Matching Items (341)
Description
This work examines star formation in the debris associated with collisions of dwarf and spiral galaxies. While the spectacular displays of major mergers are famous (e.g., NGC 4038/9, ``The Antennae''), equal mass galaxy mergers are relatively rare compared to minor mergers (mass ratio <0.3) Minor mergers are less energetic than major mergers, but more common in the observable universe and, thus, likely played a pivotal role in the formation of most large galaxies. Centers of mergers host vigorous star formation from high gas density and turbulence and are surveyed over cosmological distances. However, the tidal debris resulting from these mergers have not been well studied. Such regions have large reservoirs of gaseous material that can be used as fuel for subsequent star formation but also have lower gas density. Tracers of star formation at the local and global scale have been examined for three tidal tails in two minor merger systems. These tracers include young star cluster populations, H-alpha, and [CII] emission. The rate of apparent star formation derived from these tracers is compared to the gas available to estimate the star formation efficiency (SFE). The Western tail of NGC 2782 formed isolated star clusters while massive star cluster complexes are found in the UGC 10214 (``The Tadpole'') and Eastern tail of NGC 2782. Due to the lack of both observable CO and [CII] emission, the observed star formation in the Western tail of NGC 2782 may have a low carbon abundance and represent only the first round of local star formation. While the Western tail has a normal SFE, the Eastern tail in the same galaxy has an low observed SFE. In contrast, the Tadpole tidal tail has a high observed star formation rate and a corresponding high SFE. The low SFE observed in the Eastern tail of NGC 2782 may be due to its origin as a splash region where localized gas heating is important. However, the other tails may be tidally formed regions where gravitational compression likely dominates and enhances the local star formation.
ContributorsKnierman, Karen A (Author) / Scowen, Paul (Thesis advisor) / Groppi, Christopher (Thesis advisor) / Mauskopf, Philip (Committee member) / Windhorst, Rogier (Committee member) / Jansen, Rolf (Committee member) / Arizona State University (Publisher)
Created2013
Description
This six month IRB approved qualitative study was held at Arizona State University to see how a group of seven university dancers' body appreciation and body perception would be affected by introduction and familiarized with Bartenieff Fundamentals and other somatic practices. During this process the individuals gained knowledge about their own bodies through somatic movement activities, journal writings, group discussions, and personal interviews. Movers then used this knowledge to create movement phrases that represented their own personal journeys with body image struggles, doubts, and insecurities. These movement phrases were then linked together in a 40-minute expressive movement piece that represented the journey the group of movers had made and was still making together.
ContributorsRodgers, Patricia (Author) / Jackson, Naomi (Thesis advisor) / Britt, Melissa (Committee member) / Vissicaro, Pegge (Committee member) / Arizona State University (Publisher)
Created2014
Description
Transformation Is... is an arts practice-led research in Dance and Design, embodying and materializing concepts of structure, leadership and agency and their role in bringing about desired social transformation. My personal experiences as a foreign student interested in transformative experiences gave origin to this arts practice-led research. An auto-ethnographic approach informed by grounded theory methods shaped this creative inquiry in which dance was looked at as data and rehearsals became research fields. Within the context of social choreography, a transformational leadership style was applied to promote agency using improvisational movement scores to shape individual and collective creative explorations. These explorations gave birth to a flexible and transformable dance installation that served as a metaphor for social structure. Transformation revealed itself in this research as a sequence of process and product oriented stages that resulted in a final performance piece in which a site-specific interactive installation was built before the audience's eyes. This work became a metaphor of how individual actions and interactions effect the construction of social reality and how inner-transformation and collaboration are key in the process of designing and building new egalitarian social structures.
ContributorsSibauste Bermudez, Janelle (Author) / Kaplan, Robert (Thesis advisor) / Britt, Melissa (Committee member) / Standley, Eileen (Committee member) / Arizona State University (Publisher)
Created2014
Description
"Linked Together" is a choreographic piece inspired by at-risk youth and their ability to learn, grow, and transform their lives through dance. The idea for the piece originated from dance programs implemented with under-resourced populations in Virginia, Panama, and India. My teaching experiences in these places sparked the development of a longer, more comprehensive dance program in Arizona, with a Boys and Girls Club. The Arizona dance program included specific somatics exercises, focused on the integration of mind and body, as well as other types of improvisations, to help the participants learn about movement concepts and develop original movement.
