Anterior cruciate ligament (ACL) injuries are common orthopaedic injuries among athletes who participate in sports that involve cutting and changing directions. Many of these adolescent athletes intend to return to sports (RTS), and therefore undergo ACL reconstruction (ACLR). These athletes exhibit unfavorable landing biomechanics from muscle atrophy and asymmetrical neuromuscular control post-ACLR, putting them at a higher risk of re-injury. Thus, rehabilitation following ACLR is important to improve kinetic and kinematic outcomes and reduce re-injury risk. Biofeedback during rehabilitation is thought to be one way to potentially restore neuromuscular control deficits of athletes recovering from ACLR. Therefore, understanding the effectiveness of a biofeedback intervention on factors associated with re-injury among post-ACLR patients is essential in successful RTS. The purpose of this study is to analyze the effect of a 6-week biofeedback intervention on eccentric knee joint power (ECCKP), limb stiffness, and limb stiffness symmetry (using normalized symmetry index, NSI), in addition to secondary lower extremity outcomes that are associated with these metrics, during landing among patients following ACLR. This study used data collected from an ACL-Biofeedback Trial (ClinicalTrials.gov: AR069865) where participants were randomized into a biofeedback (BF) or control group (C). The BF group received visual and tactile feedback during a series of controlled squats while the C group participated in several online and in-person educational sessions. Participants completed 10 stop-jump tasks before (pre), after (post), and 6 weeks after (ret) the intervention. Kinetic, kinematic, and ground reaction forces (GRF) were collected from embedded force plates and 3D motion capture. Partaking in a biofeedback intervention did not improve ECCKP, limb stiffness, or limb stiffness NSI compared to controls. A group-by-time interaction was found for hip excursion (p=0.035), and a main effect of time was found for ECCKP, with this variable increasing by 18.5% from pre to ret (p=0.001). In addition, when considering surgical versus non-surgical limbs, this cohort exhibited interlimb asymmetries in stiffness, peak resultant GRF (rGRF), and time to reach peak rGRF (p<0.009). Further, a group-by-limb interaction (p=0.005) and a 7.1% reduction in peak rGRF were found from post to ret (p=0.02). Participants in this study also exhibited limb stiffness asymmetry greater than 10%, which supports existing literature that observed interlimb asymmetries in athletes following ACLR around the typical RTS time (9-12 months post-ACLR). The results from this analysis demonstrated that the current biofeedback intervention was inadequate in improving ECCKP, limb stiffness, and limb stiffness NSI, but additional biofeedback studies with larger sample sizes that investigate task dependencies are needed to better understand the effectiveness of biofeedback interventions. / Master of Science / Anterior cruciate ligament (ACL) injuries are common orthopaedic injuries among athletes who participate in sports that involve cutting and changing directions. Many of these adolescent athletes intend to return to their pre-injury level, therefore undergo a surgical procedure called ACL reconstruction (ACLR). However, following this procedure, athletes display unsafe and stiff landing patterns due to muscle weakness and asymmetrical neuromuscular, or mind-body, control post-ACLR, which increases their risk of re-injury once they return to sport (RTS) following recovery. Rehabilitation for patients following ACLR is of the utmost importance in improving unsafe movement patterns to reduce the risk of re-injury. Biofeedback training refers to receiving external signals that can be processed and transferred to the muscles in the body. This technique aims to restore the neuromuscular deficits of athletes following ACLR and could potentially be helpful during ACLR rehabilitation. Therefore, understanding the effectiveness of a biofeedback intervention on outcomes associated with an increased risk of re-injury in patients following ACLR is important to safely RTS. The purpose of this study is to determine the effect of a 6-week biofeedback intervention on the ability of the knee to absorb impact forces (quantified as eccentric knee joint power, ECCKP), limb stiffness, and limb stiffness symmetry (measured with normalized symmetry index, NSI), along with secondary outcomes related to these variables, among patients following ACLR. This study used data collected from an ACL-Biofeedback Trial (ClinicalTrials.gov: AR069865) where participants were randomized into a biofeedback (BF) or control group (C). The BF group received visual and resisted feedback during a series of controlled squats while the C group participated in several online and in-person educational sessions. Participants completed 10 stop-jump tasks before and after the intervention, and biomechanical data was obtained. The biofeedback intervention did not result in an improved ability for the knee to absorb impact from landing, and it was not able to decrease limb stiffness or limb stiffness asymmetry. It was able to improve hip excursion, which allows for a favorable, less upright posture when landing. ECCKP improved for both groups, indicating that the biofeedback did not add extra benefit to the participant's rehabilitation outside of the study. Asymmetries were observed between the surgical and non-surgical limbs in limb stiffness, peak GRF, and the time it takes to reach this peak GRF. This sample exhibited limb stiffness asymmetry greater than the recommended 10% threshold, raising concern for when these athletes RTS. The results from this analysis demonstrated that the current biofeedback intervention was inadequate in improving ECCKP, limb stiffness, and limb stiffness NSI, but biofeedback in ACLR rehabilitation can still be efficacious in improving hip biomechanics and overall neuromuscular control but may be task-dependent and call for a larger sample size.

