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John Bickham field notebook: AK2001-AK2500.pdf
No full textBound book, each page corresponds to a karyotype slide data.Data pages for AK2501-AK3000 corresponding to unique identifiers of specimens/samples examined for biological research. Specimens are primarily housed at Texas A&M University; Biodiverstiy Research and Teaching Collection
Isla Piedra: Coastal Shoreline Change of an Ancient Human Settlement on the Gulf of Mexico
No full textAlong the Gulf of Mexico, on the northwest corner of the Yucat��n Peninsula, sits the northern coastal plain of the State of Campeche. The shoreline of this plain is impacted by coastal processes and ecological succession based on low-energy waves that transport and deposit sediment. These processes form a muddy shoreline with extensive wetlands, characterized by estuaries, mangrove forests, floodplains (ci��nagas) and islands of vegetation known as hardwood hammocks (petenes). This dynamic ecological frontier is a transition zone between marine and terrestrial environments, perpetually undergoing change. Ancient human settlements of varying levels of complexity have been documented along this shoreline, all of which were subject to dynamic coastal processes���such as the case of Isla Piedra. However, there has been limited exploration into whether these dynamics have modified the landscape of these settlements over time. This research seeks to determine if the ancient inhabitants of Isla Piedra experienced a different coastal landscape compared to today and how this influenced their adaptive behaviors. First, the relationship between coastal geomorphology and ancient human settlements is established. Then, through change detection methods, a series of remote sensing satellite images of the coastline are analyzed to identify differences indicative of landscape changes. Based on the detected alterations, this research proposes potential shoreline changes that Isla Piedra inhabitants may have experienced during its primary period of ancient occupation. This change provides a foundation for future research about site formation and adaptive strategies developed by the island���s inhabitants
Anger-Induced Early Childhood Respiratory Sinus Arrhythmia and Parenting Style: Predictors of Toddler Externalizing Behavior Problems and School Readiness
No full textEarly childhood emotional regulation has been linked to favorable academic, behavioral and socioemotional outcomes. Respiratory sinus arrhythmia (RSA) in response to an emotion induction has been studied as an indicator of emotional regulation. This study investigated children���s dynamic RSA change in response to a negative-affect evoking laboratory episode, and how RSA relates to behavior problems and school readiness. The sample consisted of 58 typically developing children (males = 24, mean age = 3.1, SD = .02) and their parents (mothers = 56, mean age = 35.04, SD = 5.25) in the Bryan-College Station area. Greater RSA suppression during the anger induction was associated with lower externalizing behavioral problem scores and higher school readiness scores. Children of authoritarian parents had the highest school readiness scores across levels of RSA suppression but the highest externalizing problems for those with low emotional regulation. Girls showed more pronounced patterns of RSA suppression whereas boys��� RSA levels remained comparatively flat over the anger induction. My study contributes to the emotion regulation literature from a family study perspective while employing multi-method assessments of child temperament. The findings shed further insight to the relationship between emotion regulation and cognitive performance. This research has implications for preschool readiness, cognition and behavioral interventions
Quantitative Analysis of Strain Response Measured by Low-Frequency Distributed Acoustic Sensing During Hydraulic Fracturing
No full textThis master's thesis investigates the pivotal role of strain measurements in hydraulic fracturing operations, employing Low-Frequency Distributed Acoustic Sensing (LF-DAS) technology to monitor strain changes during treatments. A significant gap in the existing research is addressed by systematically analyzing strain decay beyond the fracture domain corridor. The thesis investigates the impact of parent-well depletion and completion design on hydraulic fracture geometry, employing a decline factor of the strain decay curve as a key analytical tool. This analysis is supported by a geomechanics model, providing a comprehensive understanding of the dataset. Furthermore, the study conducts a comprehensive analysis of Hydraulic Fracture Test Site-2 (HFTS-2), considering the maximum cumulative strain change and decline factor of the strain decay curves. The thesis outlines a well-structured workflow for processing and analyzing LF-DAS cross-well strain data
Impact of Organic Management Practices on Soil Greenhouse Gas Emissions from Cotton-Winter Cover Crop Systems in East-Central Texas
No full textConventional cotton production practices demand extensive management involving high pesticides, fertilizers, and tillage inputs, contributing significantly to environmental impacts. To address these concerns, we explored the potential of organic cotton systems employing diverse cover crops, manure, and biochar to mitigate soil greenhouse gas (GHG) emissions while preserving soil carbon and nitrogen. Our field experiment, conducted in the humid subtropical climate of East-Central Texas, assessed various cover crops such as oats (Avena sativa), Austrian winter pea (Pisum sativum), purple top turnip (Brassica rapa subsp. rapa), and mixed species cover crops compared against a control (no cover crop) over three consecutive years. We monitored soil GHG emissions, moisture, and temperature dynamics throughout the cover crop and cotton seasons.
