473 research outputs found
Exploring H.pylori seropositivity as a risk factor for type 2 diabetes
Background: In the US, the percentage of adults with diagnosed diabetes are higher in members of racial and ethnic minority groups compared to non-Latino Whites. Understanding why such disparities exist has been less forthcoming.
Methods: Secondary data analysis was conducted using the National Health and Nutrition Examination Survey (NHANES) 1999-2000 cross-sectional data.
Results: H.pylori seropositivity was highest in Mexican Americans (43.7%), lowest in non-Hispanic Whites (18.1%). Diabetes was highest in non-Hispanic Blacks (5.9%); lowest in non-Hispanic whites (4.3%). H.pylori seropositivity was associated with greater likelihood of having type 2 diabetes (1.927, 95% CI 1.142, 3.257) compared to H.pylori negative in unadjusted model. After adjustment, H.pylori seropositivity was no longer associated with diabetes. Obesity (aOR 4.94, 95% CI 2.672,9.133) was associated with having type 2 diabetes compared to normal weight. Non-Hispanic Blacks (2.436, 95% CI 1.489,3.984) and Mexican Americans (1.896, 95% CI 1.002,3.587) had greater odds of diabetes compared to Whites. For nearly all stratified analyses, H.pylori did not have a significant association with type 2 diabetes although several other noteworthy findings emerged. A chance finding, where H.pylori was associated with greater likelihood of diabetes in Mexican Americans, 60-85, \u3e25 BMI, may be worth a closer look.
Conclusion: Findings indicate weight status, obesity in particular, is the strongest predictor of diabetes followed by Black race. Stratified analyses suggest increasing racial disparities over the course of the life span
Modeling and Performance Evaluation of Electromagnetic Suspension Systems for the Hyperloop
In 2012, the founder of SpaceX, Elon Musk, proposed a new method of transportation known as the Hyperloop. The proposed system, which would serve as the fifth method of transportation, described the fundamental theory of traveling in a near-vacuum tube at high speeds in a pod-like vehicle. Since Musk made his proposal, various companies and universities have investigated the Hyperloop concept in order to make it a reality.
Researchers in the engineering and scientific community are currently investigating an effective electromagnetic suspension system design for the Hyperloop. It is hypothesized that a passive magnetic levitation (maglev) suspension system, as similarly designed for maglev trains, can be properly modeled and designed to provide optimized performance results for the proposed transportation method. The electromagnetic suspension design will utilize a specific arrangement of permanent magnets known as the Halbach array. In introducing linear velocity to the magnets, they will induce eddy currents along a conducting surface, and as a result, will create a force of levitation that will sustain the full weight of the capsule. Researchers have also proposed that in using a method of active magnetic levitation, where angular velocity instead of linear velocity is applied to the arrangement of magnets, the electromagnetic suspension will have improved control in stabilizing the induced levitation force and in keeping the displacement gap between the Hyperloop capsule and the conducting track constant.
