Digital Commons Network^™

The Effect Of Ignoring Statistical Interactions In Regression Analyses Conducted In Epidemiologic Studies: An Example With Survival Analysis Using Cox Proportional Hazards Regression Model, Kristina Vatcheva, Joseph B. Mccormick, Mohammad H. Rahbar

School of Mathematical & Statistical Sciences Faculty Publications

Objective: To demonstrate the adverse impact of ignoring statistical interactions in regression models used in epidemiologic studies.

Study design and setting: Based on different scenarios that involved known values for coefficient of the interaction term in Cox regression models we generated 1000 samples of size 600 each. The simulated samples and a real life data set from the Cameron County Hispanic Cohort were used to evaluate the effect of ignoring statistical interactions in these models.

Results: Compared to correctly specified Cox regression models with interaction terms, misspecified models without interaction terms resulted in up to 8.95 fold bias in estimated …

Improved Analysis Of Gw150914 Using A Fully Spin-Precessing Waveform Model, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov

Physics & Astronomy Faculty Publications

This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-one body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessingspin waveform model (precessing EOBNR) developed within the EOB formalism. We find good agreement with the …

Cardiovascular And Autonomic Nervous System Function: Impact Of Glucose Ingestion, Hydration Status And Exercise In Heated Environments, Kate Suzanne Early

LSU Doctoral Dissertations

Cardiovascular function is under the influence of autonomic nervous system, both of which can be assessed non-invasively. The purpose of this dissertation was to examine these non-invasive markers of cardiovascular and autonomic function and their relationships with exercise training, glucose ingestion and hydration status. A series of three studies were conducted to gain insight to various influences on cardiovascular and autonomic function. The first study examined the influence of exercise training of brachial artery flow-mediated dilation (BAFMD) using meta-analytic techniques. Sixty-six studies included in the analysis demonstrated exercise training improves BAFMD compared to controls. Results indicated exercise training significantly alters …

Numerical Simulations Of Wind Effects On Wave Nonlinearity And Hurricane-Induced Sediment Transport On Louisiana Coast, Ke Liu

LSU Doctoral Dissertations

The objective of this study is to model wind effects on wave nonlinearity and the sediment suspension, transport and redistribution caused by hurricanes. The following questions are addressed through numerical simulations: (1) How do winds affect wave triad interactions and wave shape in the shallow water? (2) What is the role of hurricanes in coastal landscape evolution? Do they create more erosion or deposition? (3) Where does the observed post-hurricane deposition on coastal wetlands come from? First, wind effects were incorporated into a Boussinesq-type wave model, and evolution equations were derived for triad interactions with winds. Second, a coupled modeling …

Idling Women: The Domestic Bildungsroman And The American City, 1830-1900, Jordan L. Von Cannon

LSU Doctoral Dissertations

In Idling Women: The Domestic Bildungsroman and the American City, 1830-1900, I explore urban narratives of female non-development. In city novels featuring female protagonists, there are two normative arcs of development: either women find new opportunities for marriage, work, and, in some cases, independence in the city, or they fall prey to threats of seduction, poverty, and even death. However, these two plotlines fail to accommodate stories of women who wait to develop, fail at it, or otherwise resist what might be considered character growth. By problematizing distinctions between idleness and the American “work ethic” often tied to the industrialized …

There’S A Skid Row Everywhere, And This Is Just The Headquarters: Impacts Of Urban Revitalization Policies In The Homeless Community Of Skid Row, Douglas Mungin

LSU Doctoral Dissertations

This dissertation tracks the historical shift from containment strategies for managing homeless populations in Skid Row to current strategies of using police and the penal system to periodically sweep the street of these unwanted bodies. This shift hinges on the construction of homelessness as a crisis requiring immediate and ongoing intervention. First, the state produces and reproduces homelessness as a state of crisis by withdrawing or denying support and public services and disallowing alternative, subsistence modes of survival. Then, it issues the performative utterance of the area as unclean or unsanitary. Developers and city officials mobilize the police to erase …

Factors Influencing The Perceived Effectiveness Of The Transition Assistance Program Among Exiting Military Servicemembers At Military Installations In Louisiana, Timothy L. Rose