Simultaneously, we conducted multiple laboratory incubations to assess the carbon and nitrogen mineralization of these cover crops in combination with poultry litter manure, examining associated GHG emissions. Our laboratory simulations also considered the impact of tillage practices on residue mineralization. Additionally, we investigated the potential of cotton residue biochar to mitigate GHG emissions during cover crop and manure decomposition.
Our findings revealed that cover crops with a lower C:N ratio, especially legume and mixed species, exhibited higher GHG emissions. However, incorporating biochar alongside cover crops demonstrated significant emission reduction. Furthermore, we observed that cover crops led to reduced soil moisture during their growth phase but contributed to increased water retention during cotton seasons
Design & Manufacture of Additive Manufactured Polymer-Metal Interfaces
No full textThis research investigates the design and manufacture of additively manufactured polymer-metal interfaces while correlating their processing, structure, properties, and performance (PSPP). Our primary goal is to tailor interface design and manufacture to effectively withstand tensile, shear, and combined loading, while fulfilling the constraints of avoiding adhesives or fasteners between the components. To achieve this goal, this study employs mechanical interlocking between polymer and metal surfaces (at a specific size-scale) that includes repeated geometry features (unit-cells) additively manufactured onto the metal surface, and the polymer additively ���infilled��� onto them. The geometrical designs were tailored taking into consideration the advantages and limitations of ���PBF-LB��� for the metal printing (316L stainless-steel), and ���MEX-TRB��� for the polymer printing (PCABS). The study includes the evaluation of various factors affecting the interface ���quality���, including unit-cell shape/size/distribution designs and their implications for polymer filling vs. load capability, the effect of manufacturing process parameters on the interface, and their impact on stress distribution and eventually performance under various loading scenarios. FEA simulations were employed to tailor designs and to parametrically predict the stress-based performance of the interfaces; insights into stress distributions, load capacity and critical points were obtained. Finally, candidate interface designs were additively manufactured, and their performance analyzed under various loading conditions. Altogether, this research strives to facilitate the use of polymer-metal interfaces within additive manufactured components
CRISPR-CAS12 Nanoparticles Alter Macrophage Function to Improve Inflammation After Traumatic Brain Injury in Mice
No full textOne of the first physiological and cellular events after a traumatic brain injury (TBI) is inflammatory-driven progressive neurodegeneration. The major players in this process are the brain resident immune microglia/macrophage cells (MG/Ma), which release inflammatory cytokines to cause an excess amount of inflammation. However, the largest obstacle to current TBI treatment is the challenge of targeting these MG/Ma cells. We designed a lipid nanoparticle (LNP) that can overcome this problem by locally delivering a clustered regularly interspaced short palindromic repeats (CRISPR) gene editing system specifically targeting the mitogen-activated protein kinase 9 (MAPK9) gene to polarize resident MG/Ma from their proinflammatory to anti-inflammatory state.
First, the CRISPR technology was combined with the LNPs to create a CRISPR-LNP system that was conjugated to an ionized calcium-binding adapter molecule 1 (Iba-1) antibody to increase specificity to central nervous system macrophages. We investigated the delivery efficacy of the CRISPR-LNP to reach the injured brain by comparing intravenous or intranasal administration. Then, we used a standardized cortical impact device to inflict a traumatic brain injury in adult male C57BL/6J mice. The data was visualized and analyzed using an advanced in vivo imaging system (IVIS), immunofluorescence analysis, and immunohistochemical staining with in situ hybridization.
