Matching Items (6)
Filtering by
- Creators: School of Earth and Space Exploration
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
The giant green sea anemone, Anthopleura xanthogrammica, hosts two different endosymbiotic algae. One is a unicellular chlorophyte, Elliptochloris marina; the other is Symbiodinium muscatinei, a dinoflagellate. Hosting these different symbionts influences the life history strategy of A. xanthogrammica's congener A. elegantissima, directly impacting its reproductive strategy (asexual vs. sexual). My study sought to examine whether the type and density of symbiont also affects the reproductive condition of A. xanthogrammica, which reproduces only sexually. Gonad development was measured in anemones from Slip Point, Clallam Bay, WA and Tongue Point, WA along with symbiont type and density per mg of anemone protein. The results indicate a trend towards brown anemones having more developed gonads, especially in males. This may mean that A. xanthogrammica anemones that host zooxanthellae are more reproductively fit than zoochlorellate anemones. Thus, it may be favorable for anemones to host zooxanthellae. This is especially true in summer months when the high temperatures and mid-day low tides coincide with the period of most rapid gonad development.
ContributorsGasbarro, Ryan Patrick (Author) / Neuer, Susanne (Thesis director) / Rutowski, Ronald (Committee member) / Bingham, Brian (Committee member) / Barrett, The Honors College (Contributor) / School of Earth and Space Exploration (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
This research focuses on a geologic controversy regarding the stratigraphic position of the Hermit Formation outside of the Grand Canyon, specifically in Sedona, Arizona. The goal of this research is to provide additional constraints on this dispute by pinpointing the transition to the Hermit Formation in Sedona, if possible. To accomplish this, we use field observations and detrital zircon dating techniques to compare data we collected in Sedona with data previously published for the Grand Canyon. Fossil evidence in Sedona and near Payson, Arizona is also used to aid correlation. Starting from the Grand Canyon, the Hermit Formation pinches out to the southeast and, hypothetically obstructed by the Sedona Arch, does not reach Sedona. Detrital zircon data show similar age distributions between the Grand Canyon and Sedona rock units, but the results are not strong enough to confidently correlate units between these two localities. The data collected for this study suggest that if the Hermit Formation is present in Sedona, it is limited to higher up in the section as opposed to occupying the middle portion of the section as is currently interpreted. To determine with greater accuracy whether the Hermit Formation does exist higher in the section of Sedona, more detrital zircons should be collected and analyzed from the part of the section that yielded a relative increase in young zircons aged 200-600 Ma.
ContributorsFinger, Mikayla (Co-author) / Spitzer, Patrick (Co-author) / Reynolds, Stephen (Thesis director) / Semken, Steven (Committee member) / DeVecchio, Duane (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Lactase persistence is the ability of adults to digest lactose in milk (Segurel & Bon, 2017). Mammals are generally distinguished by their mammary glands which gives females the ability to produce milk and feed their newborn children. The new born therefore requires the ability to breakdown the lactose in the milk to ensure its proper digestion (Segurel & Bon, 2017). Generally, humans lose the expression of lactase after weaning, which prevents them being able to breakdown lactose from dairy (Flatz, 1987).
My research is focused on the people of Turkana, a human pastoral population inhabiting Northwest Kenya. The people of Turkana are Nilotic people that are native to the Turkana district. There are currently no conclusive studies done on evidence for genetic lactase persistence in Turkana. Therefore, my research will be on the evolution of lactase persistence in the people of Turkana. The goal of this project is to investigate the evolutionary history of two genes with known involvement in lactase persistence, LCT and MCM6, in the Turkana. Variants in these genes have previously been identified to result in the ability to digest lactose post-weaning age. Furthermore, an additional study found that a closely related population to the Turkana, the Massai, showed stronger signals of recent selection for lactase persistence than Europeans in these genes. My goal is to characterize known variants associated with lactase persistence by calculating their allele frequencies in the Turkana and conduct selection scans to determine if LCT/MCM6 show signatures of positive selection. In doing this, we conducted a pilot study consisting of 10 female Turkana individuals and 10 females from four different populations from the 1000 genomes project namely: the Yoruba in Ibadan, Nigeria (YRI); Luhya in Webuye, Kenya; Utah Residents with Northern and Western European Ancestry (CEU); and the Southern Han Chinese. The allele frequency calculation suggested that the CEU (Utah Residents with Northern and Western European Ancestry) population had a higher lactase persistence associated allele frequency than all the other populations analyzed here, including the Turkana population. Our Tajima’s D calculations and analysis suggested that both the Turkana population and the four haplotype map populations shows signatures of positive selection in the same region. The iHS selection scans we conducted to detect signatures of positive selection on all five populations showed that the Southern Han Chinese (CHS), the LWK (Luhya in Webuye, Kenya) and the YRI (Yoruba in Ibadan, Nigeria) populations had stronger signatures of positive selection than the Turkana population. The LWK (Luhya in Webuye, Kenya) and the YRI (Yoruba in Ibadan, Nigeria) populations showed the strongest signatures of positive selection in this region. This project serves as a first step in the investigation of lactase persistence in the Turkana population and its evolution over time.
