Physical Sciences and Mathematics Commons^™

Changes In Large-Scale Extreme Precipitation In Over Taiwan And The Northeast United States : Past And Future, Lexi Henny

Legacy Theses & Dissertations (2009 - 2024)

Large-scale extreme precipitation over (1) the mid-Atlantic and Northeast United States and (2) Taiwan is attributed to weather types such as atmospheric river (AR), TC, and extreme integrated vapor transport (IVT). Statistically significant increases in season-total EP day precipitation are seen at many GHCN stations in winter, summer, and fall in the mid-Atlantic and Northeast region, and at certain high-elevation grid points in Taiwan Mei-yu season. During the cold season of winter and spring, the U.S.-based changes come from AR-associated EP days and are associated with strengthened southwesterly winds and IVT either within EP days, in the season mean, or …

Multiple Imputation In High-Dimensional Data With Variable Selection, Qiushuang Li

Legacy Theses & Dissertations (2009 - 2024)

This dissertation focuses on the development of multiple imputation models and algorithms for high-dimensional data with variable selection structures. Leveraging on the multivariate linear mixed-effects model with missing responses for clustered data, we incorporate the variable selection routines using spike-and-slab priors within the Bayesian variable selection framework. Specific choice of these priors allow us to "force'' variables of importance (e.g. design variables or variables known to play role in missingness mechanism) into the imputation models. Our ultimate goal is to improve computational speed by removing unnecessary variables. Markov chain Monte Carlo techniques have been designed to sample from the implied …

Amyloid Fibril Formation And Polymorphism : A Critical Role Of Sulfur-Containing Amino Acid Residues, Tatiana Quiñones-Ruiz

Legacy Theses & Dissertations (2009 - 2024)

Protein aggregation that results in the formation of amyloid fibrils has been linked to many neurodegenerative disorders, including Alzheimer’s disease and Parkinson’s disease. The sulfur atoms in methionine (Met) and cysteine (Cys) residues of proteins can be readily oxidized, significantly affecting their properties. Oxidation of sulfur-containing amino acids has recently been shown to affect protein fibrillation. This work presents novel findings on Cys and Met redox reactions that are related to the formation of amyloid fibrils and on the polymorphism of a model fibrillogenic protein, hen egg white lysozyme (HEWL). Biophysical techniques including Raman spectroscopy, atomic force microscopy, electron paramagnetic …

Presto : Fast And Effective Group Closeness Maximization, Baibhav L. Rajbhandari

Legacy Theses & Dissertations (2009 - 2024)

Given a graph and an integer k, the goal of group closeness maximization is to find, among all possible sets of k vertices (called seed sets), a set that has the highest group closeness centrality. Existing techniques for this NP-hard problem strive to quickly find a seed set with a high, but not necessarily the highest centrality.

Calculational Methods In Conformal Field Theory, Thomas Andrew Vandermeulen

Legacy Theses & Dissertations (2009 - 2024)

We examine conformal field theories and their gaugings (orbifolds), first on the torus and then on surfaces of higher genus. Specific attention is paid to performing explicit calculations, to which end we introduce a number of specialized formalisms. Namely, the technology of flavored partition functions allows for a general treatment of orbifolds in theories with conserved currents, and Arakelov geometry facilitates the derivation of novel expressions for geometric quantities appearing commonly on higher genus worldsheets. Ultimately, we leverage the resulting expressions in the calculation of correlation functions via degeneration of Riemann surfaces.

Computational Methods For Propagation Of Optical Fields With The Angle-Impact Wigner Function, Jeremy Wittkopp

Legacy Theses & Dissertations (2009 - 2024)

In designing an optical setup for an experiment, one usually turns to simulations first in order to model the propagation of light through the proposed system. This way, the experimenter can determine if the system is operating as intended. In order for these simulations to be useful, they need to properly describe the propagation of light. In order to simplify calculations, most contemporary software makes assumptions on the nature of the light being propagated. Specifically, simulations typically consider optical fields that are beam-like (i.e., most of the rays comprising the field deviate only slightly in angle from the beam's primary …

Stability And Differential Privacy Of Stochastic Gradient Methods, Zhenhuan Yang

Legacy Theses & Dissertations (2009 - 2024)

Recently there are a considerable amount of work devoted to the study of the algorithmic stability as well as differential privacy (DP) for stochastic gradient methods (SGM). However, most of the existing work focus on the empirical risk minimization (ERM) and the population risk minimization problems. In this paper, we study two types of optimization problems that enjoy wide applications in modern machine learning, namely the minimax problem and the pairwise learning problem.

