Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

City University of New York (CUNY)

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1 - 30 of 2458

Full-Text Articles in Physical Sciences and Mathematics

Mechanistic And Synthetic Studies Of Oxidopyrylium Cycloaddition Reactions, Lauren P. Bejcek Jun 2021

Mechanistic And Synthetic Studies Of Oxidopyrylium Cycloaddition Reactions, Lauren P. Bejcek

Dissertations, Theses, and Capstone Projects

Cycloaddition chemistry has historically served as a robust route to stereo-rich and highly functionalized cyclic and heterocyclic compounds. Herein we describe our examination of 3-hydroxy-4-pyrone-derived oxidopyrylium cycloadditions in both mechanistic considerations as well as the unique synthetic advancements of their corresponding cycloadducts. Chapter 1 is a literature review where we specifically outline the use of oxidopyrylium cycloadditions in the synthesis of natural products. This includes the mention of previous syntheses prior to 2008, and a more thorough examination of the natural products synthesized from 2008 to present. The work exploits this chemistry as a facile route to highly complex 7-membered ...


Learn Biologically Meaningful Representation With Transfer Learning, Di He Jun 2021

Learn Biologically Meaningful Representation With Transfer Learning, Di He

Dissertations, Theses, and Capstone Projects

Machine learning has made significant contributions to bioinformatics and computational biol­ogy. In particular, supervised learning approaches have been widely used in solving problems such as bio­marker identification, drug response prediction, and so on. However, because of the limited availability of comprehensively labeled and clean data, constructing predictive models in super­ vised settings is not always desirable or possible, especially when using data­hunger, red­hot learning paradigms such as deep learning methods. Hence, there are urgent needs to develop new approaches that could leverage more readily available unlabeled data in driving successful machine learning ap­ plications in this ...


Synthetic And Biological Studies On Benzazepine Derivatives As Dopamine Receptor Ligands, Rajan Giri Jun 2021

Synthetic And Biological Studies On Benzazepine Derivatives As Dopamine Receptor Ligands, Rajan Giri

Dissertations, Theses, and Capstone Projects

Dopamine (DA) receptors, members of the G-protein coupled receptors (GPCRs) family, are divided in two groups based on their transmembrane structural homology domains: D1R-like (D1R, D5R sub-types) and D2R-like DA receptors (D2R, D3R and D4R sub-types). Disturbances in dopaminergic neurotransmission are associated with several CNS disorders. Hence, DA receptor selective ligands have been sought as pharmacological agents to normalize perturbations in the dopaminergic system. Despite several notable efforts, the discovery of highly selective ligands for dopamine receptor sub-types has proved challenging due to close transmembrane structural similarity, especially between DA receptor sub-types within the same group.

The 1-phenylbenzazepine scaffold is ...


Emergent Photophyiscs In Diketopyrrolopyrrole Superstructures, Andrew Levine Jun 2021

Emergent Photophyiscs In Diketopyrrolopyrrole Superstructures, Andrew Levine

Dissertations, Theses, and Capstone Projects

Organic semiconductors have received substantial attention as active components in optoelectronic devices because of their processability and customizable electronic properties. Tailoring the organic active layer in these devices to exhibit desirable optoelectronic properties requires understanding the complex and often subtle structure-property relationships governing their photophysical response to light. Both structural organization and frontier molecular orbitals (FMO) play pivotal roles in energy relaxation processes, and complex interplay between organization and orbital energies are difficult to anticipate based upon the molecular structure of the components alone, especially in systems comprised of multiple components. In pursuit of design rules, there is a need ...


Skyrmions And Biskyrmions In Magnetic Films, Daniel Capic Jun 2021

Skyrmions And Biskyrmions In Magnetic Films, Daniel Capic

Dissertations, Theses, and Capstone Projects

Skyrmions have garnered significant attention in condensed matter systems in recent years. In principle, they are topologically protected, so there is a large energy barrier preventing their annihilation. Furthermore, they can exist at the nanoscale, be manipulated with very small currents, and be created by a number of different methods. This makes them attractive for use in potential computing applications. This work studies ferromagnetic skyrmions. In particular, it highlights our small contributions to the field of skyrmions in condensed matter systems, specifically in thin-film ferromagnets.


