Filter Dissertations and Theses By:
Microspherule Protein Msp58 and Ubiquitin Ligase EDD Form a Stable Complex that Regulates Cell Proliferation
Year of Dissertation:
A complex molecular network is put into place at specific phases of the cell cycle to prevent unscheduled cell division that could result in malignant cell growth. Emerging evidence shows that still uncharacterized proteins play crucial functions at those cell cycle transition points. Nuclear protein Msp58 and EDD E3 ubiquitin ligase have been implicated in different aspects of cell proliferation and reported to be abnormally expressed in numerous types of cancers. The molecular mechanisms underlying Msp58 and EDD functions, however, are not well understood. The work presented here shows that Msp58 and EDD form a stable protein complex that regulates cell viability and proliferation. Interestingly, knockdown of EDD by RNA interference leads to a significant accumulation of Msp58 protein, which suggests that EDD serves as a negative regulator of Msp58. In addition, our in vivo ubiquitination assays and analyses of various cell lines treated with translational and proteasomal inhibitors demonstrate that Msp58 is regulated post-translationally by the ubiquitin-proteasome pathway. These results imply that EDD ligase activity is involved in this regulatory process. Using flow cytometry analyses and biochemical characterization of Msp58 and/or EDD depleted cells, we show that the Msp58-EDD complex plays important roles in cell cycle progression via the control of cyclin gene expression. In particular, silencing Msp58 and/or EDD alters the protein levels of cyclins B, D and E. Taken together, our data suggest that a set of the biological roles attributed to Msp58 and EDD may be executed in the context of the complex that they form, thereby revealing a novel molecular mechanism for these two proteins to accomplish their functions.
Propagation of Non-Stationary Noise in Waveguides
Year of Dissertation:
This thesis consists of research regarding pulse and noise propagation in dispersive media. The research consists of three parts. In Part I we develop an approach for the propagation of non-stationary noise in waveguides, and in particular, we focus on the two-plate waveguide, which is a standard model for the ocean. he fundamental aim is to obtain the propagation of the space-time autocorrelation function. In our formulation, the noise is described by a Wigner spectrum, from which the autocorrelation function can be obtained. We discuss how to obtain the Wigner spectrum of a noise field from the Wigner spectrum of the noise that created it. We show that the Wigner spectrum of the field can be expressed in terms of the Wigner spectrum of the driving noise function and the Wigner distribution of the Green's function. We calculate the Green's function and its Wigner distribution for the two-plate waveguide. A number of special cases are considered, and we show how our result reduces to a known special case. In Part II, we study the evolution of non-stationary noise in dispersive media in terms of modes and show how modes evolve and how they are effected by sources. Each mode satisfies a Schr\"odinger-type equation where the ``Hamiltonian'' may not be Hermitian. The Hamiltonian operator corresponds to the dispersion relation where the wavenumber is replaced by the wavenumber operator. A complex dispersion relation corresponds to a non-Hermitian operator and indicates that we have attenuation. The case of arbitrary initial conditions is developed. The results expand on a previous approximation in terms of the Wigner distribution of a single mode. This solution requires one to obtain the initial modal functions from the given initial wave, and the cross-Wigner approximation between different modal functions. The approximation is obtained for general linear wave equations by transforming the equations to phase space, and then solving in the new domain. A number of examples are given. In Part III we consider the motion of a ``particle'' in a medium of variable index of refraction whose motion is governed by Snell's law. A stratified medium is considered. We give a derivation of the Newtonian forces that govern the motion and show that a position-dependent variable mass is necessary. Explicit expressions are given for the velocity and acceleration components of the particle. These are derived directly from Snell's law. It is further shown that momentum is conserved along the interface, and that Snell's law follows from this conservation law. We apply the equations of motion and find the conditions for a SOFAR channel, a phenomenon where rays are trapped in a channel.
