Static and Dynamic Error Correction of a Computer-Aided Mechanical Navigation Linkage for Arthroscopic Hip Surgery

While beneficially decreasing the necessary incision size, arthroscopic hip surgery increases the surgical complexity due to loss of joint visibility. To ease such difficulty, a computer-aided mechanical navigation system was developed to present the location of the surgical tool relative to the patient¿s hip joint. A preliminary study reduced the position error of the tracking linkage with limited static testing trials. In this study, a correction method, including a rotational correction factor and a length correction function, was developed through more in-depth static testing. The developed correction method was then applied to additional static and dynamic testing trials to evaluate its effectiveness. For static testing, the position error decreased from an average of 0.384 inches to 0.153 inches, with an error reduction of 60.5%. Three parameters utilized to quantify error reduction of dynamic testing did not show consistent results. The vertex coordinates achieved 29.4% of error reduction, yet with large variation in the upper vertex. The triangular area error was reduced by 5.37%, however inconsistent among all five dynamic trials. Error of vertex angles increased, indicating a shape torsion using the developed correction method. While the established correction method effectively and consistently reduced position error in static testing, it did not present consistent results in dynamic trials. More dynamic paramters should be explored to quantify error reduction of dynamic testing, and more in-depth dynamic testing methodology should be conducted to further improve the accuracy of the computer-aided nagivation system.

Revision of a Liquid Fuel Airblast Atomizer and Installation of a Laser Extinction System for Measurement of Soot Produced During Liquid Fuel Combustion

Studying liquid fuel combustion is necessary to better design combustion systems. Through more efficient combustors and alternative fuels, it is possible to reduce greenhouse gases and harmful emissions. In particular, coal-derived and Fischer-Tropsch liquid fuels are of interest because, in addition to producing fewer emissions, they have the potential to drastically reduce the United States' dependence on foreign oil. Major academic research institutions like the Pennsylvania State University perform cutting-edge research in many areas of combustion. The Combustion Research Laboratory (CRL) at Bucknell University is striving to develop the necessary equipment to be capable of both independent and collaborative research efforts with Penn State and in the process, advance the CRL to the forefront of combustion studies. The focus of this thesis is to advance the capabilities of the Combustion Research Lab at Bucknell. Specifically, this was accomplished through a revision to a previously designed liquid fuel injector, and through the design and installation of a laser extinction system for the measurement of soot produced during combustion. The previous liquid fuel injector with a 0.005" hole did not behave as expected. Through spray testing the 0.005" injector with water, it was determined that experimental errors were made in the original pressure testing of the injector. Using data from the spray testing experiment, new theoretical hole sizes of the injector were calculated. New injectors with 0.007" and 0.0085" orifices were fabricated and subsequently tested to qualitatively validate their behavior. The injectors were installed in the combustion rig in the CRL and hot-fire tested with liquid heptane. The 0.0085" injector yielded a manageable fuel pressure and produced a broad flame. A laser extinction system was designed and installed in the CRL. This involved the fabrication of a number of custom-designed parts and the specification of laser extinction equipment for purchase. A standard operating procedure for the laser extinction system was developed to provide a consistent, safe method for measuring soot formation during combustion.