An Empirical Study Of Refactorings And Technical Debt In Machine Learning Systems, Yiming Tang, Raffi T. Khatchadourian, Mehdi Bagherzadeh, Rhia Singh, Ajani Stewart, Anita Raja May 2021

An Empirical Study Of Refactorings And Technical Debt In Machine Learning Systems, Yiming Tang, Raffi T. Khatchadourian, Mehdi Bagherzadeh, Rhia Singh, Ajani Stewart, Anita Raja

Publications and Research

Machine Learning (ML), including Deep Learning (DL), systems, i.e., those with ML capabilities, are pervasive in today’s data-driven society. Such systems are complex; they are comprised of ML models and many subsystems that support learning processes. As with other complex systems, ML systems are prone to classic technical debt issues, especially when such systems are long-lived, but they also exhibit debt specific to these systems. Unfortunately, there is a gap of knowledge in how ML systems actually evolve and are maintained. In this paper, we fill this gap by studying refactorings, i.e., source-to-source semantics-preserving program transformations, performed ...


Application Of Randomness In Finance, Jose Sanchez, Daanial Ahmad, Satyanand Singh May 2021

Application Of Randomness In Finance, Jose Sanchez, Daanial Ahmad, Satyanand Singh

Publications and Research

Brownian Motion which is also considered to be a Wiener process and can be thought of as a random walk. In our project we had briefly discussed the fluctuations of financial indices and related it to Brownian Motion and the modeling of Stock prices.


Factoring: Difference Of Squares, Thomas Lauria Apr 2021

Factoring: Difference Of Squares, Thomas Lauria

Open Educational Resources

This lesson plan will explain how to factor basic difference of squares problems


Automated Evolution Of Feature Logging Statement Levels Using Git Histories And Degree Of Interest, Yiming Tang, Allan Spektor, Raffi Khatchadourian, Mehdi Bagherzadeh Apr 2021

Automated Evolution Of Feature Logging Statement Levels Using Git Histories And Degree Of Interest, Yiming Tang, Allan Spektor, Raffi Khatchadourian, Mehdi Bagherzadeh

Publications and Research

Logging—used for system events and security breaches to more informational yet essential aspects of software features—is pervasive. Given the high transactionality of today’s software, logging effectiveness can be reduced by information overload. Log levels help alleviate this problem by correlating a priority to logs that can be later filtered. As software evolves, however, levels of logs documenting surrounding feature implementations may also require modification as features once deemed important may have decreased in urgency and vice-versa. We present an automated approach that assists developers in evolving levels of such (feature) logs. The approach, based on mining Git ...


Math 215: Introduction To Statistics, Cuny School Of Professional Studies Apr 2021

Math 215: Introduction To Statistics, Cuny School Of Professional Studies

Open Educational Resources

Introduces the basic principles of statistics and probability, with an emphasis on understanding the underlying concepts, real-world applications, and the underlying story that the numbers tell. Uses Microsoft Excel’s statistical functions to analyze data. Provides an introduction to probability, descriptive statistics, hypothesis testing, and inferential statistics.


Math 102: Mathematics In Contemporary Society, Cuny School Of Professional Studies Apr 2021

Math 102: Mathematics In Contemporary Society, Cuny School Of Professional Studies

Open Educational Resources

Designed to provide students with an understanding of the mathematical ideas and methods found in the social sciences, the arts, and business, this course covers the fundamentals of statistics, scatter plots, graphics in the media, problem-solving strategies, dimensional analysis, and mathematical modeling. Students can expect to explore real world applications.


Eas 201: Nature Of New York, Cuny School Of Professional Studies Apr 2021

Eas 201: Nature Of New York, Cuny School Of Professional Studies

Open Educational Resources

Provides an introduction to ecological reasoning through study of New York City’s geologic origins and transformations over time: natural and man-made environments, cultural history, biological diversity, habitats, and invasive species. Lectures, discussion, virtual labs and field experiences show how various elements have combined over time to form the current urban metropolis. Students will formulate testable hypothesis, collect and analyze field data, create well-developed laboratory reports.


Ast 101: Introductory Astronomy, Cuny School Of Professional Studies Apr 2021

Ast 101: Introductory Astronomy, Cuny School Of Professional Studies

Open Educational Resources

An exploration of our solar system’s creation and the planets in our solar system using the latest scientific information, recent probe data, and new discoveries in the science of extra-solar planetary astronomy. This course is based in part upon materials developed by the American Museum of Natural History and is used with permission by the School of Professional Studies for this course.