LSU Doctoral Dissertations

As proven in the aftermath of World War II, whenever the U.S. government shifts its efforts from wartime mobilization to peacetime demobilization, the Department of Defense (DoD) faces the complex task of transitioning military personnel to civilian life. In March of 2015, the researcher began an exploratory evaluation of the Transition Assistance Program (TAP) employment workshops. The primary purpose of this study was to determine the influence of selected personal and professional demographic characteristics on the perceptions of the effectiveness of the Transition Assistance Program (TAP) in accomplishing its stated purposes among exiting military servicemembers at military installations in Louisiana. …

East Meets West: A Musical Analysis Of Chinese Sights And Sounds, By Yuankai Bao, Jiazi Shi

LSU Doctoral Dissertations

In the wake of the Chinese Cultural Revolution (1966-76) and with China’s new “Open Door” policy toward Western culture and Western music, Chinese composers have adapted Western compositional techniques. The new generation of Chinese composers have expressed in various ways of their research to the heritage of Western composers. Yuankai Bao is one of the new generations of Chinese composers. The topic of this paper is the integration of Chinese and Western compositional techniques in Chinese folk songs. The purpose of this research is to find out how Yuankai Bao connects Chinese pentatonic scale to Western harmony, and how he …

Isolation And Identification Of Foodborne Pathogens And Spoilage Bacteria In Environmental And Food Samples, Myriam Evelyn Gutierrez Barberena

LSU Doctoral Dissertations

Escherichia coli O157:H7 has become an important problem for human health in the United States. Scientific studies indicate cattle herds as primary reservoirs of E. coli O157:H7. To diagnose this pathogen, proper isolation and identification methods are crucial. From five different culture media, CT-SMAC and CHROMagar™ O157 results analyzed simultaneously were the best option for an effective detection of environmental E. coli O157. Despite extensive research at feedlots and dairy farms, there is limited information available on the prevalence of E. coli O157:H7 at cow/calf operations. From 28 small-scale cow/calf operations in the state of Louisiana, we observed an 8% …

An Assessment Of The Economic Feasibility Of Establishing A Biofuel Industry In The State Of Louisiana, Alessandro Holzapfel

LSU Master's Theses

As national interests continue to encourage the development of advanced cellulosic biofuels, through legislation, research support and other means, a wide range of alternative agricultural crops are being evaluated in various regions of the country as potential feedstock material for biofuel processing facilities. Previous research has shown that both energy cane and sweet sorghum can be successfully grown in Louisiana. This study evaluated the economic feasibility of utilizing energy cane and sweet sorghum as biofuel feedstock crops. Economic analysis focused on two primary factors: estimation of feedstock cost and optimal location of processing facilities. Five cropping sequences were evaluated in …

Exploring Organizational Resilience Asset And Its Antecedents For Effective Internal Crisis Communication, Young Kim

LSU Doctoral Dissertations

Nowadays crises are omnipresent with daily news headlines as reminders. The public continues to see or experience many different crises that affect numerous individuals and organizations as well as society in general. Against this backdrop, corporate communication professionals, for effective crisis management, are expected to help the organizations and their leaders make decisions, as well as communicate clearly when crises arise. Considering a fast changing media environment, recent scholars have called for new approaches to crisis communication to enhance theoretical developments. They suggested that researchers should take a broader context beyond the dominant crisis communication research perspectives based on the …

An Investigation Of The Generalizability Of Buoyancy From Academics To Athletics, Jackie Rae Victoriano

LSU Master's Theses

Buoyancy, the ability of an individual to handle everyday setbacks, has been applied successfully to academics, and has implications for performance and well-being. The purpose of this investigation was to determine if the concept of buoyancy can be successfully applied to the domain of sports (i.e., athletic buoyancy). This study sought to examine the relationship between academic and athletic buoyancy, as well as the efficacy of five sport-oriented predictors (5Cs), confidence, coordination (planning), commitment, composure (anxiety), and control, on both athletic and academic buoyancy. Sport club athletes (N = 285) aged 18 to 31 years completed a one-time survey assessing …

Fishes Associated With Oil And Gas Platforms In Louisiana's River-Influenced Nearshore Waters, Ryan Thomas Munnelly

