Two Essays in Financial Economics

Chapter 1 of this study investigates the link between a firm’s capital structure and their industry competitive behavior. Given the competitive behavior in certain markets, Cournot or Bertrand, we investigate if there are any inborn characteristics of these markets’ competitive behavior that would create an incentive for Cournot firms to have a different strategic debt level than Bertrand firms. Related theories argue that any industry’s competitive behavior, whether it is Bertrand or Cournot would typically consist of a certain type of debt and pursue a certain type of competitive strategy, based on its classification. In this study, we investigate the debt level of a sample of firms classified into either Cournot or Bertrand competition, i.e. explore competitive behavior as a characteristic of firms that tend to be associated with different debt ratios and determine if the competitive market type does in fact lead to a varying debt ratio target. We used two different measures to categorize competition type, the CSM and the SI measure. Our findings indicate that there is no significant difference between differentiated debt levels between Bertrand and Cournot firms. Chapter 2 of the study examines various factors that may affect American Depository Receipts’ trading volume distribution between their home and US markets. These include factors not previously considered in the extant literature. One such factor is the trading motive (hedging or speculative) of investors. Other factors examined include price impact, relative volatility, market to book ratio, as well as a cultural dimension factor: individualism. Controlling for time-specific effects, we find that the relative motive measure of cross-listed firms has a positive relationship on the trading volume distribution. In addition, when looking at a small sample of firms with different motive factors, we find that hedging motive in the home country leads to an increased proportion of trading in the host country relative to the home country, while speculative motive leads to a decrease in the volume share of the host country relative to the home country. A positive and significant relationship is also observed between volatility and the log of trading volume share. The relationship is negative for liquidity and visibility in relation to the trading volume distribution of cross-listed firm’s stocks. Culture difference at home relative to host is found to positively impact trading volume distribution of cross-listed stocks

Layer-by-Layer Assembled Nanowire Networks Enable Graph Theoretical Design of Multifunctional Coatings

Multifunctional coatings are central for information, biomedical, transportation and energy technologies. These coatings must possess hard-to-attain properties and be scalable, adaptable, and sustainable, which makes layer-by-layer assembly (LBL) of nanomaterials uniquely suitable for these technologies. What remains largely unexplored is that LBL enables computational methodologies for structural design of these composites. Utilizing silver nanowires (NWs), we develop and validate a graph theoretical (GT) description of their LBL composites. GT successfully describes the multilayer structure with nonrandom disorder and enables simultaneous rapid assessment of several properties of electrical conductivity, electromagnetic transparency, and anisotropy. GT models for property assessment can be rapidly validated due to (1) quasi-2D confinement of NWs and (2) accurate microscopy data for stochastic organization of the NW networks. We finally show that spray-assisted LBL offers direct translation of the GT-based design of composite coatings to additive, scalable manufacturing of drone wings with straightforward extensions to other technologies

The Irish potato famine pathogen Phytophthora infestans originated in central Mexico rather than the Andes

Phytophthora infestans is a destructive plant pathogen best known for causing the disease that triggered the Irish potato famine and remains the most costly potato pathogen to manage worldwide. Identification of P. infestan’s elusive center of origin is critical to understanding the mechanisms of repeated global emergence of this pathogen. There are two competing theories, placing the origin in either South America or in central Mexico, both of which are centers of diversity of Solanum host plants. To test these competing hypotheses, we conducted detailed phylogeographic and approximate Bayesian computation analyses, which are suitable approaches to unraveling complex demographic histories. Our analyses used microsatellite markers and sequences of four nuclear genes sampled from populations in the Andes, Mexico, and elsewhere. To infer the ancestral state, we included the closest known relatives Phytophthora phaseoli, Phytophthora mirabilis, and Phytophthora ipomoeae, as well as the interspecific hybrid Phytophthora andina. We did not find support for an Andean origin of P. infestans; rather, the sequence data suggest a Mexican origin. Our findings support the hypothesis that populations found in the Andes are descendants of the Mexican populations and reconcile previous findings of ancestral variation in the Andes. Although centers of origin are well documented as centers of evolution and diversity for numerous crop plants, the number of plant pathogens with a known geographic origin are limited. This work has important implications for our understanding of the coevolution of hosts and pathogens, as well as the harnessing of plant disease resistance to manage late blight.Keywords: coalescent analysis, biological invasion, oomycete, population genetics, stramenopil

