The Gap in the wall : containment and abandon in seventeenth-century Chinese fiction

McMahon, Robert Keith University Microfilms International 1984 국내박사

Attitudes about sports culture, sexual violence, and leadership roles among college student-athletes

McMahon, Sarah Rutgers The State University of New Jersey - New B 2005 해외박사(DDOD)

Violence against women is a major social problem, impacting millions of women and girls in the United States each year. Sexual assault, often called rape, is particularly extensive and devastates the lives of victims in numerous ways, as they experience a range of physical, emotional, and psychological problems. One of the factors recognized by feminist researchers as contributing to the occurrence of sexual assault is the role of all-male settings or subcultures, such as fraternities and men's athletic teams. While extensive research has been conducted on fraternities, the same research has not been applied to athletics, nor has it been examined in the field of Social Work. The overall purpose of this study was to explore the culture of college athletics to better understand the ways in which it may or may not be rape supportive. Using a combination of quantitative and qualitative methods, this study gathered data from male and female student-athletes through three main methods: the distribution of a survey designed to assess attitudes about sexual assault and social change; focus groups conducted with nine selected men's and women's sports teams; and individual interviews held with 22 male and female athletes to explore the ways in which sport culture may or may not contribute to a rape supportive atmosphere. This study also aimed to uncover ways in which members of the student-athlete culture can and already influence the atmosphere in ways that are likely to decrease sexual assault. Results from this study included support for the notion that certain rape prone contexts exist within the student athlete culture, and that these are sanctioned in subtle yet powerful ways. This study also found that there are student athletes who currently work for social change on issues of violence against women and also that there exists the potential to do more. This information will assist educators in developing more effective intervention efforts, with the ultimate goal of decreasing the incidence of sexual assault.

Characterizing unexpected inhibitors of HIV-1 replication

McMahon, Moira Ann The Johns Hopkins University 2010 해외박사(DDOD)

HIV-1, Herpes Simplex Virus, and Hepatitis B Virus are common pathogens that can establish lifelong infection. Drugs have been developed to specifically target these viruses. Although not a cure, drug treatment has shown to prolong patient survival and improve quality of life. Some of the earliest antivirals and new drugs being developed are based on a critical feature of the viral life cycle. In order to proliferate and promote infection, viruses must replicate their genome which is carried out by a virally encoded polymerase and the use of other host components. Some of the best drugs for treating viral infections are nucleoside analogs, which mimic nucleotides but lack critical features for proper DNA elongation. For infections like Herpes Simplex or Hepatitis B, treatment with a single drug is typical. For HIV-1 treatment, the use of drug combinations, or highly active anti-retroviral therapy, is the only effective means for inhibiting viral replication. Our initial studies stemmed from a HIV-1/Hepatitis B co-infected patient taking the Hepatitis B drug entecavir, a guanine nucleoside analog. In this patient, the start of entecavir treatment resulted in a concurrent decrease in plasma HIV-1 RNA levels by about 1 log, suggesting the drug directly inhibited HIV-1 replication. We followed up this clinical observation by using an in vitro HIV-1 infectivity assay to show that entecavir is a potent inhibitor of HIV-1 reverse transcription and that it can select for the M184V active site mutation in reverse transcriptase both in vitro and in patients. We also wanted to identify other inhibitors of HIV-1 replication. We used the Johns Hopkins Clinical Compound Library to screen for inhibitors of HIV-1 replication using a single round infectivity assay. Of ∼3,000 compounds tested, we identified 20 that inhibited infection. Most interesting was the Herpes Simplex Virus-2 drug acyclovir, which although not a potent inhibitor of HIV-1 replication, demonstrated considerable activity within clinical concentrations. Mechanistic studies showed that acyclovir triphosphate is a substrate for HIV-1 reverse transcriptase and that the V75I HIV-1 drug resistant variant is selected for in vitro. Follow up data consider the necessity of herpes co-infection for acyclovir anti-HIV-1 activity.