In order to approach this engineering problem, a specific methodology composed of literature review, calculation analysis, simulation, and testing evaluation has been selected for the purpose of obtaining satisfactory results for the proposed electromagnetic suspension systems. Through literature review, the physical theoretical models behind the proposed technology will be fully investigated in order to properly apply them as the foundational architecture of the suspension system. A mathematical model of the proposed suspension system will be designed and tested through MATLAB, for comparing the theoretical models with experimental data of existing technologies. Furthermore, the simulation results will be observed and analyzed in order to properly evaluate the figures of merit of the electromagnetic suspension methods
A DACA Initiative: Transformative Organizational Change at the School of Medicine
The purpose of this revelatory case study is to explore how the DACA Initiative (DI) transformed the School of Medicine (SOM) beyond just changing student demographics. In this research, I specifically explored if, through the DI, SOM organizationally changed enough to be considered transformative change in its efforts to enhance the acceptance and support of DACA medical students. In addition, I looked at the evolution of the financial operations at SOM to support DACA medical students. The research questions that guided this study were: As a result of the DI, did the organizational changes implemented by SOM to accept and support DACA medical students result in transformative change for SOM? What makes DACA students feel welcomed at an institution and how did SOM evolve to make them feel welcomed? Data was collected from focus groups and interviews that explored what the DI means to different SOM stakeholders: DACA alumni, and key personnel from leadership and administrators. In addition, individual interviews were conducted with three of the five financial institutions that loaned money to SOM DACA medical students for medical school tuition. Transformative Organizational Change theory and Institutional Culture and Context framework were combined to allow me to look at both the change that is occurring and the location of that change within the organization. The research uncovered SOM\u27s journey embracing DACA students and showcases resilience and commitment to diversity, though commitment levels vary within the university. Potential discrepancies between public support and private hesitations raise questions about true dedication to inclusivity, urging transparency and consistent communication from the University. As competition to attract DACA students into professional programs increases, sustaining support and evolving initiatives beyond recruitment become essential for long-term success
CryoCart Restoration and Vacuum Pipe Construction
Propulsion systems that utilize hypergolic propellants have been used to power space vehicles since the beginning of the space program. Liquid methane and oxygen propulsion systems have emerged as an alternative and have proven to be more environmentally friendly. The incorporation of liquid methane/liquid oxygen (LOX) into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the system. Consequently, reducing the total mass of the vehicle which is a crucial aspect that is considered when planning space missions to both the Moon and Mars [1]. Project Morpheus has made significant advancements in liquid oxygen/liquid methane propulsion system technologies by incorporating a LOX/methane propulsion system to a vertical test bed. The vehicle consisted of a 5,000 lb main engine and four 20 lb remote control system (RCS) engines that utilize liquid methane/LOX as its propellant [1]. The vehicle completed successful flight testing at Kennedy Space Center in 2014 which marked the completion of the Morpheus project. Subsequent projects utilizing Morpheus' vertical test bed have been developed to make further advancements. One of the subsequent projects consisted of the addition of a smaller 2,000 lb main engine and a cold helium heat exchanger which would make it possible for a pressurant tank systems to be send to Mars or the Moon by significantly decreasing the overall mass and volume of the pressurant tank. The hot fire tests of the integrated system with the smaller main engine and cold helium heat exchanger were successful at sea level, but further studies are being conducted to better understand how the vertical test bed will behave under thermal-vacuum conditions. For this reason, the integrated vehicle will be taken to Plum Brook to be tested in a chamber capable of simulating these conditions. To ensure that the vehicle will function properly under vacuum conditions, testing will be first completed at the component level. During this process, the igniter of the main engine and the RCS thrusters will be tested under a vacuum. To complete the testing of the components, the test setup first needed to be finalized. The CryoCart is being used to feed the propellants to the test article. The CryoCart is a movable test set-up that was developed in 2009 to provide a mobile platform for testing oxygen/methane systems with hot-fire capability up to 100 lbf. The CryoCart consists of three different systems: Oxygen, Methane, and liquid Nitrogen. The Oxygen and Methane systems are placed into two different carts while the liquid nitrogen system is mainly located in the methane cart. Over the years, the CryoCart has been utilized for different projects and has undergone deterioration. For this reason, a new phase has been developed to rebuild it to working conditions once again. During my internship, I was aiding in the construction and restoration of the CryoCart. In