I document that a significant number of insiders violate SEC reporting requirements by filing transactions after the legally required deadline. Although these violations are straightforward for the SEC to detect, instances of reporting violations persist. Prior to Sarbanes-Oxley, 29% of open market transactions fell outside the required reporting window. Following the enactment of SOX, 8% of all transactions continue to violate the filing deadline. During the filing delay trades are unknown to outside market participants and earn significant abnormal returns. I show that almost a quarter of filing violations are made by insiders that egregiously violate the reporting requirement. This subgroup realizes significantly greater abnormal returns for purchases and sales leading up to the reporting date. Most filing violations take place during periods of high information asymmetry, and insiders privately earn significant abnormal returns. Collectively, these findings indicate that a subgroup of insiders extract information rent from private knowledge during windows of unreported trading. The SEC reacts to numerous insiders disregard this reporting requirement by charging a small percentage of the total violators for wrongdoing. I employ a unique data set of SEC cases brought against top managers who fail to meet the filing requirements. By comparing the trades in indictments to similar non-indicted transactions, I assess that the SEC pursues insiders that violate the reporting requirement egregiously and are a manager at larger firms. While the coverage of these actions is thin, it significantly deters insiders from filing late after the enforcement. In addition, firm insiders may trade on private information concerning forthcoming innovations. Before high-quality innovations become public knowledge, I find that insiders significantly increase their holdings in the firm. After a patent for a breakthrough innovation is granted, the firm realizes significant abnormal returns. By insider, I find that members of the Corporate Suite increase their holdings around the application date and are the only insiders that earn significant abnormal returns following the grant date. These results suggest that key insiders can identify breakthrough patents ex-ante and utilize this information advantage before the innovation becomes public knowledge. These innovations translate into an increase in firm value.

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Symmetry is considered an attractive facial characteristic, though it is very rare as most humans have some degree of asymmetry. Though most cases are subtle enough to go undetected, more severe cases of asymmetry can result in marked facial deformity. It has been found that facial asymmetry presents as a comorbid condition with other severe malocclusions. While many causes of facial asymmetry have been thoroughly investigated, such as cleft lip/palate, unilateral craniosynostosis and hemifacial microsomia, the genetic cause of asymmetries associated with dentofacial malocclusions has yet to be investigated. Studies have shown that muscle strength, size, and fiber type can influence bone size and density. The masseter muscle is frequently involved in development of sagittal malocclusion, and left/right fiber-type differences have been previously found in subjects with facial asymmetry. Still, the contribution of muscle function to the development of facial asymmetry is unclear. Symmetry is a genetically controlled human characteristic, as is the careful breaking of symmetry during development to allow for appropriate organ formation necessary for life. Many genes have been identified to play a role in this initial breaking of symmetry, as well as the maintenance of left-right differential expression. Among these genes, the Nodal Pathway plays a particularly important role. Expression of Nodal Signaling Pathway (NSP) genes, which provide positional and patterning information during embryogenesis, vary significantly in facial asymmetry subjects. PITX2, a downstream NSP effector, patterns changes in gene expression on left-right sides through gradient density signaling. PITX2 is reportedly expressed in adult human skeletal muscle satellite cells suggesting NSP gene activity is a key factor in both development and maintenance of facial asymmetry in adulthood. A human transcript microarray was used to evaluate whether these genes involved with normal coding of symmetry during development were differentially expressed in masseter muscle from patients with or without facial asymmetry. This study evaluated orthognathic surgery patients with varying