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LEDs for Controlled Environment Agriculture: Leveraging Light to Optimize Crops
No full textIndoor agriculture is a growing industry with many of its benefits being recognized. Light emitting diodes (LEDs) reduce production costs compared to traditional light sources. LEDs emit narrow bandwidths of light that allow growers to easily change the wavelengths plants are being grown under by using different combinations of wavelengths. Manipulating the light that plants are grown under is a method to change their physiology which is the basis of this thesis. The goal of the first two studies was to investigate how different light spectra can be used to enhance the nutrition content, growth, and morphology of kale and tomatoes to improve the quality of food grown under LEDs. Results from these studies showed that generally green and blue LEDs led to more nutrients in kale leaves and tomato fruit while red light lowered the nutritional quality. In kale, antioxidant capacity and phenolic content was highest under blue light while green light produced the highest mineral contents (p \u3c 0.05). Antioxidant capacity of tomato fruit was higher in treatments with blue and green than red while the mineral content of fruit showed the same general pattern (p \u3c 0.05). There were no significant differences in the yield of kale grown to the baby leaf stage or in the total amount of tomato fruit harvested per plant under the different LED wavelengths. However, the height of plants increased under red light which could be negative in a vertical farm setting. Overall, the results show that growers can be more flexible with the wavelengths of light without sacrificing yield in kale and tomatoes, and there may be a benefit to leaving red light out. The third study of this thesis was to understand the gene expression changes that occur under different wavelengths and how they may explain the physiological differences observed in the first study on kale. RNA sequencing was performed on kale grown under pure red, green, or blue LEDs and compared to a control that was grown under all of the LEDs in combination. Green and blue LEDs resulted in more differentially expressed genes (DEGs) while kale grown under red LEDs had an expression profile similar to the control. Kale grown under blue light showed antioxidant enzymes and proteins involved with phenolic biosynthesis were upregulated which potentially explains the physiological differences observed in the prior studies. Under green LEDs kale upregulated many heme binding genes and oxidoreductases, specifically cytochrome P450s. This may explain the significantly higher iron content of kale grown under green light, and supports other literature on green light perception by plants which has remained largely unknown until recently. The transcriptomic data from this study can further the understanding of how plants respond to light, and more mechanisms will be revealed when paired with metabolomic data
Seeing Red: Hostile Attribution Bias, Aggression, and Antisocial Personality Disorder Traits
Get PDFAntisocial personality disorder (ASPD) is a destructive and severe mental illness that costs the U.S. trillions of dollars annually. Although ASPD is significantly correlated with acts of aggression, violence, and imprisonment, not all individuals with ASPD are aggressive. In samples without ASPD, increased aggression has been linked to an error in social information processing, which is referred to as hostile attribution bias (HAB).
The current study tested the extent to which HABs, or the tendency to attribute hostility to neutral or ambiguous stimuli, predicted aggression above and beyond ASPD traits in participants with a history of incarceration. Participants (N = 76) were recruited through West Virginia’s Division of Probation Services and Reddit. Measures assessing demographics, ASPD traits, aggression, and HABs were completed via Qualtrics. It was hypothesized that HAB scores would predict aggression over and beyond ASPD traits. Analyses revealed that HABs significantly predicted aggression beyond ASPD traits when measured via a personality disorder assessment but not when measured via a psychopathic personality assessment. Further, HABs significantly predicted reactive, but not proactive, aggression beyond ASPD traits when measured via a personality disorder assessment. Results suggest that HAB is a significant predictor of aggression and could be a potential target for interventions
Subjective Cognitive Decline: Examining the Contributions of Adverse Childhood Experiences and Social Determinants of Health
