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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Cenotaph: A Composition for Computer-Generated Sound

Rogers, Rowell S. (Rowell Seldon) 08 1900 (has links)
Cenotaph is a work of fifteen minutes duration for solo tape realized on the Synclavier Digital Music System at the Center for Experimental Music and Intermedia. All of the sound materials in the work consist of resynthesized timbres derived from the analysis of digital recordings of seven different human voices, each speaking the last name of one of the Challenger astronauts. The work's harmonic resources are derived in a unique way involving partitioning of the octave by powers of the Golden Section. The work is in a single movement divided into three sections which function as prologue, action, and epilogue, respectively. This formal structure is reinforced by differentiation of harmonicmaterials and texture. Although Cenotaph cannot be performed "live" and exists only as a recording, a graphic score is included to assist analysis and study.
2

Developing and Evaluating Computer-Based Teamwork Skills Training for Long-duration Spaceflight Crews

Hixson, Katharine 01 January 2013 (has links)
Due to the long-duration and long distance nature of future exploration missions, coupled with significant communication delays from ground-based personnel, NASA astronauts will be living and working within confined, isolated environments for significant periods of time. This extreme environment poses concerns for the flight crews' ability to maintain cohesiveness and teamwork. If teamwork behaviors (i.e., communication, coordination, and collaboration) and cohesion are impacted, the mission success and crew safety can be threatened. Teamwork training is critical to ensuring that team cohesion and performance are maintained. Yet, delivering this training is challenging, as spaceflight crews are geographically dispersed across the globe and often train on different schedules. Designing and implementing an eLearning teamwork skills training, which can be delivered asynchronously, is a valuable and necessary initiative. However, questions remain regarding the most effective strategies, sequence and scope for team training. This design-based research constructed and validated a computer-based instructional unit for teamwork skills training, using the educational research and development model. The unit was validated through a formative evaluation process consisting of preliminary and main field-testing. The testing utilized an expert review methodology in which teamwork training subject matter experts at NASA, instructional designers and trainers at NASA, and experts on the astronauts at NASA evaluated the prototype. Upon analyzing the results and feedback, revisions were made to the prototype. The overall results of the data collection stages of the process indicate that a relevant, beneficial and potentially effective teamwork skills training unit was created. The educational research and development process resulted in the development of a teamwork skills training program that is ready for operational testing and dissemination. Additionally, a detailed example of adherence to instructional design principles and processes is provided.
3

Does Spaceflight Increase the Chance of Female Astronauts Developing Uterine Cancer?

Mosa, Areej 01 May 2018 (has links) (PDF)
One of the main questions put forth by NASA and the European Space Agency (ESA) is whether or not an organism, especially mankind, can complete an entire life cycle in space. With this in mind, it is essential to study the effect of spaceflight on reproductive tissues. Using simulated microgravity techniques and whole-body radiation we sought to determine if females subjected to a simulated spaceflight environment have increased incidences of uterine cancer. Uterine tissue from mice subjected to simulated spaceflight was analyzed using immunohistochemical staining and western blot analysis. Two pathways commonly activated in cancer were investigated. Additionally, the uterine tissue was evaluated for gross morphological changes using standard histological staining. The findings of this study indicate that none of the treatment parameters used to simulate the spaceflight environment were found to induce uterine cancer.
4

Human Leukocyte Transcriptome Changes in Response to Altered Gravity Environments: Investigations Using Bed Rest Participants and Astronauts Aboard the International Space Station

Stratis, Daniel 05 September 2023 (has links)
Introduction: Space is an extreme environment exposing astronauts to microgravity and cosmic radiation resulting in immune dysfunction. To overcome the complex challenges of studying astronauts in space, bed rest studies represent an alternative model simulating microgravity exposure on Earth. We sought to characterize the steady state transcriptome changes in leukocytes isolated from two microgravity models: (1) participants to 60 days of bed rest and (2) astronauts to ~6 months of spaceflight. Methods: The bed rest study recruited twenty healthy men receiving a nutritional supplement or not; the spaceflight study had fourteen male and female astronauts participate. For both studies, ten blood samples were collected over three study phases, leukocytes were isolated, and transcriptomes were quantified using high throughput RNA-sequencing. My pipeline of data analysis applied differential expression (DE) methods and functional enrichment to identify gene expression changes and pathways responding to the altered gravity environments of both bed rest and spaceflight models. Results: Temporal differential expression identified transcriptome modulation reflecting multisystem shifts and immune dysregulation in response to the transitions to and from bed rest (2,415 DE genes) and spaceflight (247 DE genes). Interestingly, later bed rest and in-flight timepoints trended towards stable RNA levels with no differential expression. The bed rest study found the nutritional intervention had no mitigating effects on transcriptome changes (0 DE genes), and the spaceflight study revealed down-regulation in response to spaceflight followed by an opposite up-regulation upon return to Earth. Conclusion: The altered gravity environments of bed rest and spaceflight significantly modulated leukocyte transcriptome compositions revealing immune dysfunction at the molecular level. Future analyses utilizing the higher quality bed rest dataset is required to isolate the effect of microgravity from other space stressors and apply validation experiments to develop gene biomarkers indicative of immune deconditioning.
5

