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Full-Text Articles in Physical Sciences and Mathematics

Scientia: Fall 2018 Nov 2018

Scientia: Fall 2018

Scientia

Gerald Koocher Steps Down as Dean; Calculus, Conquered; Math Magic; New Programs: We've Got a Degree in That; Lab Notes; To Croatia, With Curiosity; Human Nature Inextricable from Scientific Advances; The Scientists of Summer


A Wave From Einstein Jun 2018

A Wave From Einstein

DePaul Magazine

The discovery in 2015 of gravitational waves 100 years after Albert Einstein predicted their existence gave scientists a new way of understanding the universe. This discovery, made possible by decades of work and the collaborative efforts of astrophysicists around the world offers a window into how science advances. The concept of science as a way of knowing is discussed.


Cataclysmic Variable Stars In The Sloan Digital Sky Survey, Sinead Humphrey, Samantha Smiley, Andres Munoz, Brian Saboriendo May 2018

Cataclysmic Variable Stars In The Sloan Digital Sky Survey, Sinead Humphrey, Samantha Smiley, Andres Munoz, Brian Saboriendo

DePaul Discoveries

The purpose of this study is to identify Cataclysmic Variables (CVs) using spectroscopic and photometric data. CVs are useful for studying plasma physics in extreme conditions such as the high temperature and strong magnetic fields seen in CV accretion disks. They are also critical for understanding the evolution of binary stars, both in the field and in globular clusters. This project used photometric and spectroscopic data from the Sloan Digital Sky Survey (SDSS) to identify and classify CVs. 6,000 objects were selected based on multi-color criteria and analyzed using spectral data. Approximately 1% of these objects in the sample were …


Exact Recovery Of Prototypical Atoms Through Dictionary Initialization, Greg Zanotti, Enrico Au-Yeung May 2018

Exact Recovery Of Prototypical Atoms Through Dictionary Initialization, Greg Zanotti, Enrico Au-Yeung

DePaul Discoveries

In dictionary learning, a matrix comprised of signals Y is factorized into the product of two matrices: a matrix of prototypical "atoms" D, and a sparse matrix containing coefficients for atoms in D, called X. Dictionary learning finds applications in signal processing, image recognition, and a number of other fields. Many algorithms for solving the dictionary learning problem follow the alternating minimization paradigm; that is, by alternating solving for D and X. In 2014, Agarwal et al. proposed a dictionary initialization procedure that is used before this alternating minimization process. We show that there is a …


United States Population Future Estimates And Long-Term Distribution, Sean P. Brogan May 2018

United States Population Future Estimates And Long-Term Distribution, Sean P. Brogan

DePaul Discoveries

The population of the United States has always increased year over year. Even now with decreasing birth rates, the overall population continues to grow when looking at conventional models. The present study specifically examines what would happen to the U.S. population if we were to maintain the current birth and survival rates into the future. By 2050, our research shows that the U.S. population will become much older and cease to grow at all.


The Search For The Cyclic Sieving Phenomenon In Plane Partitions, William J. Asztalos May 2018

The Search For The Cyclic Sieving Phenomenon In Plane Partitions, William J. Asztalos

DePaul Discoveries

The efforts of this research project are best understood in the context of the subfield of dynamical combinatorics, in which one enumerates a set of combinatorial objects by defining some action to guide the search for underlying structures. While there are many examples with varying degrees of complexity, the necklace problem, which concerns the possible unique configurations of beads in a ring up to rotational symmetry, is a well-known example. Though this sort of approach to enumeration has been around for a century or more, activity in this area has intensified in the last couple of decades. Perhaps the most …


Life Cycle Assessment Of Four Different Sweaters, Sarah Nolimal May 2018

Life Cycle Assessment Of Four Different Sweaters, Sarah Nolimal

DePaul Discoveries

Life cycle assessment (LCA) is a methodological tool to describe the impacts of a product over its lifetime, from ‘cradle to grave.’ Despite increased employment of LCA, textile LCA studies are often private, outdated, not transparent, or lack accurate data. Further, we know of no LCA study specific to sweaters. This screening LCA combines published literature and data from OpenLCA databases (Ecoinvent 3.3 and GaBi Professional) to conduct a comparative LCA for four sweaters. To determine the composition of these sweaters, we massed and assessed the material composition of 117 sweaters in October 2015. Based on results, our study compares …