LSU Master's Theses

A distinctive feature of coastal Louisiana is the unrivaled network of oil and gas installations (platforms) extending from inshore waters to the deep Gulf of Mexico. Since 2007 there has been a 38% reduction in platform numbers with the highest removal rates occurring in shallow (< 18 m) nearshore waters. Many fishes and invertebrates are attracted to platforms, presenting a unique opportunity to study detailed species-specific responses to the river-influenced hydrographic characteristics of Louisiana’s nearshore zone (5–25 km water depth). Prior studies of fishes around platforms focused on a few relatively large platforms in water depths ≥ 18 m. However, about one-third of all platforms are small, unmanned and non-drilling platforms located in waters < 18 m depth. Paired video and hydrographic data were collected at 150 small platforms in < 18 m water depth during the summers of 2013–2014. Fifty-four species of fishes were associated with small platforms. The assemblage(s) included juveniles of 29 species, indicating the importance of nearshore platforms as diverse nursery habitat. The coastal zone was divided into three regions based on broad-scale interactions between freshwater input and bathymetry driving major distinctions in interregional hydrography and fish assemblages. Co-occurring within this expansive artificial reef network is the second largest hypoxic area (dissolved oxygen (DO) < 2.0 mg l−1) on Earth. Platforms offer reef-like habitat features in the upper water column that may offer refugia for some reef-associated species during hypoxic events. Significant intraregional differences in physicochemical features were related to the presence of hypoxia (defined as DO < 50% saturation), as well as the distribution of sandy shoals. Eleven species accounted for most of the assemblage dissimilarities, composing ~93% of fishes observed. Habitat suitability indices for these 11 species provided information about habitat selection across horizontal and vertical physicochemical gradients throughout the coastal zone, and within hypoxic and well-oxygenated stratified water columns. East Bay, near the outlet of the Mississippi River, exhibited less hypoxia and a distinct fauna that included four adult goliath grouper (Epinephelus itajara). This endangered fish was observed during spawning season (summer), suggesting that East Bay might support a spawning aggregation.

Fear No Evil: Making Sense Of Intersectionality And Fear Of Crime Amongst Blacks In High Crime Neighborhoods, Melinda Jackson

LSU Doctoral Dissertations

The extant literature on fear of crime has relied almost entirely upon quantitative data and was criticized as atheoretical due to its focus on the demographic characteristics associated with vulnerability. Emerging qualitative research on fear of crime has begun to overcome this limitation by drawing upon an intersectional lens, but quantitative assessments have yet to fully incorporate this theoretical development. The current study addresses this limitation by analyzing qualitative data collected through semi-structured interviews and quantitative data collected as part of a large-scale survey. The primary goal of this dissertation is to take an intersectional approach to understand the relationships …

Here's To The Next 40 Years, Marcy S. Wallace

Mitchell Hamline Law Review

No abstract provided.

Dietary Plant Lectins May Be An ‘Unknown Etiology’ In Parkinson’S Disease And Dietary Bioactive Compounds Affect Lifespan And Fat Storage Aspects Of Caenorhabditis Elegans, Mingming Wang

LSU Doctoral Dissertations

Dietary bioactive compounds benefit health while some might induce pathological processes. Parkinson’s disease (PD) is the second most common neurodegenerative disease. Braak and Hawkes hypothesized that the gastrointestinal tract may be a potential site of neuronal invasion by an “unknown pathogen” leading to some Parkinsonism. Neurotoxin botulinum or ricin can trans-synaptically transport in nervous system. Our hypothesis 1: dietary plant lectins might be responsible for the “unknown pathogen” causing PD. Pomegranate juice (PJ) have antioxidant and anti-obesity effects. Our hypothesis 2: PJ increases lifespan in C. elegans and reduces fat storage. Study 1: Post-feeding rhodamine or TRITC tagged dietary lectins …

Introduction: An Intentional Conversation About Public Engagement And Decision-Making: Moving From Dysfunction And Polarization To Dialogue And Understanding, Jessica Dubois, Sharon Press

Mitchell Hamline Law Review

No abstract provided.