Get PDFSubjective cognitive decline is one’s awareness of their own consistent memory loss or confusion that interrupts their day-to-day activities (CDC, 2022; Roehr et al., 2017). Several risk factors for subjective cognitive decline, such as demographic social determinants of health (SDOH) and adverse childhood experiences (ACEs) have been identified through previous research (Alzheimer’s Association, 2016; Dening & Sandilyan, 2015); however, less is known about the interaction between demographic SDOH and ACEs on subjective cognitive decline. The current study sought to examine how demographic SDOH (i.e., age, sex, race, and education) (research question 1) and ACEs (i.e., physical abuse, sexual abuse, and household dysfunction) (research question 2) influenced subjective cognitive decline among middle-aged and older adults (M = 67 years old). Additionally, we aimed to better understand the interaction between demographic SDOH and ACEs on subjective cognitive decline (research question 3). Using the 2020 Behavioral Risk Factor Surveillance System (BRFSS) data (CDC, 2020), a two- step hierarchical logistic regression was conducted, with demographic SDOH included in the first step and ACEs included in the second step. Both Step 1 (F(3, 1905) = 36.92, p \u3c .001, R2 = .087) and Step 2 (F(3, 1902) = 9.36, p \u3c .001, R2D = .013) were significant, where SDOH and ACEs uniquely contributed to the variance explained in subjective cognitive decline (F(8, 1902) = 26.49, p \u3c .001, R2 = .096) . It was expected that older adults would report experiencing more subjective cognitive decline; however, our first hypothesis was not supported. Younger age was associated with more subjective cognitive decline, which is not consistent with previous research. The remaining hypotheses for our first research question were supported, where identifying as female, identifying as a member of a marginalized racial group, and having lower educational attainment were associated with more subjective cognitive decline, which is similar to previous findings. Our results also revealed that experiencing more ACEs was associated with more subjective cognitive decline, which supported our second hypothesis. To assess whether the effects of SDOH moderate the influence of ACEs on subjective cognitive decline, a series of moderated regression analyses were conducted. Although main effects emerged for individual SDOH and ACEs, no significant interactions among the two variables emerged. None of our hypotheses regarding the moderation of SDOH on ACEs and subjective cognitive decline were supported. Overall, our results revealed that both SDOH and ACEs uniquely contributed to the variance explained in subjective cognitive decline. Future research would benefit from examining the effects of demographic SDOH and ACEs on subjective cognitive decline by implementing longitudinal designs to better understand the lingering effects of childhood adversity and other sociodemographic influences on subjective cognitive decline at mid and late life
Prolific Phalluses - Male Figural Art of the Colima: An examination of the presence and meaning behind the representation of the phallus in Colima art
Get PDFThe Art of Carmen Herrera: Understanding Cuban-American Art through the Lens of Modern Art Theory
Get PDFAn Observational Census of Post-Merger Galaxies and Supermassive Black Hole Pair Evolution
Get PDFMassive galaxy mergers are a fundamental consequence of the dynamic evolution of the Universe and play a central role in the evolution of galaxies. Because all massive galaxies harbor a central supermassive black hole (SMBH; M ≥ 106 M⊙), studying these merging systems with electromagnetic (EM) techniques constrains galaxy evolution models and provides a systematic means to examine the astrophysical mechanisms that facilitate the growth of SMBHs. These growing SMBHs are observable across the EM spectrum as Active Galactic Nuclei (AGN). Massive galaxy mergers are a natural formation mechanism for an SMBH pair, eventually evolving into an SMBH binary (SMBHB). As the sources of low-frequency gravitational waves detectable by pulsar timing arrays, robust EM identification of a population of SMBH pairs and binaries will greatly enhance the discoveries in the next age of multi-messenger astronomy. In this dissertation, I explore the radio population of post-merger galaxies using multi-waveband techniques and directly target late-stage SMBH pair evolution through investigations of their parsec-scale radio environment.
First, I explore the radio-emitting population of post-merger galaxies by synthesizing new, high-resolution Jansky Very Large Array observations with archival radio surveys. Spanning five orders of magnitude in spatial scale and two decades in radio frequency, I discover that the majority of post-mergers in this sample host low-luminosity, compact (\u3c 1 kpc), steep-spectrum radio sources. Then, using multi-waveband techniques, I identify which of these sources is associated with an AGN and interpret this population with regard to AGN triggering mechanisms and feedback efficiency. I also predict the power of next-generation radio instruments in SMBHB studies using these radio AGN as a meta-sample.