Hand grip performance with the bare hand in the extravehicular activity globe

Roesch, J. Richard January 1986 (has links)
Astronauts have complained of difficulty in grasping tools, hand fatigue, and hand/forearm pain during extravehicular activities. This study was conducted to examine hand grip performance with a bare hand and in a spacesuit glove at two different pressures, with three hand positions and two elbow positions. Sixteen subjects, selected from the suited-subject pool at the Johnson Space Center, gripped a hand dynamometer encased in a vacuum chamber designed to simulate the operating pressures in space. The results for the bare hand condition showed a significant effect for hand position and a significant elbow/hand interaction. The spacesuit glove at operating pressure was responsible for an average 42% grip strength decrement from the bare hand condition. A new procedure for determining hand size from projected hand surface area revealed that bare and gloved-hand grip strength was highly correlated with hand size, as were body weight, height, and forearm circumference. / M. S.
6

A minimalistic model of resistance training : effects on skeletal muscle function during unloading

Schulze, Kimberley E. January 1999 (has links)
Since astronaut time and energy are at a premium, effective countermeasures must be designed to maximize benefits while minimizing time/energy cost. Therefore, our intent was to design and evaluate a low volume, high intensity resistance training program (RTP) on the preservation of knee extensor and plantar flexor size, strength and neuromuscular function in response to unloading. A total of 32 subjects participated. Sixteen men underwent 21 days of unilateral lower limb suspension (ULLS) and were assigned to control (no RTP) (ULLS-CON, n=8) or countermeasures (ULLS-CM, n=8). The remaining subjects were ambulatory for 21 days and were assigned to no RTP (n=8) or countermeasures (n=8). Countermeasure subjects performed RTP every third day during the suspension period (total=6). The RTP consisted of 2 maximal isometric contractions (MVC), 1 set of 10 concentric/eccentric isotonic repetitions, and 1 set to exhaustion, at 80% of 1-repetition maximum (1RM). There was no change in muscle function in ambulatory subjects. Whole muscle cross sectional area (CSA) measured by computed tomography (CT) decreased 7% (thigh) and 7.5% (calf) in ULLS-CON (p<0.05), and was unchanged in ULLS-CM. MVC decreased 16.5% in both quadricep and calf muscles in ULLS-CON (p<0.05) and increased 6% in the quadricep of ULLSCM (p<0.05). Maximal concentric (CNC) and eccentric (ECC) isokinetic strength decreased an average of 18% and 17% in the knee extensors and plantar flexors of ULLS-CON, respectively (p<0.05) and was unchanged in ULLS-CM. 1RM decreased 16% in both quadricep and calf of ULLS-CON (p<0.05) and was unchanged in ULLSCM. Knee extensor work capacity, evaluated during 30 maximal CNC contractions (3.14 rad•sec-'), decreased 18% in ULLS-CON (p<0.05). Neural activation of knee extensors and plantar flexors was measured by electromyography (EMG). Submaximal v.lat, v.med, gast and sol EMG increased in ULLS-CON (p<0.05) and was unaltered in ULLSCM. Maximal EMG decreased 20% and 26% in v.1at and v.med, respectively in ULLSCON (p<0.05). ULLS-CM showed a 15% and 28% increase in v.med and gast maximal EMG (p<0.05). These data suggest knee extensor and plantar flexor muscle size, strength and neuromuscular function were preserved during unloading using a low volume, high intensity RTP performed every third day. / School of Physical Education
7

Suppression of osteoblast activity by disuse is prevented by low magnitude mechanical loading through a bone morphogenic protein-dependent Mechanism

