Ultra Efficient Commercial Transport Challenge- NASA Design Challenge- X-JAB-ECT

Today’s aircraft require new innovation to be able to produce the same amount of lift, but with the design decrease the amount of drag produced. The X-JAC ECT has the ability and is an innovative airframe to reduce today’s fuel costs. The baseline comparison for the X-JAB is the Boeing 747-400 aircraft, the payload, range, speed, and altitude are the same f or the X-JAB and the 747. Through use of supercritical airfoils, the X-JAB was designed as a blended wing body aircraft to produce more lift while evenly balancing the weight of the aircraft and the payload. Through parametric analysis and flow simulations, the X-JAB is able to achieve a 31.6% reduction in fuel costs compared to the Boeing 747-400.

Securities Litigation Risk for Foreign Companies Listed in the U.S.

We study securities litigation risk faced by foreign firms listed on U.S. exchanges. We find that U.S. listed foreign companies experience securities class action lawsuits at about half the rate as do U.S. firms with similar levels of ex ante litigation risk. The lower rate appears to be driven partly by higher transaction costs in uncovering and pursuing litigation against foreign firms. However, once a lawsuit triggering event like an accounting restatement, missing management guidance, or a sharp stock price decline occurs, there is no difference in the litigation rates between a foreign and comparable U.S. firm. This suggests that effective enforcement of securities laws is constrained by transaction costs, and the availability of high quality information that reveals potential misconduct is an important determinant of a well-functioning litigation market for foreign firms listed in the U.S

Involvement of Innate Immune System in Late Stages of Inherited Photoreceptor Degeneration

Retinitis pigmentosa (RP) is a group of inherited retinal degenerations that lead to progressive vision loss. Over 200 mutations in 60 different genes have been shown to cause RP. Given the diversity of genes and mutations that cause RP, corrective gene therapy approaches currently in development may prove both time-consuming and cost-prohibitive for treatment of all forms of RP. An alternative approach is to find common biological pathways that cause retinal degeneration in various forms of RP, and identify new molecular targets. With this goal, we analyzed the retinal transcriptome of two non-allelic forms of RP in dogs, rcd1 and xlpra2, at clinically relevant advanced stages of the two diseases. Both diseases showed very similar trends in changes in gene expression compared to control normal dogs. Pathway analysis revealed upregulation of various components of the innate immune system in both diseases, including inflammasome and complement pathways. Our results show that the retinal transcriptome at advanced stages of RP is very similar to that of other retinal degenerative diseases such as age-related macular degeneration and diabetic retinopathy. Thus, drugs and therapeutics already in development for targeting these retinopathies may also prove useful for the treatment of many forms of RP

Analyzing the Linguistic Features of Standardized Math Items: A Text Mining Approach

The following is a five-chapter dissertation surrounding the use of text mining techniques for better understanding the language of mathematics items from standardized tests to improve linguistic equity of these items to support assessment of English Language Learners. Introduction: The dissertation begins with an overview of the problem that English Language Learners are likely not able to demonstrate their full mathematical ability due to the construct irrelevant variance caused by these items being written in English. This introduction also introduces the idea of text mining as a methodology for use in exploring this test design issue. Article 1: This article presents an exploratory study of the vocabulary used in released math test items for grades 3-8. The author collected and cleaned the data to arrive at a final corpus of 5674 math problems. Next, a series of text mining techniques were performed including the “bag of words” approach, sentiment analysis, and Latent Dirichlet Allocation (LDA). The bag of words approach generated an overall word list for the entire corpus, by grade level, and by mathematical domain. For each of these lists, the majority of the words found were polysemous, meaning they had multiple meanings, which is inappropriate for ELLs. The sentiment analysis results showed that there was not any obvious negative sentiment found in these items. Finally, the LDA results showed that there were 9 latent topics found within the language of these items. Article 2: This article is an exploratory study of the state of the parts of speech used in released math standardized test items for grades 3-8. The author collected and cleaned the data to arrive at a corpus of 5674 math problems. Next, a series of parts of speech analyses were performed to better understand the grammatical structures used within current mathematics items, as well as a bigrams and trigrams analysis of the most commonly used phrases found within these items. The variation in parts of speech and readability of these items was tracked across grade levels and was found to become more complicated as the grade level increased. The grammatical parts of speech were also used to predict the item difficulty for those items (N = 1627) with some of these parts of speech being found to negatively correlated with item difficulty estimates. Article 3: This article describes the development of an open-source text parser for multiple-choice mathematics items intended for students in grades 3-8. To train this parser, initially, seven machine learning classification algorithms were used to predict item difficulty as measured by p-value. The most accurate of these models was a special kind of Support Vector Machine called a Support Vector Classifier which had almost 50% accuracy. This parser was trained to estimate approximate item difficulty level as well as to identify problematic vocabulary words, estimate the readability of the question, and support the user to know which problematic parts of speech are being used in the item. Math Item Parse is operational but is still in a prototype stage because a larger training set is needed to improve the model accuracy. Final Discussion: The dissertation concludes with a short discussion that describes how these findings impact educators, test developers, methodologists, and policy makers, and discusses the biggest limitations of this dissertation and offers some next steps

OHMI: The Ontology of Host-Microbiome Interactions

Host-microbiome interactions (HMIs) are critical for the modulation of biological processes and are associated with several diseases, and extensive HMI studies have generated large amounts of data. We propose that the logical representation of the knowledge derived from these data and the standardized representation of experimental variables and processes can foster integration of data and reproducibility of experiments and thereby further HMI knowledge discovery. A community-based Ontology of Host-Microbiome Interactions (OHMI) was developed following the OBO Foundry principles. OHMI leverages established ontologies to create logically structured representations of microbiomes, microbial taxonomy, host species, host anatomical entities, and HMIs under different conditions and associated study protocols and types of data analysis and experimental results