The title "Linked Together" suggests that all people are connected in many ways, regardless of personal differences such as socioeconomic status or language. The dancers included myself, Arizona State University (ASU) dance students, as well as Boys and Girls Club dance program participants. For the concert, all dancers portrayed stories and concepts related to empowerment through emotionally charged movement, and thereby provided audience members with a visceral lens through which to see the transformative powers of dance. The data collected from this project through observations, surveys, and interviews suggest that constructive behaviors that are internalized through dance can flow seamlessly into the non-dance world, encouraging people to think creatively, collaborate with others, gain a sense of ownership, and feel empowered in all parts of life.
The title "Linked Together" suggests that all people are connected in many ways, regardless of personal differences such as socioeconomic status or language. The dancers included myself, Arizona State University (ASU) dance students, as well as Boys and Girls Club dance program participants. For the concert, all dancers portrayed stories and concepts related to empowerment through emotionally charged movement, and thereby provided audience members with a visceral lens through which to see the transformative powers of dance. The data collected from this project through observations, surveys, and interviews suggest that constructive behaviors that are internalized through dance can flow seamlessly into the non-dance world, encouraging people to think creatively, collaborate with others, gain a sense of ownership, and feel empowered in all parts of life.
ContributorsDaniel, Chareka (Author) / Fitzgerald, Mary (Thesis advisor) / Britt, Melissa (Committee member) / Manning, Linda (Committee member) / Arizona State University (Publisher)
Created2015
Description
The design, fabrication and testing of a novel full waveguide band ortho-mode transducer (OMT) for operation from 750-1150 GHz is presented in this dissertation. OMT is a device that separates orthogonal polarizations within the same frequency band. At millimeter and sub millimeter wavelengths, OMTs can achieve precise characterization of the amplitude, spectrum and polarization of electromagnetic radiation by increasing spectral coverage and sensitivity while reducing aperture size, optical spill and instrumental polarization offsets. A fully planar design is implemented with the use of Robinson OMT model along with a planar finline circuit. CST Microwave Studio is used to design and simulate OMT. Existing finline circuits which were fabricated using photolithographic techniques on a thin dielectric substrate were employed. The finline chips are fabricated on a thin (1 µm) SOI substrate with thick (5 µm) gold finline metallization and gold beam leads for chip grounding. The OMT is designed with H plane splits in the through arm and E plane splits in the side arm to comply with the existing machining tools and technique. Computer Numerical Controlled (CNC) machining is used to fabricate the OMT split block. The OMT is tested at Jet Propulsion Laboratory (JPL) using Agilent PNA-X VNA and VDI WR1.0 extension heads. In the future, this OMT design could be a part of a fully integrated dual polarization mixer block, with the input horn, OMT and both mixers fabricated in a single flangeless split block. In Radio Astronomy, integrated dual polarization mixers of this type will increase the signal processing speed by 40%. This type of OMT can also be used for terahertz RADAR and communication purposes.
ContributorsSirsi, Siddhartha (Author) / Groppi, Christopher (Thesis advisor) / Aberle, James T., 1961- (Thesis advisor) / Mauskopf, Philip (Committee member) / Arizona State University (Publisher)
Created2014
Description
Public engagement is increasingly viewed as an important pillar of scientific scholarship. For early career and established scholars, however, navigating the mosaic landscape of public education and science communication, noted for rapid “ecological” succession, can be daunting. Moreover, academics are characterized by diverse skills, motivations, values, positionalities, and temperaments that may differentially incline individuals to particular public translation activities.
ContributorsAmorim, Carlos Eduardo G (Author) / Dasari, Mauna (Author) / Durgavich, Lara (Author) / Hinde, Katie (Author) / Kissel, Marc (Author) / Lewton, Kristi L (Author) / Loewen, Tisa (Author)
Created2021
Description
Fruit and vegetable consumption among school children falls short of current recommendations. The development of Public-Private Partnerships (PPP), which combine the resources of government entities with the resources of private entities, such as businesses or not-for-profit agencies, has been suggested as an effective approach to address a number of public health concerns, including inadequate fruit and vegetable consumption. The United States Department of Agriculture's (USDA) Fresh Fruit and Vegetable Program (FFVP) provides fruits and vegetables as snacks at least twice per week in low-income elementary schools. In addition to increasing fruit and vegetable consumption behaviors at school, children participating in the FFVP have been found to make more requests for fruits and vegetables in grocery stores and at home, suggesting the impact of the program extends beyond school settings. The purpose of this multicase study was to describe key stakeholders' perceptions about creating PPPs between schools and nearby retailers to cross-promote fruits and vegetables in low-income communities, using the FFVP. Semi-structured interviews were conducted with participants from three cases groups: grocery store/produce managers (n=10), district FFVP personnel (n=5) and school FFVP personnel (n=12). Data were analyzed using a directed content analysis approach using constructs from the Health Belief Model, including benefits, barriers, strategies, and motivation. While findings varied by case group, key benefits of creating a PPP included the potential to increase store sales, to enhance public relations with the community, and to extend the impact of the FFVP to settings outside of schools. Barriers included offering expensive produce through the FFVP, time/labor-associated costs, and needing approval from authorities and supervisors. Strategies for developing a PPP included using seasonal produce and having clear instructions for teachers and staff. Stakeholders reported being motivated to create a PPP by the potential to improve health outcomes in children and by wanting to help the community. Both objective and subjective measures were suggested to measure the success of such a partnership. Finally, the educational component of the USDA's Supplemental Nutrition Assistance Program (SNAP-Ed) has the potential to serve as a catalyst for organizing a PPP between FFVP-participating schools and nearby grocery stores.
