University at Albany, State University of New York
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The Role Of Atmospheric And Oceanic Feedbacks In Orbital And Millennial Timescale Variability Of The Coupled Climate-Carbon System
Get PDFAn intriguing mechanism of the Pleistocene glacial-interglacial cycles is the phase locking of internal climate oscillations to external forcings, suggesting the leading role of the natural climate variability in the past climate changes on orbital timescales. Similarly, the millennial-scale variability over the last glacial period may be attributed to unforced climate dynamics. One of the central themes of the climate sciences is to acquire a fundamental understanding of climate feedbacks over a broad range of timescales. The main objective of this thesis is to identify the characteristic natural variability in a fully coupled climate-carbon model from orbital to millennial timescales, and the essential feedback processes contributing to such behaviors, such as the role of the oceanic carbon cycle in the dynamical structures of the warm climates
The Characteristic Polynomial And Its Applications
Get PDFThis dissertation examines some applications of the characteristic polynomial where are complex square matrices and . In particular, it proves that a Coxeter system is completely determined by its characteristic polynomial with respect to the Tits representation and that the characteristic polynomial for pairs of projection matrices can be calculated using their orthogonal decomposition described by Halmos~\cite{Hal}. A consequence of this calculation is that their characteristic polynomial is a complete unitary invariant for the pairs of projections, which may be alternatively proven by their trace. These results have been published in~\cite{HY}. The unitary equivalence of tuples of projections, the spectral equivalence of axial point groups, and the irreducibility of the characteristic polynomial of the braid group with respect to the Burau representation are also considered
The Impact Of Wildfire Activities On Air Quality And Solar Energy In New York And California
Get PDFAn increasing trend of wildfire activity over North America over the past decades has been observed. Elevated surface fine mode particulate matter (PM2.5) concentration and reduction of solar radiation during the smoke episodes have been widely reported. Given that the intensity and frequency of wildfires are expected to increase under changing climate, the impact of smoke aerosols on air quality and solar energy could become more significant. This study aims to characterize the transport of smoke aerosols and quantify their impact on local air quality and solar energy over New York (NY) and California (CA) States. A multi-year analysis of smoke cases during the summer of 2017-2022, case studies of smoke events in September of 2017 and June of 2023 over NY, and numerical experiments of the 2020 wildfire over CA were conducted. Various analyses were conducted, including 1) identification of smoke plumes using satellite measurements, ground-based observations, and aerosol reanalysis products, 2) quantification of the contribution of smoke aerosols to local air quality and solar radiation, and 3) characterization of the transport process and vertical mixing of smoke events. Results of multi-year analysis showed that transported smoke aerosols introduced an increase of daily PM2.5 of 3-4 ?g m-3 on average over NYS. Besides, 30.0% - 40.0% of the polluted days were associated with transported smoke aerosols. The record-breaking smoke event in June 2023 led to an increase of PM2.5 by 15-fold - 60-fold while annually occurred less extreme smoke events caused an enhancement of PM2.5 by 3-fold. Analysis of case studies reveals that synoptic subsidence, entrainment process, and turbulent mixing collectively contributed to the downward transport of smoke aerosols and the enhancement of surface PM2.5 concentrations. During the summer of 2020 over CA, results of model simulation show that wildfire activity leads to an increase of monthly aerosol optical depth by 0.2-0.7 and reduction of clear-sky global horizontal irradiance by 3-10%. Future studies considering a range of variability in wildfire activities (e.g. geographic location, size, and time of year) and the key factors which determine air quality and solar energy impacts of the transported smoke aerosols, such as plume rise, large-scale circulation, aerosol physical/chemical processes, and PBL evolution, are recommended
The Role Of Sexual Scandal In Politics & Policy
Get PDFThis study aims to further our understanding of political scandal more broadly, as well as the classification of sexual scandal cases more specifically. With regards to sexual political scandal, the research looks to answer (1) How candidate evaluations of a politician under sexual political scandal are impacted based on aspects of their identity (gender and family values) and (2) How candidate evaluations of a politician under sexual political scandal impacted by an ever-shifting public-private divide (the exposure process). The dissertation begins with an interdisciplinary overview of the literature, which is organized into five distinct facets to create a new and comprehensive understanding of the scandal process. Then, there is an overview of the mixed-method research design (focus groups and experimental surveys) and its strengths in addressing the research questions. Following this foundation, the empirical chapters lay out the findings as they relate to gender, hypocrisy, and scandal exposure and candidate evaluations, as well as additional findings that emerged from both the focus group and by analyzing characteristics of the recipients of the scandal information. Lastly, there is discussion of bettering our understanding of scandal and pragmatic uses of this research for various audiences
