The Cytotoxic Effects of Trimethylpentane on Rat Renal Tissue

The primary objective of the investigation was to determine the acute cytopathologic effects of 2,3,4 -trimethylpentane, a major constituent of gasoline, on renal tissue of the mature male rat. Three groups of 9 Fischer-344 rats each were administered trimethylpentane by gavage twice weekly for 7, 14, or 28 days at a concentration of 1.5 ml/kg body weight. The tissues were fixed by perfusion, and subsequently processed for scanning and transmission electron microscopy. Al though the manifestations of hydrocarbon toxicity were evident in all experimental tissues examined, the extent and magnitude of cellular lesions increased as the exposure period progressed. The only structural change detected within the glomerular complex was a significant increase in the number of microvilli associated with various branches of the podocytes. Cells of the proximal convoluted tubule were characterized by the presence of membrane -bound, PAS positive hyaline droplets. At focal points along segments P1 and P2 of the proximal tubule intact epithelial cells dissociated from the basal lamina, underwent necrosis, and subsequently collected along the length of the tubular lumen. The cellular debris concentrated at the corticomedullary junction. Tubules at the site were dilated focally and the epithelial lining was attenuated. Results of the study indicate that the manifestations of trimethylpentane toxicity among renal cells are associated with the proliferation of hyaline droplets

Perchlorate Toxicity and Risk Assessment

Ammonium perchlorate is the oxidizer ingredient in solid propellant mixtures for rockets, missiles and munitions such as Titan, Minuteman, Peacekeeper, Hawk, Polaris and the Space Shuttle. Perchlorate salts may also be used in medicine, matches, munitions and pyrotechnics (illuminating and signaling flares, colored and white smoke generators, tracers, incendiary delays, fuses, photo-flash compounds and fireworks). Perchlorate is also found in lubricating oils, finished leather, fabric fixer, dyes, electroplating, aluminum refining, manufacture of rubber, paint and enamel production, as an additive in cattle feed, in magnesium batteries and as a component of automobile air bag inflators.\u2

Advantages and Disadvantages of Using Internet-Based Survey Methods in Aviation-Related Research

Within the last decade, numerous online populations, such as SurveyMonkey ® and Amazon’s ® Mechanical Turk ®(MTurk), have been established allowing researchers to gather data involving diverse populations. These resources offer an alternative to traditional laboratory settings hosted at universities, where many studies utilize students as the available and accessible population. While these online portals do provide new opportunities, they also contain unique advantages and disadvantages. This paper synthesizes the advantages and disadvantages of using online populations to conduct research in the aviation field. Some of the advantages are: easier access to new populations, larger sample sizes, more balanced ratio of genders, lower cost, more timely data collection, reliable data, and anonymity of participants. Some of the disadvantages are: unrepresentative samples, lower response rates, financial motivation issues, limited access to certain portals, limited length of study, non-behavioral data, and lack of follow-up data. In addition, the authors share their personal experiences of using these portals and summarize previous literature researching online populations

Attitudes Toward Controlled Rest in Position (CRIP): A Gender Comparison Between Pilots and Non-Pilots

Prior studies demonstrate that controlled rest in position (CRIP) may help compensate for pilot fatigue. CRIP allows for one pilot to nap in their cockpit seat during the cruise phase of flight, provided that certain policies and procedures are followed by the other crew members during this period. The purpose of this research was to gather information from consumers and pilots on their willingness to fly if the pilots utilized CRIP. Our project employed a two-study design that manipulated both the length of the flight and the number of passengers onboard. Additionally, affect measures were collected through the use of a valid Likert scale to determine if affect had any mediating effect on the willingness to fly of participants. Study 1 was deployed to consumers while Study 2 sampled from both consumers and pilots. The findings indicated female respondents were significantly less willing to fly when CRIP was used than males, while pilots were willing to fly across all conditions. Affect was shown to be a mediating variable in all but one condition in both Study 1 and Study 2 between the types of passengers. The paper provides a discussion on these findings, identifies practical implications, and provides suggestions for future research

A form with a message : didacticism, adolescence, and femininity in young adult novels

In this thesis, I discuss the uses of two different forms of young adult novels for relaying messages about adolescence and femininity to adolescents from adult authors. I explore the traditional and organized quest narrative as written by Anne McCaffrey in her Harper Hall Trilogy with a young female hero. The requirements for the quest make the hero both isolated and above average, which in turn causes the hero to portray a complicated view of femininity and a linear adaptation of the adolescent journey. I then discuss the requirements and allowances of realism in Carolyn Mackler's The Earth, My Butt, and Other Big, Round Things. The result of the realistic novel for young adults is proof that there is no clearly defined reality, adolescent path, or femininity. The protagonist is left to choose her own definitions and manipulate what she sees and hears from others. I conclude that the form of the novel directly dictates the wisdom passed from adult to adolescent, and the explanation of the adolescent journey for young women differs as a direct result of form

