We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral data set of the δ Ori Aa binary system. The four observations, obtained with Chandra ACIS HETGS, have a total exposure time of ≈ 479 ks and provide nearly complete binary phase coverage. Variability of the total X-ray flux in the range of 5–25 Å is confirmed, with a maximum amplitude of about ±15% within a single ≈ 125 ks observation. Periods of 4.76 and 2.04 days are found in the total X-ray flux, as well as an apparent overall increase in the flux level throughout the nine-day observational campaign. Using 40 ks contiguous spectra derived from the original observations, we investigate the variability of emission line parameters and ratios. Several emission lines are shown to be variable, including S xv, Si xiii, and Ne ix. For the first time, variations of the X-ray emission line widths as a function of the binary phase are found in a binary system, with the smallest widths at ϕ = 0.0 when the secondary δ Ori Aa2 is at the inferior conjunction. Using 3D hydrodynamic modeling of the interacting winds, we relate the emission line width variability to the presence of a wind cavity created by a wind–wind collision, which is effectively void of embedded wind shocks and is carved out of the X-ray-producing primary wind, thus producing phase-locked X-ray variability. Based on data from the Chandra X-ray Observatory and the MOST satellite, a Canadian Space Agency mission, jointly operated by Dynacon Inc., the University of Toronto Institute of Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna.

Illicit use of prescription stimulants (IUPS) has become more common in the late adolescent and emerging adulthood populations. This study examined the impact of close friend and parent disapproval/approval on IUPS in college students. A sample of 903 college students (MAge = 19.23) completed a questionnaire assessing variables including lifetime IUPS (14.59% of sample), and perceived close friend/parent disapproval/approval of either academic or recreational IUPS. A 2 X 2 chi-square test of independence was used to analyze data regarding perceived close friend/parent disapproval/approval and IUPS. There were four primary findings. First, students were significantly less likely to report having engaged in IUPS if they perceived close friend (CHI2 (1) = 55.99, p < .001) or parent disapproval (CHI2 (1) = 31.99, p < .001) of IUPS for academic purposes. Second, students were significantly less likely to report having engaged in IUPS if they perceived close friend disapproval of IUPS for recreational purposes (CHI2 (1) = 24.38, p < .001). Third, students were significantly more likely to report having engaged in IUPS if they perceived close friend approval (CHI2 (1) = 51.17, p < .001) and parent approval (CHI2 (1) = 7.87, p = .005) for academically-motivated IUPS. Fourth, students were significantly more likely to report having engaged in IUPS if they perceived close friend approval for recreationally-motivated IUPS (CHI2 (1) = 33.86, p < .001). Future researchers should focus on conducting longitudinal studies to confirm if perceived close friend and parent approval function as risk factors for IUPS and if disapproval functions as a protective factor. Future research is also needed to help identify whether student perceptions of disapproval and approval are accurate (i.e., do close friends and parents really approve or disapprove of IUPS?). Finally, investigators should work to assess whether increased perceptions of disapproval can function to reduce level of IUPS (i.e., not just lifetime prevalence) and whether increases in perceived approval function to exacerbate IUPS. Results of these kinds of research efforts would better inform whether psychoeducational interventions should target decreasing approval and increasing disapproval perceptions in order to both prevent and reduce IUPS behaviors.

Eagles Overhead provides a critical history of US Air Force Forward Air Controllers and examines their role, status, and performance in the Air Force's history. It begins by examining the US's initial adoption of air power, and American participation in aerial combat during World War I and traces the FACs' contributions to every US Air Force air campaign from the Marne in 1918 to Mosul in 2017. However, since 2001 FACs' contributions have been sporadic. Eagles Overhead asks why, despite the critical importance of FACs, have they not been heavily used on US battlefields since 2001? It examines the Air Force FAC's theoretical, doctrinal, institutional, and historical frameworks in the first nine chapters to assess if the nature of air warfare has changed so significantly that the concept and utility of the FAC has been left behind. Or, has the FAC been neglected since 2001 because the Air Force dislikes the capability as it clouds the service's doctrinal preferences? From these examinations, Eagles Overhead draws conclusions about the potential future of Air Force FACs.