Comprehensive Current Flow Modeling And Circuit Parameter Analysis For A Brushed Dc Motor Regenerative Braking System
Get PDFThe literature surrounding regenerative braking systems deals heavily with control system analysis and less to do with the electrical analysis of the circuitry itself. This thesis develops a step-by-step current flow model for a single-phase brushed DC motor regenerative braking system using the RL unit step-response equation as a starting point. This model and the equations derived from it will be analyzed to see what limitations arise from the circuitry on the overall performance of the system, such as non-ideal resistances, switching delays, and affects from current draw of accessory circuitry. The efficiency will be calculated in the context of the percentage change between the peak charge returned to the battery in an ideal and non-ideal model, with the non-ideal model consisting of the non-ideal resistances and switching delays. Each chapter will expand the model to include more non-ideal elements such as to make the resulting equations more accurate to a real-world system, and the accuracy of the equations will be determined through comparison with measured values found using a MATLAB model made using the initial current flow equations. Comparison with the model showed a great deal of accuracy for the calculated parameters using the equations derived in this thesis, and inaccuracies are explained through the approximations that were necessary to take in order for algebraic derivations to be possible. Through the derivation and analysis of these models and equations, this thesis will provide a mathematical framework for quantitatively analyzing and comparing the performance of regenerative braking systems, as well as how the different non-ideal elements affect the system
Barrier Removal Prioritization To Increase Climate Resiliency And Aquatic Connectivity For Communities In The Upper Susquehanna Basin
Get PDFThe streams and rivers of the Upper Susquehanna Basin have been heavily modified over centuries through deforestation of nearshore areas and creation of physical barriers, such as dams and culverts. Dams and undersized culverts negatively affect aquatic organisms by modifying habitat conditions and restricting movement of these organisms. In addition, improperly maintained dams and undersized culverts can intensify flooding impacts and negatively affect water quality. A standardized method is needed to determine which barriers should be prioritized for assessment and potential replacement or removal based on multiple ecosystem and societal factors. The goal of this analysis was to have a small number of easily defined metrics that are manageable for restoration professionals, while having the metrics be varied enough to allow these professionals to facilitate effective decision-making based on their own priorities. With the recent influx of federal and state funds for climate resiliency and habitat restoration projects, the methods presented in this analysis can address existing bottlenecks and inform planning decisions on barrier removal
Exploring Nucleic Acid Modifications For Rna-Based Therapeutics: Insights From Molecular Dynamics Simulations
Get PDFNucleic acid modifications are pivotal in biological processes due to their multifaceted roles. They regulate gene expression by modulating transcription, with modifications in the nucleic acid, sugar group, or in its phosphate backbone. In our investigation, we explore the use of molecular dynamics simulations to study nucleic acid modifications for potential applications in RNA-based therapeutics. These modifications introduce nonstandard atoms, such as selenium, and new parameterizations must be performed to properly simulate in GROMACS. These parameters govern bonded (strength of bonds, angles and dihedrals) and non-bonded (size and charges) interactions for each of the atoms in the modification. The first part focuses on parameterizing and modeling 12 distinct modifications of the wobble uridine at the 34th position in bacterial transfer RNAs (tRNAs). These modifications are introduced by the mnm enzyme pathway and can shift the base-pairing preferences from A-ending to G-ending codons, specifically with the geranyl modification. Sulfur, selenium, and geranyl modifications are introduced at the second position of uridine and aminomethyl (nm), methylaminomethyl (mnm), and carboxy-methylaminomethyl (cmnm) modifications occur at the fifth position. All-atom molecular dynamics simulations (MDS) were carried out to characterize the hydrogen bonding patterns and base-pairing specificities of the modified uridine with A/C/G/U base pairs. The simulations revealed how modifications like thiolation, selenation, and introduction of a geranyl group impact hydrogen bonding and could modulate translation by altering codon recognition. The second part describes parameterization of antisense oligonucleotides (ASOs) targeting the insulin receptor (INSR) gene and their influence on alternative splicing relevant to myotonic dystrophy. A minigene reporter system containing INSR exon 11 was constructed along with wild-type and mutant sequences. Simulations assessed how ASO binding to this region could rescue aberrant splicing patterns caused by sequestration of muscleblind-like (MBNL) proteins in the disease state. Overall, this work provides molecular insights into RNA modifications and demonstrates the utility of simulations for developing RNA-targeting therapeutics
A Multi-Century Reconstruction Of Sea Surface Temperature, Salinity, And Density From A Northern Red Sea Coral.