Three Essays on Bentham
Year of Dissertation:
The dissertation was written in the three essay format. In Essay One I discuss the elements of Bentham's philosophical method, both as described by Bentham and as implied or exemplified by a variety of Bentham's texts. It will show that Bentham's principles of morals and legislation, though intended to have practical (political) effect, have also methodological significance, as they are grounded in grammatical and semantic constructs (constructs that affect `method' - the form of one's enquiry). In Essay Two I describe the elements of Bentham's conception of justice, based on Halevi, Sidgwick and other historical sources, and as they appear in Bentham's work. Bentham's approach to `justice' hinges on his theory of fictions, primarily because `justice' is, according to Bentham, a `fictitious entity' - not having a superior genus. It is for this reason that Bentham introduces a new kind of definition - paraphrasis, and I hope to show that this is where a distinction made in Bentham between `adjective' and `substantive' terms helps explain the necessity of this new kind of definition and also helps us define `justice' in itself. One of the conclusions of the second essay will be that there is a great similarity between the terms defining Justice in Bentham and the terms defining Method. In other words, `doing the right thing' and `having chosen the right method' seem to amount to the same thing. This also demonstrates the way Bentham employs the term `right' - primarily in its `adjectival' form. In Essay Three I discuss the conception of `right' in Bentham in the context of the French and American declarations of rights, and we see how Bentham presents the notion of `political rights' in stead of `natural rights'. Benthams' idea of `political rights' derives its validity from the `principle of the artificial identity of the interests of governors and the governed', or in other words, from the authority given to government by the governed. In the second part of Essay Three I show how, contrary to some critics, Bentham's theory of justice and rights does provide adequate individuation of persons. The dissertation as a whole, I hope, shows the continuity between what traditionally belongs to the `content' of political theories and what belongs to their `form' or method. This is being achieved primarily by offering to replace the traditional `content/form' (or `substance/method') distinction with the distinction between `substantive' and `adjective' terms, which also allows us to see the similarity between the definitions of `method' and `justice' and the proper employment of the term `right'. Both `method' and 'justice' are highly abstracted entities, and as such cannot be defined in themselves by the traditional terms and formulas of definition (definition by genus and difference). It is the emphasis on `adjectival' terms, which are compatible with the new kind of definition - paraphrasis - that allows us to arrive at a partial definition of `method' and `justice'. And since with `paraphrasis' the `adjectival' terms are being employed in a new way, their meaning changes. This change of the meaning of the terms used to define `method' and `justice' helps us see that `justice' is a transformative entity by nature. I also arrive at the conclusion that the mere initiation of the enquiry into `justice' causes a transformation of the terms of the enquiry, its mode (method), and the person of the one conducting it.
Guided Tours: The Layered Dynamics of Self, Place and Image in Two American Neighborhoods
Year of Dissertation:
This work complicates our understanding of the creation, knowledge and experience of everyday experience in two heterogeneous neighborhoods in Brooklyn, New York and Oakland, California. This project incorporates conceptual, epistemological and methodological questions. The concern with the everyday is explored by addressing how everyday places are known and experienced, weaving local with global, personal with political, embodied with ideological, in two neighborhoods marked by American post-World War II urbanism. Challenging conceptions of the role of the expressive, the individual and the visual in research, the work shows that a combination of embodied walking and expressive representational photographic strategies--my "guided tours" method--can show us new ways of knowing about the physical and phenomenal everyday world. The evocative and embodied power of being physically in place--through walks or drives--is juxtaposed with a process of photographic production and reflection, utilizing photography's evocative relationship to the real as a prompt for storytelling. From this unique method, this work develops a typology of "layered dynamics" to understand how everydayness is continually created through processes of knowing, negotiating and experiencing, as places and lives are woven together. These layered dynamics are the intersecting and changing forces and motions that come from and change lives in a neighborhood; they characterize the system of a place, and constitute the everyday experience of places we inhabit.
DOES A COURSE IN CLASSROOM MANAGEMENT AFFECT TEACHERS' SELF-PERCEIVED EFFICACY IN CLASSROOM MANAGEMENT?
Year of Dissertation:
The literature on teacher burnout clearly indicates that classroom management problems are primary causes contributing to teachers leaving the field. Efficacy beliefs influence the individual's cognition and affect to mobilize the necessary psychological resources to accomplish a specific task. Lower perceived self-efficacy in classroom management directly impacts personal accomplishment. While much research has examined teacher efficacy in general, little research has looked at classroom management in particular. This study sought to contribute to the teacher efficacy in classroom management literature by investigating if a course in classroom management increased teacher efficacy in classroom management as contrasted with a comparative graduate course in the exceptional child. The investigator administered at pre and posttest the Teacher Efficacy in Classroom Management and Discipline Scale (SEBM) and used the71 graduate students' course grades along with behavior vignettes as a means to externally validate their self-perceived teacher efficacy beliefs. The current study also investigated the effect of mediating variables, such as gender, age, ethnicity, the number of years teaching, child or childless, socio-economic status, undergraduate and graduate grade-point averages on teacher efficacy in classroom management. The results indicated that students in the classroom management course were significantly better at identifying target behaviors and interventions for the behavior vignettes than were students in the exceptional child course. In addition, teaching experience for classroom management students related positively to classroom management self-efficacy scores at posttest, but not at pretest, and none of the other mediating variables related to self-efficacy scores. Participants in the classroom management course did not statistically differ in gains on classroom management self-efficacy scores as compared with participants in the exceptional child course. Moreover, there was no significant relationship between course grades and posttest self-efficacy scores for both classes. Results are discussed in terms of implications for school psychologists, study limitations, and suggestions for future research.