skeletal malocclusions. The patients were categorized based on vertical, transverse, and sagittal discrepancies, as well as the presence or absence of facial asymmetry (n= 93). The subjects were appropriately diagnosed as open or deep bite, class I, II, or III, and treatments planned for the appropriate surgical correction. All of the patients required bimaxillary sagittal split osteotomy, at which point masseter muscle samples were collected. Eleven patients were included in this study. Of the eleven, two of the patients were classified with facial asymmetry. Samples were disrupted in QIAzol Lysis Reagent, RNA was isolated using a Qiagen miRNeasy Mini Kit according to the manufacturer’s instructions, and quality of the total RNA was tested by Agilent Bioanalyzer and Nanodrop spectrophotometry. Samples were used for quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) and protocols for microarray analysis were conducted as described in the Ambion WT Expression Manual and the Affymetrix GeneChip Expression Analysis Technical Manual. The eleven samples were analyzed by Principal Components Analysis (PCA) to detect fold-changes for each transcript. From this, differences in global gene expression between the two asymmetric and eight remaining subjects were evident, as the two asymmetric patients clustered separately from the malocclusion patients without asymmetry. To find differentially expressed transcripts step-up t-tests were performed to correct for false discovery rate (FDR) comparing the two asymmetric samples to the eight symmetric samples. Differences were considered significant if step-up p-values were ±2 between groups. Differential gene expression was confirmed with ten of the 22 Nodal Pathway genes in asymmetric patients. Extracellular mediators Nodal and Lefty expression was 1.39 and 1.84 fold greater (P&lt; 3.41 x 10-5) whereas integral membrane Nodal-modulators NOMO1,2,3 were -5.63 to -5.81 (P &lt; 3.05 x 10-4) less in asymmetric subjects. Two of the three Nodal Pathway mediators decreased significantly with negative fold differences (-7.02, -2.47; P &lt; 0.003). PPM1a, one of the two negative intracellular mediators, had a significantly decreased fold difference of -3.79 with asymmetry (P , 4.59 x 10-6). PITX2, an asymmetry factor known to influence the size of type II skeletal muscle fibers in adults was also decreased in facial asymmetry (P&lt; 0.05). The down regulation of Nodal Pathway genes suggests its involvement in development of asymmetry. PITX2 expression differences also contribute to skeletal and muscle development in this condition. The overall data trend was for moderate to large decreases in gene expression for approximately 60% of the Nodal pathway genes. Further histological analysis of masticatory muscle fiber types will be necessary to determine how variations in bilateral masticatory muscle phenotype contribute to jaw asymmetry in subjects with posterior facial asymmetry. Finally, the methods used in this study should be conducted with a larger sample population, including a wider variety of different types of asymmetry. / Oral Biology

Yes / Although facial symmetry correlates with facial attractiveness, human faces are often far from symmetrical with one side frequently being larger than the other (Kowner, 1998). Smith (2000) reported that male and female faces were asymmetrical in opposite directions, with males having a larger area on the left side compared to the right side, and females having a larger right side compared to the left side. The present study attempted to replicate and extend this finding. Two databases of facial images from Stirling and St Andrews Universities, consisting of 180 and 122 faces respectively, and a third set of 62 faces collected at Abertay University, were used to examine Smith¿s findings. Smith¿s unique method of calculating the size of each hemiface was applied to each set. For the Stirling and St Andrew¿s sets a computer program did this automatically and for the Abertay set it was done manually. No significant overall effect of gender on facial area asymmetry was found. However, the St. Andrews sample demonstrated a similar effect to Smith, with females having a significantly larger mean area of right hemiface and males having a larger left hemiface. In addition, for the Abertay faces handedness had a significant effect on facial asymmetry with right handers having a larger left side of the face. These findings give limited support for Smith¿s results but do also suggest that finding such an asymmetry may depend upon some as yet unidentified factors inherent in some methods of image collection.

