Determining where B. pseudomallei is present in the environment is crucial for understanding the potential risk to humans of acquiring melioidosis since almost all infections with B. pseudomallei are independently acquired from the environment. In Chapter 2, our goal was to gain a better understanding of the prevalence and geographic distribution of B. pseudomallei and other Burkholderia spp. in the environment in Puerto Rico. The results from Chapter 2 suggest that B. pseudomallei is widely dispersed but rare in the environment in Puerto Rico. In Chapter 3, we isolated a member of the Bpc, B. thailandensis, from the Western Hemisphere for the first time. B. thailandensis is of interest from a public health standpoint due to its potential to cause infection as a fortuitous pathogen and to the melioidosis community since B. thailandensis is often used as a surrogate in the laboratory instead of B. pseudomallei due to the reduced restrictions required. In Chapter 4, we proposed two novel Bpc species, B. mayonis sp. nov. and B. savannae sp. nov., isolated from soils from multiple locations in northern Australia. The addition of B. mayonis sp. nov. and B. savannae sp. nov. results in a total of eight species within this significant complex of bacteria that are available for future studies. Understanding the genomics and virulence of B. pseudomallei and its closest relatives in Bpc is important for identifying robust diagnostic targets specific to B. pseudomallei and understanding evolution of virulence in B. pseudomallei
Molecular signatures of selection in Populus fremontii: precipitation and temperature as drivers of genomic variation
No full textForests, which cover 30% of the Earth’s surface, are experiencing rapid environmental change, due in part to anthropocentric activities that alter global temperatures and patterns of precipitation. Forest trees, which are often distributed across broad environmental gradients, typically harbor molecular signatures of selection, detected as “outlier loci,” in response to an environmental gradient. In this study, I queried a genomic data set from 60 sites across Populus fremontii’s range consisting of > 15,542 single nucleotide polymorphisms (SNPs) for signatures of selection in response to 19 biovariables associated with temperature and precipitation. Two analyses that identify putative outlier loci, Redundancy Analysis (RDA) and Latent Factor Mixed Model (LFMM), were used to search for genetic x environmental associations, which are indicative of signatures of molecular selection. Between the two methods, 1,358 candidate loci were found to be correlated with precipitation and 656 with temperature. These results suggest local adaptation has occurred in Populus fremontii across a climatic gradient in terms of both precipitation and temperature. Outlier loci that showed particularly strong associations with temperature and precipitation were mapped across the species range to examine how their allele frequencies change in response to environmental variation. Of the four mapped loci, three displayed strong linear relationships with changes in precipitation and temperature, while one locus showed high levels of variation across the species range. Mapping of candidate outlier loci to the genome of P. trichocarpa, a closely related species, identified genes and gene regions that are responsible for biologically important functions including cold tolerance and drought stress. These results strongly suggest that the genome of P. fremontii is under strong environmental selection, with precipitation playing a larger role in driving adaptive genomic variation than temperature. Findings from this study provide valuable insight into how environmental variation shapes genomic variability in forest trees and can guide their adaptive management in the context of ongoing climate change