Quan 201: Quantitative Reasoning And Society, Cuny School Of Professional Studies Apr 2021

Quan 201: Quantitative Reasoning And Society, Cuny School Of Professional Studies

Open Educational Resources

An interdisciplinary introduction to the ways in which data can be used to enhance thinking and decision-making capacities, including using simple statistical techniques, creating visual representations of quantitative data, deriving accurate conclusions from quantitative data, and using data effectively in analyses and arguments. Assignments build capacity to evaluate and write clearly about quantitative evidence using methods for analyzing and communicating about data that do not require complex mathematics.


Eas 250: Oceanography, Cuny School Of Professional Studies Apr 2021

Eas 250: Oceanography, Cuny School Of Professional Studies

Open Educational Resources

Oceanography is an interdisciplinary field studying the processes and interrelationships of geology, chemistry, geography, geophysics, meteorology, and biology. This course focuses on how scientific processes and scientific understanding are applied to questions such as: Which factors control life in the ocean? How do we know what we know about the ocean? What's at the bottom of the ocean? How does the water in the ocean move? How are human activities and climate change altering the ocean? Oceanographic data is used to understand the ocean and its interactions with the rest of the planet.

This course is based in part ...


Math 120 Precalculus Review, York College Math 120 Students, Virginia L. Thompson Apr 2021

Math 120 Precalculus Review, York College Math 120 Students, Virginia L. Thompson

Open Educational Resources

No abstract provided.


Superfluid Swimmers, German Kolmakov, Igor S. Aranson Feb 2021

Superfluid Swimmers, German Kolmakov, Igor S. Aranson

Publications and Research

The propulsion of living microorganisms ultimately relies on viscous drag for body-fluid interactions. The self-locomotion in superfluids such as 4He is deemed impossible due to the apparent lack of viscous resistance. Here, we investigate the self-propulsion of a Janus (two-face) light-absorbing particle suspended in superfluid helium 4He (He-II). The particle is energized by the heat flux due to the absorption of light from an external source. We show that a quantum mechanical propulsion force originates due to the transformation of the superfluid to a normal fluid on the heated particle face. The theoretical analysis is supported by the ...


Diurnal Cycle Of Passive Microwave Brightness Temperatures Over Land At A Global Scale, Zahra Sharifnezhad, Hamid Norouzi, Satya Prakash, Reginald Blake, Reze Khanbilvard Feb 2021

Diurnal Cycle Of Passive Microwave Brightness Temperatures Over Land At A Global Scale, Zahra Sharifnezhad, Hamid Norouzi, Satya Prakash, Reginald Blake, Reze Khanbilvard

Publications and Research

Satellite-borne passive microwave radiometers provide brightness temperature (TB) measurements in a large spectral range which includes a number of frequency channels and generally two polarizations: horizontal and vertical. These TBs are widely used to retrieve several atmospheric and surface variables and parameters such as precipitation, soil moisture, water vapor, air temperature profile, and land surface emissivity. Since TBs are measured at different microwave frequencies with various instruments and at various incidence angles, spatial resolutions, and radiometric characteristics, a mere direct integration of them from different microwave sensors would not necessarily provide consistency. However, when appropriately harmonized, they can provide a ...


Molecular Speciation Of Size Fractionated Particulate Water-Soluble Organic Carbon By Two-Dimensional Nuclear Magnetic Resonance (Nmr) Spectroscopy, Marie-Cecile Chalbot, Salma Siddiqui, Ilias G. Kavouras Feb 2021

Molecular Speciation Of Size Fractionated Particulate Water-Soluble Organic Carbon By Two-Dimensional Nuclear Magnetic Resonance (Nmr) Spectroscopy, Marie-Cecile Chalbot, Salma Siddiqui, Ilias G. Kavouras

Publications and Research

Particulate matter is associated with increased morbidity and mortality; its effects depend on particle size and chemical content. It is important to understand the composition and resultant toxicological profile of particulate organic compounds, the largest and most complex fraction of particulate matter. The objective of the study was to delineate the nuclear magnetic resonance (NMR) spectral fingerprint of the biologically relevant water-soluble organic carbon (WSOC) fraction of size fractionated urban aerosol. A combination of one and two-dimensional NMR spectroscopy methods was used. The size distribution of particle mass, water-soluble extract, non-exchangeable organic hydrogen functional types and specific biomarkers such as ...