Dwarf carbon (dC) stars are main-sequence stars with carbon molecular bands (C_2, CN, CH) in their optical spectra. They are an important class of post-mass transfer binaries since, as main-sequence stars, dCs cannot have produced carbon themselves. Rather, the excess carbon originated in an evolved companion, now a white dwarf, and was transferred to the dC. Because of their complex histories, dCs are an excellent sample for testing stellar physics, including common-envelope evolution, wind accretion, mass transfer efficiencies, and accretion spin-up. However, their fundamental properties remain a mystery, and this impedes efforts to use dCs to constrain the evolution of binary systems. Here, I have investigated the observed properties of dCs, both as a population and as individual objects. Using multi-epoch spectroscopy, I constrained the dC binary fraction to be consistent with 100% binarity. The best-fit orbital separation distribution agrees with the few known dC orbital periods, and suggests a bimodal distribution (one sample with mean periods of hundreds of days, the other thousands of days). I also built a set of optical templates to find and classify additional dCs in spectroscopic surveys. Further, I discovered periodic variability in photometry of 34 dCs, dramatically increasing the number of measured periods. This allowed me to investigate mass transfer mechanisms that are likely to be important in the formation of dCs. Interestingly, some of these objects have short periods (P < 2d), indicating they have gone through a common-envelope phase. I explored the implications of these short-period dCs and how they will allow for constraints to be placed on the physics of common-envelope evolution. Finally, I searched for signs of spin-up and activity in dCs using X-ray emission. From this, I found that dCs are consistent with being rapid rotators, similar to what is observed in samples of normal young dwarfs. In summary, this dissertation presents the most extensive set of dC observational properties that has been compiled to date. I have confirmed the binary origin of dCs and linked some to post-common-envelope binaries. My work has provided a firmer foundation for the use of dCs to explore many essential astrophysical phenomena.

Intimate partner violence against women is a major problem in society. Violence has a negative impact on the victims and the person who abused the woman often needs professional help. Being able to get good personal treatment in a professional context has one of the great importance for the victim. The purpose of this study is to investigate how violence in close relationships has increased during Covid-19 and to be able to highlight how staffs who work in the women's shelter experience their work situation during the prevalent Covid-19 pandemic and how the pandemic affects the way you work with violence in close relationships. This study has a qualitative method where the empirical is collected through four to five semi-structured interviews with the women's shelter working from four different municipalities.

The Florida Department of Education revised the Common Core State Standards into what are now known as the Florida Standards in February 2014, approving 99 revisions to the original standards that were accepted in 2010 (Dunkelberger, 2014). The purpose of this research was to identify current teachers# attitudes towards the new Language Arts Florida Standards (LAFS), specifically regarding teachers# perceptions of text complexity and close reading as enacted in the reading curriculum. Additionally, this study will attempt to identify how teachers# attitudes impact their implementation of the new standards. This research used a self-administered survey to collect the teacher perceptions of the LAFS in six different categories. The sample entailed the participation of 21 practicing teachers from the Central Florida area. The survey revealed that, although teachers don't necessarily dislike the construction of the standards, they feel that they are not knowledgeable in some integral areas of the LAFS, such as text complexity and close reading. The implications of the results are discussed, and some improvements for the future of the LAFS are given.