Probing The Stability And Solution Processability Of Metal Chalcogenide Semiconducting Materials, Mengwen Yan

Legacy Theses & Dissertations (2009 - 2024)

Metal chalcogenide (MCh) semiconductors have long research history due to their earth abundance, easy synthesizability, and accessible band gap tunability. People have realized their functionality as p-type semiconductors that provide good hole mobility and conductivity within the materials. However, MChs have easier reaction pathway with gas molecules (H2O and O2) compared to other semiconductors such as metal oxides. Also, poor solution processability of all MChs make low-cost thin film fabrication methods hard to achieve. In this thesis, we target to understand both the chemical stability and solution processability of MCh materials. ZnSe based inorganic organic layered hybrids (LHs) were exfoliated …

Raman Spectroscopy Of Aged Waterlogged Bones: Protocol Optimization, Bailey Hoplight

Chemistry

Current methods used for determining the age buried bones for forensic purposes are heavily affected by environmental conditions, can be susceptible to scientific bias and the interpretation can vary from investigator to investigator. Raman Spectroscopy can potentially be used as an automatic method to analyze the composition of bone eliminating the human factor. To test this hypothesis, we will use Raman spectroscopy to potentially identify the burial time of bones. The change in the chemical composition of the pig bones was probed using a Raman spectrometer with a 785nm excitation wavelength. Other parameters of the Raman instrument were optimized to …

The Analysis Of Relationships Between Lightning Strikes And Particulate Matter 2.5 Utilizing Statistical And Numerical Modeling Methods Applied To The 2020 Wildfire Season, Megan Schiede

Atmospheric & Environmental Sciences

Throughout 2020, ambient air pollution was reduced as a result from limiting anthropogenic activities to mitigate the spread of COVID-19. Not all air pollution is created the same as measurements of particulate matter 2.5 (PM2.5) were generally unaffected by this reduction due to PM2.5s source from wildfires. Despite influences from COVID-19 lockdowns, rises in PM2.5 concentrations can be attributed to the anomalously active wildfire season of 2020. As climate change progresses, these extraordinarily active seasons can be classified as the “new normal”; thus, comprehension of such events are vital. Given the ability of lightning to naturally cause wildfires, there exists …

Observations And Analysis Of The 7 October 2020 Derecho, Maxim Couillard

Atmospheric & Environmental Sciences

A serial derecho impacted Upstate New York and western Massachusetts on the afternoon of 7 October 2020, resulting in 120 damaging wind reports alonga 515-km swath. The magnitude and extent of this event was unexpected and not well forecast, motivating a closer examination. This study seeks to better understand the conditions prior to and during the derecho to diagnose what led to such a damaging wind event. The synoptic forcing for this event was an upper- level jet with a broad, negatively tilted trough over the northeast U.S. and southeast Canada. The upper-level pattern provided forcing for a 990-hPa surface …

Space Weather And Criminal Violence : A Longitudinal Analysis Of Major Us Urban Areas, Richard Mcmillan

Legacy Theses & Dissertations (2009 - 2024)

The study of criminology began with the investigation of the physical features of humans committing crimes such as homicide. The study of space weather includes the investigation of the physiological manifestations of various forms of space weather on terrestrial-bound humans. These two fields of inquiry are joined in this investigation of the association of space weather with the incidence of criminal violence in the United States. This study of the possibility that a physical force emanating from the Sun or from outer space can affect human behavior in the form of criminal violence is part of a long search for …

Hierarchical Modelling Of Raman Spectroscopic Data Demonstrates The Potential For Manufacturer And Caliber Differentiation Of Smokeless Powders, Nathan Russell Bartlett

Legacy Theses & Dissertations (2009 - 2024)

With the rise of gun-based crime and the advent of lead-free ammunition reducing the effectiveness of previously used methods, the analysis of smokeless powders to better understand organic gunshot residues is now more important than ever. One method that has shown potential is Raman spectroscopy, a relatively quick, nondestructive, and non-contact analysis method. To investigate whether Raman spectroscopy could be used to characterize individual powders, samples of smokeless powders from three manufacturers, Remington, Federal, and Winchester, each with two 9mm caliber and two .38 caliber ammo types, were dissolved, and their Raman spectra were collected. A hierarchical modelling system was …