Modeling And Analysis Of Affiliation Networks With Subsumption, Alexey Nikolaev Feb 2021

Modeling And Analysis Of Affiliation Networks With Subsumption, Alexey Nikolaev

Dissertations, Theses, and Capstone Projects

An affiliation (or two-mode) network is an abstraction commonly used for representing systems with group interactions. It consists of a set of nodes and a set of their groupings called affiliations. We introduce the notion of affiliation network with subsumption, in which no affiliation can be a subset of another. A network with this property can be modeled by an abstract simplicial complex whose facets are the affiliations of the network.

We introduce a new model for generating affiliation networks with and without subsumption (represented as simplicial complexes and hypergraphs, respectively). In this model, at each iteration, a constant number ...


Speech Enhancement Using Speech Synthesis Techniques, Soumi Maiti Feb 2021

Speech Enhancement Using Speech Synthesis Techniques, Soumi Maiti

Dissertations, Theses, and Capstone Projects

Traditional speech enhancement systems reduce noise by modifying the noisy signal to make it more like a clean signal, which suffers from two problems: under-suppression of noise and over-suppression of speech. These problems create distortions in enhanced speech and hurt the quality of the enhanced signal. We propose to utilize speech synthesis techniques for a higher quality speech enhancement system. Synthesizing clean speech based on the noisy signal could produce outputs that are both noise-free and high quality. We first show that we can replace the noisy speech with its clean resynthesis from a previously recorded clean speech dictionary from ...


Role Of Protonation State Changes And Hydrogen Bonding Around The Oxygen Evolving Complex Of Photosystem Ii, Divya Matta Feb 2021

Role Of Protonation State Changes And Hydrogen Bonding Around The Oxygen Evolving Complex Of Photosystem Ii, Divya Matta

Dissertations, Theses, and Capstone Projects

The mechanism of natural photosynthesis involves the use of solar energy to produce O2 we breathe and food and fuel we intake. This process results in the biological oxidation of water that takes place at room temperature, neutral pH using earth abundant elements Ca and Mn. Understanding how this challenging chemical reaction occurs in photosynthesis can be useful for designing better artificial photosynthetic complexes that can be used as biofuels. My doctoral work is to study the deprotonation and oxidation events elucidating the mechanistic details of proton coupled electron transfer reaction in a photosynthetic protein.

The O2 evolution ...


A New Feature Selection Method Based On Class Association Rule, Sami A. Al-Dhaheri Feb 2021

A New Feature Selection Method Based On Class Association Rule, Sami A. Al-Dhaheri

Dissertations, Theses, and Capstone Projects

Feature selection is a key process for supervised learning algorithms. It involves discarding irrelevant attributes from the training dataset from which the models are derived. One of the vital feature selection approaches is Filtering, which often uses mathematical models to compute the relevance for each feature in the training dataset and then sorts the features into descending order based on their computed scores. However, most Filtering methods face several challenges including, but not limited to, merely considering feature-class correlation when defining a feature’s relevance; additionally, not recommending which subset of features to retain. Leaving this decision to the end-user ...


Third Harmonic Generation: A Method For Visualizing Myelin In The Murine Cerebral Cortex, Michael Redlich Feb 2021

Third Harmonic Generation: A Method For Visualizing Myelin In The Murine Cerebral Cortex, Michael Redlich

Dissertations, Theses, and Capstone Projects

Here we present the use of Third Harmonic Generation (THG) for the label-free imaging of myelinated axons in the murine cerebral cortex. Myelin plays an important role in the processes of learning and disease. However, much of the myelin biology research thus far has focused on white matter tracts where myelin is more visible. Much is still unknown, particularly with regard to myelin in gray matter. First, we engage in THG microscopy using an optical parametric oscillator pumped by a titanium-sapphire laser to demonstrate the utility of the technique for imaging myelin in vivo. Second, we investigate the use of ...


Interactions Of Organic Fluorophores With Plasmonic Surface Lattice Resonances, Robert J. Collison Feb 2021

Interactions Of Organic Fluorophores With Plasmonic Surface Lattice Resonances, Robert J. Collison

Dissertations, Theses, and Capstone Projects

It is common knowledge that metals, alloys and pure elements alike, are lustrous and reflective, the more so when a metal surface is flat, polished, and free from oxidation and surface fouling. However, some metals reflect visible light, in the 380 nm to 740 nm range of wavelengths, much more strongly than others. In particular, some metals reflect wavelengths in certain portions of the ultraviolet (UV), visible, and near-infrared (NIR) regime, let us say 200 nm to 2000 nm, while absorbing light strongly in other segments of this range. There are several factors that account for this difference between various ...