ContributorsGruner, Jessie (Author) / Ohri-Vachaspati, Punam (Thesis advisor) / Evans, Browynne (Committee member) / Bruening, Meg (Committee member) / Tasevska, Natasha (Committee member) / Hekler, Eric (Committee member) / Arizona State University (Publisher)
Created2017
Description
Despite the literature suggesting that fruits and vegetables (F&V) can have a protective outcome against overweight, obesity and chronic diseases, consumption is still inadequate. In order to address under consumption of F&V among children, schools have become a platform for a variety of food programs. The Fresh Fruit and Vegetable Program (FFVP), a United States Department of Agriculture (USDA) initiative, aims to increase exposure and consumption of F&V in low-income school children by providing F&V snacks. Participation in FFVP has been associated with higher preference and consumption of F&V and research also suggests that the program has the potential to decrease rates of overweight and obesity. The benefits of this program have been found to extend outside of the school setting, with higher requests for F&V at home and at the grocery store. This study aims to explore how children’s participation in the FFVP influences home food environments and shopping practices through qualitative analysis focus group data. Four focus groups were held with parents (n=25) from three FFVP participating schools. The data was analyzed using an inductive thematic analysis approach to find themes within the discussions. The findings were grouped into three categories: General Perceptions of FFVP, Impact of FFVP on the Home Food Environment, and Impact of FFVP on Shopping Practices. For General Perceptions of FFVP, themes were: Children learn about and enjoy F&V, awareness of farm to school programs, and children make healthier choices. Impact of FFVP on the Home Food Environment included the themes: Choosing heathier foods and snacks, parent F&V behaviors, children request F&V at home, and children talk about or bring F&V home. Finally, Impact of FFVP on Shopping Practices included the themes: children’s involvement in shopping, children request to buy F&V, children request non-produce items, and parents decline or limit unhealthy requests. This qualitative study provides valuable insights about how FFVP participation influences child and family behaviors towards F&V at home and in the grocery store. School food programs, such as the FFVP, have a positive influence on F&V related behaviors among children and should be continued and expanded.
ContributorsAcosta Ortiz, Marina (Author) / Ohri-Vachaspati, Punam (Thesis advisor) / DeWeese, Robin (Thesis advisor) / Gruner, Jessie (Committee member) / Arizona State University (Publisher)
Created2018
Description
The Milky Way galaxy is a powerful dynamic system that is highly efficient at recycling material. Stars are born out of intergalactic gas and dust, fuse light elements into heavier elements in their cores, then upon stellar death spread material throughout the galaxy, either by diffusion of planetary nebula or by explosive events for high mass stars, and that gas must cool and condense to form stellar nurseries. Though the stellar lifecycle has been studied in detail, relatively little is known about the processes by which hot, diffuse gas ejected by dying stars cools and conglomerates in the interstellar medium (ISM). Much of this mystery arises because only recently have instruments with sufficient spatial and spectral resolution, sensitivity, and bandwidth become available in the terahertz (THz) frequency spectrum where these clouds peak in either thermal or line emission. In this dissertation, I will demonstrate technology advancement of instruments in this frequency regime with new characterization techniques, machining strategies, and scientific models of the spectral behavior of gas species targeted by these instruments.
I begin this work with a description of radiation pattern measurements and their use in astronomical instrument characterization. I will introduce a novel technique to measure complex (phase-sensitive) field patterns using direct detectors. I successfully demonstrate the technique with a single pixel microwave inductance detectors (MKID) experiment. I expand that work by measuring the APEX MKID (A-MKID) focal plane array of 880 pixel detectors centered at 350 GHz. In both chapters I discuss the development of an analysis pipeline to take advantage of all information provided by complex field mapping. I then discuss the design, simulation, fabrication processes, and characterization of a circular-to-rectangular waveguide transformer module integrated into a circularly symmetric feedhorn block. I conclude with a summary of this work and how to advance these technologies for future ISM studies.