Policy assessment of medical imaging utilization: Methods and applications

McMahon, Pamela Markell Harvard University 2005 해외박사(DDOD)

We developed and applied decision-analytic methods to two controversial uses of diagnostic imaging technologies: diagnosing Alzheimer's disease (AD) with positron-emission tomography (PET) and screening for lung cancer with computed tomography (CT). In Chapter 2, we evaluated strategies for the diagnosis of early-stage AD: usual care (a clinical exam plus a structural imaging test) with or without an additional functional imaging exam (PET or functional magnetic resonance imaging [fMRI]). Using our best estimates for inputs, PET yielded fewer benefits (at a higher cost) than usual care, and fMRI had an incremental cost-effectiveness ratio (vs. usual care) of $598,800/quality-adjusted life year (QALY). Our main conclusion was that resources should be allocated towards developing better therapies, not improving diagnostic tests. The published article informed Medicare's National Coverage Decision, an example of the use of modeling to inform decision making in practice. Chapter 3 reviews lung cancer screening trials and discusses two limitations of published cost-effectiveness analyses of lung cancer screening: their use of stage-shift models and their methods for accounting for smokers' elevated competing mortality. In Chapter 4, we estimated heart disease and other-cause (non-lung cancer, non-heart disease) mortality rates, stratified by gender, race (black/white), age group, and smoking status. These mortality rates were inputs for the model described below. We developed a Bayesian approach to synthesize survey data linked to mortality outcomes, vital statistics data, and published risk ratios from cohort studies, correcting for known inconsistencies between the datasets. In Chapter 5, we developed a comprehensive microsimulation model of lung cancer, populated with cohorts of the U.S. population. The natural history model simulated lung cancer development, growth, and metastasis, not transitions between disease stages (e.g., local to regional), avoiding biases inherent in stage-shift models. Survival depended on the underlying disease stage and treatment received. The model (-screening) was calibrated to observed incidence rates, survival rates, and characteristics of cancers (cell type, stage, size), and validated by reproducing existing trial results (+screening). As evidence-based decisions, policies, and guidelines become the standard among health care payers and providers, decision-analytic modeling and Bayesian evidence synthesis will serve as important tools for formally combining information.

Accessing and deciphering metabolic potential using heterologous hosts

McMahon, Matthew D The University of Wisconsin - Madison 2012 해외박사(DDOD)

Bioactive microbial metabolites are integral to human health and food production in industrialized society. Among these are the antibiotics that have transformed human well-being, but resistance is rapidly reducing the size of the useful arsenal of antibiotics. The resistance problem is made more serious by the shrinking pipeline of new antibiotics, which has resulted in part from rediscovery of metabolites. Potential sources of new molecules include the silent majority of unculturable bacteria and gene clusters with no associated metabolites, as commonly found in Actinomycete bacteria, but new methods are needed to gain access to this metabolic potential. Functional metagenomics uses a heterologous host to isolate the metabolite-encoding genes from a mixture of native hosts whose metabolic diversity masks molecule of interest or cannot be cultured. However, using Escherichia coli as a heterologous host limits expression of genes in metagenomic DNA. Here, we present a system in Streptomyces lividans for expanding accessible metabolic potential in functional metagenomics to include genes from the actinomycetes, a group with diverse metabolic potential whose genes are poorly expressed in E. coli. With this expression system, we found 12 functionally active clones that contain a gene previously not known to be involved in bacterial melanin biosynthesis, two different mechanisms responsible for hemolytic activity, and a putative sigma factor responsible for elevating production of a native secondary metabolite biosynthetic cluster in S. lividans. Furthermore, we investigated the heterologous production and in vitro analysis of one class of valuable secondary metabolites, the nonribosomal peptides. We confirm the importance of the MbtH-like superfamily of proteins in nonribosomal peptide biosynthesis through in vitro analysis of the Mycobacterium tuberculosis siderophore mycobactin. Heterologous coproduction of mycobactin NRPSs with MbtH in E. coli and in vitro analysis unveil a revised model for mycobactin biosynthesis that provides several potential new antitubercular antibiotics and targets. We also provide a model for how to use MbtH-like proteins in the characterization of nonribosomal peptides previously recalcitrant to in vitro biochemical analysis.