Then, I directly investigate SMBHB evolution in a subset of these post-mergers by carrying out a targeted Very Long Baseline Array (VLBA) survey, totaling over 1300 hours of observations. Multi-frequency intensity maps of the milliarcsecond-scale radio emission reveal no secondary radio-emitting companion in any of these post-mergers. I then present compelling relative astrometric and morphological arguments that support a hypothesis in which SMBH pair evolution is highly efficient and that at least some SMBHBs can attain sub-pc orbital separations in astrophysical environments, overcoming the final parsec problem and entering the gravitational-wave regime. This work represents the most sensitive high-resolution survey to date targeting SMBHB evolutionary signatures, attaining μJy-level precision in our VLBA intensity maps and probing radio emission signatures down to L = 1020 W Hz-1. This survey illustrates the intensive observing campaign required to accurately assess the radio-emitting population of SMBHBs.
Lastly, I present the results of a targeted VLBA analysis to test the recoiling SMBH (rSMBH) hypothesis for the changing-look AGN Mrk 1018. rSMBHs are post-SMBHB coalescence systems that have so far remained observationally elusive. Through advanced astrometric calibration techniques, I place strict constraints on proper motion measurements of the milliarcsecond radio core, discovering low-significance proper motion in Right Ascension. Then, I interpret this result within the context of three distinct models: the secular evolution of a radio AGN; the orbital evolution of a SMBHB; or the kinematic signature of a rSMBH. When considering the apparent velocity of the dominant kinematic component of Mrk 1018, I conclude that this must be associated with an outflowing sub-component of the VLBI radio jet, although this does not rule out the rSMBH scenario. I then summarize future observational experiments that may be able to distinguish between the secular evolution of a radio AGN and the kinematics of a rSMBH
Investigation of Synergistic Effect between Polystyrene and Polyethylene under Conventional Thermal Heating and Microwave Heating
Get PDFSingle-use plastics (Low Density Polyethylene, LDPE; Polystyrene, PS; Polypropylene, PP) are increasingly used in the modern world, with their usage growing every year. An effective method to manage the resulting waste is urgently needed, as landfilling and incineration have proven harmful to the environment in the long term. Mechanical recycling may not maintain the desirable characteristics of the single-use plastics through several cycles. Pyrolysis emerges as a promising approach to address plastic waste. Given that single-use plastic waste often comes in a mixture, combining plastic in the feedstock is a viable solution to effectively convert these polymers altogether to gain market value. The emergence of microwave heating technology enhances plastic pyrolysis by significantly improving heating efficiency. Contributed to penetrative and selective heating capabilities of electromagnetic waves. This advancement can potentially enhance the catalytic pyrolysis process to yield more valuable products. These hypotheses were tested in detail.
The depolymerization of LDPE, PS, and their mixture was investigated under conventional thermal and microwave conditions. PS and LDPE were studied for co-pyrolysis performance in a thermal reactor. In both catalytic (using HZSM-5 as catalysts) and non-catalytic cases, PS had higher degradation temperature than LDPE. When the plastics were mixed, the reaction temperature decreased. Compared to individual PS or LDPE depolymerization, the mixture demonstrated a different depolymerization mechanism. Additionally, the PS-LDPE 1:1 blend yielded higher amounts of BTX (benzene, toluene, xylene) compared to PS and LDPE alone. The reaction mechanism was supported by the in-situ FTIR, which showed prolonged BTX production during the mixed plastic catalytic degradation. The interaction between the radicals released from PS and LDPE cracking was hypothesized to enhance BTX aromatics production in the presence of HZSM-5 catalysts.
The catalytic co-pyrolysis of PS and LDPE were tested in the presence of electromagnetic waves. The mixed plastics exhibited synergistic effects, leading to increased BTX production under microwave conditions. Individually, PS and LDPE were observed to possess a separate pyrolysis mechanism. However, when pyrolyzed together in a mixture, their intermediates interacted with each other. With the presence of HZSM-5 catalyst, the product distribution favored BTX production due to the synergy mechanism. The microwave-assisted pyrolysis of mixed plastic was compared between microwave heating and conventional heating methods. Overall, microwave heating offers more efficient heating. Ultimately, resulting in higher conversion rates and better yield towards BTX products.