The Effect Of Distance And Angle On Electronic Couplings Between F8bt-Based Oligomers, Jacob H. Wat May 2018

The Effect Of Distance And Angle On Electronic Couplings Between F8bt-Based Oligomers, Jacob H. Wat

DePaul Discoveries

Organic semiconductors are often used as light-absorbers in photovoltaic devices and studying the energy flow through these materials is an important field of research. The energy flow is controlled by electronic coupling between the organic semiconductor molecules, which is affected by the distance between the molecules and their relative orientation. Here we calculated the couplings as a function of distance and relative orientation based on semi-empirical calculations of the low-lying excited states of pairs of organic semiconductor molecules. We showed that as distance increased, electronic couplings approach zero. Electronic couplings calculated as a function of rotation were maximized as the …


Synthesis Of A Bipyridine Ligand For Metal-Triggered Supramolecular Polymers, Andrew D. Gould May 2018

Synthesis Of A Bipyridine Ligand For Metal-Triggered Supramolecular Polymers, Andrew D. Gould

DePaul Discoveries

Intermolecular forces, such as H-bonding, ionic interactions and metal chelation between small molecules, can lead to the assembly of higher-order supramolecular nanostructures. A metal chelator, 2-(Pyridin-2-yl) pyridine-5-carboxylic Acid (a bipyridine derivative), is expected to aid in the formation of supramolecular structures as part of amphiphilic molecules that self-assemble in solution in the presence of metal ions. The bipyridine ligand currently under synthesis can be prepared through a five-step synthesis scheme. The second reaction of this synthesis (the coupling of two pyridine rings) resulted in a combination of the desired 1,2,5-isomer, as well as an unforeseen 1,2,3-isomer. Future research will therefore …


Risk Factors Associated With Missed Medical Appointments Among Hiv-Positive Young Men Who Have Sex With Men, Willie Love, Douglas Bruce May 2018

Risk Factors Associated With Missed Medical Appointments Among Hiv-Positive Young Men Who Have Sex With Men, Willie Love, Douglas Bruce

DePaul Discoveries

Young men who have sex with men (YMSM) are overrepresented in the HIV epidemic in America. Retaining HIV positive YMSM in HIV care is very critical to reduce the overall burden of the HIV epidemic in America. Our study focused on identifying significant risk factors that affects retention in care for YMSM. Missing two or more medical appointments was how we measured retention in care. Using data gathered from ATN 086-106 study. This ATN cross-sectional study provided HIV positive males and females between the ages of 12 and 24 with an extensive questionnaire. The goal of this study was to …


Correlates Of Adherence To Antiretroviral Therapy Among Hiv-Positive Young Men Who Have Sex With Men, Janelle Flores, Douglas Bruce May 2018

Correlates Of Adherence To Antiretroviral Therapy Among Hiv-Positive Young Men Who Have Sex With Men, Janelle Flores, Douglas Bruce

DePaul Discoveries

Adherence to antiretroviral therapy (ART) is important in HIV management. The objective of this study was to analyze the risk factors for non-adherence to ART in HIV-positive young men who have sex with men (YMSM). Data pertaining to possible risk factors for non-adherence was collected from ATN086-106, a study protocol within the Adolescent Trials Network of HIV/AIDS Interventions (ATN). Variables that were significantly associated with non-adherence to ART in bivariate analyses were entered into multivariate logistic regression models to identify correlates of non-adherence to ART. The results indicate that YMSM who used marijuana and methamphetamine and missed medical appointments were …


Depaul Discoveries Volume 7 Cover, Martha Lazarski May 2018

Depaul Discoveries Volume 7 Cover, Martha Lazarski

DePaul Discoveries

No abstract provided.