Most studies of the investment-cash flow sensitivity hypothesis in the literature compare estimates of the sensitivity coefficients from cross sectional regressions across groups of firms classified into more or less financially constrained groups based on some measure of perceived financial constraint. These studies report conflicting results depending on the classification scheme used to stratify the sample. They have been criticized on conceptual and methodological grounds. In this study we mitigate some of these problems reported in the literature by using the insights from Cleary, Povel and Raith (2007) in a new research design. We test for the significances of the changes in the investment-cash flow sensitivity, in a time-series rather than cross sectional framework, for the same set of firms surrounding an exogenous shock to the firms' information asymmetry. The CPR (2007) model predicts an unambiguous increase (decrease) in investment-cash flow sensitivity when information asymmetry of the firm increases (decreases). Further, by examining the differences in the sensitivity coefficients we expect some of the biases in the coefficient from measurement errors in Q to cancel out. The two events we study are (i) the implementation of SOX which is expected to decrease information asymmetry from improved and increased disclosure and (ii) the deregulation of industries which is expected to increase information asymmetry largely from the lifting of price controls and entry barriers. We report that information asymmetry decreases following SOX and that there is a commensurate decrease in the investment-cash flow sensitivity, pre- to post SOX. The hypothesis that a greater change in investment cash flow sensitivity is associated with a greater change in information asymmetry is only weakly supported by the data. We also report that information asymmetry increases following deregulation with a commensurate increase in investment cash flow sensitivity, pre to post deregulation. The hypothesis of a greater increase in the sensitivity for subsamples with a greater increase in information asymmetry is not supported by the data. Overall, however, the study supports the investment-cash flow sensitivity hypothesis using a research design that corrects for some of the problems identified in the existing literature on the hypothesis. / Ph. D.

Research indicates a warming global climate leads to change in the spatial and temporal characteristics of precipitation. Although precipitation is inherently variable through time and space, for some water-sensitive stakeholders, the evenness with which precipitation is distributed through a time interval rivals the importance of total precipitation amount and frequency within that period. This study uses a relatively new approach of analyzing inequity in the temporal distribution of precipitation to examine the recent historical record of precipitation across the United States. The Gini coefficient (GC), which has been commonly used in the field of economics to measure wealth distribution, was used here to assess inequity in the temporal distribution of daily precipitation through seasonal and annual timeframes. Additionally, the Lorenz asymmetry coefficient (LAC) was used to assess the magnitude of daily precipitation events (light, heavy) associated with inequity in the temporal distribution of precipitation. The concept of using these two metrics together to quantify changes in the character with which precipitation occurs across a time interval has yet to be documented for areas within the United States. Therefore, this study expands upon previous research of long-term hydroclimatic change and variability by illustrating the combined ability of these two relatively under-utilized metrics, the GC and the LAC, to enhance quantification of recent change in the characteristics of the temporal distribution of daily precipitation across the United States. The first element of the research presented here is demonstration of the utility of the GC and LAC metrics using data from the physically diverse mid-Atlantic sub-region of the United States. This research used station-level daily precipitation data to compute historic time series of intra-annual and intra-seasonal precipitation amount, precipitation frequency, GC, LAC, variance (V), and interquartile range (IQR). The results of this portion of the research show that when compared to other simpler measures of characterizing variability (i.e., V and IQR), the GC is relatively robust to both the number of days with precipitation and the total precipitation received in a temporal increment (i.e., season or year). The research expanded in scale to the continental United States, requiring data integration to a regional level to facilitate data analysis and physical understanding. The analysis used gridded seasonal means (1981 – 2010) of four precipitation characteristics: precipitation amount, precipitation frequency, GC, and LAC to delineate regions of homogenous precipitation characteristics. To accomplish this, a multi-step regionalization technique was employed. Specifically, the historic seasonal means were subjected to a Principal Components Analysis (PCA), and the resulting component scores were subjected to several cluster analysis techniques. The average linkage clustering technique produced the most logical clustering solution, indicating that 15 regions of homogenous precipitation exist within the contiguous United States. It is argued that the regions better serve hydroclimatic analyses than the nine climate regions designated by the United States National Centers for Environmental Information (NCEI). The third element of the research integrates the first two research elements in study of recent United States hydroclimate variability and change. For the 15 United States hydroclimate regions, regionally averaged water year time series (1949 – 2018) of precipitation amount, precipitation frequency, GC, and LAC were computed using in-situ precipitation data gathered from the NCEI's Global Historical Climatology Network (GHCN)-Daily database. The time series of all precipitation characteristics for each region were then subjected to the nonparametric Mann-Kendall trend test to assess the