1,170 research outputs found
The effects of carboxylic acids in aluminum anodizing
Hard-anodized alumina coatings were formed in sulfuric acid at low temperature and high current density in the presence of carboxylic acid additives. Citric acid, trimesic acid, mellitic acid and ethylenediaminetetraacetic acid (EDTA) were utilized in varying concentrations. The additives were chosen for their capacity to form complexes with tri-valent aluminum and hence impart chemical stability to the coatings. The coatings were sealed in boiling water, and corrosion resistance was observed in a high pH solution of potassium hydroxide. The coatings were examined using scanning electron microscopy (SEM) to assess coating thickness and pore dimensions. Thicker coatings were produced when the additive inhibited oxide coating dissolution, increasing corrosion resistance. Overall, carboxylic acid additives showed a positive impact on corrosion resistance when coupled with sealants. More research in this field could improve products used in cleaning and cooking environments to withstand conditions of high and low pH
Dietary Change Among Canis Familiaris During the Late Ceramic Period on the Maine-Maritime Peninsula: A Case Study From the Holmes Point West Site (ME 62-8), Machias Bay, Maine
Archaeological study of Indigenous pasts has been characterized by a focus on objects over people. This study attempts to humanize the past by illuminating human agency in the human-dog relationship through a case study of dog health and diet during the Late Ceramic period (ca. 950 – 450 BP) in the Maine-Maritime Peninsula region. To circumvent the cycle of western knowledge building and marginalization of Indigenous communities, past Wabanaki people and their relationships with dogs are positioned at the center of research questions presented here. Few studies in the Northeast have analyzed dog remains from the Ceramic period (ca. 3050 – 450 BP) and none from the Late Ceramic period for subsistence trends. This thesis addresses that gap and evaluates dog diet and human and canine relationships through an analysis of canine faunal collections at the Holmes Point West site (ME 62-8) in Machias Bay, Maine. Special emphasis is placed on legacy canine collections representing the remains of two dog burials excavated in 1973. A minimum of four canine individuals are the subject of analyses undertaken here. Individuals are contextualized through investigation of available health and pathology information, existing site records, relevant historical and ethnographic accounts, regional ceramic chronologies, and new and established radiocarbon dates. These traditional lines of evidence are complemented by a study of bone collagen stable isotopic values of δ13C and δ15N derived from canine individuals for information about past diet. Dietary evidence from dogs is used as an analogy for human diet, following the Canine Surrogacy Approach (CSA), which is based on established understandings of social and food-sharing practices at the heart of the human-dog relationship. This method has been used by researchers to infer human diet when human remains are unavailable or not preferable for study. Findings suggest that canine individuals at the Holmes Point West site may have fulfilled diverse roles, based on the varying ages of individuals present and wide-range of depositional contexts. Stable isotope analysis suggests that canines consumed an increasingly terrestrially-oriented diet ca. 600 BP, a change from the overwhelmingly marine-oriented diets of canines during the earlier Ceramic period. Overall, results suggest major subsistence changes for dogs and potentially Wabanaki people at the Holmes Point West site during the Late Ceramic period, a period of intermittent contact between Europeans and Indigenous people. This case study offers a new approach for understanding subsistence changes in the region and provides a framework to examine human agency through the remains of dogs. This research addresses several gaps in regional archaeological datasets. Dog remains from an understudied time period are examined, addressing calls by previous researchers in the region for more contextualized case studies to further our understanding of human and dog dietary relationships. This research also helps to address gaps that exist between the ethnographic and archaeological records for the Late Ceramic and Protohistoric periods. Lastly and most importantly, this case study underscores the importance of the human-dog relationship within a hunting, fishing, and gathering community in the Maine-Maritime Peninsula region
Good Hair, Bad Hair: African-American Hair Relations in the Early Twentieth Century
Abby E. Brisbon, College \u2709, History Good Hair, Bad Hair: African-American Hair Relations in the Early Twentieth Century Why an African-American woman chooses to do her hair in any particular style embodies a complex history of an evolving relationship with acceptable standards of beauty, both within the community and as part of the larger society. This project will examine that evolution from the opening of Madame CJ Walker’s business in 1905 through the Great Depression. What do cultural expressions such as advertisements, literature, and art say about how African-American women might have internalized the beauty standards that were placed upon them, and how did their ideas about hair evolve over the first part of the century
Examining the effects of Fadrozole, an aromatase inhibitor, on testosterone and estrogen production of domestic chicken embryos (Gallus gallus)
The hypothalamic-pituitary-gonadal (HPG) axis is responsible for the production of the hormones testosterone and estradiol, and testosterone is thought to contribute to regulation of the axis through a negative feedback mechanism. Regulation by negative feedback involves the product of a pathway turning off that pathway when enough product is made. However, because the enzyme P450 aromatase converts testosterone to estradiol, estradiol may also contribute to regulation of the HPG axis and other phenomena that have been attributed to testosterone, like the inhibition of immune function. Previous studies have injected birds with an aromatase inhibitor (presumably reducing estradiol production) and shown a subsequent increase in the immunity of the injected birds as compared to their controls, implying that estradiol was decreasing immune function. In order to support the hypothesis that it is estradiol, not testosterone, which is inhibiting immune function, it is important to show that a decrease in estradiol and not a subsequent increase in testosterone is what is leading to the decreased immunity. In order to test this hypothesis that estradiol is inhibiting immune function, it is important to determine whether estradiol is a contributor to negative feedback of the HPG axis. In this thesis, I tested the hypothesis that estradiol affects negative feedback in the HPG axis. Chicken embryos were injected with either Fadrozole, an aromatase inhibitor, or a vehicle solution on day 13 of incubation. Two days later, the embryos were bled for hormone quantification and genetic sexing. Genetic sexing was obtained through DNA extraction, PCR, and gel electrophoresis. Hormone levels were compared across treatment and sex through ELISA assays. By using embryos, the immediate effects of Fadrozole on negative feedback of the HPG axis were assessed. In contrast, recent studies of looking at androgen exposure have mainly focused on the post-hatch stages of development.