Mechanisms of Vocal Coordination in Zebra Finches
Year of Dissertation:
Social animals frequently emit communication calls. Although these calls are often innate in their acoustic structure, they can be used adaptably to coordinate behavior with other individuals. It is not known, however, what each animal needs to learn in order to achieve and maintain synchronized call patterns with others. To study this process, we have developed a vocal robot that can be programed to generate call patterns or to sense a bird’s contact (short) calls and respond with precisely timed call answers. By varying the robot’s vocal behavior, including call timing and rhythm, we tested how interacting zebra finches adapt to different call patterns produced by a partner robot bird. This approach allows us to assess engagement and the capacity to synchronize calls between females (vocal non-learners) and males (vocal learners) as well as birds with different levels of developmental social experience. We also tested if forebrain structures that are known to be involved in song learning are required for the coordination of calls. We discovered that zebra finches can learn to adjust the timing of their responses to a robot bird partner within minutes. Further, when challenged with complex rhythms containing jamming elements, birds dynamically adjusted the timing of their calls in anticipation of jamming. Blocking the song system cortical output dramatically reduced the precision of birds’ response timing and abolished their ability to avoid jamming. Surprisingly, we observed this effect in both males and females, indicating that the female song system is functional rather than vestigial. We then tested if social interactions during development are necessary for birds to acquire the capacity to synchronize and adapt their call timing to those of a partner bird robot. We found that socially isolated birds were extremely imprecise in the timing of their responses. Further, they were unable to avoid disruptive jamming. Interestingly, these results were very similar to those observed after blocking the forebrain song system in socialized birds. We conclude that social interactions during development are necessary for zebra finch males to develop the capacity to precisely adapt the timing of their calls. Further, the capacity to synchronize calls must be acquired independently from that of song learning. Finally, we investigated if, and to what extent, birds can take into account the behavior of a third party while interacting with a partner. Using miniaturized wireless audio transmitters, we found that when two birds are interacting simultaneously with the vocal robot and with each other, they can avoid jamming with each other and with robot by cooperatively changing the latencies of their answer calls. These qualitative results suggest that birds are capable of adjusting the timing of their calls with respect to more than a single partner bird. Together, our results uncover behavioral and physiological mechanisms that give rise to vocal coordination, bridging a functional gap between innate and learned vocalization abilities.
RELIGION, SPIRITUALITY AND THE FAMILY IN THE LIVES OF AFRICAN AMERICAN ELDERLY MEN
Year of Dissertation:
The purpose of this study was to provide information about the ways in which African American elderly men raised in the South in Mississippi, during the height of Segregation, managed to survive and live successful lives. The study seeks to illustrate how these men incorporated religion, spirituality and their families as sources of strength and psychological buffers against the many adversarial circumstances that they faced. Qualitative data were drawn from the interviews of eleven subjects, representative of stellar examples of success within their communities. The method of analysis was grounded theory developed by Glaser and Straus. Patterns that emerged from the data were sorted, categorized and identified as codes. An analysis of the codes revealed the following major findings regarding these men. For these men life in Mississippi was limited and difficult because of Segregation. As a result their options about how they would live their lives were gravely influenced and they were under threat of danger on a daily basis. The findings also suggest that these men used religious affiliation, which in many instances is culturally inherent, as a means to cope with the psychological pressures as well as seeking support from their family, and community. Despite the circumstances these men went through, there is much to learn from black males who do thrive. In my sample of now elderly black men, I suggest that these men were able to negotiate and withstand horrific trials, similar to the present day challenges being faced because of a belief in a higher power and deep faith in religion. The study seeks to highlight the ways that these men have used their belief in God to lead successful lives.
The Impact of Emotions on Stereotyping and Discrimination in Workplace Selection: The Role of Certainty Appraisals
Year of Dissertation:
In the present studies, an appraisal tendency approach (e.g., Lerner & Keltner, 2000, 2001) was adopted to make predictions regarding the role of emotional certainty in the use of stereotypes in a workplace context. This approach suggests that emotional certainty increases reliance on heuristic processing strategies, as evidenced by greater use of stereotypes. The current research examined stereotypes associated with physical attractiveness (Studies 1 & 3) and age (Study 2). In Studies 1 and 2, participants completed an emotional memory task designed to induce one of four specific emotions representing two different levels of emotional certainty. They then reviewed interview footage, a résumé, and qualifying criteria before rating the hypothetical job candidate's personality and employability. In Study 3, participants completed four measures of dispositional emotion: anger, fear, happiness, and hope. All other features of the study were identical to Study 1. In Study 1, emotions high in certainty (compared to uncertainty) led to more favorable personality and employability ratings for attractive (compared to unattractive) candidates. In Study 2, the same pattern of results emerged for younger (compared to older) candidates. However, in Study 3, contrary to predictions, trait emotions characterized by high certainty (compared to uncertainty) did not lead to more favorable personality and employability ratings for attractive (compared to unattractive) candidates. Taken together, the findings contribute to a growing literature suggesting that certainty appraisals, when associated with temporary, incidental emotions, are a useful predictor of the likelihood that stereotypes will be applied in decision-making.