Get PDFThe Red Sea Outflow Water (RSOW), an intermediate water mass formed in the northern Red Sea, is a primary Red Sea water circulation process. Understanding these water circulation processes gives us an insight into this region\u27s climate dynamics. The intermediate water formation is one of the main processes of the water circulation in the northern Red Sea and feeds the Indian Ocean with saltier and colder water. Despite understanding the RSWO\u27s association with the North Atlantic Oscillation (NAO), its historical response to this climate mode remains unclear. There has not been a long-term record to analyze the relationship between the RSOW and other climate modes, such as the NAO and the Atlantic Multidecadal Oscillation (AMO), over the last 300 years. This study presents 235-year monthly reconstructions of sea surface temperature (SST), salinity (SSS), and density from a Porites spp. coral in the northern Red Sea to explore the impact of NAO and AMO on RSOW formation. Spectral analysis reveals significant variance in winter interannual Sr/Ca at 6.7 and 5.6 years, while δ18Ocoral and δ18Osw exhibit significant variance at periods of ~100 years, identified as the AMO. Since 1870, the negative AMO phases have increased 18Ocoral (density) and 18Osw (salinity) with a frequency of 69.5-46 years and a 10-year lag, and vice versa for positive AMO phases. Sr/Ca did not show a correlation with the AMO and spectral analysis only correlated significantly with high frequencies 6.7, 5.6, and 3.8. This suggests that multidecadal modes did not influence this coral record’s Sr/Ca but high-frequency modes instead. The AMO influence on density and salinity in this region suggests that this climate mode influences the pre-conditions of intermediate water formation. These findings suggest that the AMO significantly influences northern Red Sea SSS and density variability, providing valuable insights into the influences of the AMO on multidecadal timescales; this potentially can be influencing part of the water circulation in this region such as the RSOW
Determining The Roles Of Whib-Like Transcription Factors In Mycobacterium Abscessus
Get PDFMycobacterium abscessus is a non-tuberculous mycobacteria that causes lung infections or skin and soft tissue infections. M. abscessus is innately resistant to antibiotics, requiring a long multi-antibiotic treatment regimen, with a low 45% cure rate for lung infections. The WhiB-like transcription factors are limited to the actinomycete class, which includes Mycobacteria. These proteins regulate multiple cellular processes, including growth and division, responses to oxidative, nitrosative or pH stress, and antibiotic resistance. Our work describes three WhiB-like transcription factors: WhiB7, which regulates antibiotic resistance, WhiB2, with a role in cell division, and Mab1756, an unstudied regulator similar to WhiB2. We used ChIP-seq experiments to locate genomic binding sites of each transcription factor, as well as phenotypic studies to identify the roles of each in the bacterium.WhiB7 binds 56 locations on the M. abscessus genome, directly upregulating acetyltransferases, ribosome-associated proteins, transcriptional regulators, membrane proteins, and biosynthesis and metabolic proteins. WhiB7 binds to an A/T-rich DNA motif found about 23 or 33 bases upstream of the transcription start site. A few of the upregulated proteins showed novel antibiotic resistance effects, in the absence of WhiB7. Mab1756 binds 130 intergenic regions on the M. abscessus genome, WhiB2 binds 158 intergenic regions, and 98 of these regions are bound by both transcription factors. These binding sites likely regulate proteins involved in DNA replication and maintenance, the ribosome and translation, lipid and glycan metabolism, transcription factors and enzymes. Mab1756 binds to a CTTGAC motif, while WhiB2 binds the WhiA motif, GACAC. Cells overexpressing Mab1756 can have a longer length phenotype. The WhiB2 protein has highest expression in cells at mid-log phase, and under nutrient starvation, as was previously documented. This work indicates new roles for WhiB-like transcription factors in M. abscessus. Further studies on WhiB7 may elucidate functions of the biosynthetic or ribosome-associated proteins it upregulates. Further study of Mab1756 and WhiB2 may validate a role in cell division through cell wall remodeling, as well as further roles in DNA replication or translation
Multi-Task Learning For Hybrid Communication Waveforms: Exploring Model Enhancement Techniques And Establishing Task Relationships
Get PDFWireless communications have become ubiquitous, enabling seamless connectivity and driv- ing innovations across various domains. As we look to the future, visible light communication (VLC) is a promising technology that offers the potential to revolutionize how we transmit and receive data. It seamlessly integrates multiple functionalities, including localization, control/sensing, and high-speed data transmission.This thesis proposes a multi-task learning deep convolutional neural network approach to optimize a hybrid waveform for VLC-enabled networks. By integrating Beacon Posi- tion Modulation (BPM), Beacon Phase Shift Keying (BPSK), and OFDM symbols within a virtual Pulse Width Modulation (PWM) envelope, this waveform supports localization, control/sensing, and high-speed data transmission. The proposed multi-task learning (MTL) model employs a cross-stitch unit to learn shared representations between BPM and BPSK classification tasks. Extensive experiments demonstrate the model’s superior performance over single-task models, achieving high accuracy, fast convergence, and significant reductions in model complexity. Furthermore, this thesis quantifies task relationships within the multi- task learning framework by analyzing cross-stitch weights. The results reveal a high positive correlation between BPM and BPSK tasks, with values of 0.71 and 0.65, indicating a strong effective learning of shared representations for related tasks. These findings contribute to VLC-enabled networks by providing a unified learning framework that optimizes multiple functionalities while offering high computational efficiency