Estradiol levels in female Fadrozole treated embryos were significantly lower than in female control embryos, but this pattern was not seen in males. This could be due to the greater amount of estradiol and aromatase in females as compared to males. Additionally, females had a significantly higher level of estradiol than males, which is consistent with published literature and is most likely due to the major role that estrogen plays in female development. There was no significant difference in testosterone levels between treatment groups or sexes, implying that it is the decrease in estradiol, and not a subsequent increase in testosterone, that lead to the increase in immunity in Fadrozole treated embryos in previous studies. This work also implies that estradiol is not affecting negative feedback in the HPG axis of chicken embryos but that it may in fact be affected by testosterone
State Drug Testing Requirements for Welfare Recipients: Are Missouri and Florida\u27s New Laws Constitutional
This Summary examines the framework set up by the Supreme Court for analyzing the constitutionality of drug testing on welfare recipients. It discusses the states\u27 implementation of such programs, and specifically analyzes laws recently passed by Florida and Missouri that authorize drug-testing requirements on welfare recipients. The likely outcome of challenges to these laws appears to be dependent, at least in part, on whether the law provides for suspicionless drug testing or calls for drug testing based on some reasonable suspicion of drug use
Nutrient Composition and Sediment Size in Stream Sediments
Precision conservation is the use of geospatial analysis of high-resolution datasets to determine the location where restoration will be the most effective based on elements like stream location, watershed size, and neighboring land use. For four years, Susquehanna University has worked with the Chesapeake Conservancy to study the effects of stream restoration throughout nine different watersheds in Centre, Montour, Union, and Northumberland counties. Sites are monitored before and after stream restoration has been implemented to determine the effects of restoration and best management practices on factors such as species diversity, fish populations, water quality, mean grain size of sediments, and nutrient concentrations in stream sediment. At 31 different sites, a one hundred-meter reach is electroshocked for fish, and five sediment samples are taken from a pool, riffle, eddy, a run from pool to a riffle, and a run from a riffle to a pool. The sediment samples were analyzed for grain size and nutrient concentrations, including ammonia, nitrate, and phosphate. Stream restoration should help improve stream quality by reducing erosion and the amount of fine sediments entering the stream. It was found that as mean grain size of sediments decreased, nitrate and ammonia concentrations increased, while phosphate concentrations showed no significant correlations to grain size. Increasing amounts of clay, silt, and ammonia in sediment samples also correlated to heavily agriculturally impacted streams. Also, fish populations decreased as nutrient concentrations increased, with a significant correlation to nitrate. By studying nutrient concentrations and their correlation to mean grain size, we hope to demonstrate that best management practices can improve both fish and macroinvertebrate habitat and reduce the potential nutrient storage in the stream channel sediments
Leaf Phenology and Freeze Tolerance of the Invasive Tree Pyrus calleryana (Rosaceae) and Potential Native Competitors
Pyrus calleryana is quickly becoming one of the most problematic invasive species in the Eastern and Central part of the United States. Pyrus calleryana is an early successional species that quickly proliferates in highly disturbed soils such as old fields and younger prairies. Currently, this species poses a large threat to land managers as it changes the successional trajectories of forest and prairie systems, creating new novel ecosystems. Pyrus calleryana outcompetes most native early successional species and is relatively understudied. The mechanism in which Pyrus calleryana utilizes to dominate ecosystems are not fully understood, but one theory is Pyrus calleryana extended leaf phenology in comparison to other native woody successional species. We hypothesized that Pyrus calleryana has a longer leaf phenology than two native woody species, Populus deltoides and Plantanus occidentalis. We observed these three species at 3 sites in Dayton, OH from December 2019 to November of 2020. A frost event in May also gave us the opportunity to understand frost tolerance with these species. We found that Pyrus calleryana began leafing out almost a month before its native competitors in the spring and kept its leaves on significantly longer than both P.deltoides and P.occidentalis (p\u3c0.001) throughout the fall. During the frost event, almost every single leaf on P.occidentalis died and almost 70% of the leaves on P.deltoides were damaged. However, Pyrus calleryana only had damage on 6% of its leaves. Our experiment suggests that Pyrus calleryana uses an extended leaf phenology as a mechanism to outcompete native successional species as it is able to photosynthesize longer, which builds up carbon and nutrient reserves, and is able to withstand frost events
Looking Ahead With the World in Their Hands: The Postsecondary Aspirations of East Island Youth
New Tools for Storytelling: Flexible Ethnicity and Adaptation in Comics & Television
This thesis examines different forms of storytelling by using graphic novels, comic books and television series to efficiently do so. The first chapter features a fairly new comic called Ms. Marvel where the superhero is a teenage Muslim instead of the traditional blue-eyed, blonde-haired superhero. The chapter describes Marvel Comics’ direction of changing ethnicity, sex, gender, etc. to better suit the vastly-growing and diverse consumer market. Chapter two concentrates on the tool of flashbacks in a comic called Bitch Planet and in a television show called Orange is the New Black. The use of flashbacks is investigated, further demonstrating its ability to humanize characters. Chapter three focuses on adaptation as a form, tracing its roots from creation to present-day. In the chapter, I discuss the call and current need for changes within adaptations. I also examine an original comic called Preacher, while also comparing it to the newly-finished TV series adaptation by the same name. Throughout the three chapters, portable ethnicity, flashbacks and adaptation are all a common theme and all play a part in the storytelling of these pieces
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