The Acute Effects of the COVID-19 Pandemic on Physical Activity and Sedentary Behavior in University Students and Employees

International Journal of Exercise Science 13(5): 1326-1339, 2020. The COVID-19 pandemic has closed non-essential businesses which may alter individuals’ leisure behaviors. Consequently, physical activity and sedentary behavior may be negatively impacted as many fitness and recreational centers have been closed. This study aimed to examine the impact of the pandemic on physical activity and sedentary behavior in a sample of university students and employees before and after the university cancelled face-to-face classes and closed campus. Participants (N = 398) completed the validated Godin physical activity questionnaire and the International Physical Activity Questionnaire which assessed physical activity and sedentary behavior pre- and post-cancellation of face-to-face classes. Participants were also separated in the groups (low, moderate, high physical activity) based upon a tertile split of pre-pandemic total physical activity. Physical activity group by time ANOVAs were used to assess potential changes in total physical activity and sedentary behavior. Post-cancellation sedentary behavior was greater (F (1, 388) = 9.2, p = 0.003, partial η2 = 0.032) than pre-cancellation. Physical activity group moderated (F (2, 395) = 22.0, p \u3c 0.001, partial η2 ≥ 0.10) changes in total physical activity from pre- to post cancellation. The high activity group decreased physical activity whereas the moderate and low activity groups increased physical activity (t ≥ 2.4, p ≤ 0.02, Cohen’s d = 0.23). While the university closure increased sedentary behavior across the sample, it only decreased physical activity in participants who were the most active pre-cancellation. Pandemic-related closure of facilities designed for physical activity may disproportionately impact active individuals

Mutations Affecting HVO_1357 or HVO_2248 Cause Hypermotility in Haloferax volcanii, Suggesting Roles in Motility Regulation

Motility regulation plays a key role in prokaryotic responses to environmental stimuli. Here, we used a motility screen and selection to isolate hypermotile Haloferax volcanii mutants from a transposon insertion library. Whole genome sequencing revealed that hypermotile mutants were predominantly affected in two genes that encode HVO_1357 and HVO_2248. Alterations of these genes comprised not only transposon insertions but also secondary genome alterations. HVO_1357 contains a domain that was previously identified in the regulation of bacteriorhodopsin transcription, as well as other domains frequently found in two-component regulatory systems. The genes adjacent to hvo_1357 encode a sensor box histidine kinase and a response regulator, key players of a two-component regulatory system. None of the homologues of HVO_2248 have been characterized, nor does it contain any of the assigned InterPro domains. However, in a significant number of Haloferax species, the adjacent gene codes for a chemotaxis receptor/transducer. Our results provide a foundation for characterizing the root causes underlying Hfx. volcanii hypermotility

Improved eukaryotic detection compatible with large-scale automated analysis of metagenomes

Background: Eukaryotes such as fungi and protists frequently accompany bacteria and archaea in microbial communities. Unfortunately, their presence is difficult to study with “shotgun” metagenomic sequencing since prokaryotic signals dominate in most environments. Recent methods for eukaryotic detection use eukaryote-specific marker genes, but they do not incorporate strategies to handle the presence of eukaryotes that are not represented in the reference marker gene set, and they are not compatible with web-based tools for downstream analysis. Results: Here, we present CORRAL (for Clustering Of Related Reference ALignments), a tool for the identification of eukaryotes in shotgun metagenomic data based on alignments to eukaryote-specific marker genes and Markov clustering. Using a combination of simulated datasets, mock community standards, and large publicly available human microbiome studies, we demonstrate that our method is not only sensitive and accurate but is also capable of inferring the presence of eukaryotes not included in the marker gene reference, such as novel strains. Finally, we deploy CORRAL on our MicrobiomeDB.org resource, producing an atlas of eukaryotes present in various environments of the human body and linking their presence to study covariates. Conclusions: CORRAL allows eukaryotic detection to be automated and carried out at scale. Implementation of CORRAL in MicrobiomeDB.org creates a running atlas of microbial eukaryotes in metagenomic studies. Since our approach is independent of the reference used, it may be applicable to other contexts where shotgun metagenomic reads are matched against redundant but non-exhaustive databases, such as the identification of bacterial virulence genes or taxonomic classification of viral reads

LIF Measurements of the Cylindrical Hall Thruster Plume

This paper presents a Laser Induced Fluorescence (LIF) investigation of ion velocity profiles in the plume of the Fully Cylindrical Hall Thruster (FCHT) recently developed at the Princeton Plasma Physics Laboratory. These measurements confirm a previously measured ∼ 7% increase in the exhaust velocity when the cathode keeper draws an excess current (overrun mode). Furthermore, it was found that velocity directions in the plume remain relatively unchanged for the cusped and direct magnetic field configuration in both overrun and non-overrun modes. It is shown that the reported plume narrowing in the overrun mode is due to the shift of the acceleration and ionization regions inward toward the anode. This conclusion is supported by the potential profiles extracted from the LIF measurements, which indicate that in the overrun mode a larger fraction of potential fall occurs inside the thruster. Recent probe measurements further substantiate these findings [Raitses et al. , Phys. Plasma 16, 057106 (2009)]. The ratio of the potential fall experienced by ions inside the thruster over the actual potential drop within the thruster increases from 20% in the non-overrun regime with magnets in the direct configuration to 70% in the overrun mode with magnets in the cusped configuration. Magnetic field lines outside the thruster channel are found to be not equipotential, with the degree of equipotentiality gradually increasing at the thruster exit toward the edge