Capital Structure Choices and Survival in a Deregulated Environment

We examine the impact of capital structure choices for survival in a deregulated industry. Financial leverage in particular has been identified by numerous prior studies as a major determinant of the probability of survival in most industries. In the course of a deregulation, the debt overhang effect stemming from high leverage negatively affects the ability of existing firms to survive when a regulatory shock occurs (Zingales, 1998). Following such a regulatory shock, and consistent with the tradeoff and debt overhang theories of capital structure, firms are more likely to reduce their level of leverage (Ovtchinnikov, 2010). This causes the expected costs of financial distress to rise higher and we can expect a negative association between leverage and survival in a deregulated industry. However, in a highly competitive setting, firms may signal their level of quality by contracting for more debt instead of equity (Ross, 1977). This signaling perspective can therefore induce the existence of a positive association between leverage and survival in a deregulated context. Using a sample of private trucking firms, we test this hypothesis and find a negative association between leverage and survival. In a refined analysis aimed at distinguishing high “quality” versus low “quality” firms, we adopt the “excess capacity” approach of De Vany and Saving (1977). Consistent with our initial findings, we find that the negative association between leverage and survival increases with the level of excess capacity

What Factors Influence the Imposter Phenomenon amongst Collegiate Flight Students?

The need for commercial airline pilots has been increasing significantly, and with the mandatory retirements projected in the next decade, the airline pilot workforce will have an injection of younger pilots. Previous research has studied the effects and prevalence of the Imposter Phenomenon (IP) in young professionals, especially graduate students, and academics. The phenomenon is particularly prevalent for female graduate students and academics. The purpose of this study is to observe the prevalence of the Imposter Phenomenon in collegiate pilots. Participants for the study are recruited from amongst collegiate flight students enrolled in a 4-year aviation university in Florida. A multiple regression analysis using backward stepwise regression will be employed to determine which factors influence the presence of Imposter Phenomenon in collegiate Part 141 pilots. 11 factors are tested as potential predictors (independent variables) in the study. These are age, gender, ethnicity, education level, total flight hours, pilot certification level, personality, measure of self-efficacy, measure self-handicapping, and perceived organizational support. The dependent variable will the participants level of Imposter Phenomenon, measured by using the 20-question validated Clance (1985) Imposter Phenomenon scale. The data collection process in currently underway, with the data analysis and results being completed and compiled by the end of 2019. This is an initial study in a line of future studies seeking to collect data from outside the collegiate pilot population, with the objective of creating a prediction model of Imposter Phenomenon within the United States pilot population

Technique for high axial shielding factor performance of large-scale, thin, open-ended, cylindrical Metglas magnetic shields

Metglas 2705M is a low-cost commercially-available, high-permeability Cobalt-based magnetic alloy, provided as a 5.08-cm wide and 20.3-$\mu$m thick ribbon foil. We present an optimized construction technique for single-shell, large-scale (human-size), thin, open-ended cylindrical Metglas magnetic shields. The measured DC axial and transverse magnetic shielding factors of our 0.61-m diameter and 1.83-m long shields in the Earth's magnetic field were 267 and 1500, for material thicknesses of only 122 $\mu$m (i.e., 6 foil layers). The axial shielding performance of our single-shell Metglas magnetic shields, obtained without the use of magnetic shaking techniques, is comparable to the performance of significantly thicker, multiple-shell, open-ended Metglas magnetic shields in comparable-magnitude, low-frequency applied external fields reported previously in the literature.Comment: 4 pages, 5 figure

A Conceptual Model for a Universal Severity of Emergency Report (USER): An Example in Aviation

In emergency situations, it is important that information be communicated quickly, concisely, and efficiently. Breakdowns can occur when the receiver of the emergency call does not fully understand the information that the person is sending. The purpose of this paper is to present a new model for enhancing communication between the sender and receiver in emergency situations. The Universal Severity of Emergency Report (USER) is a model designed to be used in emergency situations and convey more information about the current state of the person declaring the emergency than is currently offered by emergency communication channels. USER provides three key pieces of vital information: severity of the situation, capabilities of the sender, and ability to communicate. Severity identifies the level of the emergency on a scale of 1, 2, or 3. Capabilities use the colors white, yellow, and red to indicate the current self-determined capabilities of the individual. Communicate notifies the receiver if the individual is able to communicate or is unable to communicate. This paper presents this concept in an aviation context, but USER has the potential to be used in any number of industries, including medical, military, shipping, transportation, space flight, and law enforcement