significance of each trend, and the Sen's slope estimator was used to quantify the magnitude of the trend. Time series that characterize two key atmospheric characteristics, total column water vapor and static stability, were also computed for each region. For most of the 15 study regions, water year total precipitation and precipitation frequency increased through the latter half of the 20th century. The largest magnitude of change in water year total precipitation and precipitation frequency occurred in the time series of regions located within the eastern and northern portions of the contiguous United States. Results also show that inequity in the temporal distribution of water year precipitation increased through the 70-year study period for most of the 15 study regions. Combined, these results indicate that days with light and heavy precipitation are becoming more prevalent at the expense of days with moderate precipitation. Furthermore, variability in the time series of some precipitation characteristics for several regions coincide with variability in the atmospheric variables that characterize total column water vapor and static stability, however the dominant driver of hydroclimatic change across the contiguous United States remains elusive. / Doctor of Philosophy / Research indicates a warming global climate leads to change in the spatial and temporal characteristics of precipitation. These changes could adversely affect some water-sensitive stakeholders who are concerned not only with the amount of precipitation received over time, but also with the manner in which the precipitation is distributed through time – all at once, or spread evenly. The Gini coefficient (GC), which has been commonly used in the field of economics to measure wealth distribution, was used here to assess inequity in the temporal distribution of daily precipitation through seasonal and annual timeframes. Additionally, the Lorenz asymmetry coefficient (LAC) was used to assess the magnitude of daily precipitation events (light, heavy) that were primarily responsible for inequity in the distribution of daily precipitation amounts through each time interval. The research presented here used gridded seasonal means (1981 – 2010) of four precipitation characteristics: precipitation amount, precipitation frequency, GC, and LAC to delineate regions of homogenous precipitation characteristics. Through this process, 15 hydroclimatic regions were delineated within the contiguous United States. Regionally averaged annual time series (1949 – 2018) of precipitation amount, precipitation frequency, GC, and LAC were computed for each region using station-level precipitation. The time series of each precipitation characteristic, and for each region were then examined for statistical trends through the 70-year study period. Regional time series which characterize two key atmospheric characteristics, total column water vapor and static stability, were also computed for each region. For most of the 15 study regions, water year total precipitation and precipitation frequency increased through the latter half of the 20th century. The largest magnitude of change in water year total precipitation and precipitation frequency occurred in the time series of regions located within the eastern and northern portions of the contiguous United States. Results also show that precipitation became less evenly distributed across the water year through the 70-year study period for most of the 15 study regions. Combined, these results indicate that days with light and heavy precipitation are becoming more prevalent at the expense of days with moderate precipitation. Furthermore, variability in the time series of some precipitation characteristics for several regions coincide with variability in the atmospheric variables that characterize total column water vapor and static stability, however the dominant driver of hydroclimatic change across the contiguous United States remains elusive.

Spider orb-webs have evolved to intercept prey, absorb and dissipate the kinetic energy from prey impact, and retain prey until a spider can subdue their catch. Orb-web structure and function engages scientists from many disciplines, including engineering, behavior, materials science, ecology, and evolution. This dissertation examines the sticky capture spiral component of an orb-web. This composite material is made of supporting fibers covered in sticky glue droplets. These threads are both adhesive and extensible, and their performance is influenced by ambient conditions. The questions I addressed are framed in an ecological context, although they also add to our understanding of materials science. The results of the first study showed that temperature increased the viscosity of glycoproteins within Argiope aurantia droplets, mediating the effect of daily humidity changes, an important environmental effect on the glue's performance. The second study demonstrates that capture spiral droplets of spiders that build webs in habitats ranging from full sun to shade and nocturnal species (Argiope aurantia, Leucauge venusta, Neoscona crucifera, Verrucosa areenata, Micrathena gracilis) is resistant to degradation after a day's worth of UVB exposure. Conversely, after the equivalent of two days of UVB exposure the glue degrades in webs built by M. gracilis that build webs in the shade and N. crucifera, a nocturnal species. The less harsh UVA has little affect on capture spiral glue function, both for species that build webs in full sun and those that build webs at night. The third study documented web asymmetry in Argiope trifasciata orb-webs and identified differences in droplet characteristics across the webs. These spiders differently allocated resources, with the bottom region of the web having twice the droplet volume as the top, and half the ratio of aqueous to glycoprotein material as the inner droplets. Additionally, during foraging times, the bottom of the web experiences higher humidity than the top, which has the potential to increase droplet toughness in this region. This study expands the understanding of web asymmetry by examining the differences in glue characteristics as an additional level of flexibility for web fine-tuning. / Ph. D.