Permaculture As An Ecopedagogy Curriculum And Alternative Theory Of Development : An Exploration Of The Ecological Consciousness Of Rural Western Kenyan Farmers Using Photo-Voice With A Farmer Field School During Covid-19, David Yisrael Epstein

Legacy Theses & Dissertations (2009 - 2024)

This dissertation explores two main questions of farmers in Western Kenya – how they see farming as a creative process and their role in that – and how change is made possible in their community. I explore stories from farmers themselves, using photographs they have taken and stories they tell about those photographs, which answer these two questions. In doing so, I attempt to understand the degree to which collective action has taken root in a community exposed to a permaculture based curriculum within a farmer field school. It also importantly seeks to understand what happens when such a curriculum …

Exposing Gan-Generated Faces Using Deep Neural Network, Hui Guo

Legacy Theses & Dissertations (2009 - 2024)

Generative adversarial network (GAN) generated high-realistic human faces are visually challenging to discern from real ones. They have been used as profile images for fake social media accounts, which leads to high negative social impacts.In this work, we explore a universal physiological cue of the eye, namely the pupil shape consistency, to identify GAN-generated faces reliably. We show that GAN-generated faces can be exposed via irregular pupil shapes. This phenomenon is caused by the lack of physiological constraints in the GAN models. We demonstrate that such artifacts exist widely in high-quality GAN-generated faces. We design an automatic method to segment …

Long-Term Trends And Variability Of Pm₂.₅ Mass, Chemical Components, And Sources Over Nys, Hesham Abdelmonem Hassan

Legacy Theses & Dissertations (2009 - 2024)

Eighteen years of ambient PM2.5 mass and major components are used in this study to harmonize the carbonaceous fraction of PM2.5 data, and to examine long-term trends and seasonal variability changes. The major decreasing trend of PM2.5 mass and major inorganic ions reflects the ambient concentration response to clean air regulations and policies.Although elemental carbon shows a decreasing trend in agreement with most other PM2.5 components, organic carbon shows a different behavior of no-trend to slightly increasing trend in some sites. Organic carbon behavior indicates the growing role of non-combustion sources at the expense of decreasing combustion sources. Seasonal trends …

Stubbornly Merging Discrete Vector Fields, Douglas W. Lenseth

Legacy Theses & Dissertations (2009 - 2024)

We address the basic question in discrete Morse theory of combining discrete gradientfields that are partially defined on subsets of the given complex. This is a well-posed question when the discrete gradient field V is generated using a fixed algorithm which has a local nature. One example is ProcessLowerStars, a widely used algorithm for computing persistent homology associated to a grayscale image in 2D or 3D. While the algorithm for V may be inherently local, being computed within stars of vertices and so embarrassingly parallelizable, in practical use it is natural to want to distribute the computation over patches Pi, …

An Entropic Approach To Dynamics, Pedro Henrique Moreira Pessoa

Legacy Theses & Dissertations (2009 - 2024)

The present thesis deals with different aspects of probability, the method of maximum entropy, information geometry, and dynamical systems and their applications to statistical physics and complex systems. Those topics come together in the framework for dynamics termed entropic dynamics. Work on the topic was initiated by my PhD advisor Professor Ariel Caticha and many colleagues at University at Albany as a method for explaining the dynamical processes in quantum mechanics from first principles of probability theory.

Signal Yields And Detector Modeling In Xenon Time Projection Chambers, And Results Of An Effective Field Theory Dark Matter Search Using Lux Data, Gregory Ransford Carl Rischbieter

Legacy Theses & Dissertations (2009 - 2024)

The nature of dark matter continues to be one of the biggest remaining mysteries in physics. Astrophysical measurements indicate that dark matter makes up more than a quarter of the Universe's total energy density, and it is well-motivated that dark matter is comprised of Weakly Interacting Massive Particles (WIMPs). Direct detection techniques utilizing liquid and gaseous noble elements have become the primary method of probing the potential non-gravitational interactions between WIMPs and Standard Model matter, with the leading technology being the dual-phase Time Projection Chamber (TPC). The Large Underground Xenon (LUX) and its second-generation successor, LUX-ZEPLIN (LZ), are two xenon …

The Mountain Gap Wind Of The Isthmus Of Tehuantepec And Its Impact On Tropical Cyclogenesis In The Eastern Pacific, Adolfo Lugo Rios

Atmospheric and Environmental Sciences Theses and Dissertations

In this dissertation we research two aspects of the mountain gap wind northerlies of the Isthmus of Tehuantepec in Southern Mexico. The causes of extreme gap wind northerlies, emphasizing the causes by tropical weather systems, like easterly waves troughs or hurricanes, and the impacts of an extreme gap wind events on tropical cyclogenesis.