the initial stages of the process, I updated the fluid and electrical schematics for the oxygen, methane, and test article systems. The original CryoCart consisted of an electrical panel that utilized electromechanical relays and a terminal to drive the igniter power and signal, as well as the main fuel and oxygen valves. This electrical panel connected to the CryoCart through various wire harnesses that could be found exiting from the CryoCart. First, it was determined how these harnesses connected to the electromechanical relays so that they worked correctly. Once the electrical system was understood, an alternative for the electromechanical relays and the Molex connectors used throughout the system was sought since these components can often prove to be unreliable. Solid State relays and MIL connectors were purchased to serve as replacements. Upon arrival of the parts, crimping and wiring was completed to install the new solid state relays and MIL connectors. During the replacement of the relays and connectors, system checks of the electrical system were ran to ensure that the system was working correctly. While completing system checks, the pressure transducers that were not functioning properly were also replaced and any issue with the wiring or signal was addressed. Once the electrical components were replaced, the restoration of the fluid system began. Parts of the tubing in the CryoCart had to be rebuild and often consisted of sizing, cutting, bending, filing, and sanding the tubing to prepare it to be flared. Many components had to be proof-tested to bring their certifications up to date, and several components had to be replaced. Various flex hoses, valves, and fittings were send to the Clean Lab because they were new, dirty, or had gone through proof-testing. Once they arrived from the cleaning lab they had to be put back to the system and leak checks and functional tests were conducted. In the Nitrogen system, the copper tubing located in the Oxygen cart was rebuild and Aerogel insulation was added to this section. A new gaseous nitrogen system was added to the CryoCart to purge the vacuum tube which will serve as the test chamber. Once the CryoCart was completed, construction of parts of the vacuum tube began. A flange was manufactured with welded fittings to hold the line of the vacuum pump as well as some extra fittings which will serve as extra inlets used to introduce fluid lines to the vacuum tube. Stress analysis was ran in this flange to ensure that it would not fail under vacuum conditions. The fluid lines leading from the air side of the vacuum to the test article were also constructed and added to the mount that had already been manufactured. Three different sets of tubing were constructed to accommodate the seven different RCS thruster and the main engine igniter that are going to be tested. Full electrical system checks were completed to ensure that all the wire harnesses and valves were functioning. Upon the completion of the CryoCart and the vacuum tube, hot fire testing for the RCS thrusters and the main engine igniter are going to begin. During this time any issues encountered with the engines or igniter will be addressed to ensure that the components function under vacuum conditions. After successful completion of testing, the vertical test bed, Morpheus, will be rebuilt and prepared to be sent to Plum Brook. In Plum Brook, the vehicle will be tested in the thermal-vacuum chamber to demonstrate that integrated lox-methane propulsion system operation in space-like conditions. This internship has allowed me the opportunity to gain valuable hands on experience and to develop skills that will aid in my education as well as in the workforce, while at the same time helping me determine that I would like to further pursue a career in propulsion engineering
How to Attract Children and Adults to the Same Beverage through Package Design
The purpose of this study was to determine if children and adults could be attracted to the same beverage through package design. This study surveyed particpants in the San Luis Obispo Area on prefernece of different juice labels. The survey asked the preference of different juice labels based on typeface, size and layout of the logo, contrast, type of substrate, and color. The survey participants were in different age groups ranging from 4 years old to those over 40 years old.
Results from one hundred sixty-one responses indicated although not all age groups were attracted to the same elements of a beverage label, patterns did arise in some age groups’ preferences. This data can allow beverage companies to reach a larger target market successfully, thus increasing sales
Newton-Okoukov bodies and symplectic embeddings into non-toric rational surfaces
We develop new methods of both constructing and obstructing symplectic
embeddings into non-toric rational surfaces using the theory of Newton-Okoukov
bodies. Applications include sharp embedding results for concave toric domains
into non-toric rational surfaces, and new cases of non-existence for infinite
staircases in the non-toric setting.Comment: 33 pages, 6 figures. Minor edits to v1. To appear in Journal of the
London Mathematical Societ
Elementary SFT Spectral Gaps And The Strong Closing Property
We formulate elementary SFT spectral invariants of a large class of
symplectic cobordisms and stable Hamiltonian manifolds, in any dimension. We
give criteria for the strong closing property using these invariants, and
verify these criteria for Hofer near periodic systems. This extends the class
of symplectic dynamical systems in any dimension that satisfy the strong
closing property.Comment: 76 pages, 5 figures. Comments welcome
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