The past few decades have seen rapid improvement in technologies related to remote sensing, specifically in digital photogrammetry and the use of unmanned aerial vehicles (UAVs). This has presented new opportunities to collect imagery at both a high temporal and spatial resolution to create detailed digital elevation models (DEMs) and investigate small-scale geomorphological features and their development over time. The high-resolution capacity of this methodology is well-suited to the study of a variety of terrains in which many critical geomorphological features are low relief and difficult or impossible to delineate using traditional remote sensing datasets. This study utilizes UAV-based imagery collection and data analysis, in conjunction with sedimentological analysis, of two study sites in Iceland and southern Ontario. The primary objective of this work is to explore the utility of integrating high-resolution spatial surveys with more traditional field techniques to identify geomorphological features, interpret their depositional origin, and quantify temporal changes in their form. The first study was completed on the forefields of Öldufellsjökull and western Sléttjökull, two surge-type outlet glaciers of the Mýrdalsjökull Ice Cap in southeast Iceland. Glacial deposits are important sources of paleoclimatic information but not all deposits are formed by processes that reflect the overall climatic conditions of a region; surge-type (fast-flowing) glaciers undergo periodic episodes of rapid ice movement, often unrelated to ambient climatic conditions. Remotely sensed data and field investigations were combined to complete a landsystem analysis of the forefields at each of Öldufellsjökull and western Sléttjökull, and an unmanned aerial vehicle (UAV) was used to collect high-resolution imagery of areas of particular interest. The forefields of Öldufellsjökull and western Sléttjökull, lack many of the characteristics typical of surge-type landsystems and instead are more similar to the active temperate landsystem common in Iceland. The identification of landforms considered to be diagnostic of surge-type glacier behaviour was only possible through a targeted high-resolution UAV survey suggesting that small-scale diagnostic landforms may be overlooked in many investigations. The second study area focused on the Niagara Escarpment in Hamilton, Ontario, a major landform resulting from extensive glacial and fluvial erosion of Paleozoic sedimentary rocks during the late Quaternary. In Hamilton, the Niagara Escarpment is a steep faced cuesta composed of Ordovician and Silurian sedimentary rocks. Recent rockfalls onto roads crossing the escarpment have raised serious concerns about its stability. To address these concerns, and to provide more information on erosional processes active along the escarpment in Hamilton, a comprehensive study of the Niagara Escarpment was completed including the collection of multi-temporal photogrammetric surveys of select rock faces, and detailed sedimentological and fracture analysis. A comprehensive lithological investigation was completed of all accessible rock outcrops in Hamilton to identify areas most likely to experience erosion based on site characteristics. A second component of this investigation was to evaluate the utility of using high-resolution imagery combined with Structure from Motion (SfM) software to detect temporal changes on the escarpment face. A staged erosion study was conducted in which lithological blocks of a known size were removed from the escarpment face at a selected site, to determine the lower limits of detection of erosion using this methodology. The study found that the location of block removal (erosion) was consistently identified, but the calculated volume of blocks removed was less accurately determined, differing by an average of 175% from the known volume of the block. A further study using this same methodology tested its ability to identify areas of natural loss (erosion) from the escarpment face. Based on multiple surveys taken 14 months apart at a selected study site, approximately one third of the area of interest experienced either loss (erosion) or gain (deposition) of material. There appear to be clear connections between lithology, density of fracturing, and the location of material loss (erosion); areas of the outcrop characterised by interbedded shales, and those areas exposing densely fractured sandstone or dolostone, were most likely to erode. The lithological characteristics of the Niagara Escarpment, including the strength of individual stratigraphic units, their vertical arrangement, and their density of fracturing, as well as climatic and hydrological factors (e.g., groundwater flow, location of surficial water features, mean annual temperature, mean annual precipitation etc.), all contribute to the amount and types of erosion active on the exposed rock face. The studies reported in this thesis have integrated high-resolution, close-range imagery with traditional field techniques to explore the characteristics and development of geomorphological forms in different terrain types. In each of the studies, the importance of collecting high-resolution imagery (<10 cm) to map geomorphological features of various scales is highlighted. / Dissertation / Doctor of Science (PhD)

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A simple, effective design for enclosing portable generators to reduce the radiated noise is an idea that seems to be desired by the consumers in this market. This investigation is to determine the feasibility of producing such an enclosure for a generator. Several engineering aspects are incorporated in the design of the enclosure. The first, and probably the most paramount, are the acoustical effects of the enclosure itself. The investigation follows the theories for insertion loss of a close fitting enclosure. The thesis examines the system behavior of a close fitting enclosure that most acoustic text books ignore and how the material stiffness, density and source-to-enclosure distance affect the insertion loss and effectiveness of the enclosure. Measured and theoretical sound pressure level around the generator before and after the application of the enclosure are presented using standards described by ISO standard 1344. The second important consideration for the enclosure design involves the heat transfer characteristics. The requirements of cooling air to the generator are discussed. Also presented are some acoustic design considerations to prevent any "direct line of sight" to any of the necessary openings which will help in the overall insertion loss. The use of an optimal engineering design technique is presented, demonstrating its strengths and weakness in this application. The optimization method used for the study is the Hooke and Jeeves, or pattern search method. This method solved for the optimum material properties in approximately 30 iterations depending on the initial starting points and the desired weighting parameters. / Master of Science