The Design, Fabrication, And Validation Of A Film Cooled Rotating Turbine Cascade With An Actively Cooled Shroud In A Closed Loop Wind Tunnel, Christopher Michael Drewes

LSU Master's Theses

To test shroud and blade cooling effectiveness, a closed loop, heated wind tunnel housing a film cooled rotating turbine cascade with prescribed blade and vane geometry surrounded by a fully cooled shroud with a leading edge gap were designed and assembled on Louisiana State University’s campus. Heat transfer coefficients and film cooling effectiveness results were computed using a 1-D semi-infinite solid conduction analysis of material temperatures obtained with liquid crystal thermography. Proper analysis required a step change in air temperature; so a bypass loop provided mainstream air heating while maintaining the shroud and blades at ambient temperature. Also, analysis required …

Reliability Of Auditory-Perceptual Ratings Of Dysarthric Speech: Hypokinetic Dysarthria Secondary To Parkinson's Disease, Jessica Lynn Miller

LSU Master's Theses

Perceptual judgment has been the gold standard in clinical practice, especially regarding differential diagnosis and treatment of dysarthria. Thus, it is critical to establish the reliability of perceptual ratings of the speech characteristics associated with different types of dysarthria. Despite its importance, the reliability and sensitivity of perceptual ratings of speech disturbance have been somewhat questioned. The purpose of this study was to examine the interrater reliability of ratings of perceptual characteristics and the saliency of these characteristics as related to hypokinetic dysarthria. Due to the feasibility issue, the scope of the study was limited to hypokinetic dysarthria associated with …

Transatlantic Trade And Investment Partnership: Implications To Global Wine Market, Natalia Antosova

LSU Master's Theses

Transatlantic Trade and Investment Partnership was first introduced in 2013, with the goal of liberalization of the trade and investments, better coordination of trade by specific regulations, enhancing intellectual property protection and lifting government’s impediments to trade. This Thesis is concerned on potential implications of the TTIP on the wine industry in the European Union and particular consequences related to EU wine producers. The literature review of this paper is developed with the purpose to bring general knowledge in the matter of the TTIP. In addition, linkages of the TTIP with the political economy are provided in the latter part …

Characterization Of Sulfur Chemistry In Louisiana Coastal Wetland Soils Using X-Ray Absorption Fine Structure (Xafs) Spectroscopy, Negar Dehghani Tafti

LSU Master's Theses

Sulfur is one of the most abundant elements in the environment, which plays a vital role in the growth and functioning of plants and microorganisms. It is found in an extended variety of species in gases, liquid, and solid forms and present in various nature systems. Wetlands are one of the largest global sinks/sources of sulfur. Being existing in a variety of oxidation states, sulfur contributes to biogeochemical cycles of coastal wetlands through involving in humification processes as well as influence on metal sulfide formation and consequently, methanogenesis and greenhouse gas emission. In this study, we have evaluated sulfur chemistry …

Effect Of Tillage And Fertilization On Agronomics And Nutrient Uptake Of Sweet Sorghum And Soil Test Extractable P And K After Four Years Of A Monocrop Production System, Jifeng Li

LSU Master's Theses

Sweet sorghum [Sorghum bicolor (L.) Moench] (SS) has been grown in the southern United States to produce syrup for many years. There is an interest in SS as a biofuel feedstock due to its high sugar content and high total biomass. Currently, little is known about the nutrient demand for SS or how it responds to tillage and fertilization. The objectives of this study were to: 1) evaluate the effects of tillage and phosphorus (P) and potassium (K) fertilization on SS agronomics, 2) evaluate nitrogen (N), P, and K uptake and nutrient partitioning in SS, 3) determine P and K …

Spatiotemporal Distribution Of The Himalayan Leucogranite: Implications For Mountain-Building As A Function Of Indian Slab Dynamics, Hongcheng Guo

LSU Master's Theses

The Himalayan orogen, as a natural laboratory for continental collision, has attracted intense research attention for decades. However, the question of how the orogen was built is still debated, and potential answers are few when considering how and why along-strike variations of the mountain-building processes occurred. Various tectonic models have been proposed to explain the kinematics of the mountain-building. These models include two dimensional models, such as wedge extrusion (Burchfiel and Royden, 1985; Grujic et al., 1996; Kohn, 2008), channel flow coupled to focused denudation (Beaumont et al., 2001; Hodges et al., 2001), tectonic wedging (Yin, 2006; Webb et al., …

Interference Energy Spectrum Of The Infinite Square Well, Mordecai Waegell, Yakir Aharonov, Taylor Lee Patti