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Two Essays in Financial Economics

Chapter 1 of this study investigates the link between a firm’s capital structure and their industry competitive behavior. Given the competitive behavior in certain markets, Cournot or Bertrand, we investigate if there are any inborn characteristics of these markets’ competitive behavior that would create an incentive for Cournot firms to have a different strategic debt level than Bertrand firms. Related theories argue that any industry’s competitive behavior, whether it is Bertrand or Cournot would typically consist of a certain type of debt and pursue a certain type of competitive strategy, based on its classification. In this study, we investigate the debt level of a sample of firms classified into either Cournot or Bertrand competition, i.e. explore competitive behavior as a characteristic of firms that tend to be associated with different debt ratios and determine if the competitive market type does in fact lead to a varying debt ratio target. We used two different measures to categorize competition type, the CSM and the SI measure. Our findings indicate that there is no significant difference between differentiated debt levels between Bertrand and Cournot firms. Chapter 2 of the study examines various factors that may affect American Depository Receipts’ trading volume distribution between their home and US markets. These include factors not previously considered in the extant literature. One such factor is the trading motive (hedging or speculative) of investors. Other factors examined include price impact, relative volatility, market to book ratio, as well as a cultural dimension factor: individualism. Controlling for time-specific effects, we find that the relative motive measure of cross-listed firms has a positive relationship on the trading volume distribution. In addition, when looking at a small sample of firms with different motive factors, we find that hedging motive in the home country leads to an increased proportion of trading in the host country relative to the home country, while speculative motive leads to a decrease in the volume share of the host country relative to the home country. A positive and significant relationship is also observed between volatility and the log of trading volume share. The relationship is negative for liquidity and visibility in relation to the trading volume distribution of cross-listed firm’s stocks. Culture difference at home relative to host is found to positively impact trading volume distribution of cross-listed stocks

Mutations in Elongation Factor 1β, a Guanine Nucleotide Exchange Factor, Enhance Translational Fidelity

Translation elongation factor 1β (EF-1β) is a member of the family of guanine nucleotide exchange factors, proteins whose activities are important for the regulation of G proteins critical to many cellular processes. EF-1β is a highly conserved protein that catalyzes the exchange of bound GDP for GTP on EF-1α, a required step to ensure continued protein synthesis. In this work, we demonstrate that the highly conserved C-terminal region of Saccharomyces cerevisiae EF-1β is sufficient for normal cell growth. This region of yeast and metazoan EF-1β and the metazoan EF-1β-like protein EF-1δ is highly conserved. Human EF-1β, but not human EF-1δ, is functional in place of yeast EF-1β, even though both EF-1β and EF-1δ have previously been shown to have guanine nucleotide exchange activity in vitro. Based on the sequence and functional homology, mutagenesis of two C-terminal residues identical in all EF-1β protein sequences was performed, resulting in mutants with growth defects and sensitivity to translation inhibitors. These mutants also enhance translational fidelity at nonsense codons, which correlates with a reduction in total protein synthesis. These results indicate the critical function of EF-1β in regulating EF-1α activity, cell growth, translation rates, and translational fidelity

Mutations in Elongation Factor 1β, a Guanine Nucleotide Exchange Factor, Enhance Translational Fidelity

Translation elongation factor 1β (EF-1β) is a member of the family of guanine nucleotide exchange factors, proteins whose activities are important for the regulation of G proteins critical to many cellular processes. EF-1β is a highly conserved protein that catalyzes the exchange of bound GDP for GTP on EF-1α, a required step to ensure continued protein synthesis. In this work, we demonstrate that the highly conserved C-terminal region of Saccharomyces cerevisiae EF-1β is sufficient for normal cell growth. This region of yeast and metazoan EF-1β and the metazoan EF-1β-like protein EF-1δ is highly conserved. Human EF-1β, but not human EF-1δ, is functional in place of yeast EF-1β, even though both EF-1β and EF-1δ have previously been shown to have guanine nucleotide exchange activity in vitro. Based on the sequence and functional homology, mutagenesis of two C-terminal residues identical in all EF-1β protein sequences was performed, resulting in mutants with growth defects and sensitivity to translation inhibitors. These mutants also enhance translational fidelity at nonsense codons, which correlates with a reduction in total protein synthesis. These results indicate the critical function of EF-1β in regulating EF-1α activity, cell growth, translation rates, and translational fidelity