Through the use of an index to diagnose the mountain gap wind strength, its evolution through the year and the mechanisms leading to extreme mountain gap winds was highlighted. The index revealed that the gap wind is strongly related to high surface pressure anomalies over the GoM …

Fluorescent Labelling Of Ribosomal Rna In Live Mammalian Cells, Amir Agharezaee

Legacy Theses & Dissertations (2009 - 2024)

This thesis describes a bio-orthogonal chemistry-based approach for new methods of fluorescence labelling of RNA in live HeLa cells via an IEDDA reaction of TCO with tetrazine. The key step of the approach is synthesis of two nucleobase analogues which were modified with TCO and a masked 5′-phosphate group using aryl phosphonamidite chemistry. Synthesis of tubercidin and uridine analogues were considered in this investigation for incorporation into RNA in live HeLa cells. Synthetic approach was successful at installing the handle containing TCO to tubercidin and uridine to make compounds 12 and 21 respectively (the synthesis of both of which are …

Dynamic Impacts Of Hadley Circulation On Saharan Desert Warming Amplification, Alejandro Manuel Ayala

Legacy Theses & Dissertations (2009 - 2024)

Changes in temperature due to climate change are not spatially uniform, and deserts and other drylands, which are greatly underrepresented in climate studies, are warming at a much faster rate than much of the globe with increasing concentrations of greenhouse gases. This strong warming amplification over deserts, termed Desert Amplification (DA), is most pronounced over the world’s largest and driest Sahara Desert and the Arabian Peninsula. The Sahara and Arabian deserts are formed in the subtropical subsiding branch of the Hadley Circulation (HC) and so the changes in large-scale subsidence associated with adiabatic heating could impact the DA dynamically. While …

X Ray Phase And Coherent Scatter Imaging Measurements, Pikting Cheung

Legacy Theses & Dissertations (2009 - 2024)

Traditional x-ray images are good for distinguishing between materials with very different absorption coefficients. However, detecting breast cancer using conventional x-ray imaging is hard because cancer tissue has similar absorption coefficients as normal tissue. Annually 43,600 women will die from breast cancer. The odds of survival are better if the cancer is diagnosed at an early stage, but mammography tends to have high rates of missed cancers. Mammography also tends to have a high false-positive rate, which leads to unnecessary biopsies. Two techniques with potential to add additional information to breast imaging have been investigated. X-ray phase imaging has been …

Spatiotemporal Variability Of Snow Depth On Arctic Sea Ice In Cmip6 Models And Satellite Data, Shengzhe Chen

Legacy Theses & Dissertations (2009 - 2024)

The Arctic has experienced rapid environmental changes in recent decades. Motivated by the important role of snow over sea ice in influencing Arctic climate variability and change, this dissertation aims to improve our knowledge of spatiotemporal variability of snow depth and processes over Arctic sea ice in the observations and model simulations.First, we evaluate snow depth over Arctic sea ice during 1993–2014 simulated by the models from the Coupled Model Intercomparison Project phase 6 (CMIP6) against recent satellite retrievals. The CMIP6 models capture some aspects of the observed snow depth climatology and variability. The observed variability lies in the middle …

The Surface Heating Efficiency Of Atmospheric Energy Flux Events During Arctic Winter, Christopher Joseph Cardinale

Legacy Theses & Dissertations (2009 - 2024)

The flux of moist static energy (MSE) into the polar regions plays a key role in the energy budget and climate of the polar regions. While usually studied from a vertically integrated perspective (Fwall), this dissertation examines its vertical structure, using the NASA-MERRA-2 reanalysis to compute climatological and anomalous fluxes of sensible, latent, and potential energy across 70◦N and 65◦S. This dissertation applies an energy budget analysis to winter-season synoptic periods of increased tropospheric (Ftrop) and stratospheric (Fstrat) energy flux convergence events and examines the processes that drive Arctic anoma lous surface warming and sea ice loss during Ftrop events. …