Mathematics, Physics, and Computer Science Faculty Articles and Research

Certain superposition states of the 1-D infinite square well have transient zeros at locations other than the nodes of the eigenstates that comprise them. It is shown that if an infinite potential barrier is suddenly raised at some or all of these zeros, the well can be split into multiple adjacent infinite square wells without affecting the wavefunction. This effects a change of the energy eigenbasis of the state to a basis that does not commute with the original, and a subsequent measurement of the energy now reveals a completely different spectrum, which we call the interference energy spectrum of …

Accommodating Retrocausality With Free Will, Yakir Aharonov, Eliahu Cohen, Tomer Shushi

Mathematics, Physics, and Computer Science Faculty Articles and Research

Retrocausal models of quantum mechanics add further weight to the conflict between causality and the possible existence of free will. We analyze a simple closed causal loop ensuing from the interaction between two systems with opposing thermodynamic time arrows, such that each system can forecast future events for the other. The loop is avoided by the fact that the choice to abort an event thus forecasted leads to the destruction of the forecaster's past. Physical law therefore enables prophecy of future events only as long as this prophecy is not revealed to a free agent who can otherwise render it …

Mathematical Frameworks For Consciousness, Menas C. Kafatos, Ashok Narasimhan

Mathematics, Physics, and Computer Science Faculty Articles and Research

If Awareness is fundamental in the universe, mathematical frameworks are better suited to reveal its fundamental aspects than physical models. Awareness operates through three fundamental laws which apply at all levels of reality and is characterized by three universal powers. We explore and summarize in general terms mathematical formalisms that may take us as close as possible to conscious awareness, beginning with the primary relationships between the observer with the observed, using a Hilbert space approach. We also examine insights from category theory, and the calculus of indications or laws of forms. Mathematical frameworks as fundamental languages of our interaction …

The Spectral Theorem For Quaternionic Unbounded Normal Operators Based On The S-Spectrum, Daniel Alpay, Fabrizio Colombo, David P. Kimsey

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper we prove the spectral theorem for quaternionic unbounded normal operators using the notion of S-spectrum. The proof technique consists of first establishing a spectral theorem for quaternionic bounded normal operators and then using a transformation which maps a quaternionic unbounded normal operator to a quaternionic bounded normal operator. With this paper we complete the foundation of spectral analysis of quaternionic operators. The S-spectrum has been introduced to define the quaternionic functional calculus but it turns out to be the correct object also for the spectral theorem for quaternionic normal operators. The fact that the correct notion of …

Characterizations Of Rectangular (Para)-Unitary Rational Functions, Daniel Alpay, Palle Jorgensen, Izchak Lewkowicz

Mathematics, Physics, and Computer Science Faculty Articles and Research

We here present three characterizations of not necessarily causal, rational functions which are (co)-isometric on the unit circle:
(i) through the realization matrix of Schur stable systems,
(ii) the Blaschke-Potapov product, which is then employed to introduce an easy-to-use description of all these functions with dimensions and McMillan degree as parameters,
(iii) through the (not necessarily reducible) Matrix Fraction Description (MFD).
In cases (ii) and (iii) the poles of the rational functions involved may be anywhere in the complex plane, but the unit circle (including both zero and infinity). A special attention is devoted to exploring the gap between the …

The H∞ Functional Calculus Based On The S-Spectrum For Quaternionic Operators And For N-Tuples Of Noncommuting Operators, Daniel Alpay, Fabrizio Colombo, Tao Qian, Irene Sabadini, Tao Qian

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper we extend the H∞ functional calculus to quaternionic operators and to n-tuples of noncommuting operators using the theory of slice hyperholomorphic functions and the associated functional calculus, called S-functional calculus. The S-functional calculus has two versions one for quaternionic-valued functions and one for Clifford algebra-valued functions and can be considered the Riesz-Dunford functional calculus based on slice hyperholomorphicity because it shares with it the most important properties.

The S-functional calculus is based on the notion of S-spectrum which, in the case of quaternionic normal operators on a Hilbert space, is also the notion of spectrum that appears …

Wiener Algebra For The Quaternions, Daniel Alpay, Fabrizio Colombo, David P. Kimsey, Irene Sabadini

Mathematics, Physics, and Computer Science Faculty Articles and Research

We define and study the counterpart of the Wiener algebra in the quaternionic setting, both for the discrete and continuous case. We prove a Wiener-Lévy type theorem and a factorization theorem. We give applications to Toeplitz and Wiener-Hopf operators.