A kinetic study was conducted on microwave heating and conventional thermal heating to determine the activation energy (Ea) of PS, LDPE and their mixture during catalytic pyrolysis. It was found that when the plastics were mixed, the Ea decreased under both heating methods. This phenomenon was attributed to the interaction between the intermediates of each plastic, in which one component facilitated the degradation of the other. Compared to thermal heating, microwave heating reduced the Ea of all plastic types, which was attributed to local heating through hotspot formations. The reaction mechanism of mixed plastic was elucidated with more pathways towards BTX production, which was corroborated with the reactor performance results
Short Episodes but Fast Friends: Examining the Effects of Parasocial Relationship Quality on Mediated Intergenerational Contact in Grace and Frankie
Get PDFBuilding on the foundations of intergroup contact theory (Allport, 1954), the parasocial contact hypothesis (Schiappa et al., 2005), and Harwood’s Contact Space (2010), this dissertation advances the existing literature on how intergenerational contact with media characters can improve young adults’ willingness to engage with older adults. Specifically, this study examines the effects of intergroup contact quality on the parasocial contact process. Episodes of the TV sitcom about older adult women, Grace and Frankie, were edited to create both a high contact quality condition and a low contact quality condition. The high contact quality condition was a montage that showed viewers more scenes or “relational data points” (30) about the main characters, Grace and Frankie, across a full season. The low contact quality condition was a pilot episode consisting of fewer relational data points about the characters (12). Though they varied in terms of the depth of information they provided about the characters, the episodes were equal in length. Participants were randomly assigned to watch one of the two episodes in a theater-like setting, and then complete a survey. The manipulation was successful; the montage condition resulted in greater perceptions of meaningfulness and contact quality than the pilot episode, even though time was held constant. However, contact quality did not initiate the parasocial contact process for both characters. The montage episode also increased parasocial relationship strength with Grace, but not for Frankie, and only parasocial relationships with Grace increased viewers’ willingness to engage with older adults more generally. Specifically, parasocial relationship strength with Grace and self-disclosure serially mediated the relationship between contact quality and willingness to engage with older adults. Likewise, PSR strength with Grace and intergroup dissonance serially mediated the effect of contact quality on willingness to engage with older adults. The different patterns of effects for the two characters may be explained by differences in how typical of older adults the young audience viewed them as being. By demonstrating that contact quality and parasocial relationships can be manipulated with montage editing, this research makes an important contribution to research efforts on character involvement. Theoretically, this study also demonstrates that relational quality is more important than relational length, or time, for prejudice reduction through mediated contact. Implications for media producers and future routes for intergenerational parasocial contact research are discussed
Ecological planning and design for creating a thriving suburban community in Lumberton, NC
Get PDFThe purpose of the project is to propose ecological planning and design techniques to create a thriving and robust suburban community in Lumberton, North Carolina. The project becomes an educational hub on agroforestry, ecological design and stewardship, and flood mitigation through stormwater strategies for Linkhaw’s Mixed Use Community Development plan. Linkhaw Farms is a 540 acre site, in a predominantly Native American community, situated on the north-east boundary of Lumberton in the Coastal Plains region of NC. It was formerly owned by the Linkhaw family for over 70 years, producing tobacco, and later rotation of annual crop production between corn and soybean.
The project is composed of urban planning, a historic wetland unique to the area (the Carolina Bay), and an educational experience of agroforestry practices. The masterplan will include restoration of the carolina bay, a community farm, a K-8 campus building, a series of forest gardens, silvopasture, and green corridors. The programming will provide educational experiences, self-sufficiency, and health and wellness for all systems of the site. The ecological design strategies will increase biodiversity, restore ecosystems, revive ancient agriculture practices, and retain stormwater on site
Guiseppe De Nittis\u27s Cityscapes of Paris: Images of Modernity 1875-1875
Get PDFThe artist Guiseppe De Nittis (1846-1884) created paintings between 1874-1875 reflecting his own experiences while living in and around the sixteenth arrondissment in Paris, France. De Nittis produced a distinctive perspective of Paris as it was being shaped by modernity and populated by the growing bourgeoisie. De Nittis’ interpreted fleeting views of Paris undergoing renovations. For example, De Nittis’ depicted freshly widened streets, public parks, and landmarks shrouded in scaffolding. De Nittis’ transient subject matter was further characterized by the portrayal of bourgeois figures in temporary Parisian moments. In summation, De Nittis’ compositions are a distinctive representation of Paris’s evolution from the Second Empire to the modernity of the post-Commune era. De Nittis signifies progress by portraying elements of contemporary architectural renovation and the habits of the bourgeoisie in those spaces