Enhancing Motivation for Physical Activity to Reduce Fall Risk Among Community Dwelling Older Adults

McMahon, Siobhan Arizona State University 2012 해외박사(DDOD)

Unintentional falls among community dwelling older adults are a common, serious and potentially preventable public health problem. In the United States, the annual incidence of fall related injuries per 100,000 persons was 4,616 in 2001, rising to 5,252 in 2008. The annual incidence of fall related deaths per 100,000 persons was 29.3 in 2000, rising to 41.86 in 2006. Older adults are particularly vulnerable to falls as they age. Potential consequences include fractures, emergency room, hospital and nursing home admissions, dependence, confusion, immobilization, depression, and death. Significant modifiable fall risk factors include muscle weakness, gait problems, and balance problems. While researchers have demonstrated the positive effects of balance and leg-strengthening physical activities, the majority of older adults do not engage in them, and the rate of falls continues to increase. Older adults participate in regular physical activity and fitness activities less often than younger populations; disparities are greater among those who are poor and living in rural communities. While knowledge about causes, risk factors, and efficacious physical activity to prevent falls has grown exponentially in the last several decades, bridging the gap between research and practice continues to be a challenge. As a strategy to address the gap between research and practice, this feasibility study utilized a tested theory, the wellness motivation theory, to address motivation for behavioral change in combination with instruction for physical activities proven to reduce fall risk. The study sample included rural, community dwelling older adults at risk of falls. The study included an innovative mobile computer to measure physical activity behavior and to augment motivational content of the intervention. Specific aims of this feasibility study were to: (a) examine the acceptability, demand, and implementation of the wellness motivation intervention (WMI) as well as the technology augmenting the WMI; and (b) evaluate the efficacy of the WMI to influence awareness of social contextual resources, behavioral change processes, physical activity, and fall risk. The WMI delivered in combination with proven multicomponent balance and strength activities was feasible and effectively increased motivation for behavioral change (social support from friends, awareness of social contextual resources, behavioral change processes) and physical activity behavior, and decreased fall risk among rural, community-dwelling older adults at risk of falls in this study. This study is the first step in a program of research focusing on enhancing motivation for physical activity that reduces falls and frailty among older adults.

Topics in theoretical and computational nanoscience: From controlling light at the nanoscale to calculating quantum effects with classical electrodynamics

McMahon, Jeffrey Michael Northwestern University 2010 해외박사(DDOD)

Interest in structures with nanometer-length features has significantly increased as experimental techniques for their fabrication have become possible. The study of phenomena in this area is termed nanoscience, and is a research focus of chemists, pure and applied physicists, electrical engineers, and others. The reason for such focus is the wide range of novel effects that exist at this scale, both of fundamental and practical interest, which often arise from the interaction between metallic nanostructures and light, and range from large electromagnetic field enhancements to extraordinary optical transmission of light through arrays of subwavelength holes. For the theoretician and computational scientist, this area has been, and continues to be rich with interesting problems to explore and phenomena to explain. For the most part, the phenomena can be explained using classical electrodynamics. However, recent experimental techniques allow individual nanostructures to be studied, questioning the accuracy of such methods at this most detailed level. Moreover, for structures with dimensions of just a few nanometers, the applicability of such methods at all needs to be questioned. Even if a system contains many hundreds of atoms or more so that a continuum level of description is adequate, the optical (and other) properties can be difficult to correctly calculate due to the importance of quantum effects. Thus, the theoretician is in trouble, and the accurate descriptions of such structures remain largely unknown. This dissertation is aimed at addressing some of the most fundamental and outstanding questions in nanoscience from a theoretical and computational perspective, specifically: (i) At the single nanoparticle level, how well do experiment and classical electrodynamics agree? (ii) What is the detailed relationship between optical response and nanoparticle morphology, composition, and environment? (iii) Does an optimal nanostructure exist for generating large electromagnetic field enhancements, and is there a fundamental limit to this? (iv) Can nanostructures be used to control light, such as confining it, or causing fundamentally different scattering phenomena to interact, such as electromagnetic surface modes and diffraction effects? (v) Is it possible to calculate quantum effects using classical electrodynamics, and if so, how do they affect optical properties?.

Domestic negotiations: Chicana domesticity as a critical discourse of US literature and culture

McMahon, Marci R University of Southern California 2007 해외박사(DDOD)