Design Simulation for Solar Energy Research and Education

Solar research is primarily conducted in regions with consistent sunlight, severely limiting research opportunities in many areas. Unfortunately, the unreliable weather in Lewisburg, PA, can prove difficult for such testing to be conducted. As such, a solar simulator was developed for educational purposes for the Mechanical Engineering department at Bucknell University. The objective of this work was to first develop a geometric model to evaluate a one sun solar simulator. This was intended to provide a simplified model that could be used without the necessity of expensive software. This model was originally intended to be validated experimentally, but instead was done using a proven ray tracing program, TracePro. Analyses with the geometrical model and TracePro demonstrated the influence the geometrical properties had results, specifically the reflector (aperture) diameter and the rim angle. Subsequently, the two were approaches were consistent with one another for aperture diameters 0.5 m and larger, and for rim angles larger than 45°. The constructed prototype, that is currently untested, was designed from information provided by the geometric model, includes a metal halide lamp with a 9.5 mm arc diameter and parabolic reflector with an aperture diameter of 0.631 meters. The maximum angular divergence from the geometrical model was predicted to be 30 mRadians. The average angular divergence in TraceProof the system was 19.5 mRadians, compared to the sun’s divergence of 9.2 mRadians. Flux mapping in TracePro showed an intensity of 1000 W/m2 over the target plane located 40 meters from the lamp. The error between spectrum of the metal halide lamp and the solar spectrum was 10.9%, which was found by comparing their respective Plank radiation distributions. The project did not satisfy the original goal of matching the angular divergence of sunlight, although the system could still to be used for optical testing. The geometric model indicated performance in this area could be improved by increasing the diameter of the reflector, as well as decreasing the source diameter. Although ray tracing software provides more information to analyze the simulator system, the geometrical model is adequate to provide enough information to design a system.

Assessment of Alcohol Reward in Prairie Voles (Microtus ochrogaster)

The purpose of our study was to assess whether prairie voles find alcohol rewarding. Prairie voles have recently become a species of interest for alcohol studies, which have traditionally used other rodent model species including several different strains of mice and rats. The prairie vole is one of only two known rodent species that readily administers high levels of unsweetened alcohol, implicating it as a potentially effective animal model for studying alcohol abuse. However, voluntary consumption does not necessarily imply that prairie voles find it rewarding. Therefore the purpose of our study was to investigate if alcohol has rewarding properties for prairie voles using three different approaches: place conditioning, flavor conditioning, and immunohistochemistry. Furthermore, we sought to characterize their reward profile and compare it to other commonly used rodent models ¿ C57BL/6 mice, DBA/2J mice, and Sprague-Dawley rats. Place and flavor conditioning are behavioral methods that rely on the learned association between a stimulus and the effects of a drug; the drug of interest in these studies is alcohol. To assess whether prairie voles will demonstrate a conditioned preference for alcohol-paired stimuli, seven place conditioning studies were run that investigated a range of different doses, individual conditioning session durations, and trial durations. Video analysis revealed no difference in the amount of time spent on the alcohol-paired floor, suggesting no conditioned place preference for alcohol. Two flavor conditioning tests were conducted to assess whether voles would demonstrate a preference for an alcohol-paired flavored saccharin solution. Voles demonstrated reduced consumption of the alcohol-paired flavored saccharin solution, regardless of dose or flavor, when alcohol administration occurred after conditioning sessions (p=<0.001). When alcohol was administered before conditioning sessions, no difference in consumption of the alcohol-paired and saline-paired flavored saccharin solutions was seen (p=0.545). Previous studies that have documented similar behavior have hypothesized that this is an example of an anticipatory contrast effect. This theory proposes that prairie voles reduce their intake of a hedonic solution (flavored saccharin solution) in anticipation of later drug administration (alcohol). However, conditioning-based behavioral methods of studying alcohol reward are highly sensitive to the parameters of the conditioned stimulus, thus it is possible that voles will not show preference for alcohol-related stimuli, even if they do find alcohol rewarding. Immunohistochemical analysis supplemented this behavioral data by allowing us to identify specific neural regions that were directly activated in response to the acute administration of alcohol. No difference in the number of activated c-Fos neurons in the Nucleus Accumbens (NAc) core or shell was seen (p=0.3364; p=0.6698) in animals that received an acute injection of alcohol or saline. There was a significant increase in the number of activated c-Fos neurons in the Paraventricular Nucleus of the Hypothalamus (PVN) in alcohol-treated animals compared to saline-treated animals (p=0.0034). There was no difference in the pixel count of activated c-Fos neurons or in the % area activated in the Arcuate Nucleus between alcohol and saline-treated animals (p=0.4523; p=0.3304). In conclusion, the place conditioning studies that were conducted in this thesis suggest that prairie voles do not demonstrate preference or aversion towards alcohol-paired stimuli. The flavor conditioning studies suggest that prairie voles do not demonstrate aversion but rather avoidance of the alcohol-paired flavor in anticipation of future alcohol administration. The preliminary immunohistochemical data collected is inconclusive but cannot rule out the possibility of neuronal activation patterns indicative of reward. Taken together, our data indicate that prairie voles hav