Solid State Nuclear Magnetic Resonance Investigations of Advanced Energy Materials
Year of Dissertation:
In order to better understand the physical electrochemical changes that take place in lithium ion batteries and asymmetric hybrid supercapacitors solid state nuclear magnetic resonance (NMR) spectroscopy has been useful to probe and identify changes on the atomic and molecular level. NMR is used to characterize the local environment and investigate the dynamical properties of materials used in electrochemical storage devices (ESD). NMR investigations was used to better understand the chemical composition of the solid electrolyte interphase which form on the negative and positive electrodes of lithium batteries as well as identify the breakdown products that occur in the operation of the asymmetric hybrid supercapacitors. The use of nano-structured particles in the development of new materials causes changes in the electrical, structural and other material properties. NMR was used to investigate the affects of fluorinated and non fluorinated single wall nanotubes (SWNT). In this thesis three experiments were performed using solid state NMR samples to better characterize them. The electrochemical reactions of a lithium ion battery determine its operational profile. Numerous means have been employed to enhance battery cycle life and operating temperature range. One primary means is the choice and makeup of the electrolyte. This study focuses on the characteristics of the solid electrolyte interphase (SEI) that is formed on the electrodes surface during the charge discharge cycle. The electrolyte in this study was altered with several additives in order to determine the influence of the additives on SEI formation as well as the intercalation and de-intercalation of lithium ions in the electrodes. 7Li NMR studies where used to characterize the SEI and its composition. Solid state NMR studies of the carbon enriched acetonitrile electrolyte in a nonaqueous asymmetric hybrid supercapacitor were performed. Magic angle spinning (MAS) coupled with cross polarization NMR techniques were used to determine what effects 200 ppm of intentionally added water would have on the decomposition of the acetonitrile. The resultant NMR spectra yielded several prominent peaks which were assigned to acetamide, glycolonitrile, formaldehyde and other lithium carbon derivatives. The aforementioned decomposition products are a believed to be a result of the acetonitrile being hydrolyzed as well as its interaction with the lithium salt. The decomposition products are deposited on electrode surface leading to operation changes in the life of the supercapacitors. The information gained from the NMR studies may be beneficial understanding the supercapacitor operation and aid in future design. Carbon nanotubes are used to enhance structural stability and performance. In this experiment NMR is used to determine if the addition of nanotubes to two types of polymer matrix changes the structural stiffness and motional dynamics. The polymers studied by direct 1H NMR observations are Polybutadiene (PB) and Polyisobutylene (PIB). PB and PIB with single walled carbon nanotubes (SWNT) as well as functionalized with fluorine (F) produce significantly stronger composites as compared to composites without SWNT.
EVOLUTION AND ETHICS
Year of Dissertation:
Does evolution inform the ancient debate about the roles that instinct (emotion/passion/sentiment/feeling) and reason do and/or should play in how we decide what to do? Evolutionary ethicists typically adopt Darwinism as a suitable explanation for evolution, and on that basis draw conclusions about moral epistemology. However, if Darwinism is to be offered as a premise from which conclusions about moral epistemology are drawn, in order to assess such arguments we must assess that premise. This reveals the highly speculative and metaphysical quality of our theoretical explanations for how evolution happens. Clarifying that helps to facilitate an assessment of the epistemological claims of evolutionary ethicists. There are four general ways that instinct and reason can function in moral deliberation: descriptive instinctivism asserts that moral deliberation is necessarily a matter of instincts because control of the instincts by our faculty of reason is regarded (descriptively) as impossible; descriptive rationalism asserts that moral deliberation is necessarily a matter of reasoning, which (descriptively) must control instinct; prescriptive instinctivism asserts that moral deliberation can involve both rationality and instinct but prescribes following our instincts; prescriptive rationalism also asserts that deliberation can be either instinctive or rational but prescribes following reason. Micheal Ruse (2012), Peter Singer (2011), and Philip Kitcher (2011) each adopt Darwinism and on that basis arrive at descriptive instinctivism, descriptive rationalism, and prescriptive instinctivism, respectively. Our current level of understanding about evolution implies that prescriptive rationalism is a more practical approach to ethical deliberation than the other three alternatives described. Evolution can inform moral epistemology, but only very generally by helping to inform us of what we can justifiably believe about ourselves and nature.