Domestic Negotiations: Chicana Domesticity as a Critical Discourse of US Literature and Culture reads the work of canonical prose-writer and poet Sandra Cisneros; Tejana visual artist and children's literature illustrator Carmen Lomas Garza; Los Angeles theater director and Hollywood actor Diane Rodriguez, specifically her collaboration with Puerto Rican playwright Migdalia Cruz; and Los Angeles painter and Hollywood set designer Patssi Valdez. The project identifies and analyzes what I call "domestic negotiations," acts asserted by contemporary Chicana authors and artists that strategically negotiate the boundaries of public and private space set up by various nationalisms, communities, and institutional affiliations. These negotiations, I argue, have become necessary survival strategies for Chicana authors and artists who desire to get their work "out there" in spaces steeped in stereotypical narratives---such as the publishing industry, specifically the youth and children's literature market, cinema, television, theater, and the museum. Each chapter is organized according to the various artistic modes and narrative strategies that Chicana artists use to disrupt and negotiate domestic confinement. These strategies include proto-feminist critiques of patriarchy, discourses of nostalgia, post-nationalist feminist narratives, "domesticana" sensibilities, narratives of melodrama and sentimentality, and glamour. In Chapter 1, I pair together Tejana author Jovita Gonzalez and New Mexican writer Cleofas Jaramillo, both writing in the early- and mid-twentieth century, to explore their "domestic negotiations" with dominant racialized discourses. Chapter 2 reads Sandra Cisneros's House on Mango Street and Carmen Lomas Garza's Cuadros de Familia and En Mi Familia as critical responses to a revivalism of patriarchal and nationalist ideologies in the late-twentieth century. In Chapter 3, I examine Diane Rodriguez's negotiations of the stereotypical confinement of Chicanas in the domestic role in popular culture, a stereotype rooted in a narrative of biological reproduction and motherhood. Chapter 4 closely reads Patssi Valdez's use of performance, punk, and avant-garde to negotiate dominant discourses of the Chicano/a movement, as well as her critical role in shaping a visual vocabulary of Chicana domesticity in the museum and Hollywood.

Departmentalization in Intermediate Elementary Grade Levels and Student Performance in Mathematics

McMahon, Paige E ProQuest Dissertations & Theses The Florida State 2019 해외박사(DDOD)

Departmentalization is a growing trend in elementary schools nationwide due to a focus on high stakes accountability testing. In a departmentalized school, teachers specialize in one to three subject areas and students benefit from the instruction of teachers with expert knowledge in their specific areas as opposed to the traditional, self-contained elementary school model where students receive instruction in multiple subjects from one teacher. This mixed methods study sought to investigate the process of departmentalizing fourth and fifth grade classrooms, and to examine the relationship between departmentalization and student achievement growth in St. Lucie Public Schools in Florida. The study found that elementary and K-8 schools with higher poverty populations, as well as schools with lower student enrollments, were the most likely to utilize departmentalization, especially a semi-departmentalized model in the fourth grade level. Students in departmentalized classrooms showed less growth over the course of the school year. The choice to departmentalize was largely teacher-directed and assignment of specific subjects to teachers was based on teachers' strength, comfort levels, and supporting student data. These findings are discussed and recommendations for the district are offered in the final chapter. 혻.

Perceptions of Sexual Violence: An Investigation of Sexual Harassment, Sexual Coercion, and Sexting

McMahon, Jennifer J ProQuest Dissertations & Theses City University of 2019 해외박사(DDOD)

Perpetration of sexual violence is a serious concern in the US, with research indicating that a substantial portion of the population has experienced some type of sexual victimization. There is sparse research that examines perceptions and judgments of sexually inappropriate behaviors, and existing research does not take into account the impact of individual differences and contextual factors. This study examined whether individuals recognize different forms of sexual harassment, sexual coercion, and sexting as inappropriate, and how these perceptions are affected by sex, age, and relationship status. A mixed sample of undergraduate students and adults within the community completed an online survey with 10 short vignettes (nine depicting varying types of sexual behavior and one [neutral] manipulation check scenario). Using a quasi-experimental 2 (Participant Sex: male/female) x 4 (Participant Age: 18-24, 25-34, 35-44, 45+) x 4 (Relationship Status: partner, friend, stranger, undefined) repeated measures design, judgments of inappropriateness on a range of sexual behaviors were examined. The results indicated a significant interaction between vignette type and each variable measured (sex, age, and relationship status) suggesting that context and individual differences interact to influence perceptions of sexual situations. More specifically, behaviors were perceived to be less inappropriate when they occurred between dating partners as opposed to friends or strangers. College-aged individuals endorsed the highest ratings of inappropriate sexual behaviors when compared to older age groups of adults. Furthermore, this study revealed substantial differences in perceptions of appropriateness between males and females, as females consistently perceived behaviors to be more inappropriate than males. These findings provide insight into individual perceptions of inappropriate sexual behaviors and highlight the importance of examining factors such as social context to ensure successful education and prevention efforts.