The Role of Antennapedia in Anteroposterior Patterning of the Drosophila Melanogaster Ventral Nervous System

A major unresolved question in developmental neurobiology is how the nervous system is adapted to the specific needs of the organism at different life stages. In the holometabolous insect Drosophila melanogaster, the larval ventral nervous system (VNS) is comprised of similar repeating segments, as opposed to the adult VNS, which varies greatly from segment to segment both in number and types of neurons. The adult-specific neurons of each segment are generated by 25 distinct types of neuronal progenitor cells called neuroblasts (NBs) that appear in a stereotyped array (Truman et al., 2004). Each NB divides repeatedly to produce a distinct set of daughter cells termed a lineage, which is bilaterally symmetric but present to varying degrees in each segment. These daughter cells can be distinguished by their position within the nervous system as well as by their axonal projections. Each of the 25 NBs produces neurons; if both daughter cells are present in a lineage then both sibling populations survived, whereas if only one projection is seen cell death occurred, leaving a hemilineage (half lineage). In some lineages, the same sibling type survives in all segments in which the lineage appears, but in others, the surviving sibling type varies across segments, resulting in a different morphology for the same lineage in different segments. How are these differences in survival and morphology controlled? The Hox genes provide positional information for developing structures along the anterior-posterior (AP) axis of animals. They encode transcription factors, thereby controlling the activity of genes down stream. In the postembryonic VNS, each NB lineage features its own characteristic expression pattern of Hox genes Antp and Ubx, which can vary from segment-to-segment, and can thereby cause variation in the number of neural cells and axonal projections that survive. This study defines the wild-type expression pattern of Antp and elucidates the role of Antp in gain of function studies. These studies are possible due to the MARCM (Mosaic Analysis with a Repressible Cell Marker) method, which allows the genetically manipulated cells to be specifically labeled in an otherwise normal, unlabeled organism. The results indicate that Antp is expressed in a segment-, lineage-, and hemilineage-specific manner. Antp is sufficient for both anterior and posterior transformations of particular lineages, including promotion of cell death and/or survival as well as axon guidance.

An Analysis of Capacities, Moral Hierarchies, and the Moral Status of Non-Human Animals in Contemporary Animal Rights Work

The primary objective of this thesis is to demonstrate the pernicious impact that moral hierarchies have on our perception and subsequent treatment of non-human animals. Moral hierarchies in general are characterized by a dynamic in which one group is considered to be fundamentally superior to a lesser group. This thesis focuses specifically on the moral hierarchies that arise when humans are assumed to be superior to non-human animals in virtue of their advanced mental capabilities. The operative hypothesis of this thesis is essentially that moral hierarchies thwart the provision of justice to non-human animals in that they function as a justification for otherwise impermissible actions. When humans are assumed to be fundamentally superior to non-human animals then it becomes morally permissible for humans to kill non-human animals and utilize them as mere instrumentalities. This thesis is driven primarily by an in-depth analysis of the approaches to animal rights that are provided by Peter Singer, Tom Regan, and Gary Francione. Each of these thinkers claim that they overcome anthropocentrism and provide approaches that preclude the establishment of a moral hierarchy. One of the major findings of this thesis, however, is that Singer and Regan offer approaches that remain highly anthropocentric despite the fact that each thinker claims that they have overcome anthropocentrism. The anthropocentrism persists in these respective approaches in that each thinkers gives humans Regan and Singer have different conceptions of the criteria that are required to afford a being moral worth, but they both give preference to beings that have the cognitive ability to form desires regarding the future.. As a result, a moral hierarchy emerges in which humans are regarded to be fundamentally superior. Francione, however, provides an approach that does not foster a moral hierarchy. Francione creates such an approach by applying the principle of equal consideration of interests in a consistent manner. Moreover, Francione argues that mere sentience is both a necessary and sufficient condition for being eligible and subsequently receiving moral consideration. The upshot of this thesis is essentially that the moral treatment of animals is not compatible with the presence of a moral hierarchy. As a result, this thesis demonstrates that future approaches to animal rights must avoid the establishment of moral hierarchies. The research and analysis within this thesis demonstrates that this is not a possibility, however, unless all theories of justice that are to accommodate animals abandon the notion that cognition matters morally.