Intranasal administration of Iba-1Ab-CRISPR-LNP produced greater specificity in binding to the injury compared to systemic administration. IVIS indicated that systemic administration led to a more significant accumulation of LNPs in the injured cortex. We found that the treatment reduced MG/Ma activation indicated by a change in macrophage morphology consistent with a reduction in the quantity of pro-inflammatory MG/Ma cells. We also found a decrease in the number of pro-inflammatory cytokines (IL-1�� and TNF��) and TUNEL-positive cells following CRISPR-LNP treatment compared with the vehicle group after 1-day post-TBI.
Our results showed that the Iba-1Ab-CRISPR-LNP reduced the MG/Ma activation indicated by morphology changes and the quantity of apoptosis of all cells after TBI. This work lays the foundation for developing a specific transformational therapeutic approach for TBI patients
An Epidemiologic Investigation on Arsenic Exposure and Its Association with Mental Health Outcomes
No full textMental health problems, characterized by a clinically important disturbance in cognitive, emotional, or behavioral aspects of an individual���s life, have garnered growing interest in the field of epidemiology due to their complex causal mechanisms, increasing prevalence, and substantial burden on modern populations. There are many causal factors suspected to impact mental health, mental illness, and emotional wellbeing including certain environmental toxins, like arsenic, although these associations are not well established. Arsenic has been shown to be a globally toxic substance that is associated with numerous health problems. Recent studies suggest that arsenic may have an impact on mental health due to its neurotoxicity.
The present research investigates the possible association between arsenic and mental health problems through a systematic review, geographically weighted regression on a county level for the 48 contiguous states with soil arsenic, and a geographically weighted regression on a county level for Texas with water arsenic exposure estimates. The systematic review demonstrated associations between Arsenic and multiple mental disorders as well as generally poor mental health. The first geographically weighted regression of the contiguous 48 states found that soil arsenic was a significant predictor of both county suicide rates and the years of potential life lost due to suicide rate. The second geographically weighted regression found that estimated water arsenic exposure was a significant predictor of both county suicide rates and number of days reported with poor mental health.
The present research suggests that arsenic may be a potential environmental risk factor for mental health outcomes. Further prospective studies with individual-level data are necessary to confirm causality and explore the interactions with other risk factors
John Bickham field notebook: AK22501-AK23000.pdf
No full textBound book, each page corresponds to a karyotype slide data.Data pages for AK23001-AK23500 corresponding to unique identifiers of specimens/samples examined for biological research. Specimens are primarily housed at Texas A&M University; Biodiverstiy Research and Teaching Collection
Culturally Responsive Coaching for African American Parents of Children with Autism: A Single-Case Analysis, Qualitative Systematic, and Practitioner Paper
No full textAfrican American children and their families face a heightened susceptibility to disparities associated with autism (Dababnah et al., 2018). While advancements have been made in mitigating racial inequities in the identification of autism, Constantino et al. (2020) still report the existence of diagnostic delays for autism in Black children. This study suggests a gap of approximately three years between the period when parents initially express concerns about their child's developmental milestones and the eventual diagnosis of autism. The purpose of these three studies were (1) to identify how culturally responsive parent coaching for African American families of children with autism can increase parent implementation of naturalistic intervention strategies by conducting a multiple-probe single case experimental design across participants; (2) to conduct a qualitative systematic review on the experience and quality of studies on African American families of children with autism; 3) To provide a practitioner guideline of culturally responsive parent coaching, for educators and service providers working with African American families of children with autism.
The findings of the study indicated that culturally responsive parent coaching is effective in improving communication for African American parents and their children with autism. The findings from the second study reports the different experiences of African American families ranging from lack of source of support, cultural differences, cost of health care services, and parents lack of prior knowledge of autism. The third study provides a guideline for practitioners who serve culturally diverse families like African American parents.
The findings of these three studies presents several implications for practice and research. Service providers and healthcare professionals need to be trained to become more culturally responsive to better serve African American families. There is also a need for more research on the implementation of culturally responsive practice with African American families of children with autism