Discrimination Between Human And Non-Human Blood Using Raman Spectroscopy And A Self-Reference Algorithm For Forensic Purposes : Method Expansion And Validation, Harrison Dickler

Legacy Theses & Dissertations (2009 - 2024)

Determining whether the origin of a bloodstain is human or non-human is an important capability of a forensic investigation. In their pioneering work, Bian et al. (Journal of biomedical optics, 2017) introduced a self-reference peak algorithm for the analysis of bloodstain Raman spectra and demonstrated a great potential of this approach for differentiating human and nonhuman blood. However, this work only used three non-human species in the creation of their model. This study investigates the capability of a self-referencing peak algorithm to discriminate between human and 18 non-human species based on the Raman spectra of blood samples. The intensity ratios …

Methodology Studies For Dearomatized Dimer And Beta-Lactone-Mediated Native Chemical Ligation In Organic Synthesis, Xinhao Fan

Legacy Theses & Dissertations (2009 - 2024)

Chapter 1: Dimers of naphthalenol derivatives were synthesized by photocatalysis, cobalt(II) acetylacetonate. Several functional groups were tolerant of its skeleton. This novel dimer was connected through a reversible sigma bond. Its reversibility was confirmed by chiral HPLC and 1H-NMR experiments. Through EPR and Stern-Volmer quenching experiments, we proposed the reaction mechanism. The reversibility property can be potentially beneficial in polymers, self-healing, and memory materials.Chapter 2: We report an epimerization-free native chemical ligation reaction by β-lactone-mediated peptides. This approach can achieve Thr-Xaa efficiently and rapidly. Besides, it has a broad side-chain tolerance. Through the competition reaction experiment, it was demonstrated that …

Municipal Solutions To Climate Change ; A Case Study Of Stream Daylighting In Suffolk County, New York, Madison Hrysko

Legacy Theses & Dissertations (2009 - 2024)

During the 1950’s and 1960’s Suffolk County, New York experienced rapid urbanization and development. To pave way for infrastructure, hydrological modifications were made to the land including the burial of naturally flowing streams. Daylighting streams is the nature-based process of bringing buried streams back to the surface. In turn, restoring ecosystem services, increasing local resilience to climate change impacts, and expanding biodiversity. Minimal research has been done using GIS technology alongside a set of criteria to select best fit streams for daylighting. This thesis aims to fill that gap by identifying best and second-best fit streams for daylighting in Suffolk …

Synthesis Of Oligonucleotides Containing Unnatural Backbone And Regulation Of Crispr Activity Using Inverse Electron Demand Diels-Alder Chemistry, Alyssa Hoy

Legacy Theses & Dissertations (2009 - 2024)

This thesis describes the synthesis of an oligonucleotide containing an unnatural neutralbackbone. The backbone was constructed using bio-orthogonal inverse electron demand Diels- Alder chemistry between trans-cyclooctene (TCO) and tetrazine (Tz). A TCO phosphoramidite was synthesized and attached to solid support for strand propagation. Uridine monomers containing either bis-TCO or bis-Tz were also synthesized. The oligonucleotide strand was formed by sequential ligation of the bis-Tz and bis-TCO monomers. The oligonucleotide was analyzed using mass spectrometry. This thesis also describes the synthesis of sgRNAs containing non-canonical nucleobases, m1A, m6A, s2U and s4U using the ‘split-and-click’ methodology. The synthetic sgRNAs were assembled using …

Understanding Changes In Precipitation, Wildfires, And Possible Governing Factors Over Central Equatorial Africa, Yan Jiang

Legacy Theses & Dissertations (2009 - 2024)

Tropical rainforests are global epicenters of biodiversity and modulators of climate. A long-term drying trend has occurred in the Congo Basin since the 1980s and this raises great concerns for sustaining the Congolese rainforest and local rain-fed agriculture. Motivated by documented rainfall changes and the need to improve understanding of main factors influencing precipitation variability and changes in Central Equatorial Africa (CEA), this dissertation conducts synthesized studies on 1) quantifying variations in precipitation seasonality by focusing on dry season duration, 2) estimating cascading wildfire risks associated with changes in precipitation patterns, and estimating impacts of 3) the tropical Indian Ocean …