Dependence of Positronium Lifetime on Temperature in Porous Materials

A positron and electron can form the bound state called positronium. When positronium is formed in a porous material, its lifetime is based on the electron density of the pore walls, temperature, and pore size according the Rectangular Extenstion to the Tao-Eldrup Model. Positronium Annihilation Lifetime Spectroscopy is an established technique of finding positronium lifetimes. Using this technique, we find positronium lifetimes at various temperatures and compare these to the expectations of the model. We find that the pore size relationship is consistent, but more data must be gathered under different conditions in order to draw conclusions about relationships between lifetime, temperature, and pore size.

The Supreme Court Confirmation Process and Its Implications

In recent history, there has been a trend of increasing partisan polarization throughout most of the American political system. Some of the impacts of this polarization are obvious; however, there is reason to believe that we miss some of the indirect effects of polarization. Accompanying the trend of increased polarization has been an increase in the contentiousness of the Supreme Court confirmation process. I believe that these two trends are related. Furthermore, I argue that these trends have an impact on judicial behavior. This is an issue worth exploring, since the Supreme Court is the most isolated branch of the federal government. The Constitution structured the Supreme Court to ensure that it was as isolated as possible from short-term political pressures and interests. This study attempts to show how it may be possible that those goals are no longer being fully achieved. My first hypothesis in this study is that increases in partisan polarization are a direct cause of the increase in the level of contention during the confirmation process. I then hypothesize that the more contention a justice faces during his or her confirmation process, the more ideologically extreme that justice will then vote on the bench. This means that a nominee appointed by a Republican president will tend to vote even more conservatively than was anticipated following a contentious confirmation process, and vice versa for Democratic appointees. In order to test these hypotheses, I developed a data set for every Supreme Court nominee dating back to President Franklin D. Roosevelt¿s appointments (1937). With this data set, I ran a series of regression models to analyze these relationships. Statistically speaking, the results support my first hypothesis in a fairly robust manner. My regression results for my second hypothesis indicate that the trend I am looking for is present for Republican nominees. For Democratic nominees, the impacts are less robust. Nonetheless, as the results will show, contention during the confirmation process does seem to have some impact on judicial behavior. Following my quantitative analysis, I analyze a series of case studies. These case studies serve to provide tangible examples of these statistical trends as well as to explore what else may be going on during the confirmation process and subsequent judicial decision-making. I use Justices Stevens, Rehnquist, and Alito as the subjects for these case studies. These cases will show that the trends described above do seem to be identifiable at the level of an individual case. These studies further help to indicate other potential impacts on judicial behavior. For example, following Justice Rehnquist¿s move from Associate to Chief Justice, we see a marked change in his behavior. Overall, this study serves as a means of analyzing some of the more indirect impacts of partisan polarization in modern politics. Further, the study offers a means of exploring some of the possible constraints (both conscious and subconscious) that Supreme Court justices may feel while they decide how to cast a vote in a particular case. Given the wide-reaching implications of Supreme Court decisions, it is important to try to grasp a full view of how these decisions are made.

Running in Heels: an Analysis of Advertisements By Female Senate Candidates

Female candidates have become more successful in the political arena, specifically in the United States Senate. Today, females make up twenty percent of the total Senate seats. Despite this increase, females are still underrepresented in Washington. As such, understanding the roadblocks to equality will help us achieve parity. In an attempt to understand various challenges that female senatorial candidates face, this project looks at a specific element of their campaign, TV advertisements. Assessing candidate advertisements will help us understand whether gender affects strategic campaign decisions. Specifically, this project investigates the relationship between candidate gender and casting and setting of TV advertisements. Does gender influence the makeup of political ad spots? In order to understand this relationship more completely, I employ both quantitative data and case study analysis for same-gender and mixed-gender primary and general election contests in 2004 and 2008. Ultimately, candidate gender has little to no effect on casting of senatorial advertisements across both election cycles. Despite this variation in casting, we observe consistent findings across three settings, the political setting, the home setting, and the neighborhood setting. In both 2004 and 2008, female candidates use smaller proportions of ad frames with the political setting in comparison to their male counterparts. Female candidates in both election cycles also employed greater proportions of ad frames with the home and neighborhood setting compared to male candidates. These discrepancies point to a distinction in advertisement strategy depending on gender of the candidate.