I begin this work with a description of radiation pattern measurements and their use in astronomical instrument characterization. I will introduce a novel technique to measure complex (phase-sensitive) field patterns using direct detectors. I successfully demonstrate the technique with a single pixel microwave inductance detectors (MKID) experiment. I expand that work by measuring the APEX MKID (A-MKID) focal plane array of 880 pixel detectors centered at 350 GHz. In both chapters I discuss the development of an analysis pipeline to take advantage of all information provided by complex field mapping. I then discuss the design, simulation, fabrication processes, and characterization of a circular-to-rectangular waveguide transformer module integrated into a circularly symmetric feedhorn block. I conclude with a summary of this work and how to advance these technologies for future ISM studies.
ContributorsDavis, Kristina (Author) / Groppi, Christopher E (Thesis advisor) / Bowman, Judd (Committee member) / Mauskopf, Philip (Committee member) / Jellema, Willem (Committee member) / Pan, George (Committee member) / Trichopoulos, Georgios (Committee member) / Arizona State University (Publisher)
Created2018
Description
The development of new Ultra-Violet/Visible/IR range (UV/Vis/IR) astronomical instrumentation that use novel approaches for imaging and increase the accessibility of observing time for more research groups is essential for rapid innovation within the community. Unique focal planes that are rapid-prototyped, low cost, and provide high resolution are key.
In this dissertation the emergent designs of three unique focal planes are discussed. These focal planes were each designed for a different astronomical platform: suborbital balloon, suborbital rocket, and ground-based observatory. The balloon-based payload is a hexapod-actuated focal plane that uses tip-tilt motion to increase angular resolution through the removal of jitter – known as the HExapod Resolution-Enhancement SYstem (HERESY), the suborbital rocket imaging payload is a Jet Propulsion Laboratory (JPL) delta-doped charge-coupled device (CCD) packaged to survive the rigors of launch and image far-ultra-violet (FUV) spectra, and the ground-based observatory payload is a star centroid tracking modification to the balloon version of HERESY for the tip-tilt correction of atmospheric turbulence.
The design, construction, verification, and validation of each focal plane payload is discussed in detail. For HERESY’s balloon implementation, pointing error data from the Stratospheric Terahertz Observatory (STO) Antarctic balloon mission was used to form an experimental lab test setup to demonstrate the hexapod can eliminate jitter in flight-like conditions. For the suborbital rocket focal plane, a harsh set of unit-level tests to ensure the payload could survive launch and space conditions, as well as the characterization and optimization of the JPL detector, are detailed. Finally, a modification of co-mounting a fast-read detector to the HERESY focal plane, for use on ground-based observatories, intended to reduce atmospherically induced tip-tilt error through the centroid tracking of bright natural guidestars, is described.
In this dissertation the emergent designs of three unique focal planes are discussed. These focal planes were each designed for a different astronomical platform: suborbital balloon, suborbital rocket, and ground-based observatory. The balloon-based payload is a hexapod-actuated focal plane that uses tip-tilt motion to increase angular resolution through the removal of jitter – known as the HExapod Resolution-Enhancement SYstem (HERESY), the suborbital rocket imaging payload is a Jet Propulsion Laboratory (JPL) delta-doped charge-coupled device (CCD) packaged to survive the rigors of launch and image far-ultra-violet (FUV) spectra, and the ground-based observatory payload is a star centroid tracking modification to the balloon version of HERESY for the tip-tilt correction of atmospheric turbulence.
The design, construction, verification, and validation of each focal plane payload is discussed in detail. For HERESY’s balloon implementation, pointing error data from the Stratospheric Terahertz Observatory (STO) Antarctic balloon mission was used to form an experimental lab test setup to demonstrate the hexapod can eliminate jitter in flight-like conditions. For the suborbital rocket focal plane, a harsh set of unit-level tests to ensure the payload could survive launch and space conditions, as well as the characterization and optimization of the JPL detector, are detailed. Finally, a modification of co-mounting a fast-read detector to the HERESY focal plane, for use on ground-based observatories, intended to reduce atmospherically induced tip-tilt error through the centroid tracking of bright natural guidestars, is described.
ContributorsMiller, Alexander Duke (Author) / Scowen, Paul (Thesis advisor) / Groppi, Christopher (Committee member) / Mauskopf, Philip (Committee member) / Jacobs, Daniel (Committee member) / Butler, Nathaniel (Committee member) / Arizona State University (Publisher)
Created2019