My research is focused on the people of Turkana, a human pastoral population inhabiting Northwest Kenya. The people of Turkana are Nilotic people that are native to the Turkana district. There are currently no conclusive studies done on evidence for genetic lactase persistence in Turkana. Therefore, my research will be on the evolution of lactase persistence in the people of Turkana. The goal of this project is to investigate the evolutionary history of two genes with known involvement in lactase persistence, LCT and MCM6, in the Turkana. Variants in these genes have previously been identified to result in the ability to digest lactose post-weaning age. Furthermore, an additional study found that a closely related population to the Turkana, the Massai, showed stronger signals of recent selection for lactase persistence than Europeans in these genes. My goal is to characterize known variants associated with lactase persistence by calculating their allele frequencies in the Turkana and conduct selection scans to determine if LCT/MCM6 show signatures of positive selection. In doing this, we conducted a pilot study consisting of 10 female Turkana individuals and 10 females from four different populations from the 1000 genomes project namely: the Yoruba in Ibadan, Nigeria (YRI); Luhya in Webuye, Kenya; Utah Residents with Northern and Western European Ancestry (CEU); and the Southern Han Chinese. The allele frequency calculation suggested that the CEU (Utah Residents with Northern and Western European Ancestry) population had a higher lactase persistence associated allele frequency than all the other populations analyzed here, including the Turkana population. Our Tajima’s D calculations and analysis suggested that both the Turkana population and the four haplotype map populations shows signatures of positive selection in the same region. The iHS selection scans we conducted to detect signatures of positive selection on all five populations showed that the Southern Han Chinese (CHS), the LWK (Luhya in Webuye, Kenya) and the YRI (Yoruba in Ibadan, Nigeria) populations had stronger signatures of positive selection than the Turkana population. The LWK (Luhya in Webuye, Kenya) and the YRI (Yoruba in Ibadan, Nigeria) populations showed the strongest signatures of positive selection in this region. This project serves as a first step in the investigation of lactase persistence in the Turkana population and its evolution over time.
ContributorsJobe, Ndey Bassin (Author) / Wilson Sayres, Melissa (Thesis director) / Paaijmans, Krijn (Committee member) / Taravella, Angela (Committee member) / School of Earth and Space Exploration (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The Star Planet Activity Research CubeSat (SPARCS) will be a 6U CubeSat devoted to photometric monitoring of M dwarfs in the far-ultraviolet (FUV) and near-ultraviolet (NUV) (160 and 280 nm respectively), measuring the time-dependent spectral slope, intensity and evolution of M dwarf stellar UV radiation. The delta-doped detectors baselined for SPARCS have demonstrated more than five times the in-band quantum efficiency of the detectors of GALEX. Given that red:UV photon emission from cool, low-mass stars can be million:one, UV observation of thes stars are susceptible to red light contamination. In addition to the high efficiency delta-doped detectors, SPARCS will include red-rejection filters to help minimize red leak. Even so, careful red-rejection and photometric calibration is needed. As was done for GALEX, white dwarfs are used for photometric calibration in the UV. We find that the use of white dwarfs to calibrate the observations of red stars leads to significant errors in the reported flux, due to the differences in white dwarf and red dwarf spectra. Here we discuss the planned SPARCS calibration model and the color correction, and demonstrate the importance of this correction when recording UV measurements of M stars taken by SPARCS.
ContributorsOsby, Ella (Author) / Shkolnik, Evgenya (Thesis director) / Ardila, David (Committee member) / School of Earth and Space Exploration (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Gamma-ray bursts (GRBs) are a type of astrophysical transient resulting from the most energetic explosions known in the universe. The explosions occur in distant galaxies, and their bright initial emission may only last a few seconds. Colibri is a telescope being built at the San Pedro Martir Observatory in Baja, CA, MX with high sensitivity in order to study these events at a high redshift. Due to how quickly GRBs occur, it is essential to develop an image reduction pipeline that can quickly and accurately detect these events. Using existing image reduction software from Coatli, which was programmed and optimized for speed using python, numerous time trials were performed in order to determine if the pipeline meets the time requirements with various factors being adjusted. The goal of this experiment is for the telescope to respond to, capture, and reduce the images in under 3 minutes. It was determined that the reduction was optimized when the number of files to be reduced was set equal to 16 or higher by changing the batch number and the blank sky subtraction function was performed. As for the number of exposures, one can take up to four 30 second exposures or twenty 5 second exposures and reduce them in under 3 minutes.
ContributorsHeiligenstein, Wren (Author) / Butler, Nathaniel (Thesis director) / Jansen, Rolf (Committee member) / Dimitrova, Tzvetelina (Committee member) / Barrett, The Honors College (Contributor) / School of Earth and Space Exploration (Contributor)
Created2024-05
Description
This study was conducted in order to determine whether the lagomorphs of 111 Ranch- Aztlanolagus agilis, Hypolagus arizonensis, and Sylvilagus cunicularius- could be distinguished based on femora. This is because while there is a large quantity of disarticulated lagomorph postcranial fossils from 111 Ranch, the chief diagnostic traits of A. agilis and H. arizonensis are the enamel patterns on their third premolars, leaving a large swath of specimens unidentifiable by diagnostic traits alone. Specimens from the Arizona Museum of Natural History were measured and compared to specimens known to be from these genera. Additionally, morphological traits in mandibles were used to identify mandible specimens, which in turn were used to identify fossils with the same specimen label. Statistical tests such as t-tests and principal components analyses were used to examine the distributions of sizes and locate clusters of datapoints likely corresponding to each genus. Some of these could be linked to a genus based on one particular specimen, P15156, which had been identified as Hypolagus based on its mandible morphology and size. The majority of the Museum'a specimens were thus associated with one of the three species, save for those which were too damaged and intermediate in size to confidently categorize.
ContributorsTkacik, Stephanie Marie (Author) / Farmer, Jack (Thesis director) / Reed, Kaye (Committee member) / McCord, Robert (Committee member) / School of Earth and Space Exploration (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05