Some Model Theory Of Free Groups, Christopher James Natoli Feb 2021

Some Model Theory Of Free Groups, Christopher James Natoli

Dissertations, Theses, and Capstone Projects

There are two main sets of results, both pertaining to the model theory of free groups. In the first set of results, we prove that non-abelian free groups of finite rank at least 3 or of countable rank are not A-homogeneous. We then build on the proof of this result to show that two classes of groups, namely finitely generated free groups and finitely generated elementary free groups, fail to form A-Fraisse classes and that the class of non-abelian limit groups fails to form a strong A-Fraisse class.

The second main result is that if a countable group is elementarily ...


3d Object Detection, Instance Segmentation And Classification From 3d Range And 2d Color Images, Xiaoke Shen Feb 2021

3d Object Detection, Instance Segmentation And Classification From 3d Range And 2d Color Images, Xiaoke Shen

Dissertations, Theses, and Capstone Projects

We address the problem of 3D object detection and instance segmentation by proposing a novel object segmentation and detection system. First, we detect 2D objects based on RGB, Depth only, or RGB-D images. A 3D convolutional-based system, named Frustum VoxNet, is proposed. This system 1) generates frustums from 2D detection results, 2) proposes 3D candidate voxelized images for each frustum, and uses a 3D convolutional neural network (CNN) based on these candidates voxelized images to perform the 3D instance segmentation and object detection. Although the volumetric data representation is widely used for 3D object classification, there are fewer works on ...


The C. Neoformans Cell Wall: A Scaffold For Virulence, Christine Chrissian Feb 2021

The C. Neoformans Cell Wall: A Scaffold For Virulence, Christine Chrissian

Dissertations, Theses, and Capstone Projects

Cryptococcus neoformans is a globally distributed opportunistic fungal pathogen and the causative agent of life threatening cryptococcal meningoencephalitis in immunocompromised individuals, resulting in ~180,000 deaths each year worldwide. A primary virulence-associated trait of this organism is the production of melanin. Melanins are a class of diverse pigments produced via the oxidation and polymerization of aromatic ring compounds that have a characteristically complex, heterogenous, and amorphous structure. They are synthesized by representatives of all biological kingdoms and share a multitude of remarkable properties such as the ability to absorb ultraviolet (UV) light and protect against ionizing radiation. Melanin production in ...


A Geospatial Habitat Suitability Model To Determine The Spatial And Temporal Variability Of Ulva Blooms In Jamaica Bay, New York, Kristine T. Erskine John Feb 2021

A Geospatial Habitat Suitability Model To Determine The Spatial And Temporal Variability Of Ulva Blooms In Jamaica Bay, New York, Kristine T. Erskine John

Dissertations, Theses, and Capstone Projects

The main objective of this study involves the development of a habitat suitability model for the Ulva genus in Jamaica Bay, New York. This incorporates several steps that were initiated by the selection of the most suitable water quality parameters that facilitate the successful growth of Ulva. These water quality parameters include dissolved oxygen, pH, temperature, salinity, nitrate + nitrite, ammonium, phosphates, dissolved organic nitrogen, dissolved organic carbon, depth and Secchi depth. This water quality data was generated by the Department of Environmental Protection. The Secchi depth and Jamaica Bay bathymetry data were necessary for the calculation of the % light to ...


Introduction To Computers And Programming Using Python: A Project-Based Approach, Esma Yildirim, Daniel Garbin, Mathieu Sassolas, Kwang Hyun Kim Jan 2021

Introduction To Computers And Programming Using Python: A Project-Based Approach, Esma Yildirim, Daniel Garbin, Mathieu Sassolas, Kwang Hyun Kim

Open Educational Resources

Welcome to the “Introduction to Computers and Programming using Python: A Project-based Approach”. This book is designed to teach basic programming skills to students who are new to the field of computing using a project-based learning approach. It has been designed to give freedom to the instructor, both in format and topics ultimately used throughout the course. While we provide 13 turnkey projects, it is only expected that 3 or 4 are used over the course of a semester, and all projects are provided both as textual instructions (the student version of this OER) and Jupyter Notebooks (one with and ...