Relationship Repair After Infidelity: Looking at Other Perspectives

Prior research examining relationship repair after infidelity scenarios tends to focus primarily on heterosexual relationships, and often does not take into consideration the nuance between emotional and sexual infidelity, which, according to evolutionary psychology theories, tends to be salient to individuals based on their reproductive challenges. This research intended to rectify that dearth, hypothesizing that non-heterosexual participants would be more likely to repair a relationship where a partner has committed sexual infidelity than they would be to repair a relationship where a partner has committed an emotional infidelity. As well, based on prior research, there were expectations for sex differences in the likelihood of repairing a relationship after infidelity by a partner for participants in committed relationships, with female participants likely to repair emotional infidelity and male participants likely to repair sexual infidelity. In a survey of volunteers online, likelihood of repair for relationships after sexual or emotional infidelity was related to the sexual orientation of participants. Homosexual/other individuals were equally likely to repair their relationship after an emotional or sexual infidelity was committed by a partner and were more likely to repair a relationship after a partner committed a sexual infidelity than heterosexual individuals were. A qualitative question component obtained more information about the participants¿ logic behind their reconciliation choices, and these results along with the quantitative results are discussed and interpreted using themes from earlier research.

Attachment and Coping With Two Kinds of Relationship Stressors

This study evaluated the relationship between recalled parental treatment, attachment style, and coping with parental and romantic stressors. A group of 66 undergraduate students completed the Parental Bonding Instrument (PBI) (Parker, Tupling, & Brown, 1979), a measure of attachment style (Simpson, 1990), general questions regarding the intensity and frequency of parental and romantic stressors, and their typical ways of coping with each type (Vitaliano, Russo, Carr, Maiuro, & Becker, 1985). Data analysis showed that attachment scores were significantly correlated with coping with both kinds of stress. The most significant correlations were found between attachment and coping with romantic stressors. Overall, high or low use of a specific approach to coping was consistent in the face of parental and romantic stressors. Further, exploratory analysis revealed that the habitual intensity of the experienced stressors could act as a moderator of coping techniques.

Coping With a Family Member's Death: Parenting, Religiosity, and Parent-Child Communication

The present study had three major aims. First, this study was a basic descriptive exploration of the frequency and nature of parent-child communication about death. Second, this study conducted a quantitative analysis to identify predictors of communication and bereaved children¿s emotional and behavioral problems. Third, this study was also a qualitative analysis of parents¿ descriptions of how religious views shape conversations about death and how conversations are beneficial. Based on prior research, it was predicted that positive child outcomes would be associated with parental warmth, religiosity, adaptive coping, positive religious coping, and frequent parent-child communication about death. Conversely, it was predicted that negative child outcomes would be associated with parental psychological control, maladaptive coping, negative religious coping, and less frequent parent-child communication about death. Additionally, it was hypothesized that parents¿ religious and spiritual views would shape parent-child communication about death, and parents would describe numerous benefits of discussing death with children. Parents completed a series of survey measures assessing their religiosity, coping strategies, parent-child communication about death, and their children¿s emotional and behavioral symptoms. Almost 80% of parent-child dyads discussed death at least once a week, and children initiated approximately half of these conversations. Parent-child communication about death was predicted by parents¿ warmth toward and acceptance of their children and inversely predicted by children¿s hyperactivity and social problem solving. Higher levels of children¿s social problem solving could predict lower frequency of parent-child communication about death if children were holding frequent, meaningful, and comforting conversations with friends and other adults. Higher levels of parents¿ psychological control predicted more emotional and behavioral problems in the child. Parents¿ adaptive coping had significant relationships with all of the dimensions of parent-child communication about death. Qualitative analyses revealed that parents perceived their religious beliefs as shaping conversations about death and grief as an individualized journey. A majority of parents described the emotional, social, and intellectual benefits of holding parent-child conversations about death. This study contributes to the literature by further describing parent-child communication about death, identifying its predictors, and investigating parents¿ religiosity and coping strategies in relation to child well-being. Overall, this study revealed the importance of assessing global parenting characteristics (i.e., warmth/acceptance and psychological control) when examining parent-child relationships and communication about death. Furthermore, this unique study illustrates the value of qualitative data when examining parent-child communication about death and religiosity.