Patel, Mamta Jashvantlal 15 January 2008 (has links)
Musculoskeletal pathologies associated with decreased bone mass, including osteoporosis and disuse-induced bone loss, affect millions of Americans annually. Many pharmaceutical treatments have slowed osteoporosis, but there is still no countermeasure for bone loss observed in astronauts. Additionally, high magnitude and low frequency impact has been recognized to increase bone and muscle mass under normal but not microgravity conditions. However, a low magnitude and high frequency (LMHF) mechanical load experienced in activities such as postural control has also been shown to be anabolic to bone. While several clinical trials have demonstrated that the LMHF mechanical loading normalizes bone loss in vivo, the target tissues and cells of the mechanical load and underlying mechanisms mediating the responses are unknown. As such, the objectives of this project are to analyze cellular and molecular changes induced in osteoblasts by LMHF loading and to investigate the utility of a LMHF mechanical load in mitigating microgravity-induced bone loss. The central hypothesis of the project is that simulated microgravity or disuse conditions induce bone loss by inhibiting expression of genes critical in regulating bone formation, osteoblast differentiation, and subsequent mineralization while a LMHF mechanical load prevents these effects. To test this hypothesis, we developed an in vitro disuse system using the Random Positioning Machine (RPM). For the first time, we reported systemic gene expression studies in 2T3 preosteoblasts using the RPM disuse system showing that 140 genes were altered by RPM exposure with over two-fold statistically significant changes. Moreover, we also utilized an independent simulator called the Rotating Wall Vessel (RWV) to partially validate the in vitro disuse systems and to confine the list of genes to those most critical in regulating bone formation. After comparative studies, we constricted the list to 15 commonly changed genes, three of which were not only decreased with disuse but also increased with mechanical loading in vivo. Furthermore, we employed the RPM disuse system to evaluate the mechanism by which a LMHF load mitigates bone loss. Exposure of osteoblasts to the RPM decreased both ALP activity and mineralization even in the presence of bone morphogenic protein 4 (BMP4), and the LMHF mechanical loading prevented the RPM-induced decrease in both markers. Mineralization induced by LMHF mechanical loading was enhanced by treatment with BMP4 and blocked by the BMP antagonist noggin, suggesting a role for BMPs in this response. In addition, LMHF mechanical loading rescued the RPM-induced decrease in gene expression of ALP, runx2, osteomodulin, parathyroid hormone receptor 1, and osteoglycin. These findings show that osteoblasts directly respond to LMHF mechanical loading, potentially leading to normalization or prevention of bone loss caused by disuse or microgravity conditions. The mechanosensitive genes identified here provide potential targets for pharmaceutical treatments that may be used in combination with LMHF mechanical loading to better treat osteoporosis, disuse-induced bone loss, or microgravity-induced bone loss.
8

Analysis and Definition of the BAT-ME (BATonomous Moon cave Explorer) Mission / Analys och bestämning av BAT-ME (BATonomous Moon cave Explorer) missionen

Muresan, Alexandru Camil January 2019 (has links)
Humanity has always wanted to explore the world we live in and answer different questions about our universe. After the International Space Station will end its service one possible next step could be a Moon Outpost: a convenient location for research, astronaut training and technological development that would enable long-duration space. This location can be inside one of the presumed lava tubes that should be present under the surface but would first need to be inspected, possibly by machine capable of capturing and relaying a map to a team on Earth.In this report the past and future Moon base missions will be summarized considering feasible outpost scenarios from the space companies or agencies. and their prospected manned budget. Potential mission profiles, objectives, requirements and constrains of the BATonomous Moon cave Explorer (BAT-ME) mission will be discussed and defined. Vehicle and mission concept will be addressed, comparing and presenting possible propulsion or locomotion approaches inside the lava tube.The Inkonova “Batonomous™” system is capable of providing Simultaneous Localization And Mapping (SLAM), relay the created maps, with the possibility to easily integrate the system on any kind of vehicle that would function in a real-life scenario.Although the system is not fully developed, it will be assessed from a technical perspective, and proper changes for a viable system transition for the space-Moon environment will be devised. The transition of the system from the Batonomous™ state to the BAT-ME required state will be presented from the requirement, hardware, software, electrical and operational point of view.The mission will be devised into operational phases, with key goals in mind. Two different vehicles will be presented and designed on a high engineering level. A risk analysis and management system will be made to understand the possible negative outcomes of different parts failure on the mission outcome.
9

A study of International Space Station ground/crew communication methods with applications to human Moon and Mars missions

Esper, Jennifer Eileen. January 2007 (has links)
Thesis (M.S.)--Mississippi State University. Department of Aerospace Engineering. / Title from title screen. Includes bibliographical references.
10

A Study of International Space Station Ground/Crew Communication Methods with Applications to Human Moon and Mars Missions

Esper, Jennifer Eileen 05 May 2007 (has links)
The International Space Station utilizes many different forms of written and verbal communication between the flight crews and ground control personnel. This study analyzes the historical use of three regular communication methods, Daily Planning Conferences, Weekly Planning Conferences and written Daily Summaries, as well as specific, science and internal maintenance events for characteristics and perceived effectiveness across eight expeditions (4 ? 11). The results are recommendations for the continued use of, or substitution for, these methods for future long-duration human space missions, specifically to the Moon and to Mars. General conclusions are that most of the conference content could have been relayed through written/electronic methods, and that the Daily Summaries are considered succinct and effective as a communication cornerstone. Conclusions formed from the study of individual events involved the importance of well-written crew procedures, the effective stowage and retrieval of necessary materials and the selection of well-defined science experiments.

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