Psychometric evaluation of an electronic Asthma Symptom Diary for young children

Abstract Background Patient-reported outcome measures that facilitate self-report by children are needed to reduce the bias of proxy report. We previously developed an electronic Pediatric Asthma Symptom Diary (ePASD) to assess the severity of daily asthma symptoms and proximal impacts in children aged 6–11 years with mild to severe asthma. The ePASD, administered via a digital application with visuals, sounds, and text, is uniquely designed to minimize the importance of reading skills on children’s ability to self-report accurately. Here, we describe the ePASD’s psychometric properties. Methods Ninety-one children aged 6–11 years with mild to severe asthma and their caregivers participated in 2 study visits, which consisted of training on the provisioned device and completing asthma-specific clinical outcome assessment (COA) questionnaires. The children self-completed the ePASD at home twice daily for 8 consecutive days. The scoring of the ePASD was guided by factor analyses, inter-item correlations, and internal consistencies. Reliability, discriminating ability, construct validity, and responsiveness were evaluated for ePASD items and candidate scores. Results All COAs included in the study—the ePASD, Asthma Control Questionnaire (ACQ), Childhood Asthma Control Test, Pediatric Asthma Quality of Life Questionnaire–Standardized (PAQLQ[S]), and global ratings—demonstrated that the children exhibited few asthma-related symptoms and impacts at all timepoints, and consequently, showed little change over time. Internal consistencies (all Cronbach’s alphas ≥ 0.52) and test-retest reliabilities (all intraclass correlation coefficients ≥ 0.60) were largely satisfactory. Patterns of convergent and divergent correlations supported the construct validity of ePASD scores. The ePASD symptom scores correlated moderately to strongly with PAQLQ(S) Symptom scores (all correlations ≥ − 0.46) and with ACQ scores (all correlations ≥ 0.42), as predicted. Evidence of the discriminating ability of ePASD items and composite scores was demonstrated by known-groups analyses. Conclusions The ePASD is a reliable and valid measure of asthma symptoms and proximal impacts in children aged 6–11 years with mild, moderate, or severe asthma. These results lay the psychometric groundwork for use of the ePASD in future clinical trials for the management of pediatric asthma. An ongoing pediatric asthma treatment trial is anticipated to provide evidence of the ePASD’s responsiveness to change

Production and qualification of an electrospun ceramic nanofiber material as a candidate future high power target

In an effort to develop and design next generation high power target materials for particle physics research, the possibility of fabricating nonwoven metallic or ceramic nanofibers by electrospinning process is explored. A low-cost electrospinning unit is set up for in-house production of various ceramic nanofibers. Yttria-stabilized zirconia nanofibers are successfully fabricated by electrospinning a mixture of zirconium carbonate with high-molecular weight polyvinylpyrrolidone polymer solution. Some of the inherent weaknesses of electrospinning process like thickness of nanofiber mat and slow production rate are overcome by modifying certain parts of electrospinning system and their arrangements to get thicker nanofiber mats of millimeter order at a faster rate. Continuous long nanofibers of about hundred nanometers in diameter are produced and subsequently heat treated to get rid of polymer and allow crystallize zirconia. Specimens were prepared to meet certain minimum physical properties such as thickness, structural integrity, thermal stability, and flexibility. An easy innovative technique based on atomic force microscopy was employed for evaluating mechanical properties of single nanofiber, which were found to be comparable to bulk zirconia. Nanofibers were tested for their high-temperature resistance using an electron beam. It showed resistance to radiation damage when irradiated with 1 MeV Kr2++ ion. Some zirconia nanofibers were also tested under high-intensity pulsed proton beam and maintained their structural integrity. This study shows for the first time that a ceramic nanofiber has been tested under different beams and irradiation condition to qualify their physical properties for practical use as accelerator targets. Advantages and challenges of such nanofibers as potential future targets over bulk material targets are discussed