Distress Disclosure and Personality in College Students

This study examined distress disclosure, the tendency to confide unpleasant feelings and experiences to others. Other factors under consideration were gender, personality factors (such as extraversion and one's general tendency to disclose), and the identity of the person to whom individuals were asked to disclose. The subject pool included 22 male and 34 female volunteers from Bucknell University. Participants were asked to complete a measure of basic demographics, the Distress Disclosure Index, and the NEO-FFI measure of personality. They were then asked to disclose about an aspect of their lives that they personally found stressful, as if they were confiding in a best friend, a parent, or a professor, respectively. The transcriptions of those recordings were coded for length, depth, and breadth of the disclosure. The researcher hypothesized that greater length, depth, and breadth would be disclosed by females who scored highly on the Distress Disclosure Index, had high extraversion scores on the NEO-FFI, and had been asked to disclose to a best friend. The study found positive associations between openness and depth, neuroticism and depth, and gender with length, such that males were more likely to have longer disclosures. Negative associations were found between extraversion and depth, neuroticism and length, and openness and breadth. Personality factors, gender, and the disclosure target may act as better predictors of the tendency to disclose, rather than of the particular dimensions of disclosure, since every instance is unique.

Locational and Temporal Risk Associated With Campus Sexual Assault

The present study investigates the rates of victimization of sexual assault reported by undergraduates at Bucknell University. Specifically, the study aimed to determine where and when sexual assault took place, in order to pinpoint both temporal risks and locational risks associated with certain events on campus. Results of the survey were analyzed for victimization rates across class year, time of year, where victimization took place, as well as where victims and perpetrators met. Data for the study was gathered by means of anonymous survey, sent out to 1752 randomly selected undergraduates via email. Participants filled out the survey which asked if they had ever been sexually assaulted or committed a sexual assault during their past year studying at Bucknell. The results of the survey indicated that dormitories, fraternity houses, and off-campus student houses displayed significantly higher rates of victimization than other locations. In addition, increased risk of unwanted sexual contact in the fall semester was shown to be statistically significant. Moreover, results of the current study support that parties were statistically significant locations for meeting perpetrators of sexual assault. The results suggest that it may be beneficial to direct special attention towards campus sexual assault, specifically to certain locations, times of the year, and campus activities.

Greek Life and God Attachment: the Interaction of Sorority Influence and Religiosity on Women's Body Shame

The present study investigated the relationships between sorority women’s internalization of Greek thin ideals and body image, and dimensions of sorority women’s religiosity and body image. A combined relationship among sorority women’s internalization of Greek thin ideals, body image, and religiosity was also examined. Based on previous research it was expected that women’s internalization of Greek thin ideals would be associated with worse body image (in terms of body shame, body esteem, and drive for thinness) and that women’s religiosity (in terms of secure attachment to God) would be associated with better body image. Combinations of Greek thin ideal internalization and God attachment were expected to significantly predict changes in women’s body image. Women completed a series of survey measures assessing their awareness and internalization of Greek sociocultural thin ideals and their sense of community within their particular sorority. Women also completed a series of survey measures assessing their body shame, body esteem, and drive for thinness, in addition to survey measures assessing dimensions of their religiosity. The study’s findings revealed that women’s internalization of Greek thin ideals was associated with worse body image outcomes and that anxious attachment to God was associated with worse body image outcomes, particularly in relation to body shame. Moderation analyses revealed that Greek thin ideal internalization significantly interacted with anxious God attachment to predict body shame.